A comprehensive review of antimalarial medicinal plants used by Tanzanians

Abstract

Context

Tanzania has rich medicinal plant (MP) resources, and most rural inhabitants rely on traditional healing practices for their primary healthcare needs. However, available research evidence on antimalarial MPs is highly fragmented in the country.

Objective

This systematic review compiles ethnomedicinal research evidence on MPs used by Tanzanians as antimalarials.

Materials and methods

A systematic web search was conducted using various electronic databases and grey materials to gather relevant information on antimalarial MPs utilized by Tanzanians. The review was per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The data were collected from 25 articles, and MS Excel software was used to analyse relevant ethnobotanical information using descriptive statistics.

Results

A total of 227 MPs belonging to 67 botanical families and 180 genera were identified. Fabaceae (15.9%) is the most frequently utilized family. The ethnobotanical recipes analysis indicated leaves (40%) and trees (44%) are the preferred MPs part and life form, respectively. Decoctions (67%) are the dominant preparation method of remedies. Of the recorded MPs, 25.9% have been scientifically investigated for antimalarial activities with positive results. However, 74.1% of MPs have no scientific records on antimalarial activities, but they could be potential sources of remedies.

Conclusions

The study discloses a wealth of antimalarial MPs possessed by Tanzanians and suggests a need for research to authenticate the healing potential of antimalarial compounds from the unstudied MPs. Additionally, it indicates that some of the presented MPs are potential sources for developing safe, effective and affordable antimalarial drugs.

Keywords:

• Ethnobotany
• ethnomedicine
• herbal remedies
• malaria
• traditional medicine

Introduction

Malaria is one of the life-threatening diseases in malaria-endemic regions of the world (Dao et al. 2021). The disease caused about 627,000 deaths in 2020. Most deaths (99%) were due to a parasite, Plasmodium falciparum Welch (Plasmodiidae), transmitted by the Anopheles mosquito. About 90% of malaria cases and deaths occur in Africa, and most (93%) deaths occur in sub-Saharan Africa, where 95% of the global burden of malaria is concentrated. Children under five years of age are the most affected group in the region (World Health Organization, WHO 2021). In Tanzania, nearly 88.5% of the population lives in expanses considered malarious (Rumisha et al. 2019), and the country stands among the top 10 countries with high malaria transmission in the sub-Saharan region (WHO 2021). Regardless of recent developments in control strategies, malaria remains a significant public health problem and a prime cause of morbidity and mortality, particularly in children under five years (Dao et al. 2021). Regarding statistics, the disease ranks number one among outpatients and inpatients, and malaria's socio-economic impact is so high that it leads to poverty and underdevelopment (Makundi et al. 2007; Rumisha et al. 2019).

Recently, drug-resistant Plasmodium species have been reported in various studies (Wicht et al. 2020; Hodoameda et al. 2022). Explicitly, P. falciparum has established resistance to almost all presently available antimalarial drugs (White 2004; Thu et al. 2017; Rasmussen et al. 2022). Subsequently, research on antimalarial alternative medicines has intensified over the past decades (Alebie et al. 2017; Omara 2020; Tabuti et al. 2023). Generally, MPs have been the focus of many researchers to discover alternative antimalarial remedies (Ntie-Kang et al. 2014), leading to the discovery of numerous active antimalarial compounds with significant structural varieties, such as coumarins, quinones, triterpenes, quassinoids, sesquiterpenoids, limonoids, steroids, lignans, saponins and alkaloids (Phillipson and Wright 1991; Laryea and Borquaye 2019; Tiko et al. 2020).

Nearly, 80% of people in Africa, including Tanzania, still depend on MPs for treating numerous diseases, including malaria (WHO 2014; Okaiyeto and Oguntibeju 2021). This is well associated with the availability and accessibility challenges of modern health facilities and the cultural acceptability of traditional remedies. Likewise, the prevalent use of MPs is attributed to their presence on the ground and affordability. For instance, the ratio of orthodox health practitioners to the people in Africa is 1:500, whereas the proportion of modern medical practitioners to the people is 1:40,000 (WHO 2014). Thus, for most rural inhabitants, traditional healers remain their health providers (Frumence et al. 2013; Tabuti et al. 2023). Due to high dependency on MPs, communities from different settings in Tanzania have developed their medical plant collections and knowledge of their utilization, management and conservation (Kayombo et al. 2012; Mbinile et al. 2020). Many MPs are used as traditional malaria remedies in diverse areas of the country (Gessler et al. 1995; Begum et al. 2020).

Proper documentation of MPs used in managing malaria and its associated traditional knowledge establishes a critical task in preserving valuable indigenous knowledge, biological diversity and improving community admittance to and stakes in enhancing malaria control interventions. It is also essential for thought-provoking forthcoming research on the safety and efficacy of MPs and recognizing active chemical entities, which can be advanced into new homogenous phytomedicines. In contrast, ethnobotanical and ethnopharmacological investigation on aboriginal antimalarial MPs is at an elementary stage in most African countries, including Tanzania (Kidane et al. 2014; Begum et al. 2020; Manuel et al. 2020). Furthermore, research evidence on indigenous antimalarial MPs is highly fragmented, thus underscoring the solemn need for systematic documentation. Therefore, this systematic review attempted to collect and document ethnomedicinal information on antimalarial MPs and their utilization in Tanzania.

Methodology

This review has collected information on antimalarial MPs used in Tanzania. The review was performed as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement (Liberati et al. 2009) (Figure 1). A web-based literature search was conducted using various electronic databases, including Web of Science, Google Scholar, Science Direct, PubMed, Scopus, African Journals Online, Wiley online library and grey literature to access relevant works dealing with antimalarial plants. The keywords used during the investigation included antimalarial plants, malaria, traditional medicine, ethnobotany, ethnopharmacology, alternative medicine, antiplasmodial activity, antimalarial activity, chloroquine, quinine, medicinal plants (MPs) and Tanzania. The search was independently performed in each database, and published articles, theses or dissertations containing the above terms were considered and screened. Lastly, Tanzanian traditional MPs exclusively utilized for malaria were selected. This review did not consider any study that did not include botanic names of MPs and plant parts used to treat malaria. Studies that possessed required information, such as family name, scientific name, local name, growth habits, method of preparation (if available) and route of administration (if available), were extracted and considered. The accuracy of the MPs' scientific names was confirmed through the Tropicos (https://www.tropicos.org) botanical databases.

Figure 1. PRISMA study flow diagram for the antimalarial medicinal plants in Tanzania.

Ethnobotanical data analysis

The collected ethnobotanical data were entered into the Microsoft Excel software and analysed for information for descriptive statistics (percentages and frequencies) of the reported antimalarial botanical families, MPs, parts used, growth forms, modes of preparation, routes of administration and related indigenous knowledge. Also, from various literature, all recorded MPs were checked for their antiplasmodial/antimalarial activity, active phytochemicals and toxicity. The findings were subsequently presented as tables and figures.

Ethical approval statement

The statement was not required as the review did not involve human and animal participants.

Results and discussion

Medicinal plants diversity

In total, 25 ethnobotanical studies acknowledged 227 MPs belonging to 67 botanical families and 180 genera used as antimalarial from different parts of Tanzania (Table 1). Fabaceae (15.9%), Asteraceae (7.9%), Rubiaceae (6.6%), Euphorbiaceae (5.3%) and Lamiaceae (5.3%) were the most common families (Table 2). The number of antimalarial MPs recorded in this review is higher than the one recorded in Ethiopia (200 species) (Alebie et al. 2017) but less than that of Kenya (289 species) (Omara 2020). The most frequently encountered MPs were Azadirachta indica A. Juss (Meliaceae) (six times), Vernonia amygdalina Del. (Asteraceae), Bridelia micrantha (Hochst.) Baill. (Euphorbiaceae), Cassia abbreviata Oliv. (Fabaceae), Psidium guajava L. (Myrtaceae), Zanthoxylum chalybeum Engl. (Rutaceae) (five times each), Vangueria infausta Burch. (Rubiaceae), Leonotis nepetifolia (L.) R. Br. (Lamiaceae), Hoslundia opposita Vahl. (Lamiaceae) (four times each), Mangifera indica L. (Anacardiaceae), Ozoroa insignis Del. (Anacardiaceae), Pseudospondias microcarpa (A. Rich) Engl. (Anacardiaceae), Kigelia africana (Lamarck) Benth. (Bignoniaceae), Canarium schweinfurthii Engl. (Burseraceae), Momordica foetida Schum (Cucurbitaceae) and Abrus precatorius L. (Fabaceae) (three times each). The recurrent citation of particular MPs or families designates potentially higher bioactive antimalarial ingredients. Such evidence is vital for prioritizing pharmacological studies.

Table 1. List of antimalarial plants of Tanzania, life form, parts used, mode of preparation (MoP), and their route of application (RoA).

