ABSTRACT

This study evaluated the inivo analgesic and in'itro antioxidant activities of methanol extaci of Anacardium occidentalis leaf, healthy wistar albino rats weighing 80-1 00g was used to determine the analgesic activity of Anacardiuin occidental/s. Following the analgesic study, twenty (20) female wistar albino rats were grouped into five (5) and each group consists of four rats. Group I (control): received normal saline and feed, Group II (standard): received 0.0lml/kg body weight of morphine, Group III, IV and V received 250mg/kg, 500mg/kg. 750mg/kg body weight of the plant extract respectively. Two methods were used to determine ihe in vivo analgesic activity: acetic acid induced writhing and tail flick methods. Comparison was made between control and the different concentrations of the extract which includes 250mg/kg, 500mg/kg and 750mg/kg, the values are represented as mean + S.E.M and showed an increase in latency in a dose dependent manner. The extract significantly (p<O.05) reduced the number of writhing and the highest analgesic effect was seen in 750mg/kg extract which inhibited by 83.3 0% but less inhibition was observed in 250mg/kg by 44.40%. Analgesia was shown in the inhibition of nociception induced by tail immersion in 55°C hot water. The extract prolonged the latency of tail withdrawal to a similar degree as morphine with the highest reached at 90 minutes in 750mg/kg by (5.35±0.15). The antioxidant activity was assessed using various in vitro systems such as DPPI-1 scavenging activity, anti-lipid peroxidation activity and nitric oxide scavenging activity. The result revealed that methanol leave extract of Anacardiuni occidental/s exerted antioxidant activity in a concentration dependent manner, it scavenged DPPH radical by ( 83.72 ± l.08)%, Nitric oxide radical by ( 87.40+0.44 )% and lipid peroxidation by ( 88.65J0.67)% at a concentration of 500mg/mI which is the maximum concentration and shows signiflcant (p<O.05) different when compared with the contol group. The result clearly indicates thai the methanol leaf extract of Anacardiuin occidentalis exhibit analgesic activity and also shows that the extract has the potential to scavenge free radicals.