Antioxidant and tyrosinase inhibitory activities of methanol extracts from Magnolia denudata and Magnolia denudata var. purpurascens flowers

Methanolic extracts of white colored (Magnolia denudata, WME) and violet colored (M. denudata var. purpurascens, VME) flowers were prepared, and their antioxidant activities were evaluated by total phenolic contents (TPC), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (RSA), 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) RSA, and reducing power (RP). TPC of WME and VME were 85.80 and 80.96 mg/g gallic acid equivalents, respectively. DPPH RSA and ABTS RSA of WME and VME at 1 mg/mL concentration were 87.74 and 75.05, and 88.24 and 85.98%, respectively. In the case of RP, there was no significant (P < 0.05) difference between WME (1.094) and VME (1.081). Tyrosinase inhibitory activities of WME and VME were 17.48% and 8.63%, respectively.

Research Highlights► White magnolia flower (WME) contained higher phenolic content than violet one (VME). ► WME exhibited stronger tyrosinase inhibitory activity than VME. ► However, VME showed higher radical scavenging activity than WME.