Family	Species name	Vernacular name	Life form	Part used	MoP and RoA	References
Acanthaceae	Acanthus pubescens Engl. & Turril.	Amatoju	Shrub	Roots, leaves	Decoction drunk	Moshi et al. (2009) and Nondo et al. (2015)
	Hygrophila auriculata (Schum.) Heina	Kasindano/Karai	Herb	Aerial parts	Decoction drunk	Moshi et al. (2010)
	Justicia matammensis Oliv.	Kagege	Herb	Aerial parts	Infusion of dried powdered aerial parts and those of Cassia gracilior (Ghesq.) Steyaert (Fabaceae), Antherotoma naudinii Hook.f., Dissotis brazzae Cogn. (Melastomataceae), Indigofera asparagoides Taub. subsp. ephemera (J.B. Gillett) (Fabaceae), Rhynchosia minima (L.) DC. (Fabaceae) and Pentas zanzibarica (Klotzsch) Vatke (Rubiaceae), is drunk in case of cerebral malaria.	Chhabra and Mahunnah (1994)
	Thunbergia alata (Sms)	Wankula	Climber	Whole plant	Decoction drunk	Nondo et al. (2015)
Achariaceae	Xylotheca tettensis (Klotzsch) Gilg var. fissistyla (Warb.) Sleumer	Kinemya-mbopo	Shrub	Roots	Decoction drunk	Chhabra et al. (1990a)
Alliaceae	Allium sativum L.	Kitunguu swaumu	Bulb	Leaves, roots	Decoction drunk	Amri and Kisangau (2012)
Amaranthaceae	Alternanthera tenella Colla var. bettzickiana (Regel) Veldk.	Oburungu	Herb	Leaves	Juice from squeezed leaves drunk	Gessler et al. (1995)
	Cyathula cylindrica Moq.	Igifashi	Herb	Root	Decoction drunk	Ramathal and Ngassapa (2001)
Anacardiaceae	Lannea humilis (Oliv.) Engl.	Mkuruguta	Shrub	Leaves	Not specified	Hilonga et al. (2019)
	Mangifera indica L.	Mwembe	Tree	Leaves, roots, stem bark	Decoction drunk	Chhabra et al. (1987), Amri and Kisangau (2012) and Nondo et al. (2015)
	Ozoroa insignis Del.	Mwembepori	Tree	Roots, stem bark	Not specified	Ruffo (1991), Maregesi et al. (2007) and Hilonga et al. (2019)
	Pseudopondias microparpa (A. Rich) Engl.	Omuzilu/Mziku	Tree	Leaves, stem bark	Juice from squeezed leaves drunk; stem bark decoction drunk	Gessler et al. (1995), Moshi et al. (2009) and Nondo et al. (2015)
	Rhus vulgaris Meikle	Omukanja	Shrub	Leaves, roots, fruits	Decoction of leaves and roots drunk. Ripe fruits are consumed fresh.	Moshi et al. (2010) and Nondo et al. (2015)
	Sorindeia madagascariensis Thouars ex DC.	Mpilipili	Tree	Roots	Not specified	Kacholi (2020)
Annonaceae	Friesodielsia obovata (Benth.) Verdc.	Msalasi	Shrub	Stem bark	Not specified	Augustino and Gillah (2005)
	Uvaria kirkii Oliv. ex Hook. f. kirkii	Msofu	Shrub	Roots	Not specified	Chhabra et al. (1987) and Hilonga et al. (2019)
Apiaceae	Steganotaenia araliaceae Hochst	Mgurukwanoni	Shrub	Stem bark	Infusion drunk	Gessler et al. (1995)
Apocynaceae	Diplorhynchus condylocarpon (Muell. Arg.) Pichon	Mtogo	Tree	Leaves, root bark	Juice from squeezed leaves, and decoction of root bark drunk	Gessler et al. (1995)
	Funtumia africana (Benth) Stapf	Omwelamaino	Tree	Leaves	Decoction drunk	Nondo et al. (2015)
	Holarrhena pubescens (Huch-Ham) G. Don	Nalupande	Shrub	Root	Decoction drunk	Nondo et al. (2015)
	Rauvolfia vomitoria Afzel.	Mnyabusinde/Enyamasindi/Kinyabusinde	Tree	Stem bark, root bark	Decoction drunk. It makes children feel weak; hence, they should be given milk too. The stem or root bark is grounded, mixed with porridge, and consumed orally. The powder can also be combined with honey to mask the bitter taste.	Moshi et al. (2009, 2012)
	Strophanthus eminii Asch. ex Pax	Msungururu	Tree	Roots	Not specified	Hilonga et al. (2019)
Araliaceae	Schefflera goetzenii Harms	Olugogome	Tree	Leaves, stem bark	Decoction drunk	Nondo et al. (2015)
Arecaceae	Raphia farinifera (Gaertn.) Hyl.	Omubobo	Tree	Roots, stem bark	Decoction drunk	Nondo et al. (2015)
Asparagaceae	Asparagus africanus Lam.	Lipalakanga	Shrub	Roots	Decoction drunk	Shangali et al. (2008)
	Asparagus falcatus L.	Mfushobwana	Herb	Leaves	Pounded, mixed with clean water, and drink the infusion	Chhabra et al. (1990a)
	Dracaena steudneri Engl.	Omugorogoro	Tree	Stem bark	Decoction drunk	Nondo et al. (2015)
Asteraceae	Artemisia afra Jacq.	Five	Herb	Leaves	Not specified	Hilonga et al. (2019)
	Aspilia mossambicensis (Oliv.) Wild.	Ushuwarusharila/Esisa/Eshurwa	Herb	Aerial parts/whole plant	Fresh plant materials are pounded and mixed with clean water, and the infusion is taken orally. Aerial parts are combined with those of Centella asiatica (L.) Urb. (Umbelliferae), boiled, and decoction taken orally.	Moshi et al. (2009) and Nondo et al. (2015)
	Aspilia natalensis (Sond.) Wild.	Kanyamoisa	Herb	Leaves	Decoction drunk. Fresh leaves squeezed, and liquid applied to the nose.	Nondo et al. (2015)
	Aspilia pluriseta (Schweinf)	Lusharira eshurwa	Herb	Aerial parts	Decoction drunk	Nondo et al. (2015)
	Bidens biternata (Lour.) Merr. & Sherff	Rwongwe/Ongwe	Herb	Leaves	Decoction drunk	Moshi et al. (2009)
	Bidens gracilior (Hoffm.) Sherff.	Rwongeza	Herb	Leaves	Decoction mixed with leaves of Harungana madagascariensis Poir. (Guttiferae) is taken orally	Chhabra and Mahunnah (1994)
	Bidens pilosa L.	Akakurura	Herb	Roots	Decoction drunk	Chhabra and Mahunnah (1994) and Nondo et al. (2015)
	Conyza pyrrhopappa Sch.Bip. ex A.Rich.	Rufugakande	Herb	Leaves	Not specified	Hilonga et al. (2019)
	Crassocephalum mannii (Hook.f.) Milne	Akagango-Akake	Herb	Aerial parts	Pounded, boiled in water, and the decoction taken orally.	Moshi et al. (2009) and Nondo et al. (2015)
	Crassocephalum vitellinum (Benth) S. Moore	Ekishenda	Herb	Aerial parts, leaves	Decoction drunk	Nondo et al. (2015)
	Guizotia scabra (Vis.) Chiov.	Echiongosheija	Herb	Leaves	Decoction drunk	Nondo et al. (2015)
	Gynura scandens O. Hoffm.	Ekizimya mulilo	Climber	Leaves	Fresh leaves are squeezed to make juice and taken orally	Nondo et al. (2015)
	Melanthera scandens (Schum & Thonn) Roberty	Omlela	Herb	Leaves	Decoction drunk	Nondo et al. (2015)
	Senecio spp.	Ekikarabwe	Herb	Leaves	Decoction drunk	Nondo et al. (2015)
	Tridax procumbens L.	Mkakara	Herb	Leaves	Not specified	Hilonga et al. (2019)
	Vernonia amygdalina Del.	Omubilizi	Shrub	Roots, leaves	Decoction is mixed with the stem bark of Sapium ellipticum (Krauss) Pax (Euphorbiaceae), and the leaves of Dalbergia nitidula Baker (Fabaceae), Desmodium salicifolium (Poir) DC. (Fabaceae), and Eriosema psoraleoides Lam. G.Don. (Fabaceae) and taken orally.	Ramathal and Ngassapa (2001), Moshi et al. (2009, 2010), Nondo et al. (2015) and Kingo and Maregesi (2020)
	Vernonia colorata (Wild.) Drake	Ekishura	Shrub	Leaves	Decoction drunk	Nondo et al. (2015)
	Vernonia glabra (Steetz) Vatke	Msangusangu/Mkalinkali	Herb	Leaves	Decoction drunk	Ruffo (1991) and Nondo et al. (2015)
Bignoniaceae	Kigelia africana (Lamarck) Benth.	Mwegea/Mwicha	Tree	Roots, stem bark	Infusion drunk	Gessler et al. (1995), Maregesi et al. (2007) and Hilonga et al. (2019)
	Markhamia lutea (Benth) K. Schum.	Omushambya	Tree	Stem bark	Decoction drunk	Nondo et al. (2015)
	Markhamia obtusifolia (Bak.) Sprague	Mkoyoyo	Tree	Leaves, stem bark	Not specified	Hilonga et al. (2019)
	Adansonia digitata L.	Mbuyu	Tree	Leaves, fruits	Leaves are eaten as vegetables. Fruits are powdered and consumed as juice.	Nondo et al. (2015)
Boraginaceae	Ehretia amoena Klotzsch	Mkilika	Tree	Roots	Not specified	Augustino and Gillah (2005)
Balsaminaceae	Impatiens gomphophylla Bak.f	Olwitamkole	Herb	Leaves	Decoction drunk	Nondo et al. (2015)
Burseraceae	Canarium schweinfurthii Engl.	Omubafu	Tree	Stem bark, leaves	Powdering and decoction taken orally.	Moshi et al. (2009, 2012) and Nondo et al. (2015)
Canellaceae	Warburgia stuhlmannii Engl.	Sokonoi	Tree	Roots, stem bark	Not specified	Hilonga et al. (2019)
Celastraceae	Bidens Schimperi Sc. Bip ex Walp	Orwongwa	Herb	Aerial parts	Fresh parts are pounded, and the infusion taken orally.	Nondo et al. (2015)
Capparaceae	Boscia angustifolia A. Rich.	Lisingisi	Shrub	Stem bark	Decoction drunk	Maregesi et al. (2007)
Celastraceae	Maytenus senegalensis (Lam.) Exel	Omunyaburiko	Tree	Leaves, roots, stem bark	Decoction drunk	Gessler et al. (1995) and Nondo et al. (2015)
	Salacia lovetii N. Hallé & B. Mathew	Omzindabikaka	Tree	Stem bark, leaves	Decoction drunk	Nondo et al. (2015)
Chrysobalanaceae	Parinari excelsa Sabine	Kinazi	Tree	Stem bark	Decoction drunk	Gessler et al. (1995)
Clusiaceae	Garcinia buchananii Bak.	Msharazi	Shrub	Stem bark, roots	Decoction mixed with roots of Tragia furialis Prain (Euphorbiaceae) consumed orally.	Moshi et al. (2009)
Combretaceae	Combretum adenogonium A. Rich.	Muluzyaminzi	Tree	Roots, leaves	Decoction drunk	Augustino et al. (2011)
	Combretum fragrans F. Hoffm.	Mlama	Tree	Leaves, roots	Not specified	Ruffo (1991)
	Combretum longispicatum (Engl.) Engl. & Diels	Vugoveko	Tree	Roots	Not specified	Ruffo (1991)
	Combretum molle R.Br. ex G.Don.	Mlama mweusi	Tree	Leaves, roots	Decoction drunk	Amri and Kisangau (2012)
	Terminalia kaiseriana F. Hoffm.	Mkelenge	Tree	Roots, stem bark	Not specified	Hilonga et al. (2019)
	Terminalia spinosa Engl.	Mtaba	Tree	Leaves	Fresh leaves are pounded, and juice is drunk	Chhabra et al. (1989)
Convolvulaceae	Ipomoea biflora (L.) Pers.	Karandarugo	Herb	Leaves, roots	Not specified	Hilonga et al. (2019)
	Ipomoea rubens Choisy	Akataba	Climber	Leaves	Decoction drunk	Nondo et al. (2015)
Cucurbitaceae	Alchornea cordifolia (Schum & Thonn) Müell. Arg.	Omujuluzi	Shrub	Leaves	Decoction is drunk or young fresh leaves pounded, mixed with clean water, and taken orally.	Nondo et al. (2015)
	Momordica charantia L.	Kabindizi	Climber	Leaves	Not specified	Hilonga et al. (2019)
	Momordica foetida Schum.	Orwihula/Huluhundu/Lisoyui	Shrub	Whole plant, leaves	Decoction is drunk. Leaves infusion drunk	Gessler et al. (1995), Amri and Kisangau (2012) and Nondo et al. (2015)
	Zehneria scabra (L.f.) Sond.	Akabindizi	Climber	Leaves	Boil the leaves mixed with roots of Trichilia emetica Vahl (Meliaceae), then a decoction taken orally one cup is administered thrice a day for seven days.	Moshi et al. (2009, 2012)
Ebenaceae	Diospyros usambarensis F. White	Mtogo/Mwiza	Tree	Roots	Decoction drunk	Chhabra et al. (1989)
	Euclea fructucosa	Mdaladala	Shrub	Leaves, roots	Not specified	Augustino and Gillah (2005)
Euphorbiaceae	Acalypha indica L.	Obweya	Herb	Leaves, seeds	Decoction drunk	Nondo et al. (2015)
