In this study green tea leaves harvested in Kyoto（June 2014）and grown with or without shading were extracted with boiled or 80℃ water, examining for their effects in vitro on the growth of Bifidobacterium bifidum. In addition, catechins and other components included in each sample were assayed by the HPLC method. The results demonstrated that all of the extracts increased the growth of the strain. Compared with water（control）, the growth-promoting effects on the strain were 517 times higher than those with the boiled-water extract from the leaves grown without shading, 322 times than those with the boiled-water extract from the leaves grown with shading, and 308 times than those with the 80℃ extract from the leaves grown with shading. The total amount of catechins in the extracts was 343.29 mg/100 ml, 240.57 mg/100 ml, and 128.87 mg/100 ml, respectively. Thus, the green tea extracts used in this experiment may have promoted an increase in strain growth in vitro, but the degree of the effects was not necessarily proportional to catechin content.研究ノー
