Optimization of polyphenols extraction from Moringa oleifera Lam. seeds by response surface methodology and its antioxidant activity

The objective of this study is to determine the optimum extraction conditions of polyphenols from Moringa oleifera Lam. seeds and preliminarily evaluate their antioxidant activities. The optimum extraction conditions of polyphenols from Moringa oleifera Lam. seeds were investigated by response surface methodology. With the extraction of polyphenols as the target,the single factor test was carried out on the alcohol concentration,extraction temperature,extraction time and solid/liquid radio. Based on Box-Behnken and Design-Expert V8.0.6,four-factor three-level response surface methodology was carried out,and the phytochemicals in the extract of Moringa oleifera Lam. seeds were measured and their antioxidant activities in vitro were also determined. The results suggested that the regression model was very significant(p<0.0001),which could be used for the analysis and prediction of the polyphenol content of Moringa oleifera Lam. seeds. The optimal extraction conditions were as follows:66.78% ethanol as extraction solvent,an extraction temperature of 75.9℃,a solid/liquid radio of 1:12 (g/mL)and an extraction time of 1.24 h. Under these optimized conditions,the extraction yield of polyphenols was 4.134 mg/g,and the measured value was(4.125±0.017) mg/g,which was not significantly from the predicted value. The extract of Moringa oleifera Lam. seeds showed antioxidant activity in vitro. The total antioxidant activity,DPPH·free radical and ABTS⁺·free radical scavenging ability,and FRAP reducing force were separately(43.52±8.47),(0.571±0.017),(1.413±0.032)and(0.731±0.040) mg TEs/g extract. This optimization process is feasible,the polyphenols from Moringa oleifera Lam. seeds have a certain antioxidant activities.