Antinociceptive, antipyretic and anti-inflammatory effects of the ethanolic extract of ficus racemosa root

Abstract

Ficus racemosa Linn. Is known locally in Thailand as ‘Ma-Due-Au-Thum-Porn’. In these studies, we initially determined the antinociceptive property of a range of the ethanolic extract of F. racemosa root (EFR) doses in the mouse tail-flick test. Tail-flick latencies were determined in male ICR mice prior to the i.p. administration of 0.9% normal saline solution (NSS; 10 ml/kg), morphine (MO; 10 mg/kg), 2% tween 80 (10 ml/kg) or various doses of EFR (50-400 mg/kg). Tail-flick latencies were subsequently determined at 15, 30, 45, 60, 90, 120 and 240 min. The percent maximum possible effect (%MPE) was calculated and used in the determination of the area of analgesia (%MPE-min). EFR at doses of 200 and 400 mg/kg produced a significant analgesic response. In the acetic acid-induced writhing in mice, the animals were induced with i.p. injection of 0.6% acetic acid (10 ml/kg) 30 min after the i.p. administration of NSS, indomethacin (IND; 10 mg/kg), 2% tween 80 or various doses of EFR (50-400 mg/kg) and the mean writhing response was determined for 30 min. All doses of EFR tested significantly (p<0.01) decreased the mean writhing response compared to vehicle controls. Studies then determined the antipyretic property of orally administered EFR using LPS-induced fever model in rats. The animals were induced with intramuscular injection of LPS (50 µg/kg) 1 hr after oral administration of 2% tween 80, acetylsalicylic acid (ASA; 300 mg/kg) or various doses of EFR (50-800 mg/kg). Rectal temperature was measured before the pretreatment and at 1 hr interval for 7 hr after LPS injection. All doses of EFR significantly (p<0.001) reduced the increased rectal temperature produced by LPS and were found to be as potent as ASA. In the Brewer’s yeast-induced pyrexia model, eighteen hours after s.c. injection of 20% brewer’s yeast (10 ml/kg) rats were orally administered with 2% tween 80, ASA or various doses of EFR (50-400 mg/kg). Rectal temperature was measured 1-7 hr after the extract administration. All doses of EFR significantly (p<0.05) reduced the pyrexia induced by yeast and EFR doses of 200 and 400 mg/kg appeared to be equally potent as ASA. The anti-inflammatory property of the EFR was then determined using carrageenan-induced paw edema test. Rats were pretreated with i.p. administration of NSS, IND, 2% tween 80 or various doses of EFR (50-800 mg/kg) before inducing inflammatory response with s.c. injection of 1% carrageenan (0.1 ml) into the plantar surface of the right hind paws. The paw volume was measured at 1-6 hr after carrageenan injection. All doses of EFR tested significantly reduced paw volume during the second phase of edema. Taken together these results demonstrated that EFR possesses both central and peripheral analgesic activities. The mechanism of antipyretic and anti-inflammatory effects of EFR may involve in the inhibition of prostaglandin synthesis.