OBJECTIVE To map a comprehensive metabolic pathway of herbacetin in rats, specifically, to elucidate the biotransformation of herbacetin in vivo and to simultaneously monitor the pharmacokinetic process of both parent drug and its major metabolites. METHODS liquid chromatography/ion trap mass spectrometry (LC/MSn) and ultra-liquid chromatography coupled with mass spectrometry (UPLC/MS) were combined in the current study for qualitative and quantitative determinations of herbacetin and its metabolites in bile, urine and feces after both oral and intravenous administration of herbacetin to rats. Enzyme kinetic studies on the intestinal and hepatic metabolism of herbacetin were further conducted to elucidate metabolic profiles of herbacetin in rat tissues and organs. Additionally, plasma concentration profiles of herbacetin and its metabolites in rats were obtained to characterize the overall pharmacokinetic behavior of herbacetin. RESULTS It was found that herbacetin was excreted primarily from rat urine in the form of glucuronide-conjugations. Subsequent in vitro enzyme kinetic studies and in vivo pharmacokinetic investigations suggested an extensive hepatic metabolism of herbacetin and the high exposure of herbacetin- glucuronides in systemic circulation. The clearance, half- life and bioavailability of herbacetin in rats were determined as (16.4±1.92)mL·kg-1·min-1, (11.9±2.7)min, and 1.32%, respectively. On basis of these findings, a comprehensive metabolic pathway of herbacetin in rats was composed. In addition, a physiology based pharmacokinetic (PBPK) model was successfully developed with the aid of the GastroPlus to simulate the pharmacokinetic process of herbacetin in rats. Application of the PBPK modeling can provide a useful starting point to understand and extrapolate pharmacokinetic parameters among different species, populations, and disease states. CONCLUSION After oral administration, herbacetin was subjected to colonic degradation and extensive first pass metabolism, with glucuronidation as its dominating in vivo metabolic pathway.

OBJECTIVE To investigate the effect of hypoxia on the pharmacokinetic process of salidrosidein rats and to explore its underlying mechanisms. METHODS The Caco-2 cell monolayerwas exposed to 1% oxygen (O2) concentration for 24 h to build the hypoxiccell model. The transportation mode of salidroside was investigated with the aid of this hypoxia model by detecting the apparent permeability coefficient(Papp). Healthy Sprague Dawley (SD) rats were exposed to 9% O2 for 72 h for the construction of hypoxic rat model. Liver sample was subsequently collected from the hypoxic rats with an aim to identify enzymes responsible for salidroside metabolism. The expression levels of sali?droside-transporting and salidroside-metabolizing enzymes, including Sodium-dependent glucose cotrans?porters (SGLT1), β-glucosidase (GBA3)and sulfotransferase (SULT2A1), were thereafter detected by RT-PCR and Western blot. The metabolic activity of GBA3 and SULT2A1 was monitored by rat liver microsome incubation.In addition, the renal function of rats under hypoxia was assessed by detecting concentrations of blood urea nitrogen and creatinine. RESULTS The AUC and t1/2 values of salidroside in hypoxic rats were more than doubled, while the in vivo clearance was significantly reduced. Mechanistic study demonstrated that the PappA- B/PappB- A eualsto 10.3, indicating the potential active transport of salidrosile. The expression of SGLT1 and GBA3 was significantly decreased, which indicated a reduced metabolism of salidroside under hypoxia. Moreover, rat under hypoxia was found to suffer from renal dysfunction, with an abnormal value of blood urea nitrogen. CONCLUSION Due to the reduced metabolism and the abnormal renal function under hypoxia, the systemic exposure of salidroside in rats was signifi?cantly enhanced.