	Bridelia micrantha (Hochst.) Baill.	Omushamako	Tree	Roots, stem bark	Decoction drunk	Augustino and Gillah (2005), Moshi et al. (2012), Kacholi (2014), Nondo et al. (2015) and Kacholi (2020)
	Canna indica L.	Maruru	Herb	Seeds	Grounding to powder and infusion is taken orally	Nondo et al. (2015)
	Croton macrostachyus Del.	Omwowa	Tree	Stem bark	Decoction drunk	Nondo et al. (2015)
	Erythrococca bongensis Pax	Msongisongi	Tree	Leaves	Not specified	Hilonga et al. (2019)
	Euphorbia hirta L.	Kaligaruro	Herb	Leaves	Not specified	Hilonga et al. (2019)
	Jatropha curcas L.	Mubona	Tree	Leaves	Not specified	Hilonga et al. (2019)
	Phyllanthus nummulariifolius Poir	Karungi	Herb	Aerial parts	Decoction drunk	Nondo et al. (2015)
	Ricinodendron heudelotii (Baill) Pax	Kabaka njagala	Shrub	Leaves	Decoction drunk	Nondo et al. (2015)
	Sapium ellipticum (Krauss) Pax	Omushasha	Tree	Leaves, stem bark, roots	Decoction is made by boiling the roots with those of Trichilia emetica Vahl. (Meliaceae) and Alchornea cordifolia Müll Arg. (Euphorbiaceae) together with the leaves of Zehneria scabra (Linn.f.) Sond (Cucurbitaceae). The decoction is then administered orally thrice a day for seven days. Fresh leaves can be used to prepare a cold infusion.	Moshi et al. (2009) and Nondo et al. (2015)
	Suregada zanzibariensis Roxb. ex Rottler.	Mndimu pori	Shrub	Roots	Decoction drunk	Chhabra et al. (1990a) and Amri and Kisangau (2012)
	Tragia furialis Bojer	Omugonampili	Tree	Leaves	Decoction drunk	Moshi et al. (2012)
Fabaceae	Abrus precatorius L.	Kaligaligo	Climber	Leaves, roots, root bark	Powdering, mix with water and boil, then decoction is taken orally.	Gessler et al. (1995), Moshi et al. (2012) and Nondo et al. (2015)
	Acacia polyacantha Willd.	Livindwe	Tree	Roots, stem bark	Decoction drunk	Augustino et al. (2011)
	Acacia sieberiana DC.	Mnyinyi, Suha	Tree	Roots	Not specified	Hilonga et al. (2019)
	Afzelia quanzensis Welw.	Mkola	Tree	Roots	Not specified	Hilonga et al. (2019)
	Albizia anthelmintica Brongn.	Mfuleta	Tree	Roots, leaves	Infusion drunk	Chhabra et al. (1990b) and Hilonga et al. (2019)
	Albizia gummifera (J.F. Gmel.) C.A.Sm.	Mkenge	Tree	Stem bark	Decoction drunk	Chhabra et al. (1990b) and Kacholi (2014)
	Albizia lebbeck (L.)Benth.	Mlongelonge	Tree	Leaves, fruits	Not specified	Hilonga et al. (2019)
	Caesalpinia volkensii Harms	Mvoro	Shrub	Leaves	Decoction drunk	Chhabra et al. (1987)
	Cassia abbreviata Oliv.	Mulundalunda/Singwai/Mlengefu	Tree	Roots, leaves, stem bark	Decoction drunk. Leaves squeezed and juice drunk.	Chhabra et al. (1987), Ruffo (1991), Gessler et al. (1995), Augustino et al. (2011) and Hilonga et al. (2019)
	Cassia didymobotrya Fres.	Mchwelambogo/Omulembelembe	Shrub	Leaves, root bark	Decoction or infusion is drunk. Squeezed juice from pounded leaves drunk	Gessler et al. (1995) and Nondo et al. (2015)
	Cassia obtusifolia L.	Itakiri	Herb	Leaves	Decoction drunk	Gessler et al. (1995)
	Cassia singueana (Delile) Lock	Msambisambi	Tree	Leaves	Not specified	Ruffo (1991)
	Dalbergia melangensis E.P. Sousa	Omugoroa	Climber	Leaves	Decoction drunk	Nondo et al. (2015)
	Desmodium salicifolium (Poir) DC	Omukongorwanwa/Batengeliange	Herb	Aerial parts, leaves	Decoction drunk	Nondo et al. (2015)
	Dichrostachys cinerea (L.) Wight et Arn.	Mkulagembe	Shrub	Roots	Decoction drunk	Chhabra et al. (1990b)
	Dolichos kilimandscharicus Taub.	Not indicated	Herb	Leaves	Decoction taken orally	Moshi et al. (2012)
	Eriosema parviflorum E. Mey	Mshelere	Herb	Leaves	Decoction drunk	Nondo et al. (2015)
	Eriosema psoraleoides G.Don. Lam.	Orutandaigwa/Omushana	Shrub	Roots, leaves	Decoction drunk	Moshi et al. (2010)
	Erythrina abyssinica DC	Omulinzi	Tree	Flowers, stem bark	The flowers are mixed with those of Dracaena fragrans (L.) Ker Gawl. (Asparagaceae) dried and then ground into a powder which is then put into the brew or alcoholic drink being taken by the patient without his/her knowledge. The stem bark is boiled, and the decoction is taken orally.	Moshi et al. (2012) and Nondo et al. (2015)
	Erythrina sacleuxii Hua	Mlindimila, Muhemi	Tree	Stem bark, roots, leaves	Decoction or infusion drunk	Gessler et al. (1995) and Nondo et al. (2015)
	Erythrina schliebenii Harms	Mlindimila	Tree	Stem bark	Decoction drunk	Nondo et al. (2015)
	Indigofera arrecta A. Rich	Omusoroka	Herb	Aerial parts	Decoction drunk or aerial parts pounded, then mixed with water and taken orally.	Nondo et al. (2015)
	Indigofera drepanocarpa Taubert	Mbabazi	Herb	Roots	Decoction drunk	Moshi et al. (2009)
	Indigofera rhynchocarpa Welw. ex Baker	Mkundekunde	Tree	Roots	Not specified	Augustino and Gillah (2005)
	Kotschya africana Engl.	Ekyangwe ekiango	Herb	Aerial parts	Decoction drunk	Nondo et al. (2015) and Hilonga et al. (2019)
	Macrotyloma axillare (E. Mey) Verdc.	Akaihabukuru	Climber	Aerial parts	Decoction drunk	Nondo et al. (2015)
	Senna alata L.	Mgalula	Shrub	Leaves	Leaves are pounded and boiled with water, and the decoction taken orally.	Moshi et al. (2010)
	Senna occidentalis (L.) Link	Omwetanjoka	Shrub	Leaves	Decoction drunk	Moshi et al. (2012)
	Senna siamea (Lam.) H.S. Irwin & Barneby	Mjohoro	Tree	Leaves, roots	Not specified	Maregesi et al. (2007) and Hilonga et al. (2019)
	Sesbania microphylla E.Phillips & Hutch.	Msenga/Mbondo	Shrub	Leaves	Boiled together with the leaves of Orthosiphon suffrutescens (Thonning) J.K Morton (Labiatae) and Solanum aculeastrum Dunal (Solanaceae) and the decoction consumed orally	Moshi et al. (2012)
	Swartzia madagascariensis Desv.	Kasanda	Tree	Roots	Not specified	Ruffo (1991)
	Tamarindus indica L.	Musisi	Tree	Leaves, stem bark	Decoction drunk	Ruffo (1991) and Augustino et al. (2011)
	Tephrosia aequilata Bak	Endalabugazi	Herb	Whole plant	Decoction drunk	Nondo et al. (2015)
	Vachellia nilotica (L.) P.J.H. Hurter & Mabb	Ol kiloriti	Tree	Roots	Not specified	Augustino and Gillah (2005) and Hilonga et al. (2019)
	Vachellia seyal (Del.) P.J.H. Hurter	Elerai/Naju/Oltepesi	Tree	Roots	Not specified	Hilonga et al. (2019)
Guttiferae	Harungana madagascariensis Poir.	Not indicated	Shrub	Stem bark	Not indicated	Chhabra and Mahunnah (1994)
Labiatae	Clerodendrum cephalanthum Oliv.	Ekishekesheke	Climber	Leaves	Decoction drunk	Nondo et al. (2015)
Lamiaceae	Clerodendrum myricoides (Hochst.) Vatke.	Omurajio/Ekisheke/Mkuzanyana	Shrub	Stem bark, roots	Boiled in water and half a teaspoonful of the decoction is taken orally thrice a day	Moshi et al. (2009, 2010, 2012)
	Coleus barbatus (Andr.) Benth. Ex G. Don	Agacuncu	Herb	Leaves	Fresh leaves are ground, placed in water and the cold infusion drunk	Ramathal and Ngassapa (2001)
	Hoslundia opposita Vahl.	Mzitoima	Shrub	Leaves, root bark	Vapour from boiled leaves inhaled. Root bark decoction drunk	Hedberg et al. (1983), Chhabra et al. (1990a), Gessler et al. (1995) and Hilonga et al. (2019)
	Leonotis mollissima Gürke.	Iriro	Shrub	Leaves, roots	Roots decoction drunk. Leaves pounded, mixed with clean water and juice drunk.	Hedberg et al. (1983)
	Leonotis nepetifolia (L.) R. Br.	Ekitaterante	Herb	Leaves, aerial parts	Parts are boiled in water and then decoction taken orally thrice a day for five days.	Chhabra and Mahunnah (1994), Moshi et al. (2009), Nondo et al. (2015) and Salinitro et al. (2017)
	Ocimum bacilicum L.	Nyabahengele	Herb	Whole plant	Decoction drunk	Gessler et al. (1995)
	Ocimum kilimandscharicum Gürke	Kaswagara	Herb	Seeds	Infusion of powdered seeds drunk	Nondo et al. (2015) and Hilonga et al. (2019)
	Ocimum suave Willd.	Mnung'ha	Herb	Stem bark	Decoction drunk	Amri and Kisangau (2012)
	Orthosiphon thymiflorus (Roth) Sleesen	Lwamo	Herb	Leaves	Leaves are boiled and mixed with Solanum aculeastrum Dunal. (Solanaceae), and the decoction taken orally	Moshi et al. (2012)
	Platostoma africanum P. Beauv.	Nyanjaeyera	Shrub	Aerial parts	The dry powder used to make a hot infusion and taken orally	Nondo et al. (2015)
	Tetradenia riparia (Hochst.)	Omushunshu	Herb	Leaves	Leaves are boiled in water, and a glass of the decoction taken thrice a day times.	Moshi et al. (2009, 2012)
	Tetradenia urticifolia (Baker) Phillipson	Omushunshu	Herb	Leaves	For malaria, the leaves are boiled with water and a glass of the decoction is taken three times a day.	Moshi et al. (2012)
Lauraceae	Ocotea usambarensis Engl.	Mseli	Tree	Roots, stem bark	Infusion drunk	Amri and Kisangau (2012) and Kacholi (2014)
Loganiaceae	Anthocleista grandiflora Gilg	Mgabaigana	Tree	Leaves, roots, stem bark	Decoction of leaves and roots is taken orally. The dried stem bark is boiled, and a cup of the decoction taken thrice a day for five to seven days.	Moshi et al. (2009) and Nondo et al. (2015)
	Strychnos potatorum L.f	Mugwegwe	Tree	Roots, leaves	Decoction drunk	Ruffo (1991) and Augustino et al. (2011)
	Strychnos spinosa Lam.	Orurema	Shrub	Leaves	The dry powder is used to make a hot infusion and taken orally or decoction bathed for children.	Nondo et al. (2015)
Lythraceae	Lawsonia inermis L.	Eina	Herb	Leaves, seeds	Decoction of leaves drunk. Powdered seeds used to make warm infusions and taken orally.	Nondo et al. (2015)
Melastomataceae	Dissotis brazzae Congn.	Katuntunu	Herb	Aerial parts	The aerial parts are mixed with those of Solanum nigrum L. (Solanaceae) boiled and the decoction taken orally.	Moshi et al. (2009) and Nondo et al. (2015)
	Dissotis melleri Hook f.	Ekituntun	Herb	Aerial parts	Decoction drunk	Nondo et al. (2015)
	Dissotis rotundifolia (Sm) Triana	Obwehehe/Obwee	Herb	Aerial parts	Decoction or fresh aerial parts pounded then mixed with clean water and taken orally.	Nondo et al. (2015)
	Melastomastrum capitatum (Vahl) A & R Fern.	Katuntun	Herb	Aerial parts	Fresh aerial parts are pounded and mixed with clean water, and taken orally. Dry parts used to prepare a warm infusion	Nondo et al. (2015)
	Melastomastrum segregatum (Benth) A & R. Fern.	Eitulu	Herb	Aerial parts	Decoction or cold infusion is taken orally	Nondo et al. (2015)
Meliaceae	Azadirachta indica A. Juss	Omwarobaini	Tree	Leaves, roots, stem bark	Decoction and infusion drunk	Gessler et al. (1995), Augustino and Gillah (2005), Augustino et al. (2011), Amri and Kisangau (2012), Nondo et al. (2015) and Hilonga et al. (2019)
