Evaluation of antinociceptive and anti-inflammatory activities of extract and fractions of Eugenia jambolana root bark and isolation of phytoconstituents

Eugenia jambolana Lam., Myrtaceae, is a widely distributed and traditionally well known plant in India. The root bark of the plant was extracted with ethanol and then successively fractionated into petroleum ether fraction, chloroform fraction, n-butanol fraction and methanol fraction. The extract and fractions of the plant material were evaluated for the antinociceptive activity by acetic acid-induced writhing test and formalin-induced nociception test, and anti-inflammatory activity was screened by carrageenan-induced rat paw edema, cotton pellet induced granuloma formation and adjuvant induced arthritis in rat models. The test materials showed the antinociceptive and anti-inflammatory effect in dose dependent manner and the petroleum ether fraction was found to be most potent among the test materials. At 400 mg/kg b.w., p.o. dose petroleum ether fraction significantly inhibited 54.28% writhing response and 73.77% formalin induced nociception in mice. The fraction with same dose showed significant 79.31% inhibition of carrageenan-induced rat paw edema, 57.78% anti-proliferative effect and 77.93% inhibition of adjuvant induced arthritis. The bioactive petroleum ether fraction was then subjected to column chromatography which led to isolate three compounds, namely, beta-sitosterol, stigmasterol and lupeol. These compounds were characterized and identified by IR, H-1 NMR, C-13 NMR and mass spectroscopy.