Extraction and Antioxidant Activities of Magnolia kwangsiensis Figlar & Noot. Leaf Polyphenols.

Microwave-assisted extraction was employed to extract polyphenols from the leaf of Magnolia kwangsiensis Figlar & Noot.. The polyphenols yield 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. And 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.