	Khaya anthotheca (Welw.) C. DC	Mkangazi	Tree	Leaves, stem bark	Concoction drunk	Amri and Kisangau (2012)
	Pseudobersama mossambicensis (Sim) Verdc	Omusiibi	Tree	Leaves, stem bark	Decoction drunk	Nondo et al. (2015)
	Trichilia emetica Vahl.	Omushunguti/Omujunguti	Tree	Leaves, stem bark	Decoction drunk	Moshi et al. (2009) and Nondo et al. (2015)
Melianthaceae	Bersama abyssinica Fresen.	Omujalya	Shrub	Leaves, roots, stem bark	Decoction drunk	Nondo et al. (2015)
Menispermaceae	Cissampelos pareira L.	Mkulwati	Shrub	Roots	Decoction drunk	Gessler et al. (1995) and Augustino et al. (2011)
Moraceae	Antiaris toxicaria (Pers) Lesch	Omujuju	Tree	Leaves, stem bark	Decoction drunk	Nondo et al. (2015)
	Ficus exasperate Vahl.	Msasa	Tree	Leaves	Not specified	Kacholi (2014)
	Ficus natalensis Hochst.	Mlumba	Tree	Roots	Decoction drunk	Chhabra et al. (1990b)
Moringaceae	Moringa oleifera (Lam.)	Mlonge	Tree	Leaves	Decoction drunk or dry powder is used to make worm infusion and taken orally.	Nondo et al. (2015) and Salinitro et al. (2017)
Myrsinaceae	Maesa lanceolata Forsk	Omuhanga/Omuzilanyama	Tree	Leaves, roots, stem bark	Decoction drunk	Nondo et al. (2015)
Myristicaceae	Pycnanthus angolensis (Welw.) Warb.	Omunonoba	Tree	Stem bark	Decoction drunk	Nondo et al. (2015)
Myrtaceae	Eucalyptus globulus Labill.	Mkaratusi	Tree	Leaves	Not specified	Hilonga et al. (2019)
	Psidium guajava L.	Mpera	Tree	Leaves	Decoction drunk or fresh leaves pounded, mixed with clean water, and taken orally.	Ruffo (1991), Chhabra and Mahunnah (1994), Gessler et al. (1995), Augustino et al. (2011) and Nondo et al. (2015)
	Syzygium cordatum Krause	Omugege	Shrub	Leaves, stem bark	Decoction drunk	Gessler et al. (1995) and Nondo et al. (2015)
	Syzygium cumini (L.) Skeels	Mzambarau	Tree	Leaves, stem bark, flowers	Decoction of leaves or stem bark drunk. Ripe fresh fruits eaten.	Nondo et al. (2015)
	Syzygium guineense (Wild.) DC	Omuchwezi	Tree	Leaves	Decoction drunk	Nondo et al. (2015)
Olacaceae	Ximenia caffra Sond.	Mpingi	Tree	Roots	Not specified	Augustino and Gillah (2005)
Oleaceae	Jasminum dichotomum Vahl	Kigoyagoye	Climber	Leaves	Decoction is taken orally, or the plant part dried, and ground to powder then licked	Moshi et al. (2009)
Onagraceae	Ludwigia octovalvis (Jacq.) P.H. Raven spp. brevisepala (Brennan) P.H Raven	Wejunge	Herb	Leaves	Decoction drunk	Nondo et al. (2015)
Phyllanthaceae	Antidesma venosum E. Mey ex Tul.	Mjembajemba	Tree	Roots	Decoction drunk	Chhabra et al. (1993)
	Flueggea virosa (Roxb. ex Willd.) Royle	Mizwandimu	Tree	Leaves	Not specified	Hilonga et al. (2019)
	Phyllanthus reticulatus Poir.	Mkwamba mavi	Tree	Roots	Infusion drunk	Chhabra et al. (1990a)
Poaceae	Cymbopogon citratus L.	Mchaichai	Grass	Leaves	Hot infusion drunk	Nondo et al. (2015)
	Pennisetum purpureum Schum.	Olutete	Grass	Leaves	Decoction drunk	Nondo et al. (2015)
	Vossia cuspidata (Roxb.) Griff.	Ekishararago	Grass	Leaves	Decoction drunk	Nondo et al. (2015)
Polygonaceae	Oxygonum sinuatum (Hochst. & Steud. ex Meisn.) Damm.	Kachumitambogo	Herb	Roots	Not specified	Hilonga et al. (2019)
	Polygonum senegalense Meisn	Kanyanyanja	Herb	Aerial parts	Decoction drunk or pounded, then mixed with clean water and taken orally	Nondo et al. (2015)
	Rumex abyssinicus Jacq.	Akanulilizi	Herb	Aerial parts	Pounded, then mixed with clean water and taken orally	Nondo et al. (2015)
Polygalaceae	Securidaca longipedunculata Fresen.	Mnengonengo	Shrub	Roots	Decoction drunk	Chhabra et al. (1991)
Primulaceae	Maesa cordifolia Miq.	Mguti	Tree	Roots	Decoction drunk	Shangali et al. (2008)
Punicaceae	Punica granatum L.	Omukomamanga	Tree	Fruits	The outer part of the fruits are dried, then powdered and used to make a warm infusion.	Nondo et al. (2015)
Putranjivaceae	Drypetes natalensis (Harv.) Hutch.	Omushasha	Tree	Leaves, stem bark	Decoction drunk	Gessler et al. (1995)
Rosaceae	Eriobotrya japonica (Thunb.) Lindl.	Omusharazi	Tree	Roots, leaves, stem bark, fruits	Roots decoction drunk. Powdered dry stem- bark and leaves used to prepare a warm infusion. Fresh fruits eaten	Nondo et al. (2015)
	Parinari curatellifolia (Planch. ex) Benth.	Omunazi	Tree	Stem bark	Not indicated	Chhabra and Mahunnah (1994)
	Spermacoce princeae (K. Schum) Verdc	Ekaiza nkoju	Herb	Aerial parts	Decoction drunk	Nondo et al. (2015)
Rubiaceae	Catunaregam spinosa (Thunb.) Tirveng.	Kaboya	Shrub	Fruits	Not specified	Hilonga et al. (2019)
	Chassalia parvifolia K. Schum.	Mguhu	Tree	Stem bark	Concoction drunk	Amri and Kisangau (2012)
	Chassalia umbraticola Vatke	Mwataibare	Shrub	Leaves, stem bark	Decoction drunk	Nondo et al. (2015)
	Crossopteryx febrifuge (G. Don) Benth.	Mtundwambezo	Tree	Stem bark	Decoction drunk and vapour inhaled	Gessler et al. (1995)
	Gardenia vogelii Hook.f.	Entarama	Shrub	Root bark	Decoction drunk	Gessler et al. (1995)
	Hymenodictyon parvifolium Oliv. subsp parvifolium	Mazige nkeremeka (infant stool)	Climber	Aerial parts	Pounded and boiled, then decoction is taken orally	Moshi et al. (2009)
	Oxyanthus speciosus DC	Omwanikibira	Tree	Leaves	Decoction drunk	Nondo et al. (2015)
	Pavetta lynesiiBridson	Orwingula/Omuingula	Shrub	Leaves	Decoction drunk	Nondo et al. (2015)
	Pentas bussei (K. Krause)	Rusharula kibira	Herb	Aerial parts	Decoction drunk	Nondo et al. (2015)
	Psychotria kirkii (Hiern) Verdc.	Orututi	Shrub	Roots	Decoction drunk	Gessler et al. (1995)
	Psydrax parviflora (Afzel.) Bridson spp.	Omushangati	Tree	Leaves, stem bark	Decoction drunk or fresh juice squeezed to make juice and taken orally	Nondo et al. (2015)
	Rytigynia obscura Robyns	Omulokola/Lulokola	Shrub	Leaves	Decoction drunk	Nondo et al. (2015)
	Tricalysia coriacea (Benth.) Hiern.	Omshekerakibira	Tree	Roots, leaves, fruits	Leaves/roots are boiled and decoction drunk. Fresh fruits are eaten.	Moshi et al. (2009, 2012)
	Vangueria infausta Burch.	Amabungo/mabungo/Kirongomani/Mtangunda	Tree	Stem bark, leaves	The fruits and seeds are burnt and then eaten, or the leaves are boiled in water together with leaves or stem bark of Dracaena steudneri Engl. (Asparagaceae) and the decoction drunk.	Moshi et al. (2009), Nondo et al. (2015), Hilonga et al. (2019) and Kacholi (2020)
	Vangueria madagascariensis Gmel.	Mdaria	Tree	Stem bark	Decoction drunk	Chhabra et al. (1991)
Rutaceae	Citrus limon (L.) Burm.f.	Mlimao	Tree	Fruits	Not specified	Augustino and Gillah (2005)
	Harrisonia abyssinica Oliv.	Soma/Engilelo	Shrub	Roots	Not specified	Maregesi et al. (2007) and Hilonga et al. (2019)
	Teclea nobilis Del.	Omuzo	Tree	Leaves	Decoction drunk	Nondo et al. (2015)
	Toddalia asiatica (L.) Lam.	Orukwatango	Climber	Leaves	Decoction drunk	Nondo et al. (2015)
	Vepris lanceolata (Lam.) G. Don.	Mwingajini	Tree	Leaves, roots	Decoction drunk	Gessler et al. (1995)
	Zanthoxylum chalybeum Engl.	Omutaregwairungu	Tree	Leaves, roots, stem bark	Decoction drunk	Ruffo (1991), Gessler et al. (1995), Augustino et al. (2011), Nondo et al. (2015) and Hilonga et al. (2019)
Salicaceae	Flacourtia indica (Burm. l.) Merr.	Mpuguswa	Tree	Roots	Not specified	Hilonga et al. (2019)
Sapindaceae	Deinbollia borbonica Scheff.	Mmoyomoyo	Shrub	Roots	Decoction drunk	Chhabra et al. (1991)
	Haplocoelopsis africana F. O.Davies	Mkuzanyana	Tree	Stem bark	The dried stem bark is boiled with water, and the decoction is taken thrice daily.	Moshi et al. (2009)
	Lecaniodiscus fraxinifolius Bak.	Omwasha	Tree	Leaves	Decoction drunk	Nondo et al. (2015)
	Zanha africana Radlk. Exell	Mkalya	Tree	Roots	Not specified	Augustino and Gillah (2005)
Sapotaceae	Diospyros zombensis (B.L.Burtt) F.White	Nyakatidu	Shrub	Leaves, roots	Decoction or infusion drunk	Gessler et al. (1995)
	Synsepalum brevipes (Bak.) Pennington	Omukaraito/mkaraito	Tree	Stem bark	Ground and boiled, then the decoction drunk	Moshi et al. (2009)
	Synsepalum ceresiferum (Welw.) Pennington	Omumo	Tree	Stem bark	The decoction is taken orally.	Moshi et al. (2009)
Scrophulariaceae	Buchnera hispida Buch.-Ham.	Olorokilele	Herb	Whole plant	The whole plant is cooked with bonny beef without salt; then the soup is mixed with stiff porridge and taken orally.	Chhabra and Mahunnah (1994)
	Cycnium tubulosum subsp. montanum (N.E. Br.) O.J. Hansen	Maua ya watoto	Herb	Whole plant	Not specified	Hilonga et al. (2019)
Solanaceae	Datura stramonium L.	Ekitaigwa, Amalulu	Shrub	Seeds	Decoction drunk	Nondo et al. (2015)
	Physalis peruviana L.	Kitutun kikubwa	Herb	Leaves	Fresh leaves pounded mixed with water and taken orally.	Augustino and Gillah (2005) and Nondo et al. (2015)
	Solanum aculeastrum Dunal	Omulembezi/Entobatobe	Shrub	Fruits, leaves	Not indicated	Moshi et al. (2012)
Sterculiaceae	Dombeya burgessiae Gerr. ex Harv.	Mfurufuru	Tree	Leaves	Decoction drunk	Chhabra et al. (1993)
	Dombeya shupangae (K. Schum.)	Omutangarara	Tree	Leaves	Decoction drunk	Gessler et al. (1995) and Nondo et al. (2015)
	Sterculia appendiculata K. Schum.	Mgude	Tree	Leaves	Not specified	Augustino and Gillah (2005)
Ulmaceae	Trema orientalis Bullock	Omuhuwe	Tree	Leaves, stem bark	Dry powder is used to make warm infusions and taken orally.	Nondo et al. (2015) and Kacholi (2020)
Umbelliferae	Centella asiatica (L.) Urb.	Mbatama/Kutikwimo	Herb	Aerial parts	Aerial parts are mixed with a local brew, and patient is given a bowl or cup to drink.	Moshi et al. (2009) and Nondo et al. (2015)
Urticaceae	Pilea holstii Engl.	Omufura/Eimyo	Shrub	Leaves	Fresh leaves squeezed, then mixed with water and taken orally	Nondo et al. (2015)
Verbenaceae	Lantana camara L.	Lukulata	Shrub	Leaves	Decoction drunk	Nondo et al. (2015)
	Lantana trifolia L.	Omuhuchi	Shrub	Aerial parts	Decoction drunk	Nondo et al. (2015)
Vitaceae	Cissus rotundifolia (Forsk.) Vahl.	Mchazi/Kakulumo	Climber	Leaves, roots	Not specified	Hilonga et al. (2019)
	Cyphostemma adenocaule (Steud. ex A. Rich.) Descoings	Rubombo	Climber	Leaves	Not specified	Hilonga et al. (2019)
Zingiberaceae	Aframomum angustifolium (Sonn.) K. Schum.	Orushasha	Shrub	Leaves	Cold infusion drunk	Nondo et al. (2015)
	Costus afer Ker-Gawl.	Ekigagi	Herb	Roots, aerial parts	Decoction drunk or eaten raw	Chhabra et al. (1993) and Nondo et al. (2015)
Zygophyllaceae	Balanites aegyptiaca (L.) Delile	Orng'oswai	Tree	Stem bark	Not specified	Hilonga et al. (2019)

