Interaction of sesamol (3,4-methylenedioxyphenol) with tyrosinase and its effect on melanin synthesis.

Sesamin, sesamolin (lignans) and sesamol e from sesame seed (Sesamum indicum L.) e are known for
their health promoting properties. We examined the inhibition effect of sesamol, a phenolic degradation
product of sesamolin, on the key enzyme in melanin synthesis, viz. tyrosinase, in vitro. Sesamol inhibits
both diphenolase and monophenolase activities with midpoint concentrations of 1.9 mM and 3.2 mM,
respectively. It is a competitive inhibitor of diphenolase activity with a Ki of 0.57 mM and a noncompetitive
inhibitor of monophenolase activity with a Ki of 1.4 mM. Sesamol inhibits melanin synthesis
in mouse melanoma B16F10 cells in a concentration dependant manner with 63% decrease in cells
exposed to 100 mg/mL sesamol. Apoptosis is induced by sesamol, limiting proliferation. This study of the
chemistry and biology of lignans, in relation to the mode of action of bioactive components, may open
the door for drug applications targeting enzymes.