Abstract: Methods and compositions are provided for inhibiting the activity of tyrosinase in a host and, as a result, inhibiting melanin-formation. The tyrosinase-inhibitor active ingredient is a compound or mixture of compounds represented by the following structural formulae (I) and (II): ##STR1## wherein the dotted lines at a, b, c, d, e, f, g, represent an optional double bond, provided that double bonds are not at both b and c, or at both f and g, at the same time; R.sup.1, R.sup.5, R.sup.6, and R.sup.7 are each hydrogen or methyl; R.sup.2 and R.sup.8 are each no group, or each hydrogen or hydroxyl when there is no double bond at a and at f, respectively; R.sup.3 is methylene when there is a double bond at b, or hydrogen or methyl when there is no double bond at b; R.sup.4 is formyl or --(CH.sub.2).sub.n --R.sup.10, wherein R.sup.10 is hydrogen, hydroxyl, acyloxy, or cyano and n is an integer of from 1 to 3; and R.sup.9 is methylene when there is a double bond at g, or --(CH.sub.2).sub.n --R.sup.