HH Ko’s scientific contributions

In order to develop skin-whitening agents or anti-aging agents, Formosan Phyla nodiflora was evaluated for both of the potential as tyrosinase inhibitors and DPPH radical scavengers. The methanolic extract (PNME) and its four fractions of water (PNWF), ethyl acetate (PNEF), chloroform (PNCF), and n-hexane (PNHF) were prepared and then subjected to anti-tyrosinase and antioxidant evaluation. In the tyrosinase inhibition assay, PNME showed potent concentration-dependent inhibition manner with an IC50 value of 74.4µg/mL, it presented 2.3-fold potency of kojic acid (IC50 =1.2 mM, equal to 175µg/mL). As pigmentation also results from oxidation, the antioxidant activity of P. nodiflora was tested. The antioxidant activities of the different fractions tested decreased in the order of PNEF (IC50 =24.6µg/mL) > PNCF (IC50 =198.7µg/mL) > PNME (IC50 =330µg/mL) > PNHF (IC50 =357.2µg/mL) > PNWF (IC50 >500µg/mL) according to the DPPH free radical-scavenging assay. With the anti-tyrosinase and antioxidant activities, Formosan P. nodiflora contains some active constituents that might be potential candidates as skin-whitening and anti-aging cosmetics. Acknowledgements: This work was financially supported by a grant from the National Science Council of the Republic of China (NSC 96–2320-B-037–021). The authors also would like to thank Dr. Ih-Sheng Chen of the Graduate Institute of Natural Products, Kaohsiung Medical University, for botanical identification of P. nodiflora.