UV PROTECTION PROPERTIES OF TOCOTRIENOL IN PHOTOAGING AND SKIN CANCER

Abstract

THIS STUDY CLARIFIED THE CONTROVERSIES CONCERNING THE EFFICACY OF GAMMA-TOCOTRIENOL (GT3) VERSUS A-TOCOPHEROL (ATP) IN INHIBITING UVB-INDUCED PHOTODAMAGE IN RELATION TO THEIR VARYING DEGREES OF BIOLOGICAL ACTIVITY. HEREIN, WE REPORT GT3 IS MORE EFFECTIVE THAN ATP IN SUPPRESSING UVB-INDUCED DNA DAMAGE, OXIDATIVE DAMAGE, AND INFLAMMATION IN HUMAN EPIDERMAL KERATINOCYTES. THE PROTECTIVE EFFECTS OF GT3 ARE MEDIATED BY ENHANCEMENT OF DNA LESION REPAIR MECHANISM VIA THE NUCLEOTIDE EXCISION REPAIR PATHWAY. FURTHERMORE, GT3 INHIBITS UVB-INDUCED MITOGEN-ACTIVATED PROTEIN KINASE PATHWAYS. GT3 IS MORE PRONOUNCED THAN ATP TO PREVENT UVB-INDUCED PHOTOAGING AND DEVELOPMENT OF SQUAMOUS CELL CARCINOMA IN SKH-1 HAIRLESS MICE CHRONICALLY EXPOSED TO UVB AFTER 24 WEEKS AND 30 WEEKS, RESPECTIVELY. A PHASE I CLINICAL TRIAL CONDUCTED TO ASSESS SAFETY OF USE INDICATED THAT GT3 IS NOT AN IRRITANT TO THE SKIN. THESE SUPERIOR UV-PROTECTIVE EFFECTS MAY BE ASSOCIATED WITH THE PREFERENTIAL UPTAKE AND ACCUMULATION O