POLYGALAE RADIX is defined as root or root bark of Polygala tenuifolia Willdenow (Polygalaceae) in Japanese Pharmacopeia Eighteenth Edition (JP18). POLYGALAE RADIX is dispensed in Kampo prescriptions as Kihito, Kamiuntanto, and Ninjinyoeito. A method for analysis of tenuifolin, a marker compound of POLYGALAE RADIX was elaborated based on a method described in Hong Kong Chinese Materia Medica Standards. Tenuifolin contents of market samples were measured using this method. Different parts of the sample, i.e. root bark and xylem and samples of different horizontal-section diameters were compared for their tenuifolin contents.
