Evaluation of the Anti-inflammatory Effects of Methanol Extract of Rauwofia vomitera Leaves (MERVL) Using In-vivo Based Assays

Abstract

Background of the Study: The response of the body to harmful stimuli, such as tissue damage or a pathogenic infection is known as inflammation.  Rauwofia vomitera is a medicinal plant that is native to large areas of tropical Africa and it belongs to the family of Apocynaceae. It is a medicinal herb used in traditional Nigerian medicine to treat a variety of diseases, including inflammatory disorders. Aim of the Study:The present study investigated the anti-inflammatory  effects of methanol extract of Rauwofia vomitera leaves (MERVL) using  in-vivo  based assays.  Methodology: The anti-inflammatory effect of (MERVL) was ascertained using the Egg albumin -induced inflammation using in vivo assay. A total of thirty (30) adult male albino rats (130-170g) were divided into five (5) groups of six (6) rats each for the in-vivo anti-inflammatory assay. Group 1 normal; Group 2 was given 10 mg/kg body weight of Indomethacin and Groups 3, 4 and 5 were given 100, 200 and 400 mg/kg body weight of MERVL) respectively. Acute toxicity was carried out using standard method. Place and Duration of the Study: Department of Pharmacology Lab, Enugu State of University of Science and Technology Agbani Nigeria, between March 2021 and August 2021. Results: The percentage yield of the extract was 10.8%. The result of the quantitative and qualitative phytochemical screening of methanol extract of R. vomitoria leaves showed that Phenol (1590 ± 55.66) Flavonoid (1168 ± 11.43) and Tannin (1466 ± 40.73) were present in high concentration whereas, Alkaloid (549 ± 4.21) Glycoside (315 ± 61.38) and Terpenoid (162 ± 1.38) were present in moderate concentration. Saponin (1.16 ± 0.23) and Steroid (0.84 ± 0.03) were present in low concentrations. Acute toxicity tests showed no toxicity and mortality at doses up to 5000 mgkg-1. A significant (P < 0.05) reduction in the mean paw oedema was observed for all the treatment groups from 1 hour to 12 hours when compared to the normal group.  The result shown that groups treated with 100, 200 and 400 mg/kg b.w of extract inhibit the inflammation in a non-dose dependent manner with percentage mobilization of 5.7%, 14.1% and 6.2% respectively. Conclusion:  The study's results demonstrate that MERVL exhibits remarkable anti-inflammatory and anti-oxidant activities and the extract yielded a better reduction in edema and increases mobilization in leukocyte in response to agar suspension. It also demonstrates that MERVL has a modulatory effect on the vascular changes that accompany inflammation. The plant's anti-inflammatory properties could potentially result from the interaction of different photochemical substances present.  The findings suggest that, if used, the plant may serve as a source of anti-inflammatory agents.