Search

Saposhnikoviae Radix ("Boufu") is an important crude drug used in Kampo formulation. It is extracted from wild-type plants. However, recently, extraction has become difficult because of a decrease in wild-type plants. Therefore, cultivated plants account for the majority of the market, from which the crude drug is extracted. However, the cultivation techniques used are not sufficient to obtain the desirable extracts. In this study, we compared the contents of the extract and the quantitative values of characteristic constituents obtained from wild-type and cultivated plants, and found a remarkable difference. Therefore, it is considered that these indicators play an important role in the establishment of better cultivation technology.

Mangiferin, three catechins, and two catechin dimers were isolated from the roots of Salacia reticulata (SRE), and examined their inhibitory activities against several carbohydrate metabolize enzymes (sucrase, maltase, isomaltase, alpha-amylase, and aldose reductase). Among them, mangiferin was found to inhibit sucrase, isomaltase, and aldose reductase from rat with IC50 values of 87, 216 and 1.4 micrograms/ml, respectively. The inhibitory activities of mangiferin are competitive for sucrase and isomaltase with inhibitor constant (Ki) 55 micrograms/ml and 70 micrograms/ml, respectively. In order to determine the mangiferin contents in the water extracts from the roots of S. reticulata, a quantitative analytical method by means of HPLC was developed and the mangiferin contents in SRE were determined to be in the range of 0.9-2.3% by the application of this method. A high linear correlation (r = 0.934) was observed between the mangiferin contents and the sucrase inhibitory activity. In addition, this analytical procedure of mangiferin was found to be applicable for other Salacia species (S. oblonga, S. chinensis, and S. prinoides). Thus, the quantitative HPLC analysis of mangiferin was supposed to be suitable for the quality control of Salacia species and its products.