Characteristics of delayed excretion of flavonoids in human urine after administration of Shosaiko-to, a herbal medicine.
There has been little explanation of herbal medicines by modern medical sciences, including pharmacokinetics, whereas physicians follow empirical indications written in classical literature. Recent reports of herb-induced adverse reactions compelled us to proceed the investigation of a herbal medicine Shosaiko-to (TJ-9) from a pharmacokinetic point of view. To five healthy volunteers, a single 5 g dose of TJ-9, consisting of 7 herbs, was administered. We conducted HPLC analysis of the timed-urine specimens to disclose the type and amount of compounds excreted. Excretion rate-time curves were analyzed individually. Four flavonoids, liquiritigenin, baicalein, wogonin and oroxylin A, were found both in the urine and TJ-9. The glycosides in TJ-9 were absorbed after microflora hydrolysis. Davidigenin, which was not found in TJ-9, was an intestinal metabolite of liquiritigenin. Also, two flavanones, S-dihydrowogonin and S-dihydrooroxylin A, were identified as the metabolites of wogonin and oroxylin A, respectively. Excretion rate-time curves of the flavonoids were divided into three types of structure-dependent absorption, i.e. (1) the fast absorption of herbal-origin aglycons, (2) the moderately-delayed absorption of aglycons derived from herbal glycosides, and (3) markedly-delayed absorption after the molecular transformation of herbal compounds. Individual excretion profiles seemed to depend on microflora activities. Two types of flavanones, S-dihydrowogonin and S-dihydrooroxylin A, were found in a half of the volunteers, suggesting there might be two kinds of volunteers, namely, rapid and poor metabolizers of flavonoids.
Li
C
C
Department of Clinical Pharmacology, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Japan.
Homma
M
M
Oka
K
K
D000328:Adult; D002851:Chromatography, High Pressure Liquid; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000378:metabolism / Q000493:pharmacokinetics*; D005419:Flavonoids / Q000652:urine*; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D013237:Stereoisomerism; D013997:Time Factors
D004365:Drugs, Chinese Herbal; D005419:Flavonoids; C461320:shosaiko-to; D005947:Glucose