Hepatic, gastric, and intestinal first-pass effects of vitexin in rats.

CONTEXT: Recent research has demonstrated that vitexin exhibits a prominent first-pass effect. In this light, it is necessary to investigate the causes of this distinct first-pass effect. OBJECTIVE: The aim of this study was to evaluate hepatic, gastric, and intestinal first-pass effects of vitexin in rats and, furthermore, to investigate the role of P-glycoprotein (P-gp) and cytochrome P450 3A (CYP3A) in the absorption and secretion of vitexin in the duodenum. MATERIALS AND METHODS: Vitexin was infused into rats intravenously, intraportally, intraduodenally, and intragastrically (30 mg/kg). In addition, verapamil (50 mg/kg), a common substrate/inhibitor of P-gp and CYP3A, was also instilled with vitexin into the duodenum to investigate the regulatory action of P-gp and CYP3A. The plasma concentrations of vitexin were measured by the HPLC method using hesperidin as an internal standard. RESULTS: The hepatic, gastric, and intestinal first-pass effects of vitexin in rats were 5.2%, 31.3%, and 94.1%, respectively. In addition, the total area under the plasma concentration-time curve from zero to infinity (AUC) of the vitexin plus verapamil group and of the normal saline group was 44.9 and 39.8 µgc min/mL, respectively. DISCUSSION AND CONCLUSION: The intestinal first-pass effect of vitexin was considerable, and gastric and hepatic first-pass effects also contribute to the low absolute oral bioavailability of vitexin. The AUC of the vitexin plus verapamil group was slightly higher than that of the vitexin plus normal saline group (by approximately 1.13-fold), suggesting that verapamil does not play an important role in the absorption and secretion of vitexin.

Pharmacokinetics of vitexin-4″-O-glucoside in rats after intravenous application.

Vitexin-4″-O-glucoside (VOG), being a main component in the leaves of Crataegus pinnatifida Bge. var. major, was isolated and then three different doses (20, 40, and 60 mg/kg) of VOG were administered intravenously to rats. To study its pharmacokinetics, a simple and rapid HPLC method was developed using hesperidin as internal standard and the relative parameters were calculated by both compartmental and non-compartmental approach. The results showed that VOG fitted a two-compartment open model. The values of AUC increased proportionally within the range of 20-60 mg/kg. Additionally, α half-life, ß half-life, (a)CL, MRT(0→t ), MRT(0→∞ ), and terminal half-life of VOG in rats showed significant differences between 20 mg/kg and other doses. Thereby, VOG presented a dose-dependent pharmacokinetics in the range of 20-60 mg/kg and non-linear pharmacokinetics at lower dose.

LC determination and pharmacokinetic study of hyperoside in rat plasma after intravenous administration.

A simple and specific high-performance liquid chromatographic (HPLC) method was developed for the pharmacokinetic study of hyperoside (HP, isolated from the leaves of Crataegus pinnatifida Bge. var. major) in rats after intravenous administration. The plasma samples were deproteinized with methanol after addition of internal standard (I.S.), baicalin. HPLC analysis was performed on a Diamonsil C18 analytical column, using methanol-0.6% aqueous phosphoric acid (45:55, v/v) as the mobile phase with UV detection at 340 nm. The calibration curve was linear over the range of 0.8921-59.7125 microg/ml in rat plasma. The average extraction recovery of HP was 99.33+/-0.86%, and the relative standard deviations (R.S.D.s) of the intra- and inter-day precisions were no more than 7.8 and 2.5%, respectively. The lower limit of quantification (LLOQ) was 0.8921 microg/ml. The validated method was successfully applied during a pharmacokinetic study in rats after intravenous administration of HP at different doses, and all the results indicated that the pharmacokinetics of HP in rats obeyed nonlinear processes.

HPLC determination of five polyphenols in rat plasma after intravenous administration of hawthorn leaves extract and its application to pharmacokinetic study.