Table 2. Top 15 botanical families (with >3 species) from which antimalarial remedies are obtained in Tanzania.

Family	Number of Species	Percentage
Fabaceae	36	15.9
Asteraceae	19	7.9
Rubiaceae	15	6.6
Euphorbiaceae	12	5.3
Lamiaceae	12	5.3
Acanthaceae	6	2.6
Anacardiaceae	6	2.6
Combretaceae	6	2.6
Rutaceae	6	2.6
Apocynaceae	5	2.2
Melastomataceae	5	2.2
Myrtaceae	5	2.2
Cucurbitaceae	4	1.8
Polygonaceae	4	1.8
Sapindaceae	4	1.8
Others	83 (with ≤3 species)	36.6

Some MPs presented in this review have also been reported in other ethnobotanical studies conducted elsewhere as antimalarial. For instance, Senna occidentalis (Fabaceae), A. precatorius, V. amygdalina, M. indica and A. indica are reported to be the most frequently used MPs for treating Malaria in Uganda (Tabuti et al. 2023). Cyathula cylindrica Moq. (Amaranthaceae), Rhus vulgaris Meikle (Anacardiaceae), Artemisia afra Jacq. (Asteraceae), Bidens pilosa L. (Asteraceae) and K. africana have been reported in Kenya (Omara 2020), M. foetida in Uganda (Okello and Kang 2019), Zimbabwe (Ngarivhume et al. 2015) and Cameroon (Pierre et al. 2011), A. afra, M. indica, and Datura stramonium L. (Solanaceae) in Ethiopia (Mesfin et al. 2009), and Flacourtia indica (Burm. l.) Merr. (Salicaceae), and Tamarindus indica L. (Fabaceae) in Ethiopia (Nigussie and Wale 2022) and Indonesia (Taek et al. 2018), and A. indica in Nigeria (Odugbemi et al. 2006), and Kenya (Gathirwa et al. 2011; Nguta and Mbaria 2013), and Senna siamea (Lam.) H.S. Irwin & Barneby (Fabaceae) in Togo (Agbodeka et al. 2016). The wide acceptance of MPs' usage signifies their potential for treating malaria. Thus, using modern science and technology, the MPs can be used to improve the local remedies or develop new affordable contemporary drugs.

