Abstract: By means of column chromatographic techniques , 8-oxocaffeine , together with pyrimidine alkaloids ( deoxythymidine, thymine and uracil ) , flavonoidal glycoside ( engeletin) and simple phenols (1 , 2 , 4-benzenetriol , 1 , 3-benzenediol and 4-methyl-1 , 2-benzenediol ) were isolated for the first time from Pu-Er ripe tea . Since Pu-Er ripe tea is produced from the leaves of Camellia sinensis var. assamica by the post microbial fermentation process, the formation of 8-oxocaffeine should be due to the biotransformation of caffeine . On the other hand , deoxythymidine might be derived from the combination of pyrimidine alkaloid in tea leaves with microbial secondary metabolite . Both of them were found to be the new characteristic principles of Pu-Er ripe tea .

Key words: Pu-Er ripe tea