Comparative pharmacokinetics of four active components on normal and diabetic rats after oral administration of Gandi capsules.

The Gandi capsule, a famous traditional Chinese medicine (TCM), is a hospital preparation that has been widely used in China for decades for the treatment of diabetes. The aim of this study is to compare the pharmacokinetics of four of the active components of Gandi capsules, which are the primary antidiabetic ingredients, on normal and diabetic Sprague-Dawley rats following oral administration of the capsules. Baicalin, wogonoside, wogonin, loganin and puerarin (internal standard) were prepared using methanol precipitation, and the separation of the five components was achieved through a ZORBAX Eclipse Plus C18 column by gradient elution using water (containing 0.1% formic acid) and acetonitrile as the mobile phase. After oral administration of Gandi capsules to the normal and diabetic rats, plasma was harvested and analyzed using liquid chromatography coupled with tandem mass spectrometry, and the primary pharmacokinetic parameters were calculated by DAS 2.0. Compared with the normal group, some pharmacokinetic parameters especially the AUC0-48 h of the four compounds significantly increased in the diabetic groups. The results demonstrated that the four constituents in normal and diabetic rats had obvious differences in some pharmacokinetic characteristics, suggesting that the rate and extent of drug metabolism were altered in diabetic animals. The results could be helpful for demonstrating the compatibility mechanism and providing clinical medication guidance for Gandi capsules.

Elucidation of the Intestinal Absorption Mechanism of Loganin in the Human Intestinal Caco-2 Cell Model.

Loganin, iridoid glycosides, is the main bioactive ingredients in the plant Strychnos nux-vomica L. and demonstrates various pharmacological effects, though poor oral bioavailability in rats. In this study, the intestinal absorption mechanism of loganin was investigated using the human intestinal Caco-2 cell monolayer model in both the apical-to-basolateral (A-B) and the basolateral-to-apical (B-A) direction; additionally, transport characteristics were systematically investigated at different concentrations, pHs, temperatures, and potential transporters. The absorption permeability (PappAB) of loganin, which ranged from 12.17 to 14.78 × 10-6cm/s, was high at four tested concentrations (5, 20, 40, and 80µM), while the major permeation mechanism of loganin was found to be passive diffusion with active efflux mediated by multidrug resistance-associated protein (MRP) and breast cancer resistance protein (BCRP). In addition, it was found that loganin was not the substrate of efflux transporter P-glycoprotein (P-gp) since the selective inhibitor (verapamil) of the efflux transporter exhibited little effects on the transport of loganin in the human intestinal Caco-2 cells. Meanwhile, transport from the apical to the basolateral side increased 2.09-fold after addition of a MRP inhibitor and 2.32-fold after addition of a BCRP inhibitor. In summary, our results clearly demonstrate, for the first time, a good permeability of loganin in the human intestinal Caco-2 cell model and elucidate, in detail, the intestinal absorption mechanism and the effects of transporters on iridoid glycosides compounds.

Combined antihypertensive effect of luteolin and buddleoside enriched extracts in spontaneously hypertensive rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Flos Chrysanthemi is used in a variety of diseases in traditional Chinese medicine including hypertension, and the total flavonoids (rich in luteolin (LUT) and buddleoside (BUD)) of Flos Chrysanthemi is known to modulate vascular functions and reduce the blood pressure. However, the active flavonoids and their synergistic effects on anti-hypertension are still unclear. To investigate the combined anti-hypertension effects of LUT and BUD enriched extracts on spontaneously hypertensive rats (SHR), as well as the anti-hypertensive mechanism of LUT&BUD mixture. MATERIALS AND METHODS: CODA Mouse & Rat Tail-Cuff Blood Pressure System was used to measure the systolic blood pressure (SBP) and diastolic blood pressure (DBP) of SHR after treated with extracts contains with LUT and/or BUD. The expressions of Ang II, PRA, ALD, ET, PGI2 and TXB2 were investigated by ELASA. Serum NO concentration was measured by the method of Nitric acid reductase. RESULTS: A single administration of LUT, BUD, or LUT:BUD=1:1 significantly reduced SBP by about 3.35 mmHg, 4.39 mmHg and 15.42 mmHg, respectively. Chronic administration of LBM (at 60 mg/kg; p.o. for 30 days) reduced both SBP and DBP by 4.04% and 5.24% of the vehicle group, respectively. Oral administration of LBM at 60 mg/kg inhibited the serum levels of ANG, ALD and ET, but increased serum NO concentration. CONCLUSION: This study shows the synergistic anti-hypertension effects of LUT and BUD in SHR. The effects of LBM on blood pressure are associated with RAAS and endothelial system. Thus, our experiments suggest that the combination of luteolin and buddleoside from Flos Chrysanthemi are potentially useful for the therapeutic treatments for hypertension.