In this review, few MPs are reported to be used for treating malaria simultaneously in different regions. This could be attributed to the prolific distribution of the referent active ingredients among species, especially those belonging to dominant families, such as Fabaceae, Asteraceae, Rubiaceae, Euphorbiaceae and Lamiaceae. The variances in geographical and climatic conditions may also influence the availability of flora in a given locality. However, some MPs have a broader distribution and are commonly used by most communities.

Life forms

Antimalarial MPs used in Tanzania are dominated by trees (43%), followed by herbs (27%), shrubs (23%), climbers (6%) and grasses (1%) (Figure 2). The predominant use of trees in herbal remedies formulation is also reported in other ethnobotanical studies (Omara et al. 2020; Mogha et al. 2022). The local traditional healers favour using a particular life form because of their accessibility and familiarity (Shukla et al. 2018). Furthermore, cultural influence plays a substantial role in selecting MPs' life forms for preparations of herbal remedies.

Figure 2. The percentage share of life forms used for antimalarial remedies in Tanzania.

Parts used

The most commonly used MP parts for the formulation of antimalarial remedies are leaves (40%), followed by roots (23%), and stem bark (19%) (Figure 3). The MPs parts, such as seeds, fruits, flowers, buds and bulbs, known for accruing phytochemicals, are seldom used, comparable to ethnobotanical studies conducted elsewhere (Ngarivhume et al. 2015; Okello and Kang 2019). Similar to present findings, leaves of trees, shrubs and herbs are reported as the dominant plant part used for the preparation of antimalarial decoctions in some countries such as Kenya (Omara 2020), Ethiopia (Alebie et al. 2017), Nigeria (Oyeyemi et al. 2019) and Democratic Republic of Congo (Katemo et al. 2012). Plant leaves are well known for synthesizing the majority of plant secondary metabolites; hence, they are rich sources of bioactive chemical constituents. Systematic harvest of leaves poses no or little threat to the survival of MPs, encouraging frequent and safe utilization of leaves for herbal remedies preparations. Plant roots and associated structures, such as rhizomes and tubers, are rich sources of potent bioactive chemical compounds (Alebie et al. 2017). However, their persistent usage in herbal preparations can still be risky to the survival of a plant species. Therefore, proper harvesting approaches and conservation strategies are indispensable for safeguarding the sustainable utilization of MPs resources.

Figure 3. Percentage share of medicinal plant parts used for antimalarial remedies in Tanzania.

The majority (75%) of herbal remedies used as antimalarial are prepared from fresh MP materials, followed by dry form (18%) and both fresh and dry materials (7%). The predominant use of fresh materials mirrors an endeavour to capture potent volatile substances that determine the therapeutic efficacy of herbal remedies (Addis et al. 2021). The use of dry materials is favoured when the MPs are poorly accessible. Similar to other ethnobotanical reviews, some traditional practitioners collect MP materials far away from their places and practice long-term preservation (Alebie et al. 2017; Omara 2020; Ajao et al. 2022).

Preparation and administration of remedies

Antimalarial remedies are mainly prepared through decoctions (67%), followed by infusion (17%) and rarely prepared through powdering (7%), juicing (4%), steaming (3%), burning (1%), and concoction (1%) (Figure 4). Most (78%) of the herbal preparations are orally administered, as is the case for contemporary medicine, and seldom administered through the intranasal route. Only liquid from squeezed fresh leaves of Aspilia natalensis (Sond.) Wild. (Asteraceae) is reported to be applied through the nasal passage. Moreover, fresh fruits of Syzygium cumini (L.) Skeels (Myrtaceae), Eriobotrya japonica (Thunb.) Lindl. (Rosaceae), Tricalysia coriacea (Benth.) Hiern. (Rubiaceae), Vangueria infausta Burch. (Rubiaceae), roots and aerial parts of Costus afer Ker-Gawl. (Zingiberaceae) and fresh leaves of Adansonia digitata L. (Bignoniaceae) are eaten directly upon collection or after initial processing through pounding or crushing. Some MPs materials are burnt or steamed and inhaled. These findings agree with observations in other ethnobotanical studies conducted in other countries, such as Nigeria (Adekunle 2008), Ethiopia (Alebie et al. 2017), Zimbabwe (Maroyi 2013) and Kenya (Omara et al. 2020). However, a few reports (19.6%) failed to point out modes of administration of some herbal remedies.

Figure 4. The percentage share of preparation techniques for antimalarial remedies.

Malaria is an acute feverish illness mainly caused by plasmodium parasites, and its management requires adequate circulating concentrations of relevant antiprotozoal components. The oral route is an appropriate and non-offensive method of systemic therapy as it permits relatively hasty absorption and distribution of bioactive ingredients from herbal remedies, allowing sufficient therapeutic power (Teklay et al. 2013). The potential risk of enzymatic breakdown and microbial fermentation of functional chemical entities may necessitate alternative routes of herbal remedy administration.

Similarly, this review noted that a few MPs (5.2%) are used to treat malaria in combination with other plants. For instance, the infusion of dried powdered aerials parts of Justicia matammensis Oliv. (Acanthaceae) are combined with those of Cassia gracilior (Ghesq.) Steyaert (Fabaceae), Antherotoma naudinii Hook.f. (Melastomataceae) or Indigofera asparagoides Taub. ssp. (Fabaceae) or Ephemera spp. Gillett (Ephemeridae) for managing cerebral malaria. The decoctions of V. amygdalina Del. leaves and roots are combined with the stem bark of Sapium ellipticum (Krauss) Pax (Euphorbiaceae), and the leaves of Dalbergia nitidula Baker (Fabaceae), Desmodium salicifolium (Poir) DC (Fabaceae), Eriosema psoraleoides Lam. G.Don. (Fabaceae). The stem bark and roots of Garcinia buchananii Bak. (Clusiaceae) are combined with Tragia furialis Prain (Euphorbiaceae) and administered orally. Other ethnobotanical studies conducted elsewhere also reported similar observations in treating various diseases, including malaria (Maroyi 2013; Alebie et al. 2017; Omara 2020).

Other ethnomedicinal uses of antimalarial plants

Most antimalarial MPs listed in this review are used for the traditional management of other ailments in different parts of the country and elsewhere globally. For instance, in Tanzania, A. precatorius, T. indica, Z. chalybeum, C. abbreviata and Flueggea virosa (Roxb. ex Willd.) Royle, are reported to be used by Nyamwezi people to manage erectile dysfunction (Kacholi and Amir 2023), and Moringa oleifera Lam, Z. chalybeum and P. guajava are used as anti-haemorrhoids (Kacholi and Amir 2022). In Southern India, A. precatorius is reported to have multiple applications like neuromuscular effects, neuro-protective, abortifacient, antiepileptic, antiviral, antifertility, nephroprotective, immune-modulator, immune-stimulatory properties, anti-inflammatory activity and antidiabetic effect (Garaniya and Bapodra 2014). T. indica leaves and fruits are used for managing foot pain and constipation in Tanzania (Hilonga et al. 2019), while the leaves of this species are used for treating smallpox and abdominal upsets and fruits for managing constipation in Uganda (Ebifa-Othieno et al. 2017). Other plants, such as V. amygdalina, and B. pilosa are used in Tanzania (Kingo and Maregesi 2020), India (Pattanayak et al. 2017), and Trinidad and Tobago (Lans 2006) for curing urinary transmitted infections.

