Evaluation of the Analgesic Efficacy of Paracetamol in the Presence of Hibiscus sabdariffa Calyx Aqueous Extract in Rats

Abstract

The influence of various doses of the aqueous extract of Hibiscus sabdariffa calyx (AEHSC) on the efficacy of paracetamol when co-administered to rats experiencing formalin – induced pain has been examined. After appropriate treatments, each rat was monitored for pain sensation for a total period of 90 minutes. In the formalin only group of rats(group B; 250 l of 5% formalin in saline / kg bw) the pain lingered till the 90th minute. In the paracetamol (500 mg/ kg bw in dimethylsulphoxide orally by gavage) and formalin group (group C) the pain sensation abated by the 70th minute. At all the AEHSC treated groups (100,200,300,400, 500 and 600 mg/kg bw by gavage), groups D,E,F,G,H and I in which the extract was administered along with paracetamol and formalin, pain sensation ceased by the 70th minute as shown in group C rats. The most effective dose of the extract was 500 mg /kg bw in view of the steady drop in pain sensation till the 70th minute when it terminated. Evidently the analgesic efficacy of paracetamol was not lost in the presence of AEHSC.

Keywords: Analgesic efficacy, Formalin, Paracetamol, Hibiscus sabdariffa calyx, Rats