Vanida JansomSakul MoolkamChalerm JansomEkasith Skulkhu2011-02-222011-02-222011-01-242011-01-24Thammasat Medical Journal - ธรรมศาสตร์เวชสาร; Vol.10 No.1 January-March 2010; 43-51http://imsear.searo.who.int/handle/123456789/132779Purple glutinous rice (Oryza sativa L.) is widely cultivated in the north and northeast of Thailand. Its purplish black pericarp layers is rich in anthocyanin. Purple glutinous rice is a good source of fiber, minerals, and several important amino acids; furthermore, the high content of γ-oryzanol and the anthocyanin which were identified as cyanidin 3-glucoside and peonidin 3-glucoside. The aim of this study was to examine anti-tyrosinase compoundin difference local genotypes of purple glutinous rice. Among 36 genotypes of purple glutinous rice were collected, K-Entry 9 showed the highest anti-tyrosinase activity (IC50 = 369.5 μg/ml). By means of column chromatography and high performance liquid chromatography, the ethyl acetate extract yielded purified compound which inhibited tyrosinase enzyme activity with IC50 = 64.2 ± 1.04 μg/ml. The structure was elucidated by spectroscopic method as protocatechuic acid. This valuable data would be useful for standardization of purple glutinous rice products used in anti-aging and whitening cosmetics. Also, this was an alternative process for value added to purple glutinous rice Thailand local genotypesen-USFaculty of Medicine, Thammasat University, Bangkok, ThailandOriginal Articles