Antimalarial, antiplasmodial and toxicity studies

Of the reported antimalarial MPs used in Tanzania in this review, 59 (25.9%) have demonstrated therapeutic potential in pre-clinical and clinical investigations (Table 3). Antimalarial compounds with antiplasmodial activities have been identified and isolated from these MPs species (Gakunju et al. 1995; Oketch-Rabah et al. 1999; Clarkson et al. 2004; Koch et al. 2005). Regardless of the accomplishment of traditional medicinal practices and the wealth of MPs (Table 1), most antimalarial MPs studies in Tanzania are limited to ethnobotanical investigations, with extensions to the assessment of crude extracts from MPs against Plasmodium species (Weenen et al. 1990; Kweyamba et al. 2019). The gap is evident regarding studies geared towards identifying and isolating plant bioactive compounds, establishing the efficacy and safety of MPs through in vitro assays using human Plasmodium parasites and in vivo assays involving higher animal models and randomized clinical trials (Gessler et al. 1995; Malebo et al. 2015). In examining antiplasmodial activities, whether due to a specific or general toxicity effect, the experimental selectivity index (SI) must be calculated. However, in Tanzania, few studies have attempted this (Malebo et al. 2015; Kassimu et al. 2022). The discrepancy in toxicity depends on the sensitivity of the experimental animals, tissue or cells used, type of extract, nature of tested substance, dose, and mode of administration (Parasuraman 2011; Turner et al. 2011).

Table 3. Literature on antimalarial and antiplasmodial activities and toxicity of some recorded medicinal plants.

Species name	Part used	Solvent used	Antiplasmodial (IC50, μg/ml)/antimalarial activity (Plasmodium strain)	Active phytochemicals	Toxicity	Reference(s)
Abrus precatorius L.	Leaves	Methanol	85.59 (D6); >100 (W2)	Abruquinone B	Cytotoxic to KB and BC cell lines (IC50: 13.0 ± 19.8 μg/ml)	Limmatvapirat et al. (2004) and Gathirwa et al. (2011)
Albizia gummifera (J.F. Gmel.) C.A.Sm.	Leaves	Methanol	0.16 (NF54); 0.99 (ENT 30)	Alkaloids	No reports	Rukunga et al. (2007)
Allium sativum L.	Synthetic	Ethanol	Ajoene 50 mg/kg given as a single dose, prevented parasitaemia development	Ajoene	Safe in humans	Perez et al. (1994)
Artemisia afra Jacq.	Leaves	Methanol	9.1 (D6); 3.9 (W2)	Acacetin, genkwanin, 7-methoxy acacetin	Cytotoxicity observed in vero cells	Liu et al. (2009) and Muthaura et al. (2015)
Azadirachta indica A. Juss	Leaves	Water, methanol	17.9 (D6); 43.7 (W2)	Terpenoids, isoprenoids, gedunin, limonoids, khayanthone, meldenin, nimbinin	Cytotoxicity at LD50 of 101.26 and 61.43 μg/ml for water and methanol extracts, respectively	Bray et al. (1990), Kirira et al. (2006), Alshawsh et al. (2009) and Asase et al. (2010)
Balanites aegyptiaca (L.) Delile	Root bark	Chloroform	3.49 (D6)	Cytotoxicity IC50 >20 μg/ml	No reports	Koch et al. (2005)
Bidens pilosa L.	Leaves	Dichloromethane, water, methanol	8.5, 5, 11, 70 (D10)	No reports	Safe in humans	Clarkson et al. (2004) and Lai et al. (2015)
Boscia angustifolia A. Rich.	Inner bark	Chloroform	>10.0 (D6); not active	Cytotoxicity IC50 >20 μg/ml	No reports	Koch et al. (2005)
Bridelia micrantha (Hochst.) Baill.	Stem bark, leaves	Methanol	158.7 (K1)	No reports	No reports	Ajaiyeoba et al. (2005)
Caesalpinia volkensii Harms	Leaves	Ethanol, petroleum ether, methanol, water	480, 481, 490, 858, 404 (FCA: 20 GHA); 923, 960, 250, 961, 563 (W2)	No reports	No reports	Kuria et al. (2001)
Cassia didymobotrya Fres.	Leaves	Methanol	23.4 (D6); undetectable (W2)	Alkaloids	No reports	Muthaura et al. (2015)
Centella asiatica (L) Urb.	Leaves	Dichloromethane/methanol (1:1)	8.3 (D10)	Alkaloids, sesquiterpenes	No reports	Clarkson et al. (2004)
Cissampelos mucronata A. Rich	Root bark, root	Methanol, ethyl acetate	8.8 (D6); 9.2 (W2). Root extract <3.91 (D6); 0.24 (W2) for curine	Benzylisoquinoline alkaloids, curine	Slightly to moderately toxic LD50 = 288.53 mg/kg for ethanol root extract and 8500 mg/kg for methanol leaf extract	Akah and Nwafor (1999), Loomis and Hayes (2014) and Muthaura et al. (2015)
Clerodendrum myricoides (Hochst.) Vatke.	Root bark	Ethanol, chloroform	4.7 (D6); 8.3 (W2) >10 (D6)	No reports	Cytotoxicity (IC50 >20.0 μg/m)	Koch et al. (2005)
Combretum molle R.Br. ex G.Don.	Stem bark	Acetone	8.2 (3D7)	Phenolics, punicalagin, saponins, alkaloids and cardiac glycosides	No pronounced toxicity against human hepatocellular	Asres et al. (2001)
Croton macrostachyus Oliv.	Leaves	Chloroform, dichloromethane	Chemotherapeutic effect of 66–82%; 2 (D6)	Triterpenoids, lupeol	No reports	Rahmatullah et al. (2012) and Owuor et al. (2012)
Costus afer Ker Gawl.	Aerial parts	Ethanol, water	Inhibition >60% on 3D7 strain and 80% against field isolates	Flavonoids, anthraquinones, coumarins, triterpenes and tannins	Acute oral toxicity observed	Tiko et al. (2020)
Datura stramonium L.	Leaves, twigs	Ethanol	13.29 (FCB); 116.86 (W2); 46.09 (CAM06)	Flavonoids, tannins, glycosides, coumarins	Weak to no cytotoxicity observed	Laryea and Borquaye (2019)
Cymbopogon citratus L.	Leaves, roots	Water	Leaves produced suppressive effect of 20.83%, 55.56% and 80.56% while root produced suppression of 50.38%, 77.78% and 100%, all at 200, 400 and 800 mg/kg, respectively	Alkaloids, tannins, steroids, flavonoids, saponins, cardiac glycosides and anthraquinones	Non-toxic	Arome et al. (2016)
Eucalyptus globulus Labill.	Leaves	Chloroform, ethyl acetate	44.5 (D3); 43.0 (D7); 45.0 (D3); 43.17 (D7)	Tannins, saponins, steroids, terpenoids, glycosides, alkaloids, terpenes, phenolic compounds, resins, cardiac glycosides, reducing sugars, carbohydrates, acidic compounds and flavonoids	Non-toxic	Ayalew et al. (2022)
Erythrina abyssinica DC	Stem bark	Ethyl acetate	83.6% inhibition of P. falciparum at 10 μg/ml	Chalcones (5-prenylbutein and homobutein), flavanones including 5-deoxyabyssinin II, abyssinin III and abyssinone IV	No reports	Lacroix et al. (2011) and Ntie-Kang et al. (2014)
Flacourtia indica (Burm. l.) Merr.	Roots	Dichloromethane, dichloromethane/methanol (1:1), water	86.5 (D10); 78 (D10); >100 (D10)	No reports	No reports	Clarkson et al. (2004)
Flueggea virosa (Roxb. ex Willd.) Royle	Leaves	Water, methanol	2.0 (W2)	Bergenin	Non-toxic	Kaou et al. (2008) and Singh et al. (2017)
Friesodielsia obovata (Benth) Verdc.	Stem and root bark	Methanol	Moderate activity against K-1 strain of P. falciparum, with IC50 values of 23 and 9.7 μg ml^−1 reported	3′,5′-Diformyl-2′,4′,6′-trihydroxychalcone and N-formyl-7-hydroxyglaucine	Cytotoxicity activities reported	Joseph et al. (2007)
Harrisonia abyssinica Oliv.	Roots	Water, methanol	4.4 (D6); 10.25 (W2); 89.74, 79.50 (ENT 30); 86.56	Limonoids, steroids	Slightly to moderately toxic with LD50 = 234.71 and 217.34 μg/ml for water and methanol extracts, respectively	Kirira et al. (2006) and Loomis and Hayes (2014)
Harungana madagascariensis Poir.	Stem bark	Water, ethanol	9.64 (K1); <0.5 with 28.6–44.8% parasite suppression	Quinones, including bazouanthrone, ferutinin A, harunganin, harunganol A, anthraquinones, saponins, steroids	No reports	Iwalewa et al. (2008, 2009), Ntie-Kang et al. (2014) and Memvanga et al. (2015)
Holarrhena pubescens (Huch-Ham) G. Don	Roots	Methanol	Highly active against K1, DD2 and artemisinin resistant parasites	No reports	Safe in humans	Nondo et al. (2017)
Hoslundia opposita Vahl.	Leaves, roots, aerial parts	Ethyl acetate, methanol	66.2% inhibition of P. falciparum at 10 μg/ml. 79.38 (D6); 64.21 (W2); 19.73 (D6); 29.41 (W2)	Quinones, saponins, abietane Diterpenes (3 obenzoylhosloppone)	No reports	Lacroix et al. (2011) and Gathirwa et al. (2011)
Kigelia africana (Lamarck) Benth.	Bark, fruit	Chloroform/ethylacetate, methanol	59.9 (K39); 83.8 (V1/S); fruits had 165.9 (K39)	No reports	No reports	Oketch-Rabah et al. (1999)
Lantana camara L.	Leaves, twigs	Dichloromethane, dichloromethane/methanol (1:1), water	8.7 (3D7); 5.7 (W2); 11 (D10); >100 (D10); >100 (D10)	Lantanine, sesquiterpenes, triterpenes, flavonoids	No reports	Burkill (2000) and Clarkson et al. (2004)
Lantana trifolia L.	Aerial parts	Petroleum ether, chloroform, ethanol	13.2, >50, >50 (plasmodial lactate dehydrogenase)	Steroids, terpenoids, alkaloids, saponins	No reports	Katuura et al. (2007)
Leonotis nepetifolia (L.) R. Br.	Leaves	Ethyl acetate, dichloromethane/methanol (1:1), water	27.0% inhibition of P. falciparum at 10 μg/ml, 15; >100 (D10)	No reports	No reports	Clarkson et al. (2004) and Lacroix et al. (2011)
Maesa lanceolata Forsk	Twig	Dichloromethane:methanol (1:1)	5.9 (D10)	Lanciaquinones, 2,5-dihydroxy-3-(nonadec-14-enyl)-1,4-benzoquinone	No reports	Clarkson et al. (2004), Katuura et al. (2007) and Muganga et al. (2010)
Markhamia lutea (Benth) K. Schum.	Leaves	Ethyl acetate	71% inhibition of P. falciparum at 10 μg/ml	Phenylpropanoid glycosides, cycloartane triterpenoids, musambins A–C, Candmusambiosides A–C	No reports	Lacroix et al. (2011)
Markhamia obtusifolia (Bak.) Sprague
Maytenus senegalensis (Lam.) Exel	Roots	Ethanol	1.9 (D6); 2.4 (W2)	Terpenoids, pentacyclic triterpenes, e.g., pristimerin	No toxicity observed in ethanol extract	Nanyingi et al. (2009), Malebo et al. (2015) and Kassimu et al. (2022)
Momordica foetida Schum.	Shoot	Water	6.16 (NF54); 0.35 (FCR3)	Saponins, alkaloids, cardiac glycosides	Safe in humans	Froelich et al. (2007), Adia et al. (2016) and Obbo et al. (2019)
Mangifera indica L.	Leaves, stem bark	Water	The leaf/stem bark (1:2) extract (88.27%) exhibited chemosuppressive activities that was better than artesunate (88.04%) and artemisinin-based combination therapy (ACT, 84.60%)	9,12-octadecadienoic acid, oleic acid, 9,12-octadecadienal, 9-oxabicyclo (6.1.0) nonane, hexadecadienal and spirohexane	No reports	Asanga et al. (2023)
Moringa oleifera (Lam.)	Leaves	Water	Showed suppression of 35, 40 and 50%	Tannins, alkaloids, quinines, saponins, flavonoids, polyphenols, terpenoids, quercetin, kaempferol and gypenoside	Non toxic	Karthivashan et al. (2013) and Somsak et al. (2016)
Ocimum bacilicum L.	Leaves, whole plant	Ethanol	68.14 (3D7); 67.27 (INDO)	No reports	Generally safe, LD50 = 100–5000 mg/kg body weight	Fandohan et al. (2008), Loomis and Hayes (2014) and Murugan et al. (2016)
Ocimum kilimand­scharicum Gürke	Leaves, twigs	Dichloromethane	0.843 (D6); 1.547 (W2)	No reports	No reports	Owuor et al. (2012)
Ocimum suave Willd.	Leaves	Water (hot), chloroform/methanol mixture	100 mg/kg/day of extracts provided 81.45% and 78.39% parasite chemo-suppression	No reports	No reports	Kiraithe et al. (2016)
Physalis peruviana	Leaves	Water, methanol, dichloromethane	>14.7 (D6)	Alkaloids	Safe to vero cells	Kamau et al. (2020)
Polygonum senegalense Meisn	Aerial parts, leaves	Dichloromethane, water	3.1–23.5 (D2); 2.4–22.8 (W2)	Chalconoids, flavanone, homoisoflavonoid, 5,7-dihydroxy-3-(hydroxy-phenyl-methyl)-6-methoxy-chroman-4-one	No reports	Midiwo et al. (2006)
Psidium guajava L.	Leaves	n-Hexane, chloroform and ethyl acetate	Level of parasitaemia at 100, 300 and 500 mg/kg was reduced by 56.19, 63.22 and 69.96%, respectively	Alkaloids, flavonoids, tannins, saponins, steroids, phenols and terpenoids.	No reports	Alozieuwa et al. (2022)
Rumex abyssinicus Jacq.	Root	Dichloromethane	<15	No reports	No reports	Muganga et al. (2010)
Securidaca longipedunculata Fresen.	Leaves	Dichloromethane	6.9 (D10)	Saponins, flavonoids, alkaloids, steroids	No reports	Pillay et al. (2008)
Senna occidentalis (L.) Link	Leaves	Dimethyl sulphoxide, ethanol	48.80 (3D7); 54.28 (NIDO); <3	Quinones	Slightly to moderately toxic LD50 of leaf and stem extracts = 5 g/kg in mice	Tona et al. (2001), Kayembe et al. (2010), Silva et al. (2011), Loomis and Hayes (2014) and Murugan et al. (2016)
Spermacoce princeae (K. Schum) Verdc	Whole plant	Hexane, chloroform, ethyl acetate, water, methanol	>100 (K39)	No reports	No reports	Muregi et al. (2003)
Suregada zanzibariensis Roxb. ex Rottler.	Root bark	Water, methanol	≤10 (K67); (ENT36)	Alkaloids	No reports	Smolenski et al. (1975) and Omulokoli et al. (1997)
Tamarindus indica L.	Stem bark	Water	25.1% parasite suppression at 10 mg/kg (P. berghei)	Saponins (leaves), tannins (fruits)	Safe in humans	Martinello et al. (2006) and Nguta and Mbaria (2013)
Teclea nobilis Del.	Bark	70% ethanol	53.27% suppression of parasitaemia at 700 mg/kg	Tannins, alkaloids, saponins, flavonoids		Katuura et al. (2007)
		Ethyl acetate	54.7% inhibition of P. falciparum at 10 μg/ml	Quinoline alkaloids		Clarkson et al. (2004)
Toddalia asiatica (L.) Lam.	Root bark, fruits and leaves	Methanol, water, ethyl acetate, hexane	6.8 (D6); 13.9 (W2). Ethyl acetate fruit extract (1.80 mg/ml), root bark aqueous (2.43) (W2	Fluoroquinolones (nitidine, 5,6-dihydronitidine), coumarins	Slightly to moderately toxic and cytotoxicity of the extracts, except for roots hexane extracts	Orwa et al. (2013), Loomis and Hayes (2014) and Muthaura et al. (2015)
Trema orientalis Bullock	Leaves	Methanol	Murine models and β-hematin	Alkaloids, anthraquinones, xanthones, chromones, flavonoids and terpenes	No report	Olanlokun et al. (2017)
Trichilia emetica Vahl.	Leaves, twigs	Dichloromethane, methanol (1:1)	3.5 for all (D10)	Kurubasch aldehyde	No reports	Clarkson et al. (2004) and Bero et al. (2009)
Tridax procumbens L.	Whole plant	Dichloromethane/methanol (1:1), water	17 (D10), >100 (D10)	Bergenin	No reports	Weenen et al. (1990), Malik et al. (2002) and Clarkson et al. (2004)
Vachellia nilotica (L.) P.J.H. Hurter & Mabb	Stem bark	Water, methanol	>250, 153.79 (ENT 30), 73.59, 70.33 (NF 54)	Tannins, flavonoids, terpenes	LD50 of 368.11 and 267.31 μg/ml for water and methanol extracts	Kirira et al. (2006) and Alli et al. (2016)
Vernonia amygdalina Del.	Leaves	Methanol/dichloromethane, ethanol	2.7 (K1), 9.83. In vivo parasite suppression of between 57.2 and 72.7% in combination with chloroquine	Vernolepin, vernolin, vernolide, vernodalin and hydroxy vernodalin, steroid glucosides	Petroleum ether extract shows strong cytotoxicity	Challand and Willcox (2009), Lacroix et al. (2011), Stangeland et al. (2011), Amoa Onguéné et al. (2013) and Obbo et al. (2019)
Zanthoxylum chalybeum Engl.	Stem bark	Water	4.3 (NF54); 25.1 (FCR3)	Chelerythine, nitidine and methyl canadine	No toxicity recorded	Kiraithe et al. (2016) and Adia et al. (2016)

