1953 年 73 巻 2 号 p. 196-198
Houttuynia, a widely used crude drug, is the dried stems and leaves of Houttuynia cordata Thunb. (family Saururaceae) collected during the flowering season. The crude drug has been used from olden times as diuretic and the leaves have been found to contain quercitrin. Studies were carried out to determine the suitability of the collecting season. The floral spike and fruit spike were collected separately from both of which isoquercitrin, and not quercitrin, was confirmed. The leaves contained quercitrin but not isoquercitrin. Both quercitrin and isoquercitrin are 3′, 4′-dihydroxyflavonol and possess mild laxative and diuretic action. According to Ozawa, this compound also possesses rutin-like action. It follows, therefore, that if the terrestrial plant is collected during the flowering season, the additive pharmacological action of the two chemicals could be expected.