EXTRACTION AND IDENTIFICATION OF AN ANTIOXIDATIVE COMPONENT FROM PEANUT HULLS

Methanol extraction of hulls from Tainan select no. 9 (P-9) and Tainan no. 11 (P-11) peanuts produced a higher yield of a component having stronger antioxidant activity (AOA) than other organic solvents. The AOA of methanolic extracts from peanut hulls was equal to butylated hydroxyanisole and stronger than alpha-tocopherol. The methanolic extract from peanut (P-11) hulls was separated into 18 fractions by thin-layer chromatography (TLC). High antioxidant activity was found in subfractions with R(f)s of 0.20, 0.25, 0.28, 0.31 and 0.37 at 95.6%, 93.8%, 94.7%, 92.0% and 81.6% inhibition of peroxidation of linoleic acid, respectively. Further purification of the subfraction eluting at 0.20 yielded a compound with antioxidant activity of 94.8%. Based on high-performance liquid chromatography (HPLC) analysis, ultraviolet (UV) spectra and H-1 nuclear magnetic resonance (NMR), this compound was identified as luteolin.