Cytotoxic, membrane stabilizing and anti-arthritic effects of methanol extract of Ocimum gratissimum Linn. leaf.

Abstract

Ocimum gratissimum Linn. leaves have been shown to be useful in arthritis as well as related inflammatory oxidative conditions. The study investigated the cytotoxicity, membrane stabilizing and anti-arthritic effects of sequential methanol extract of the leaves. Methods: Powdered leaves were sequentially extracted with n-hexane, chloroform and methanol to obtain a resultant methanol extract (MEOg). The extract was tested for cytotoxicity using Chinese harmster ovary cell (CHO-kl) and murine macrophages (RAW 264.7) cell lines. Membrane stabilizing effect was tested by heat-induced erythrocytes haemolysis assay. Antiarthritic properties were tested by egg-albumin, formalin induced inflammation and carrageenan/kaolin induced monoarthritis models in rats. Thereafter, biomarkers of oxidative stress were evaluated using standard biochemical assays. Results: The extract did not reduce viability of CHOkl and RAW 264.7 cells. MEOg showed significant (p< 0.05) membrane stabilizing properties. MEOg at 100, 200, and 400 mg/kg dose-dependently reduced egg albumin-induced paw oedema by 24.0, 32.2, and 37.8%, respectively. Similarly, MEOg significantly {p < 0.05) decreased paw thickness compared to control in formalin-induced arthritis in rats. Furthermore, MEOg dose-dependently showed anti-inflammatory activity which was evident with decrease in paw and knee swelling, and decreased inflammatory pain in carrageenan/kaolin-induced monoarthritis in rats. The treatment decreased plasma TBARS and NO, and increased GSH and SOD levels. Conclusion: These findings support the ethno-pharmaeological use of Ocimum gratissimum leaves for ameliorating inflammation and pain of arthritis.