Analgesic and Anti-Inflammatory Activities of 80% Methanol Extract and Solvent Fractions of Ehretia cymosa Thonn (Boraginaceae) Leaves in Rodents

Abstract

Background

Ethnobotanical studies in various districts of Ethiopia reported that Ehretia cymosa (E. cymosa) is used for the management of headache, abdominal pain, arthritis and rheumatism. However, there is no scientific investigation done so far to confirm these traditional claims. Thus, the aim of this study was to assess the analgesic and anti-inflammatory effects of the 80% methanol extract and fractions of E. cymosa leaves.

Methods

The dried and pulverized leaves of E. cymosa were soaked with 80% methanol to obtain a crude extract. Fractionation was done using chloroform, ethyl acetate and water by a soxhlet apparatus. The analgesic effects of the crude extract and solvent fractions were assessed using acetic acid-induced writhing and hot plate tests whereas anti-inflammatory activities were investigated using carrageenan-induced paw edema and cotton-pellet-induced granuloma models.

Results

In all the tested doses, the 80% methanol extract and solvent fractions revealed substantial (p < 0.001) analgesic activities in acetic acid induced writhing test. In the hot plate method, all the tested doses of E. cymosa crude extract and the solvent fractions produced significant analgesic activities (p < 0.05). In the carrageenan-induced acute inflammation model, all tested doses of the crude extract and solvent fractions resulted in a significant decline in paw edema. The 80% methanol extract and solvent fractions of E. cymosa at all the tested doses significantly reduced inflammatory exudates and granuloma mass formations (p < 0.001).

Conclusion

From the results of this investigation, it can be stated that 80% methanol extract, aqueous, ethyl acetate and chloroform fractions of E. cymosa exhibited considerable analgesic and anti-inflammatory activities, supporting the plant’s traditional use as a remedy for a variety of painful and inflammatory conditions.

Keywords:

• analgesic
• hot plate
• anti-inflammatory
• Ehretia cymosa
• carrageenan-induced paw edema
• cotton pellet granuloma

Abbreviations

NO, nitric oxide; NSAID, non-steroidal anti-inflammatory drugs; COX, cyclooxygenase; IL, interleukin; AE, atropine equivalent; GAE, gallic acid equivalent; QE, quercetin equivalent; OECD, Organization for Economic Cooperation and Development.

Data Sharing Statement

The data is available on the hand of the corresponding author and provided on reasonable request.

Ethics Approval and Consent to Participate

This study was approved by the School of Pharmacy, College of Health Sciences, Addis Ababa University, ethical review committee with protocol number ERB/SOP/180a/13/2020. OECD guideline 25 was used for the welfare of the laboratory animals.

Acknowledgments

The authors would like to thank Ethiopian Public Health Institute (EPHI) and Department of Pharmacology and Clinical Pharmacy, Addis Ababa University for providing laboratory animals and chemicals.

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.

Disclosure

The authors declare that they have no conflicts of interest in this work.

Additional information

Funding

The study is supported by Addis Ababa University.