Determination of 18 beta-glycyrrhetic acid in human plasma by high-performance liquid chromatography.

A sensitive high-performance liquid chromatographic method has been developed for the determination of 18 beta-Glycyrrhetic acid in human plasma. 18 alpha-Glycyrrhetic acid was used as an internal standard. The procedure includes pretreatment by liquid-liquid extraction and chromatographic separation on a reversed-phase column with ultraviolet detection.

[Pharmacological studies on antidiarrheal effects of berberine and geranii herba].

We studied the effects of berberine and Geranii Herba extract (GH) on different diarrheal models of mice, on the contractions of the isolated guinea pig intestinal smooth muscle and on the peristalsis in the rat intestine, comparing these effects with those of atropine (ATR) and papaverine (PAP). 1) Berberine significantly inhibited both the diarrhea induced by castor oil and that induced by BaCl2 at doses higher than 25 mg/kg, p.o.

Roles of sulfhydryl compounds in the gastric mucosal protection of the herb drugs composing oren-gedoku-to (a traditional herbal medicine).

We investigated the involvement of sulfhydryl compounds in the cytoprotective effect of each component herb drug composing Oren-gedoku-to (OGT) against ethanol-induced gastric lesions and potential difference (PD) reduction in comparison with that of OGT in rats. Pretreatment with N-ethylmaleimide (NEM) significantly blocked the cytoprotective effects of OGT, Coptidis rhizoma and Phellodendri cortex, but did not block the cytoprotective effects of Gardeniae fructus and Scutellariae radix. The inhibitory effects of OGT, Coptidis rhizoma and Phellodendri cortex against the PD reduction disappeared in the presence of NEM or diethyldithiocarbamate (DDC), whereas NEM or DDC had little or no effect with Gardeniae fructus and Scutellariae radix.

[The mechanism of the inhibitory effects of oren-gedoku-to (OGT) on gastric acid secretion in rats].

The effect of oren-gedoku-to (OGT) on gastric acid secretion was examined in the perfused stomach of anesthetized rats. OGT (10-100 mg/kg) given intraperitoneally dose-dependently inhibited the gastric acid secretion stimulated by intracerebroventricular DN-1417, an analogue of TRH, but failed to inhibit the acid secretion stimulated by intracerebroventricular baclofen, an analogue of GABA. The inhibitory effect of OGT on DN-1417-induced acid secretion was antagonized by haloperidol (0.

Biliary excretion of metabolites of baicalin and baicalein in rats.

Biliary excretion of metabolites of baicalin, present in Scutellariae Radix, was investigated using rats. The bile of rats administered baicalin orally was shown to contain five major metabolites, which were identified as baicalein 6-O-beta-glucopyranuronoside (M1), 6-O-methyl-baicalein 7-O-beta-glucopyranuronoside (oroxylin A 7-O-beta-glucuronide (M2], baicalein 7-O-beta-glucopyranuronoside (M3), 6-O-beta-glucopyranuronosyl- baicalein 7-O-sulfate (M4), and baicalein 6,7-di-O-beta-glucopyranuronoside (M5) on the basis of chemical and spectroscopic evidence. The bile of rats treated with baicalein also contained the above metabolites.