Abstract

Aim: This study was designed to determine the proximate composition and mineral content of Costus afer leaf and stem, as well as to identify the most active antioxidant fraction.
Methods: The proximate composition and mineral analysis of C. afer leaf and stem were performed using the standard methods described by Pearson and Association of Official Analytical Chemist while the 1,1 diphenyl 2 picryl hydrazyl (DPPH), thiobarbituric acid reactive species (TBARS), lipid peroxidation (LPO) and total antioxidant capacity (TAC) assays were used to determine the in vitro antioxidant activity of aqueous, n-butanol, ethyl acetate and hexane fractions of C. afer leaf and stem.
Results: Proximate analysis revealed that the carbohydrate was highest in the leaf (55.83±3.71%) and stem (50.38±1.27%) while crude fat content was lowest in the leaf (1.83±0.43%) and stem (1.75±0.48%). The minerals detected in appreciable quantity in both the leaf and stem samples were calcium, magnesium, potassium, sodium, chromium, lead, manganese, nickel and copper. Further study showed that the aqueous leaf fraction exhibited a significantly (P

Key words: Costus afer; proximate; mineral; antioxidant; plant