Anti-inflammatory activity of the fruit extracts of Carpolobia lutea G. DON (Polygalaceae)

Background: Carpolobia lutea G. Don (Polygalaceae) fruits are used traditionally in treating fever, infections and inflammatory conditions.

Objectives: The study sought to evaluate the phytochemical constituents and anti-inflammatory potentials of the fruit extracts of C. lutea.

Methods: Successive extraction was done with methanol (CLFME), n-hexane (CLFn-HE), chloroform (CLFCHE), and ethylacetate (CLFETE). Anti-inflammatory activity was evaluated in vivo using carrageenan-induced paw oedema and xylene-induced ear oedema models. The phytochemical constituents were identified using gaschromatography (GC) and liquid chromatography - mass spectrometry (LC-MS).

Results: CLFME (200 mg/kg) significantly (P< 0.05) inhibited carrageenan-induced paw oedema (83.66%) and xylene induced ear oedema (89.85%). CLFn-HE, CLFCHE, and CLFETE (200 mg/kg) significantly reduced carrageenan-induced paw oedema with percentage inhibitions of 60.00, 70.00 and 65.00%, respectively. Moreover, CLFn-HE, CLFCHE, and CLFETE (200 mg/kg), reduced xylene-induced ear oedema by 69.14, 71.60, and 69.14%, respectively. Gas chromatography coupled to mass spectroscopic (GC–MS) analysis of CLFn-HE afforded oleic acid, squalene, cis-vaccenic acid, n-hexadecanoic acid, 9-octadecenoic acid (Z) methyl ester, cis- 13-octadecenoic acid and nonacosane. CLFCHE was subjected to column chromatography, fraction-31 showed a single spot using Thin layer chromatography (TLC) (n-hexane:ethylacetate, 5:5) with an Rf value of 0.70. Liquid chromatography coupled to mass spectroscopic (LC-MS) analysis of fraction-31 afforded four peaks with retention times of 0.058, 1.161, 1.572 and 3.080 min, with similar abundant ions (Base peak) of 81.1 and molecular ion (M+) of 208.2 indicating the presence of isomeric compounds.

Conclusion: The fruit extract of C. lutea possess anti-inflammatory effects which may be mediated through inhibition or release of inflammatory mediators. Thus, C. lutea fruit extract could be a potential phytotherapeutic agent in the management of inflammatory disorders.