Extraction optimization of luteolin, antioxidant compound, from Arachis hypogaea L. Hull using response surface methodology

Abstract

Luteolin is the most abundant phytochemical phenolic compound contained within peanut hulls and has broad pharmacological characteristics and high bioavailability. In this study, the extraction conditions for luteolin from peanut hulls were optimized. The effects of methanol concentration and reaction temperature on luteolin solubility were determined using the central composite design (CCD) under response surface methodology. Luteolin content within in the extracts increased with increasing temperature and organic solvent-to-water ratios. The optimal conditions for luteolin extraction were 81℃ and 87.5% methanol for a predicted extraction value of 174.51 mg/100 g, which was within 1.25% of the experimental value of 172.35 mg/100 g, confirming the predicted model. Additionally, compared to conventional stirring, the luteolin content of reflux-extracted peanut hull had a higher extraction efficiency by 42.50%. The antioxidant compound contents and antioxidant capacity of the extracts were also determined, with the effects of temperature and solvent concentration increasing along with the extracted luteolin. In this study, CCD optimized the conditions for obtaining luteolin from peanut hulls, suggesting that the improved extraction efficiency of the bioactive compound can expand the use of peanut shells in the nutraceutical and food industries.