Quantitative analysis of the tertiary alkaloids in various parts of Uncaria rhynchophylla MIQ. was made by use of high performance liquid chromatography (HPLC). The best result was obtained in the following conditions : column ; Radial Pak C8 and mobile phase ; CH3CN-0.05M AcONH4 buffer (pH 4.0) [90 : 10]. The result revealed that the constitution of the alkaloids varied markedly depending on the botanical parts examined. While oxindole alkaloids (1, 2, 3 and 6) occupy ca. 97% of total alkaloids in hook, small stem and leaf, respectively, content of indole alkaloids (mainly 8 and 10) is almost exclusive (ca. 96%) in the bark of underground part. In the bark of aerial part both oxindole and indole alkaloids were found to be contained in nearly equal amounts. The alkaloidal content is very low in the wood (aerial or underground part) but the content ratios of rare alkaloids (4 and 7) to the total alkaloids are higher than the other parts.
