The exposure of human stomach cancer KATO III cells to oolong tea polypheno
l extract [OTPE] containing oolong tea polyphenol trimer [OTP trimer] as a
main component, led to both growth inhibition and the induction of apoptosi
s. Morphological change showing apoptotic bodies was observed in the cells
treated with OTPE. The fragmentation by OTPE of DNA to oligonucleosomal-siz
ed fragments that are characteristics of apoptosis was observed to be conce
ntration- and time-dependent. These data suggest that the growth inhibition
by OTPE results from the induction of apoptosis in the KATO III cells.