Evaluation of antiinflammatory, antipyretic and analgesic properties of vitex simplicifolia leaf

Abstract

Natural products are sources of bioactive compounds and have potential for developing some novel therapeutic agent, due to their enormous chemical diversity. These diverse natural products form the basis of many traditional medicine systems throughout the world, due to their accessibility, efficacy and minimal side effects. The present study evaluated the antiinflammatory, antipyretic and analgesic properties of Vitex simplicifolia leaf. The extraction of 464.67 g of Vitex simplicifolia leaves gave an exact yield of 82.26 g and percentage yield of 17.7% using 99.5% ethanol. Subsequent partitioning using 60 g of the crude ethanol extract gave percentage yields of 4.47% for n-hexane, 2.77% for ethylacetate and 9.93% for 10% ethanol. The phytochemical composition of crude extract of Vitex simplicifolia included tannins, cardiac glycosides, anthraquinones, hydrogen cyanides, terpenoids, steroids, phenols, alkaloids, flavonoids and saponins. The acute toxicity study of the extract showed that the leaf extract was safe even at the higest dose of 5000 mg/kg body weight. The 10% ethanol fraction (100 mg/kg and 200 mg/kg b.w.) significantly (p < 0.05) inhibited the paw oedema formation induced by egg albumin at the earlier stage of inflammation (0.5 – 2 h), but the inhibition was non significant (p < 0.05) for later stages of inflammation (3 – 5 hr) when compared to that of the control. The rats treated with 400 mg/kg b.w. significantly (p < 0.05) inhibited paw oedema at 0.5hr, but the inhibition was non significant (p < 0.05) from 1hr -5hr when compared to that of the control. All the doses of the 10% ethanol fraction of the extract produced a dose and time dependent inhibition of paw oedema when compared with the control. The standard anti-inflammatory drug diclofenac sodium (10 mg/kg b. w.) had a similar trend. Similarly, varying doses of 10% ethanol fraction of the extract (0.1 mg/ml – 0.5 mg/ml) significantly (p < 0.05) inhibited phospholipase A2 activity in a concentration-related manner when compared to the control. The extract had higher inhibition percentage when compared to prednisolone of same concentration. The 10% ethanol fraction (100 - 400 mg/kg b. w.) significantly inhibited nociceptive response in dose dependent manner. The highest analgesic activity (71.84%) was obtained with extract dose of 400 mg/kg b.w., while that of the standard drug diclofenac sodium (10 mg/kg b. w.) was 38.83%. The 10% ethanol fraction of the extract (0.1 mg/ml – 0.25 mg/ml) significantly (p < 0.05) inhibited hypotonicity-induced haemolysis of human red blood cell more than indomethacin a standard, anti-inflammatory drug. The n-hexane fraction (100, 200 and 400 mg/kg b. w.) significantly (p < 0.05) inhibited yeast-induced pyrexia in rats in both dose and time dependent manner when compared to that of the control. The results of the study show that 10% ethanol fraction of the extract inhibited significantly (p < 0.05) inflammatory activity induced by egg albumin as well as nociceptive response induced by acetic acid when compared with the control. From the results, it could be inferred that the n-hexane fraction of the extract inhibited yeast-induced pyrexia. The results suggest that the inhibition of phospholipase A2 is one of the mechanisms of the anti-inflammatory effect of the plant. The investigation provides empirical evidence for the use of Vitex simplicifolia leaf extract in folkloric treatment of inflammatory, analgesic and pyretic disorders.