Analgesic and Antipyretic Activities of Gindarudine, a Morphine Alkaloid from Stephania glabra

Gindarudine (GN), a morphine alkaloid isolated from the tubers of Stephania glabra (Menispermaceae), was evaluated for analgesic and antipyretic activities because of closely resembling structure to that of thebaine. The analgesic activity of GN was evaluated on albino mice by hot plate and tail immersion methods whereas antipyretic activity was studied on Brewer's yeast-induced pyrexia rats. Fever was induced by injecting 20 ml/kg (s.c.) of 20% aqueous suspension of Brewer's yeast in normal saline and rectal temperature was recorded by clinical thermometer immediately before (-18 h) and 18 h after (0 h) yeast administration. GN at doses of 100 and 150 mg/kg, p.o. showed significant analgesic activity (p<0.05) by increasing the threshold potential of pain whereas doses of 200 and 300 mg/kg exhibited significant (p<0.05) antipyretic effect by decreasing the rectal temperature of rats in 1st, 3rd and 5th h after treatment. Aspirin (300 mg/kg, p.o.) and paracetamol (200 mg/kg, p.o.) were used as standard drugs for analgesic and antipyretic activities respectively. These findings demonstrate that GN have remarkable analgesic and anti-pyretic activities when compared with positive control and thus have great potential as a source for natural health products.