Synthesis and biological evaluation of bergenin analogues as mushroom tyrosinase inhibitors.

Yusei Kashima, Mitsuo Miyazawa

Index: Arch. Pharm. Res. 35(9) , 1533-41, (2012)

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Abstract

In this manuscript, we synthesized a series of bergenin analogues, analyzed their structural importance for two biologic activities (anitioxidant activity (ORAC) and mushroom tyrosinase inhibitory activity). Among them, compound 5 which contains catechol moiety exhibited the most antioxidant activity (3.75 μmol of Trolox equiv. per μmol of 5). Furthermore, compound 5 was found to be the most potent (IC₅₀ value = 17.5 ± 0.04 μM) when compared with the standard tyrosinase inhibitors of arbutin (IC₅₀ value = 221.8 ± 1.9 μM) and kojic acid (IC₅₀ value = 46.6 ± 3.8 μM). The bergenin moiety, the ester linkage, and benzoic acid moiety of bergenin derivatives affected two biologic activities. Tyrosinase inhibitory activity was affected by substituents of benzoic acid moiety. This manuscript provides a good foundation for the design and development of new tyrosinase inhibitors.