Utilization of Flavonoid Compounds from Bark and Wood. III. Application in Health Foods

Dietary supplements ACAPOLIA(®) and ACAPOLIA PLUS have been sold in Japan under the classification “Foods in General” for a number of years. In April 2015, the classification of “Foods with Function Claims” was introduced in Japan to make more products available to the public that were clearly labeled with functional claims based on scientific evidence. In order to obtain recognition of ACAPOLIA PLUS under this new classification, the following information needed to be established. The safety of the bark extract of Acacia mearnsii was shown from the history of the long-term safe consumption of the extract as a health supplement, together with several additional clinical safety tests. Robinetinidol-(4α,8)-catechin was detected by high performance liquid chromatography (HPLC) in the supplement and was suitable for use as the basis of the quantitative analysis. In clinical tests, the amount of change in the plasma glucose concentration in the initial 60 min after rice consumption by a test group who had been given the Acadia extract was significantly lower than the glucose concentration in the group that was given a placebo. The blood glucose incremental areas under the curve (IAUC) in the first 60 min after rice consumption were also significantly lower in the Acacia group. The functional mechanisms were explained in terms of the inhibition of the absorption of glucose in the small intestine and the reduction in the activity of the digestive enzymes caused by proanthocyanidins derived from A. mearnsii bark. As a result, ACAPOLIA PLUS was accepted as a “Food with Function Claims” in August 2016. ACAPOLIA PLUS is now sold under this new classification. The growth of a typical intestinal bacterium is inhibited by an extract containing flavonoid compounds from A. mearnsii bark; thus, one of the future directions of study must be a comprehensive investigation of the effect that flavonoid compounds, proanthocyanidins, have on intestinal bacteria.