OBJECTIVE “Eight White Herbal Powders” documented in “The Secret Formula in Lu’s House” is a well known
cosmetic whitening
prescription in ancient China This study aimed to investigate (a) the tyrosinase
inhibitory activity of the aqueous extracts of individual herbs in this formula and (b) the feasibility of utilizing 80% ethanol as an alternative extraction medium for the whitening components of the herbs METHODS The aqueous extracts of individual herbs were tested for tyrosinase inhibitory effects, using kojic acid as the positive control Comparative activity analysis was done between the aqueous and the 80% ethanol extracts for three selected herbs RESULTS Bailian showed the highest tyrosinase inhibitory activity, followed by Baizhi and Baiji However, compared with the aqueous extracts, the 80% ethanol extracts of the three herbs displayed significantly lower tyrosinase inhibitory effects, as evidenced by their substantially larger IC 50 values (by～5 9～23 times) CONCLUSION By comparison of the tyrosinase inhibitory activities of the extracts, water appeared to be a better extraction medium than 80% ethanol for the whitening constituents in Bailian, Baizhi and Baiji