Analgesic and Antipyretic Activities of n-Butanol Alkaloids Extracted from the Stem Bark Hunteria Zeylanica and its Major Constituent, Strictosidinic Acid, in Mice.

The pharmacological activities of the n -butanol alkaloids extracted from the stem bark of Hunteria zeylanica (Retz) Gardn. ex Thw. ( H. zeylanica ) and its major constituent, strictosidinic acid, on nociceptive response using writhing and hot plate tests, the antipyretic activity in yeast-induced fever, pentobarbital-induced sleep, and locomotor activity were examined in mice. Oral administration of H. zeylanica extract at 200 mg/kg significantly decreased the number of contortions and stretchings induced by acetic acid but not heat-induced pain. Strictosidinic acid (5-20 mg/kg, p.o.) also produced a similar effect but less pronounced than the extract. The antipyretic effect of strictosidinic acid (5-20 mg/kg, p.o.) was stronger than that of the extract (100-200 mg/kg, p.o.). The H. zeylanica extract dose-dependently (50-200 mg/kg, p.o.) prolonged the duration of pen-tobarbital-induced sleep but had no sign ificant effect on locomotor activity. No effect of strictosidinic acid was noted on both pentobarbital-induced sleep and locomotor activity. These results suggest that the H. zeylanica extract possesses peripheral analgesic and mild antipyretic effects and its major constituent, strictosidinic acid, exerts a similar analgesic effect with marked antipyretic activity.