Abstract:
In this study, the antioxidant property of Irvingia gabonesis seed and its effect on the serum lipids of albino rats were evaluated. Phytochemical screening and proximate composition analysis of I. gabonensis seed were carried out. Iron chelating, total antioxidant, 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide, 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and hydroxyl radical scavenging activities of I. gabonensis seed aqueous extract were equally investigated. I. gabonensis seed oil was extracted by soxhlet extraction and characterized by GC-MS. For the in vivo study, sixteen albino rats were divided into four groups, each group containing four animals, and fed with different diets for seven weeks. Group A (control) was fed standard diet while groups B, C and D were fed formulated diets containing 50% (w/w), 20% (w/w) and 10% (w/w) I. gabonensis seed respectively. At the end of the feeding period, the animals were fasted for 12 hours before sacrifice. Serum was obtained and used for lipid profile analysis. Cardiac lipid was extracted and analyzed by GC-MS to identify the fatty acid composition. Results showed that fat is the most abundant component of I. gabonensis seed (50.70%). The phytochemical screening revealed the presence of tannins, saponins, alkaloids, flavonoids, cardiac glycosides, steroids and terpenoids. The aqueous seed extract of I. gabonensis exhibited potent and appreciable antioxidant and free radical scavenging activities. Total antioxidant activity, iron chelating activity, and 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and hydroxyl radical scavenging activities at 400 μg/ml were 38.33 μg/g Ascorbic acid equivalent, 86.51%, 30.20%, 42.45 μmol/g Trolox equivalent and 60.80% respectively. There was a decrease in serum total cholesterol, triglyceride and LDL – cholesterol concentrations in the groups fed 50% Irvingia gabonensis seed compared with the control (P < 0.05). This was accompanied by a significant (P < 0.05) increase in HDL-
cholesterol concentration compared with the control. GC-MS analysis revealed the presence of palmitic, stearic and oleic acids in both the extracted seed and cardiac lipids. The study showed that increasing amount of dietary I. gabonensis fat modulated lipid metabolism by increasing the concentrations of HDL-cholesterol.
