Microwave-assisted extraction was employed to extract polyphenols from the leaf of Magnolia kwangsiensis Figlar & Noot. The yield of polyphenols was 2.44±0.02 % under the optimal conditions of RSM: acetone concentration of 70 %, ratio of solvent to material of 21 mL⋅g-1 and extraction time of 16 min. The antioxidant activities were evaluated in terms of total antioxidant ability, reducing power, DPPH⋅ and ⋅ OH scavenging activity. Results showed the polyphenols presented potential antioxidant activities, especially the stronger scavenging activity on ⋅ OH. In term of ⋅ OH scavenging activity, the IC50 value of NKA-9 purification was 0.335 mg mL-1 , equivalent to 35.23 % of VC . The IC50 values of crude extract and ethyl acetate extract were 0.580 and 0.828 mg mL-1 , equivalent to 60.99 % and 87.07 % of VC . Results indicated that M. kwangsiensis leaf polyphenols present potential antioxidant activities that make it beneficial for human health by preventing or reducing oxidative damage.
Keywords: Magnolia kwangsiensis; antioxidant activity; biological activity; microwave-assisted extraction; phytochemistry; polyphenols; response surface methodology.
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