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.