Anti-inflammatory and analgesic activities of Clerodendrum capitatum (Willd) Schum. & Thonn. (Verbenaceae) leaves

Abstract

Clerodendrum capitatum (Willd) Schumach and Thonn. (Verbenaceae) is a perennial herb, which grows up to 0.5 m to 2 m high. It is widespread over North-East, East, and South Central Africa. It is known as “bambaro or maashayi” by the Hausas of Northern Nigeria. The leaves are used traditionally to treat intercostal pain, headaches and toothaches. The aim of this study is to evaluate the anti-inflammatory and analgesic activities of the aqueous ethanol extract and fractions of C. capitatum. The anti-inflammatory activity was investigated using carrageenan induced rat paw oedema model, while acetic acid induced mice writhing model was used to evaluate the anti-nociceptive property. The oral median lethal dose values were found to be greater than 5,000 mg/kg for the aqueous ethanol extract, ethyl acetate and n-butanol fractions, while that of dichloromethane fraction was less than 2000 mg/kg using OECD method. The acetic acid induced writhing was significantly (P<0.05-0.001) reduced particularly for the EF and NF fractions at 200 mg/kg (93.12% and 98.79%). DF showed percentage inhibition of 87.59% and 81.75% at 50 and 100 mg/kg respectively. The extracts and fractions also caused a significant (P<0.05-0.001) dose dependent reduction of inflammation induced by carrageenan when compared with the negative control with the maximum inhibitory effect of 43.69% observed in Ethyl acetate fraction at 50 mg/kg dose at the 3rd hour. It can be concluded that the leaf extracts of C. capitatum possess anti-inflammatory and analgesic effects in animal models, which may be mediated through the phytochemical constituents present in the extract and fractions of the plant.

Keywords: Clerodendrum capitatum; Anti-inflammatory; Analgesic; OECD