PHITSANULOK, Thailand—Chitosan microparticles are promising carriers for enhancing the skin permeation, according to a study published in the International Journal of Cosmetic Science (2011;33(6):572-579). Although catechins found in green tea are major antioxidants, their use in cosmetic products has been limited because they do not permeate the skin well. Therefore, researchers in Thailand evaluated the cutaneous absorption of catechins from an extract of green tea and from a green tea extract–loaded chitosan microparticle. The catechin skin metabolism was also examined.
The results from their study suggest chitosan microparticles significantly improve the ability of catechins to permeate skin. The cutaneous metabolism of the catechins significantly affected their permeation profiles. Epicatechin (EC) and epigallocatechin (EGC) penetrated the skin more than epigallocatechin gallate (EGCG) and epicatechin gallate (ECG). The galloyl groups in EGCG and ECG were enzymatically hydrolysed to EGC and EC, respectively. Dehydroxylation of catechins was also observed. Chitosan microparticles effectively prevented enzymatic changes of the catechins.
