Comparative anti-inflammatory properties of Capsaicin and ethylaAcetate extract of Capsicum frutescens linn [Solanaceae] in rats

AT Jolayemi, JAO Ojewole

Abstract

Background: The analgesic effect of capsaicin (the active ingredient in Capsicum frutescens Linn. [Solanaceae]) had been reported in several studies. Current research is being directed at producing analgesics, anti-inflammatory agents with better side effect profile.

Objectives: To investigate if either the ethyl acetate extract of Capsicum frutescens Linn. [Solanaceae] (CFE) or capsaicin (Fluka Biotechnika-CPF) (in addition to the known analgesic properties) has any anti-inflammatory effect comparable to nonsteroidal anti-inflammatory analgesics (NSAIDS).

Methods: The effects of ethyl acetate extract of Capsicum frutescens Linn. [Solanaceae] (CFE) and capsaicin (Fluka Biotechnika-CPF) was examined on rat hind paw. Inflammation was induced in the rat’s hind paw by  subplantar injections of fresh egg albumin (0.5 ml/kg). Diclofenac (100 mg/kg) was used as the reference anti-inflammatory agent for  comparison, while distilled water was used as the placebo. The leucocytes count, corticosterone and C – reactive protein (CRP) levels were measured as biomarkers of inflammation. Data obtained were pooled and analysed using repeated ANOVA, in a general linear model with the CPSS software.

Results: Sub-plantar injections of fresh egg albumin (0.5 ml/kg) produced profound and time-related oedema in the rat hind paw of the ‘control’ rats. Diclofenac (DIC, 100 mg/kg, i.p.) and reference capsaicin (CPF, 2.5 mg/kg, i.p.) significantly inhibited paw swelling at (p<0.05–0.001) (CI 95%) compared to distilled water-treated ‘controls’. While the  corticosterone levels were all very low in 7 rats treated with capsaicin, the leucocytes count was within normal range in 9 rats. However, in 16 specimens randomly assigned for CRP levels, there were very high CRP readings, up to a magnitude of 10 times the normal range.

Conclusion: Capsaicin in both forms (CFE and CPF) produced  anti-inflammatory effects that were comparable to diclofenac in the experimental rat model at p<0.05. It may be concluded that capsaicin has both analgesic and anti-inflammatory properties.

Keywords: Capsicum frutescens,‘chili’, ethylacetate extract, capsaicin, anti-inflammat