Masami Higuchi

Quantitative analysis of aristolochic acids, toxic compounds, contained in some medicinal plants

The amounts of aristolochic acid I and II in four groups of medicinal plants from the Aristolochiaceae and some related plants were determined by high-pressure liquid chromatography, for Aristolochia was reported to produce interstitial nephritis caused by aristolochic acids during chronic use for the treatment of rheumatism, diuretic and analgesic. They were detected in all the plants that originated from the genus Aristolochia (Aristolochiaceae) and in some of the plants from the genus Asarum (Aristolochiaceae). The present results suggest that these medicinal plants should be prohibited to use for remedy due to the harmful effects attributed to aristolochic acids.

Effect of the rhizomes of Atractylodes lancea and its constituents on the delay of gastric emptying.

The effect of rhizomes of Atractylodes lancea on gastric disorders, in particular, the delay in gastric emptying induced by N(G)-nitro-L-arginine in rats, was investigated. Intragastric treatment with an aqueous extract (250 mg/kg) and its lipophilic fractions (4 mg/kg) significantly improved delayed gastric emptying. The major constituents of the lipophilic fraction were two sesquiterpens, hinesol and beta-eudesmol, and four known polyacetylenic compounds, atractylodin, atractylodinol, acetylatractylodinol and 4,6,12-tetradecatriene-8,10-diyne-1,3,14-triol. The activity was found in the four polyacetylenic compounds at a similar potency, but not in the two sesquiterpens. To clarify the effect of the four polyacetylenic compounds in this extract, we attempted to evaluate the activity of atractylodin, as representative, at a dose of 0.2 mg/kg based on the total amounts (0.2 mg/250 mg aqueous extract) of the four polyacetylenic compounds. In addition, atractylodin improved the delay in gastric emptying at between 0.1 and 0.3 mg/kg in a dose-dependent manner. These results suggest that the aqueous extract improved the delayed gastric emptying, and polyacetylenic compounds contributed to its activity.

Components of Panax ginseng that improve accelerated small intestinal transit

We previously clarified that Dai-kenchu-to, a Chinese prescription, was useful for improving carbachol-induced hyperperistalsis of the small intestine in vivo, and the efficacy of Ginseng Radix, a crude drug component of Dai-kenchu-to, was also confirmed. Ginseng Radix, the root of Panax ginseng C.A. Meyer, showed significant ameliorative effects on both the carbachol-induced and the BaCl(2)-induced accelerated small intestinal transit model in mice, suggesting that both an inhibitory effect on the cholinergic nervous system and direct suppressive effect on muscles were involved in the ameliorative effect of Ginseng Radix on the accelerated small intestinal transit. Ginsenoside Rb1 (4) and ginsenoside Rd (7), major components of Ginseng Radix, improved both animal models. These results suggest that ginsenoside Rb1 (4) and ginsenoside Rd (7) were representative compounds of Ginseng Radix for improving the accelerated movement of the small intestine and that these compounds partly contribute to the action of Dai-kenchu-to on small intestinal transit.