A simple and specific HPLC-UV method was developed to simultaneously determine five active compounds including vitexin-4"-O-glucoside (VG), vitexin-2"-O-rhamnoside (VR), vitexin (VIT), rutin (RUT) and hyperoside (HP) in rat plasma after intravenous administrating the hawthorn leaves extract (HLE). With baicalin as internal standard (I.S.), sample pretreatment involved a one-step extraction with methanol of 0.2 ml plasma. The HPLC assay was carried out using a Phenomsil C18 analytical column with UV detection at 332 nm. The mobile phase consisted of methanol-acetonitrile-tetrahydrofuran-1% glacial acetic acid (6:1.5:18.5:74, v/v/v/v). The calibration curves were liner over the range of 2.030-500.5, 0.1513-75.64, 0.2507-12.54, 0.5128-25.64 and 0.4032-20.16 µg/ml for VG, VR, VIT, RUT and HP, respectively. The relative standard deviations (RSD) of the intra- and inter-day precisions for the analysis of the five analytes were between 1.0 and 8.9% with accuracies (relative error) below 8.2% for the analysis of the five analytes. The average extraction recoveries of five analytes were more than 82.67 ± 4.74%. The HPLC method herein described was fully validated and successfully applied to the pharmacokinetic studies after intravenous administration of HLE solution to rats over three doses.

Investigation on the chemical constituents and variation of the flower buds of Lonicera species by UPLC-ESI-MS/MS and principle component analysis.

A rapid ultra-performance liquid chromatography-electrospray ionization tandem mass spectrometric (UPLC-ESI-MS/MS) method is developed for the qualitative identification of constituents in the flower buds of seven Lonicera species. The optimal condition of separation and detection were achieved on an AcQuity UPLC BEH C18 column with a gradient elution with acetonitrile and 0.1% acetic acid within 17 min. Among the 33 constituents detected, 6 caffeoylquinic acids (including caffeic acid), 8 flavonoids and 8 iridoid glycosides were characterized based on their fragmentation patterns in collision-induced dissociation (CID) experiments and/or by comparison with standard compounds. In addition, to statistically establish the correlation and discrimination of the Lonicera species, principle component analysis (PCA) was applied in this study. Lonicera samples were divided into well-defined groups directly related to their species based on PCA in terms of the log transformed relative contents of the major caffeoylquinic acids (including caffeic acid) as the variables. All of results indicated that the method presented here is able to classify the sample species and to reveal characteristic details of the chemical constituents of different Lonicera species.

The mechanism of hyperoside protection of ECV-304 cells against tert-butyl hydroperoxide-induced injury.

The aim of the present study was to investigate the mechanism of hyperoside protecting ECV-304 cells against tertbutyl hydroperoxide (TBHP)-induced injury. ECV-304 cell viability was measured by MTT assay. Cellular morphologic changes were observed using phase contrast microscopy. The genotoxic effects of TBHP and the protective ability of hyperoside were assessed by the Comet test. Lipid peroxidation was measured by HPLC method. The cellular redox status was determined from GSH/GSSG ratios. Apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. Western blot analysis was used to evaluate the levels of cytochrome c, p53, SIRT1, Bax and Bcl-2 expression. The results showed that 128 mumol/l hyperoside could effectively protect TBHP-treated ECV-304 cells from death, increase superoxide dismutase activity and significantly decrease malondialdehyde production. Hyperoside was effective in protecting against the induction of oxidized DNA bases and redox state alterations induced by TBHP. Furthermore, the release of proapoptotic cytochrome c from mitochondria was reduced by hyperoside, which increased the expression of antiapoptotic SIRT1 and inhibited the translocation of Bax from cytoplasm to mitochondria. Taken together, these results indicate that hyperoside is effective in protecting against the oxidative damage induced by TBHP. The mechanism of hyperoside protecting against ECV-304 cell apoptosis by TBHP is related with resuming mitochondrial function and regulating the expression of SIRT1 and Bcl-2 family members.

HPLC determination of malondialdehyde in ECV304 cell culture medium for measuring the antioxidant effect of vitexin-4''-O-glucoside.

To investigate the antioxidant effect of vitexin-4''-O-glucoside, a flavone glycoside, isolated from the leaves of Crataegus pinnatifida Bge. var. major, we developed a simple and sensitive high-performance liquid chromatography (HPLC) method to determine levels of malondialdehyde (MDA) in ECV304 cell culture medium after induction by tert-butyl-hydroperoxide (TBHP). The preparation of analyzed samples involved a one-step derivatization with thiobarbituric acid (TBA). HPLC analysis was performed on a Synergi Hydro-RP, a polar end-capped C18 column (250 x 4.6 mm, 4 mum), using an acetonitrile-ammonium acetate aqueous solution (10 mM, pH 6.8) as the mobile phase under linear gradient conditions with UV detection at 532 nm. The calibration curve was linear over 0.0125-1.25 microM MDA (r = 0.9951). Relative standard deviations (RSDs) of intra-day and inter-day precision were less than 6.1% and 5.0%, respectively. The mean recovery was 96.9 +/- 1.6%. The lower limit of quantification (LLOQ) of MDA was 0.0125 microM. This chromatographic method was successfully applied to investigating the in vitro antioxidant effect of vitexin-4''-O-glucoside. Vitexin-4''-O-glucoside (120 M) protected ECV304 cells from peroxidation induced by TBHP.

