In Vitro and In Vivo Biochemical Evaluations of the Methanolic Leaf Extract of Garcinia kola.

Garcinia kola Heckel (Guttiferae) leaves have received limited scientific attention despite their traditionally acclaimed medicinal properties. The scavenging ability of the methanolic leaf extract (MLE) of G. kola was assayed for hydroxyl radical (OH(•)), superoxide anion (O2 (-)), 1,1-diphenyl-2-picrylhydrazyl (DPPH), azinobis-3-ethyl-benzothiazoline-6-sulfonic acid (ABTS(•+)), and lipid peroxidation (LP) activity in egg yolk, rat liver, and brain homogenates. Total phenolic and flavonoid contents of the extract were also evaluated. Group I animals were given oral doses of water, whereas Group II and Group III animals received 100 and 200 mg/kg body weight (bw) MLE, respectively, for 14 days. Plasma glucose, magnesium, γ-glutamyltransferase (GGT/γGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine, and urea were evaluated. Hepatic reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), LP, and liver histopathological appearance were also assessed. The extract scavenged OH(•), O2 (-), DPPH, and ABTS(•+) and inhibited LP in egg yolk, rat liver, and brain homogenates. Furthermore, oral administration of the extract showed no adverse effects on hepatic and renal function tests. Increased hepatic GSH and nonsignificant changes in LP, GPx and SOD activities, and liver histology were observed. These results suggest that G. kola leaves have antioxidant activities which may have application in traditional medicine.