Evaluation of Anti-Inflammatory Activity of the Methanol Extracts of Premna schimperi Engl (Lamiaceae) Leaves in Rats

Background: Even though it is a protective reaction, inflammation continues to be one of the most challenging medical disorders. The current conventional anti-inflammatory drugs have many undesirable health effects and are in need of newer drugs. The purpose of this study was to evaluate the anti-inflammatory effects of an aqueous methanol crude extract of Premna schimperi leaves. Methods: Premna schimperi leaf was extracted with 80% methanol and concentrated; the concentrated extract was used to evaluate the acute toxicity and anti-inflammatory effects. For the acute toxicity study, a single dose of Premna schimperi extract at a dose of 2000 mg/kg was administered and observed for 14 days. Acute, sub-acute, and chronic anti-inflammatory models were employed to evaluate the anti-inflammatory effect of the extract compared to the standard drug. Data were analyzed with SPSS V. 27, and the significance was established with a one-way ANOVA followed by a post hoc Tukey’s test. Results: Acute oral toxicity testing at a dose of 2000 mg/kg did not show any sign of toxicity. According to the phytochemical study, the plants contained flavonoids, terpenoids, tannins, cardiac glycosides, steroids, phenolics, and anthraquinones. The extract doses of 200 mg/kg, 400 mg/kg, and 800 mg/kg of extracts effectively (p< 0.001) reduced paw edema in the acute and sub-acute models of inflammation. When compared to the negative control group, all tested doses in the chronic model significantly (p< 0.05) decreased the production of exudates and the amount of granuloma tissue. Conclusion: Premna schimperi displayed significant anti-inflammatory activity. The tested doses inhibit the formation of edema, granulomas, and exudates. Keywords: anti-inflammation, carrageenan, indomethacin, paw edema, Premna schimperi