Stability and nano-encapsulation of oxyresveratrol

The stilbene trans-oxyresveratrol is an active compound from the heartwoods of Artocarpus Lakoocha. Its stability towards light and temperature was studied compared to that of trans-resveratrol. The results revealed that trans-isomers of oxyresveratrol and resveratrol were stable towards the fluorescent light and temperature within 7 days. The UV-A radiation caused the isomerization from trans-isomer to be cis-isomer in oxyresveratrol faster than resveratrol. Cis-oxyresveratrol rapidly isomerized to be trans-oxyresveratrol via thermal process. In contrast to resveratrol, cis-resveratrol changed to be trans-resveratrol via both thermal and light pathways. Moreover, trans- and cis-isomers both of oxyresveratrol and resveratrol showed the same anti-oxidation activity. Trans-oxyresveratrol showed higher anti-tyrosinase activity than cis-oxyresveratrol while both isomers of resveratrol had low activity. Trans-oxyresveratrol-loaded nanospheres were prepared using ethyl- and methyl-cellulose blend as the polymeric shell material. The 2:1 ratio of cellulose blend and trans-oxyresveratrol gave nanospheres with the average size of 190 nm and the highest encapsulation efficiency percentage (76%). These preparing nanospheres showed a sustained release of trans-OXY at pH 5.5. In addition, trans-oxyresveratrol-loaded nanospheres can penetrated the skin barrier and accumulated at the hair folicles of the porcine ear detected by confocal laser scanning fluorescence microscopy.