Comparative analysis of the constituents in Saposhnikoviae Radix and Glehniae Radix cum Rhizoma by monitoring inhibitory activity of nitric oxide production.

During the development of natural herbal medicines in Japan, Glehniae Radix cum Rhizoma (Hamabofu in Japanese) has been used as a substitute for Saposhnikoviae Radix (Bofu). Bofu and Hamabofu are blended differently in several Kampo formulae. For example, Bofu is included in Jumihaidokuto by a manufacturer, whereas Hamabofu is included instead of Bofu in the same formula by other manufacturers. Although both Bofu and Hamabofu are used for their expected anti-inflammatory effects, differences in their medicinal properties are not well characterized. In addition, there have been very few reports comparing the pharmacological activities of the constituents in Bofu and Hamabofu. In the present study, we investigated the anti-inflammatory effects of the extracts of Bofu and Hamabofu by monitoring levels of the inflammatory mediator nitric oxide (NO) produced in rat hepatocytes. Moreover, the chemical constituents responsible for the activity were investigated. Our results showed that ethyl acetate fractions of Bofu and Hamabofu extracts contain different compounds, although both fractions suppressed NO production in rat hepatocytes. The linear dihydropyranochromones from the Bofu extract (i.e., 3'-O-angeloylhamaudol, ledebouriellol and hamaudol) suppressed NO production, whereas the coumarins from the Hamabofu extract (i.e., umbelliferone and scopoletin) also suppressed NO production. These results suggest that linear dihydropyranochromones and coumarins are responsible for the anti-inflammatory effects of Bofu and Hamabofu. It is plausible that Bofu and Hamabofu are blended differently in several Kampo formulae due to many constituents with as yet unidentified pharmacological activity.