Plasmodium species isolates: D6, 3D7, D10, FCA/GHA (FCA: 20 GHA), FCR3, K39 and NF54 are chloroquine sensitive; DD2, ENT 30, FCR3, K1, NIDO, V1/S and W2 are chloroquine resistant.

In this review, 47.5% of the cited MPs in the literature (28 species) had no reports of their toxicities, while 52.5% (29 species) were evaluated for their toxicities (Table 3). Of the evaluated MPs (Table 3), 16.9% showed no toxicity to humans, while the rest showed toxicity effect when applied. This indicates that many MPs extracts with good antimalarial activity are potentially toxic too. Notable examples are the methanol extract of Toddalia asiatica (L.) Lam (Rutaceae) (Orwa et al. 2013; Muthaura et al. 2015) and the extract of dimethyl sulphoxide or ethanol of S. occidentalis (Loomis and Hayes 2014; Murugan et al. 2016) revealed to have low to moderate toxicity. In contrast, petroleum ether leaf extract of V. amygdalina was potent as antimalarial but with potent toxicity (Adia et al. 2016; Kiraithe et al. 2016; Obbo et al. 2019). As reported earlier in Table 3, few scientific trials have been conducted on antimalarial MPs. This can be due to regulatory requirements for clinical studies and the required financial input. Therefore, this study suggests that further pharmacological and phytochemical studies for the unstudied MPs are needed to establish their antimalarial activities, efficacy, toxicity and safety.

Conclusions

This review presents, for the first time, all known MPs used by Tanzanians to treat malaria. The work has shown that indigenous knowledge of MPs in Tanzania is a good resource for malaria management. However, experimental research and advanced analysis are required to isolate, identify and validate the bioactive compounds from promising MPs, which can be used to standardize plant materials to install a reproducible herbal medicine practice and formulation of contemporary drugs. Safety and toxicological studies are paramount as some MPs are used as admixtures in managing malaria. Additionally, sustainable development and harvest of indigenous MPs' resources require collaborative engagement between researchers, traditional health practitioners, government bodies and commercial investors.

Author contributions

Conceptualization, data collection, data analysis, manuscript writing and manuscript revision: DSK.

Acknowledgements

The author is indebted to the Dar es Salaam University College of Education (DUCE) for providing space and time for this work. Moreover, the author commends all previous authors for their contribution to the knowledge of medicinal plants in Tanzania.

Disclosure statement

The author declares no competing interest in the publication of this work.

Additional information

Funding

No funding was received to undertake this work.