OBJECTIVE Paeoniflorin (PF) and albiflorin (AF) are the major active components of total peony glucosides(TPG)from Paeonia lactiflora Pal,which have many biological activities such as anti-inflammatory, antioxidation and anti-hypertension effects. The drug-drug pharmacokinetic interaction among PF,AF and TPG,the pharmacokinetic comparisons of AF between hypoxia and normoxia,the transport of AF cross the blood-brain barrier cell model and the transport of AF/PF/TPG cross Caco-2 cell model were investigated.METHODS A highly sensitive and rapid UPLC-MS method with multiple-reaction monitoring(MRM)scanning via electrospray ionization(ESI)source operating both in the positive and negative ionization mode was successfully developed and validated for simultaneous quantitation of PF and AF in rat plasma after an oral administration of PF,AF and TPG. RESULTS The validated and developed UPLC-MS/MS method was successfully applied to simultaneously determine the AF and PF concentration in rat plasma and investigate pharmacokinetic interactions after a single intragastrical ad-ministration of PF,AF,co-administration of PF with AF and TPG,respectively.The elimination of both PF co-administered with AF and PF in TPG were slower than those for PF alone and the distribution in the tissues was wider.The combination of PF with AF or TPG could significantly increase the values of the AUC, MRT and t1/2of the drug PF, and reduce the values of CL of PF. From a comparison of the main pharmacokinetic parameters among AF alone, AF combined with PF and AF in TPG, the values of the MRT and t1/2of AF in TPG were greater than that of AF alone,and there were statistically signifi-cant differences in these parameters(P<0.05,P<0.01).It was also noticed that AUC and Cmaxof PF in hypoxia rats were significantly decreased compared with that of normaxia rats, suggesting that there was a decreased exposure of PF in rats under hypoxia. The multiple active components in TPG may lead to DDIs between some P-gp substrates. CONCLUSION The clinical performance of total peony glucosides would be better than that of single constitute. The outcomes of the study are expected to serve as a basis for development of clinical guidelines on total peony glucosides usage.

Objectives To investigate the effect of paeoniflorin(PF)in ameliorating the irritable bowel syndrome(IBS)such as diarrhea and bellyache,and the barrier function of PF on intestinal epithelial cell and inflammation.Methods The diarrhea model was conducted by exposing rat to restraint stress stimulation and bellyache model was conducted by subcutaneous injection of neostig?mine to mice.The Caco-2 monolayer cell model with barrier dysfunction was established by trypsin stimulation and the inflammatory Caco-2 cell model was established by interleukin-1β(IL-1β)stimulation.On the basis of these models,effects of PF at different doses (low 14 mg/kg·d,medium 28 mg/kg·d,and high 56 mg/kg·d)on IBS syndromes and Caco-2 cell function were investigated. Re-sults PF could significantly reduce the frequency of defecation in diarrhea rat model(P<0.05)and relieve abnormal bowel move?ments in bellyache mice model(P<0.05).PF significantly increased TEER value(P<0.01),decreased the transmittance of fluores?cein(P<0.01)and up-regulated the expression of tight junction(ZO-1)protein(P<0.01).The gene and protein expression of nucle?ar factor profilin kappa Bα(IκBα)in inflammatory Caco-2 cell model was significantly improved(P<0.01)when treated with PF. Conclusion Our study proves for the first time that PF significantly ameliorated the diarrhea and bellyache symptoms of IBS in the di?arrhea model and bellyache model.The PF intervention effect on ZO-1 and IκBα protein might be one of the molecular mechanism of ameliorating the symptoms of IBS.

OBJECTIVE: To investigate the effect of Chang'an II Decoction ( II ))-containing serum on intestinal epithelial barrier dysfunction in rats. METHODS: Tumor necrosis factor (TNF)-α-induced injury of Caco-2 monolayers were established as an inflammatory model of human intestinal epithelium. Caco-2 monolayers were treated with blank serum and Chang'an II Decoction-containing serum that obtained from the rats which were treated with distilled water and Chang'an II Decoction intragastrically at doses of 0.49, 0.98, 1.96 g/(kg·d) for 1 week, respectively. After preparation of containing serum, cells were divided into the normal group, the model group, the Chang'an II-H, M, and L groups (treated with 30 ng/mL TNF-α and medium plus 10% high, middle-, and low-doses Chang'an II serum, respectively). Epithelial barrier function was assessed by transepithelial electrical resistance (TER) and permeability of fluorescein isothiocyanate (FITC)-labeled dextran. Transmission electron microscopy was used to observe the ultrastructure of tight junctions (TJs). Immunofluorescence of zonula occludens-1 (ZO-1), claudin-1 and nuclear transcription factor-kappa p65 (NF-κ Bp65) were measured to determine the protein distribution. The mRNA expression of myosin light chain kinase (MLCK) was measured by real-time polymerase chain reaction. The expression levels of MLCK, myosin light chain (MLC) and p-MLC were determined by Western blot. RESULTS: Chang'an II Decoction-containing serum significantly attenuated the TER and paracellular permeability induced by TNF-α. It alleviated TNF-α-induced morphological alterations in TJ proteins. The increases in MLCK mRNA and MLCK, MLC and p-MLC protein expressions induced by TNF-α were significantly inhibited in the Chang'an II-H group. Additionally, Chang'an II Decoction significantly attenuated translocation of NF-κ Bp65 into the nucleus. CONCLUSION High-dose Chang'an II-containing serum attenuates TNF-α-induced intestinal barrier dysfunction. The underlying mechanism may be involved in inhibiting the MLCK-MLC phosphorylation signaling pathway mediated by NF-κ Bp65.