Magnolol-induced H460 cells death via autophagy but not apoptosis.

We have reported that the protective effect of Magnolol on TBHP-induced injury in human nonsmall lung cancer H460 cells is partially via a p53 dependent mechanism. In this study, we found that Magnolol displayed a stimulatory effect at low concentrations (< or = 20 microM) whilst inhibitory effect at high concentrations (> or = 40 microM) in H460 cells. To investigate the mechanism of inducing the biphasic effect in H460 cells with Magnolol, we showed that Magnolol stimulated DNA synthesis at low concentrations and displayed an inhibition effect at high concentrations in H460 cells. More importantly, the inhibition of DNA synthesis was accompanied by the S phase cell cycle arrest and the appearance of intense intracytoplasmic vacuoles. These vacuoles can be labeled by autophagic marker monodansylcadaverin (MDC), 3-methyladenine (3-MA), an inhibitor of autophagy, was able to inhibit the occurrence of autophagy. The results of the LDH activity assay and TUNEL assay also showed that Magnolol at high concentrations inhibiting H460 cell growth was not via apoptotic pathway. Furthermore, accompanied by the occurrence of autophagy, the expression of phospho-Akt was down-regulated but PTEN significantly was up-regulated. In conclusion, Magnolol induces H460 cells death by autophagy but not apoptotic pathway. Blockade of PI3K/PTEN/Akt pathway is maybe related to Magnolol-induced autophagy. Autophagic cells death induction by Magnolol underlines the potential utility of its induction as a new cancer treatment modality.

Protective effect of magnolol on TBHP-induced injury in H460 cells partially via a p53 dependent mechanism.

The aim is to investigate the effect of Magnolol preserved H460 cells from an oxidative agent tert-butylhydroperoxide (TBHP)-induced cell death. Magnolol augmented cell survival ratio after TBHP challenged. The protective action of this drug was more efficacious than that of N-acetylcysteine (NAC) which is a putative antioxidant. DNA damage, detected by the comet assay, was diminished after treatment of Magnolol. The cells viability decreased after treatment with 0.15 mM TBHP for 24 h, accompanied by inducing apoptotic death of the cells. Cytotoxicity and apoptosis induced by TBHP were significantly inhibited or attenuated after pretreatment with 20 microM Magnolol. Magnolol contributes to the cells survival through downregulated the p53 phosphorylation and PTEN expression, and upregulated Akt phosphorylation. Taken together, Magnolol was effective against DNA single strand breaks (SSB) formation, cytotoxicity and lipid peroxidation induced by TBHP, and its effects on p53 phosphorylation, PTEN and Akt phosphorylation were due to its antioxidative function, and partially via a p53 dependent mechanism in this protective effects.

Dried Rehmannia root protects against glutamate-induced cytotoxity to PC12 cells through energy metabolism-related pathways.

Rehmannia has been shown to be clinically effective in treating neurodegenerative diseases; however, the neuroprotective mechanisms remain unclear. In this study, we established a model of neurodegenerative disease using PC12 cytotoxic injury induced by glutamate. The cells were treated with 20 mM glutamate in the absence or presence of water extracts of dried Rehmannia root of varying concentrations (70%, 50% and 30%). The different concentrations of Rehmannia water extract significantly increased the activity of glutamate-injured cells, reduced the release of lactate dehydrogenase, inhibited apoptosis, increased the concentrations of NADH, NAD and ATP in cells, ameliorated mitochondrial membrane potential, and reduced the levels of light chain 3. Taken together, our findings demonstrate that Rehmannia water extracts exert a cytoprotective effect against glutamate-induced PC12 cell injury via energy metabolism-related pathways.

Correction to Three Novel Alkaloids from Portulaca oleracea L. and Their Anti-inflammatory Effects.

