Isolation of Phytoconstituents and Evaluation of Anti-inflammatory Activity of the Leaves of Abelmoschus manihot

The present study was carried out to isolate the phytoconstituents and evaluate the anti-inflammatory activity of the petroleum ether and methanol extract of Abelmoschus manihot (Malvaceae) leaves using paw edema model. The air-dried, powdered laeves (1 Kg) were extracted over Soxhlet with petroleum ether and methanol. Two steryl alcohol, named 1-dodecanol (1) and 1-tridecanol (2) from petroleum ether exctract, together with a known acid ester, 1-tridecanoic acid methyl ester (3) from methanol extract, were isolated from Abelmoschus manihot. Their structures were elucidated by spectroscopic methods. The crude dried petroleum ether (10 g) and methanol (25 g) extracts was prepared at doses of 100, 200 and 400 mg/kg, and evaluated for anti-inflammatory using the carrageenan and histamine-induced paw edema test. The results obtained indicate that the extracts possessed significant (p < 0.01) anti-inflammatory activity, which was found to be dose-dependent. This study showed that the petroleum ether and methanol extracts of Abelmoschus manihot woody stems possess potential pharmacological active constituents responsible for inhibition of the inflammation effect.

Key words: Abelmoschus manihot, Steryl alcohol, Acid methyl ester, Anti-inflammatory activity.