Analgesic activity of flavonoids isolated from Persicaria glabra (wild)

Abstract

The present experimental study conducted to determine the four flavonoids (1–4) isolated from extracts of Persicaria glabra (Polygonaceae) and was tested for its potential central and peripheral analgesic activity. All animals were lowered on a hot plate (55 ± 0.5 °C), the observations were made before and after administration of respective drugs at 30, 60, and at the end of 90 min. In writhing method, acetic acid is administered intraperitoneal to the experimental animals to create pain sensation. The writhing movements were observed and counted for 30 min after acetic acid administration. The results showed that the compound quercetin (1) and its glycosides (3) at a dose of 100 and 200 mg/kg body weight significant analgesic activity (P < 0.05) in both central and peripheral models of analgesia used. The same doses, compounds 2 and 4 did not show any analgesic effects. Among them, quercetin (1) was the most potent in both models tested. Also due to structural difference of four compounds, a number of hydroxyl groups, substitution of –OCH3 and glycosylation, they will exhibit different analgesic responses. The P. glabra leaf extracts containing mixture of quercetin, isorhamnetin and their glycosides were effective in both the central and peripheral models of pain.