Abstract
The effect of 3 kinds of tea solution (green tea, oolong and black tea) to human saliva α-amylase activity was examined.
Black tea specifically lowered the activity of a-amylase (89 % inhibition). Judging from such a result that the activity of α-amylase was not almost changed by the tannin free black tea extract prepared using the same black tea, it was cleared that tannin was a factor for lowering the activity of a-amylase.
The amounts of tannin in the extracts of 3 kinds of tea prepared from the same tea leaves were compared with each other but no difference was confirmed between green tea and black tea (0. 19, 0.21% respectively).
However, analysis of tannin component of tea solutions by thin layer chromatography revealed that black tea contained more amount of highly polymerized tannin than other teas did.
It was strongly suggested that this highly polymerized tannin is responsible for the inhibition of human salivary α-amylase.
