Anti-inflammatory, antipyretic, and analgesic effects of Lawsonia inermis L. (henna) in rats

Crude ethanolic extract of Lawsonia inermis L. (0.25-2.0 g/kg) produced significant and dose-dependent anti-inflammatory, analgesic, and antipyretic effects in rats. The extract also produced significant increases in pentobarbitone-induced sleeping time. Using a liquid-liquid extraction procedure, the extract was fractionated into chloroform, butanol, and water fractions, and these were tested for the above activities. The butanol and chloroform fractions showed more potent antiinflammatory, analgesic, and antipyretic effects than the crude extracts, while the aqueous extract showed significantly less effect. As compared with the other extracts, the butanolic extract (500 mg/kg) was the most effective in the analgesic test. From the chloroform extract, a pure compound was isolated and identified, using chromatographic and spectroscopic techniques, as 2-hydroxy-1,4-naphthaquinone (lawsone). The isolated compound was found to possess significant antiinflammatory, analgesic, and antipyretic activity. It potentiated significantly the pentobarbitone-induced sleeping time. The anti-inflammatory effect of lawsone (500 mg/kg) was not significantly different from that of the reference drug phenylbutazone (100 mg/kg).