Analgesic activity of poly herbal formulation in experimental rats by acetic acid induced writhing test model and Hot plate model

To evaluate analgesic activity of a polyherbal formulation-PHF [hydro-alcoholic extract of Hibiscus rosa-sinensis (50mg), Fennel seeds (50mg), Prosopis cineraria (50mg), & Ficus racemosa (50mg)] compare it with Diclofenac Na by using Eddys hot plate and writhing test in Adult Wistar rats. Rats were divided into four groups of 6 each for both tests. PHF (250, 300 mg/kg, p.o. body weight) and Diclofenac Na (50 mg/kg, p.o.) made as suspensions prepared in 1% carboxy methyl cellulose (control) and were fed to rats orally. The physicochemical evaluations carried out in terms of loss on drying, ash value, extractive values and acid insoluble ash value ect. Qualitative analysis of various phytochemical constituents was determined by the well-known test protocol available in the literature. Phytochemical analysis revealed the presence of phenols, flavonoids, tannins, saponins, alkaloids.  Analgesic activity was assessed by counting the number of writhes induced by 0.7% acetic acid (10 ml/kg) in the 30 min. Number of writhing and percentage protection against writhing was evaluated. In Eddys hot plate method, they were placed individually on hot plate maintained at a temperature of 55 ± 0.5 ºC. The latency to lick the paw (reaction time) was noted at 0, 30, 60, 90 and 120 min. The cut off time was set at 20 sec to avoid damage to the skin. In acetic acid writhing method, PHF (250, 300 mg/kg, p. o.) significantly (p < 0.001) decreased the number of writhing 39±1.55*, 29.0±0.43*resp. Maximum percentage of inhibition of writhing response shown by Diclofenac Na was 73.03 %. In hot plate method, PHF showed a significant increase in the elevated basal reaction time at 30, 60, 90 and 120 min. The results indicated that the poly-herbal formulation possesses good analgesic activity in the experimental animal models. Keyword: Analgesic activity, Physicochemical evaluations, Phytochemical analysis, Hibiscus rosa-sinensis Fennel seeds, Prosopis cineraria, Ficus racemos