Comparative metabolism of two major compounds in Fructus Corni extracts by gut microflora from normal and chronic nephropathy rats in vitro by UPLC-Q-TOF/MS.

Herbal medicines are widely used as therapeutic products in many countries. Fructus Corni, a traditional herb medicine, has been clinically used to cure chronic nephropathy for thousands of years. It could be converted by gut microflora in vivo to shape its pharmacological profiles. Thus, metabolic profiles of major active constituents in Fructus Corni extracts by gut microflora from rats in healthy and nephropathy state were firstly investigated in vitro by ultraperformance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) in this study. According to the features of protonated ions, five metabolites (M1, M2, M3, M5 and M6) were found and preliminarily authenticated. Intestinal bacteria were capable of converting N0 (loganin) to its aglycone M1 (loganetin). The latter was further hydrogenated to the corresponding M2 (hydrogenated loganetin) and subsequently to M3 (hydrogenated and demethylated loganetin) by demethylation; While M5 (demethylated morronisid aglycone) and M6 (dehydroxylated morronisid aglycone) were identified as the two metabolites of N4 (morronisid) through demethylation and dehydroxylation. Gut microflora from healthy and nephropathy rats could degrade loganin and morronisid to the above metabolites. However, healthy rat intestinal bacteria showed more powerful degradation and much more amounts of M1 and M6 were obtained in their samples. Additionally, this work demonstrated that UPLC-Q-TOF/MS approach connected with MetaboLynx™ analysis software was rapid and reliable for screening and authentication of natural product metabolites.

Comparative pharmacokinetics of six major bioactive components in normal and type 2 diabetic rats after oral administration of Sanhuang Xiexin Decoction extracts by UPLC-TQ MS/MS.

A rapid, sensitive, and selective UPLC-TQ-MS/MS method was established and validated for the determination and pharmacokinetic investigation of rhein, coptisine, berberine, palmatine, baicalin and wogonoside from Sanhuang Xiexin Decoction (SXD) extracts. A Waters BEH C18 UPLC column was used with the mobile phases of Acetonitrile-0.1% formic acid-water. The lower limits of quantification (LLOQ) for rhein, coptisine, berberine, palmatine, baicalin and wogonoside were 24.16, 0.72, 0.68, 0.53, 18.07 and 28.56ng/mL, respectively. All calibration curves displayed good linearity (r2>0.995). The precision was evaluated by intra-day and inter-day assays and the RSD% were all within 9.12%, and the bias of the accuracies ranged from -7.50% to 8.03%. The recovery ranged from 74.83% to 94.32% and the matrix effects of six analytes were found to be between 90.17% and 103.10%. The stability study showed that compounds were stable during the experiment. Finally, the data showed that the pharmacokinetic (PK) profiles (especially AUC, Tmax and Cmax) of six analytes in diabetic rats were significantly diverse from that in normal group rats. The PK study under the pathological condition could provide more helpful information to guide the clinical usage of SXD to treat T2DM.

[Determination of dehydroabietic acid and abietic acid in aqueous alkali extract of Liquidambaris Resina by HPLC].

OBJECTIVE: To develop an HPLC method for content determination of dehydroabietic acid and abietic acid in aqueous alkali extract of Liquidambaris Resina. METHOD: The determination was carried out on a DIONEX C18 column (4.6 mm x 250 mm, 5 microm) eluted with acetonitrile and water containing 0.1% acetic acid. The flow rate was 1 mL x min(-1), and the detected wavelength was set at 210, 240 nm. RESULT: The peak areas and the sample quantity of the two components had good linear relationship in the range of 0.4-3.4 microg for dehydroabietic acid, and 0.6-4.8 microg for abietic acid. The average recoveries were 99.53%, 101.9%, respectively. CONCLUSION: The method was proved to be simple, accurate and used for the quality evaluation of Liquidambaris Resina.

Bolus injection of hypertonic solutions for cerebral edema in rats: challenge of homeostasis of healthy brain.

Hypertonic solutions are mainstay of osmotherapy to cerebral edema. How hypertonic solutions affect healthy brain homeostasis, however, is not fully understood. Using rat model of cerebral edema induced by local cryoinjury, we found with immunohistochemistry that less microglial activation in healthy hemishere 24 h after hypertonic saline (HS, 3% NaCl) administration, compared to mannitol (20%, the same osmotic concentration of 3% NaCl) while dehydrating the brain tissue. To see whether blood-brain barrier (BBB) or aquaporin-4 (AQP4) contribute to this difference, HS or mannitol was intra-arterially injected to normal rats, and BBB opening, ultrastructure and AQP4 immunoreactivity were examined. Evans blue extravasation indicated that BBB was opened much lighter in HS group than mannitol group at the same time points. Electron microscopy also showed edema around the capillaries slightly lighter in HS than mannitol group 24 h after injection. Meanwhile, HS injection led to AQP4 down regulation in expression similarly as mannitol, compared with NS group. These data suggested that bolus injection of hypertonic agents may lead to microglia activation in healthy brain in different extent, due to BBB compromise, instead of water movement or AQP4 expression. Hence in clinical application, BBB of healthy brain should be considered in perspective to maintain the brain homeostasis.