Antinociceptive activity and acute toxicity study of Flaveria trinervia whole plant extracts using mice.

The antinociceptive activity of Flaveria trinervia extracts by tail-flicking and writhing methods was evaluated using mice. The abdominal writhing method was carried out by administering petroleum ether, chloroform and methanol extracts orally. After 1 h of incubation, 0.6% acetic acid (10 mL kg(-1)) was administered intraperitoneally. After 5 min, each group of mice was observed for the amount of writhing for a duration of 20 min. Acetyl salicylic acid was used as the standard reference. The tail-flick method was carried out using a thermal model and the maximum possible analgesia was calculated. The LD50 values of petroleum ether, chloroform and methanol extracts were 700, 700 and 500 mg kg⁻¹, respectively. The methanol extract at 50 mg kg⁻¹ showed significant antinociceptive activity. The petroleum ether and chloroform extracts showed moderate antinociceptive activity at a dose of 70 mg kg⁻¹. The methanol extract showed more significant antinociceptive activity than the other extracts but was less effective than the standard. This investigation finds support for the ethnomedicinal claims of F. trinervia.

Analgesic activity and acute toxicity study of Semecarpus anacardium stem bark extracts using mice.

BACKGROUND: The analgesic activity of petroleum ether, chloroform and methanol extracts of Semecarpus anacardium was investigated by tail flicking and writhing method using acetyl salicylic acid as the standard reference. MATERIALS AND METHODS: The staircase method was adopted for the determination of the acute toxicity. LD(50) of the petroleum ether extract and the chloroform extract was 700 mg/kg; however, the LD(50) for the methanol extract was 500 mg/kg. After 1 h of oral administration of the extracts, 0.6% acetic acid was administered intraperitoneally and the analgesic activity was evaluated. RESULTS: The number of writhing observed in the control group was 73.33 writhes. The methanol extract showed a significant analgesic activity, with 28.33 writhes, than the petroleum ether extract and the chloroform extract. But, all the extracts showed proved to be less potent than the standard drug which showed 2.33 writhes. Animals pretreated with saline did not show a signify cant effect on the latent period of tail-flick response. The analgesic effect of the petroleum ether extract was comparatively less evident. The maximum possible analgesia (MPA) increased up to 9.1% which remained elevated above the basal levels throughout the observation period. The MPA calculated for the chloroform extract increased to 14.03%. However, the analgesic effect of the methanol extract was also observed at 0.5 h following oral administration and the effect remained significant throughout the 3 h observation period, and was increased to 20.43%. CONCLUSION: Consistent analgesic activity of all the three S. anacardium extracts was observed by both the methods. The methanol extract was more potent than the petroleum ether and chloroform extracts but was less effective than the standard drug. This investigation supported the ethnomedicinal claims of S. anacardium.