In vitro antifilarial activity, antioxidant potential and phenolic constituents of Quisqualis indica L.

Quisqualis indica L., commonly known as 'Rangoon-ki-bel' or 'Madhumalti', has been used by the traditional healers as it is active against some of the commonly occurring diseases like boils, fevers diarrhea and helminthiasis. However, no systematic and scientifically validated studies on antifilarial activity of Q. indica are available. In the present study, we report in vitro antifilarial activity of ethanolic and hydroethanolic extracts of the leaves (QILE and QILEW) and flowers (QIFE and QIFEW) of this plant on microfilariae (mf) and female adult worms of human lymphatic filariid Brugia malayi using motility and or 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT)-reduction assays. The hydroalcoholic extract of flowers (QIFEW) was found effective as it killed adult female worms (LC100: 62.5 mu g/mL) and mf (LC100: 125 mu g/mL); IC50 values for the respective parasite stages were 34.50 and 31.88 mu g/mL. SI values recorded with respect to motility of female parasite and mf was more than 20. The active principle(s) responsible for antifilarial activity may thus be present in QIFEW. The antioxidant activity results also indicated QIFEW to possess better antioxidant potential than the other extracts studied. HPLC analysis showed that the 02 keyphenolics present in hydroalcoholic extract of the flowers (QIFEW) were gallic acid and ellagic acid. In the different extracts, the concentration of gallic acid was found to vary from 26.9 mg/g to 2.50 mg/g while ellagic acid ranged between 11.5 mg/g to 6.77 mg/g. It was also observed that the leaves were rich in flavonoids whereas the flowers were rich in phenolics. The findings indicate that active molecule (s) of hydroalcoholic extractfrom Q. indica flowers may help in providing new leads for developing antifilarial agents. We believe that this is the first systematically studied report on the in vitro antifilarial activity of the hydroalcoholic extract of Q. indica flowers.