Aloe adigratana Reynolds: Preliminary Phytochemical Screening, Proximate Content, Essential Oil Analysis, and In Vitro Antifungal Activity Studies of Its Leaf Peels and Gel

Abstract

Background

Aloe species are among the most significant plants with several applications. Many of the species, however, are underexplored, owing to their scarcity and limited geographical distribution. A. adigratana Reynolds, which is common in Ethiopia, is one of the little-studied and endangered Aloe species.

Objective

This preliminary study focuses on the phytochemical screening, proximate analysis, essential oil content, and antifungal activities of A. adigratana leaf peels. Antifungal activities were also tested on the gels of the plant for comparison.

Methods

Standard procedures were used for phytochemical and proximate composition studies. Essential oil analysis was performed using a gas chromatography-mass spectrometry instrument. Using the well-diffusion method, investigations on antifungal activity were performed on three clinically isolated specimens of dandruff-causing fungus; namely, Malassezia furfur, Malassezia restricta, and Malassezia globosa.

Results

The leaf peels of A. adigratana contained alkaloids, flavonoids, tannins, and terpenes. The mean moisture, ash, and crude fat levels were 85.69, 92.20, and 8.00%, respectively, whereas the mean total protein and mean total carbohydrate values were 2.59 and 3.04%. Gas chromatography-mass spectrometry investigation confirmed the presence of fifteen essential oils. The most prevalent essential oil component was discovered to be phytol (33.78%), followed by decane (11.29%). In a dose-dependent way, the leaf latex and gel extracts prevented the growth of three dandruff-causing Malassezia fungal species (M. furfur, M. restricta, and M. globosa). Both the latex and gel demonstrated the maximum activity on M. globosa, the most prevalent fungus in the research area, with minimum inhibitory concentrations of 0.24 and 0.48 mg/mL and minimum fungicidal concentrations of 0.48 and 0.97 mg/mL, respectively.

Conclusion

In general, the proximate and essential oil compositions of A. adigratana leaves were comparable to those of other Aloe species widely used in the food, cosmetic, and pharmaceutical industries, implying that A. adigratana could be a potential future plant for such industries.

Keywords:

• Aloe adigratana
• antifungal activity
• dandruff
• essential oil
• proximate

Abbreviations

ANOVA, Analysis of variance; DMSO, Dimethyl Sulfoxide; DT, Diterpene; EI, Electron Impact; eV, Electron volt; GC-MS, Gas chromatography-mass spectrometry; MFC, minimum fungicidal concentration; MIC, Minimum inhibitory concentration; NIST, National Institute of Standards and Technology; RI, Retention index; SD, Standard deviation; SDA, Sabouraud dextrose agar; SDB, Sabouraud dextrose broth; SPSS, Statistical package for the social sciences; ST, Sesquiterpene; TIC, Total ion chromatogram; t_R, Retention time.

Data Sharing Statement

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Approval and Consent to Participate

The institutional review committees of the College of Natural and Computational Sciences and the College of Health Sciences, Mekelle University, approved the studies.

Acknowledgments

The authors are highly indebted to acknowledge Mekelle University for funding this study. They are also thankful to Mr Melaku Wondafrash, a curator at the National Herbarium at the Department of Biology, Addis Ababa University, for verifying A. adigratana specimens. Finally, the authors would like to thank the anonymous reviewers.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare that they do not have any conflicts of interest for this work.

Additional information

Funding

This study was supported by Mekelle University, PO Box 231, Mekelle, Ethiopia through the Grant No.: CRPO/MIT/LARGE/001/09.