Synthesis and in vitro biological activity of retinyl polyhydroxybenzoates, novel hybrid retinoid derivatives.

A new hybrid derived from retinol was designed to improve the stability and anti-oxidant activity of retinol and also to add whitening properties besides its usual anti-aging properties. A variety of polyhydroxybenzoates of retinol were prepared either by base-catalysis or by direct esterification of retinol and screened for such desirable properties by analyzing the in vitro biological activity of the hybrids. Some of the retinol derivatives enhanced their thermal stability and decreased photosensitivity, and exhibited an activity in collagen synthesis similar to that of retinol. In addition, the retinyl gallate 6 showed higher activities in free radical scavenging and melanogenesis inhibition than retinol. Thus, owing to its excellent stabilities, retinyl gallate 6 may be conveniently used not only as an additive for cosmetics for prevention and improvement of skin aging and whitening but also as medicine for the treatment of skin troubles.