Oleracimine and oleracimine A were isolated from Portulaca oleracea L. and described in the J. Agric. Food Chem, but the alternative structures of the two compounds are proposed on the basis of NMR analyses.

Three Novel Alkaloids from Portulaca oleracea L. and Their Anti-inflammatory Effects.

Three novel carbon skeleton alkaloids, named oleracimine (1), oleracimine A (2), and oleracone A (3), with one novel azulene carbon skeleton compound, oleracone B (4), and one known compound, ß-carboline (5), were first isolated from Portulaca oleracea L. The structures were determined using spectroscopic methods, including one- and two-dimensional nuclear magnetic resonance and high-resolution electrospray ionization time-of-flight mass spectrometry techniques. In addition, oleracimine (1) was used to investigate the anti-inflammatory effects on lipopolysaccharide-stimulated macrophages. The results of enzyme-linked immunosorbent assay, western blot, and real-time polymerase chain reaction showed that oleracimine (1) remarkably inhibited nitric oxide production and could dose-dependently decrease the secretions of interleukin 6, tumor necrosis factor α, nitric oxide, and prostaglandin E2 in cell culture supernatants as well as the mRNA of cyclooxygenase-2 and inducible nitric oxide synthase.

Cuscuta chinensis seeds water extraction protecting murine osteoblastic MC3T3-E1 cells against tertiary butyl hydroperoxide induced injury.

ETHNOPHARMACOLOGICAL RELEVANCE: Cuscuta chinensis (C. chinensis) is a well-known traditional Chinese herb that has been used to treat heart disease, diabetes, liver injury, cancer, and aging. MATERIALS AND METHODS: Murine osteoblastic MC3T3-E1 cells were treated with various concentrations of C. chinensis water extraction at different time intervals. The antioxidant effect of C. chinensis on MC3T3-E1 cells was evaluated using MTT and TUNEL assays. The effect of C. chinensis on cell cycle was analyzed by flow cytometry with propidium iodide. Lipid peroxidation was measured by the HPLC method. The cellular redox status was determined from the reduced glutathione to oxidized glutathione ratio (GSH/GSSG) and the enzymes involved in glutathione metabolism, including glutathione reductase (GR), Glutathione S-transferase (GST), and Glucose-6-phosphate dehydrogenase (G6PD). The changes in relative mitochondrial transmembrane potential (ΔΨm) in the MC3T3-E1 cells were analyzed with rhodamine 123 staining. Western blot analysis was used to evaluate the levels of cytochrome c (cyto c), Bax, Bcl-2, caspase 3, Sirt3, and IDH2 expressions. RESULTS: The C. chinensis water extraction protects tertiary butyl hydroperoxide (TBHP)-treated MC3T3-E1 cells from death in a dose-dependent manner. C. chinensis treatment significantly inhibited the reactive oxygen species (ROS) generation, malondialdehyde (MDA) production, and increased the activity of superoxide dismutase (SOD), GR, GST, and G6PD. The release of cyto c from mitochondria was reduced by C. chinensis, which increased the expression of antiapoptotic IDH2, Sirt3, and Bcl-2 and decreased the expression of Bax, cyto c, and caspase 3. CONCLUSIONS: C. chinensis modulated the oxidative stress-induced apoptosis in MC3T3-E1 cells, probably due to its antioxidant activity and functioning via mitochondria-dependent pathways.

The mechanism of vitexin-4''-O-glucoside protecting ECV-304 cells against tertbutyl hydroperoxide induced injury.

The aim of this article is to investigate the mechanism of vitexin-4''-O-glucoside (VOG) protecting ECV-304 cells against tertbutyl hydroperoxide (TBHP)-induced injury. ECV-304 cell viability was measured by MTT assay. Apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling (TUNEL) assay. Cellular morphological changes were observed using phase contrast microscopy. The change of relative mitochondrial transmembrane potential in the ECV-304 cells was analysed with rhodamine 123 staining. Lipid peroxidation was measured by the HPLC method. The results showed that 128 µmol L(-1) VOG could effectively protect ECV-304 cells against cytotoxicity induced by TBHP. VOG protected TBHP-treated ECV-304 cells from death, significantly decreased MDA production, and increased superoxide dismutase (SOD) activity and mitochondrial membrane potential (ΔΨ). Taken together, VOG protects against TBHP-induced ECV-304 cell injury partially through resuming mitochondrial function.