Extraction and identification of an antioxidative component from peanut hulls

Abstract
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 thanα‐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 Rfs 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 and1H nuclear magnetic resonance (NMR), this compound was identified as luteolin.