Anti-inflammatory and analgesic effects of methanol extract and fractions of Acalypha wilkesiana leaves.

BACKGROUND

This study was carried out to evaluate the anti-inflammatory and the analgesic potentials of Acalypha wilkesiana leaf extract in experimental animals.

METHODS

The anti-inflammatory potential was investigated using an acute rat model. Aspirin at 150 mg/kg, indomethacin at 10 mg/kg as positive control, and methanolic extracts and solvent fractions of A. wilkesiana at doses of 400 and 200 mg/kg, respectively, were administered orally to rats and compared with a negative control group given 10 mL/kg Tween 80. At an A. wilkesiana dose of 400 mg/kg body weight, the analgesic effect was also studied using the hot plate method and the acetic acid-induced writhing model in mice.

RESULTS

Percentage inhibition of the paw volume was highest in rats administered indomethacin (85.7%) followed by the group administered methanolic extract of A. wilkesiana (74.1%), whereas the group given aspirin had 65.5% inhibition of edema and the group given a 200 mg/kg dose of chloroform fraction of A. wilkesiana had 93% inhibition of increase in paw volume, a value higher than the performance of the standard drugs indomethacin (85%) and aspirin (68%). Also, the extract caused an increase in the reaction time in the hot plate test and in the acetic acid test. The mean number of writhings was significantly reduced in the group of mice administered 400 mg/kg extract of A. wilkesiana leaves (25.8±1.3) when compared with the control (46.7±1.4) but higher than the group of mice administered the standard analgesic agent paracetamol (23.5±1.3).

CONCLUSIONS

This study suggested that A. wilkesiana leaves have anti-inflammatory and analgesic potential comparable with those of standard drugs.