[Show abstract][Hide abstract] ABSTRACT: 1. The purpose of this study was to investigate the mechanism of hepatic uptake of berberine. Berberine accumulation in hepatocytes was found to be highly dependent on active uptake, which could not be explained by liver organic cation transporter (OCT) alone. 2. Our studies indicated that berberine uptake was significantly suppressed by rifampicin, cyclosporine A and glycyrrhizic acid, which act as specific inhibitors of different Oatp isoforms (Oatp1a1, Oatp1a4 and Oatp1b2) in rat hepatocytes. The combination of OCT and OATP inhibitors further reduced berberine accumulation in both rat and human hepatocytes. The uptake of berberine could be increased in human HEK293-OATP1B3 but not in OATP1B1-transfected HEK 293 cells. 3. Rifampicin could reduce the berberine liver extraction ratio (ER) and double its concentration in the effluent in isolated rat livers. Further in vivo study indicated that berberine plasma exposure could be significantly increased by co-administration of the OATP inhibitor rifampicin or the substrate rosuvastatin. 4. In conclusion, this study demonstrated that both OCT and OATP contribute to the accumulation of berberine in the liver. OATPs may have important roles in berberine liver disposition and potential clinically relevant drug--drug interactions.
[Show abstract][Hide abstract] ABSTRACT: Aim:
To investigate the mechanisms underlying the hepatotoxicity of timosaponin A3 (TA3), a steroidal saponin from Anemarrhena asphodeloides, in rats.
Male SD rats were administered TA3 (100 mg·kg−1·d−1, po) for 14 d, and the blood and bile samples were collected after the final administration. The viability of a sandwich configuration of cultured rat hepatocytes (SCRHs) was assessed using WST-1. Accumulation and biliary excretion index (BEI) of d8-TCA in SCRHs were determined with LC-MS/MS. RT-PCR and Western blot were used to analyze the expression of relevant genes and proteins. ROS and ATP levels, and mitochondrial membrane potential (MMP) were measured. F-actin cytoskeletal integrity was assessed under confocal microscopy.
TA3 administration in rats significantly elevated the total bile acid in serum, and decreased bile acid (BA) component concentrations in bile. TA3 inhibited the viability of the SCRHs with an IC50 value of 15.21±1.73 μmol/L. Treatment of the SCRHs with TA3 (1–10 μmol/L) for 2 and 24 h dose-dependently decreased the accumulation and BEI of d8-TCA. The TA3 treatment dose-dependently decreased the expression of BA transporters Ntcp, Bsep and Mrp2, and BA biosynthesis related Cyp7a1 in hepatocytes. Furthermore, the TA3 treatment dose-dependently increased ROS generation and HO-1 expression, decreased the ATP level and MMP, and disrupted F-actin in the SCRHs. NAC (5 mmol/L) significantly ameliorated TA3-induced effects in the SCRHs, whereas mangiferin (10–200 μg/mL) almost blocked TA3-induced ROS generation.
TA3 triggers liver injury through inducing ROS generation and suppressing the expression of BA transporters. Mangiferin, an active component in Anemarrhena, may protect hepatocytes from TA3-induced hepatotoxicity.
[Show abstract][Hide abstract] ABSTRACT: The anti-HIV-1 activity of mangiferin was evaluated. Mangiferin can inhibit HIV-1(Ⅲ)(B) induced syncytium formation at non-cytotoxic concentrations, with a 50% effective concentration (EC₅₀) at 16.90 μM and a therapeutic index (TI) above 140. Mangiferin also showed good activities in other laboratory-derived strains, clinically isolated strains and resistant HIV-1 strains. Mechanism studies revealed that mangiferin might inhibit the HIV-1 protease, but is still effective against HIV peptidic protease inhibitor resistant strains. A combination of docking and pharmacophore methods clarified possible binding modes of mangiferin in the HIV-1 protease. The pharmacophore model of mangiferin consists of two hydrogen bond donors and two hydrogen bond acceptors. Compared to pharmacophore features found in commercially available drugs, three pharmacophoric elements matched well and one novel pharmacophore element was observed. Moreover, molecular docking analysis demonstrated that the pharmacophoric elements play important roles in binding HIV-1 protease. Mangiferin is a novel nonpeptidic protease inhibitor with an original structure that represents an effective drug development strategy for combating drug resistance.
[Show abstract][Hide abstract] ABSTRACT: A rapid, sensitive, and specific method by high-performance liquid chromatography (HPLC) coupled to diode-array detection (DAD) and tandem mass spectrometry (MS) techniques was developed for the identification of absorbed constituents and their metabolites in rats after the oral administration of a Chai-Huang decoction (CHD), which consists of Bupleurum chinense and Scutellaria baicalensis in the proportion 1 : 1 (w/w). By comparing their retention times and MS data with those of authentic compounds and published data, a total of 14 compounds were identified in the CHD samples. In addition, eleven and seven compounds were characterized in the urine and serum samples of the rats, respectively. The results indicated that the main absorbed constituents were chrysin-6-C-arabinosyl-8-C-glucoside, chrysin-6-C-glucosyl-8-C-arabinoside, baicalin, wogonin-5-O-glucoside, oroxylin A-7-O-glucuronide, wogonoside, saikosaponin A, saikosaponin C, saikosaponin D, baicalein, and wogonin. These compounds might be responsible for the curative effects of the CHD. The findings demonstrated that the proposed method could be used to rapidly and simultaneously analyze and screen the multiple absorbed bioactive constituents in a formula of traditional Chinese medicines (TCM). This is very important not only for the pharmaceutical discovery process and the quality control of crude drugs but also to explain the mechanisms of action of TCM.
[Show abstract][Hide abstract] ABSTRACT: To profile the anti-Coxsackie virus B3 constituents of Radix Astragali, an HPLC-DAD-MS(n) analytical method, combined with an in vivo test, has been developed to identify the constituents of the active part, which has been demonstrated to have potency to inhibit the proliferation of virus in cardiac muscle, alleviate infraction in heart and elevate the survival rate of the animal. By comparing their retention time and MS data with those obtained from the authentic compounds and the published data, a total of 19 compounds, including 11 isoflavonoids and eight saponins, were identified, among which one pterocarpane glucoside was reported for the first time. The present study provides an approach to rapidly screening bioactive constituents in traditional Chinese medicines.
[Show abstract][Hide abstract] ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
[Show abstract][Hide abstract] ABSTRACT: A new iridoid alkaloid containing a spirolactone unit, plumericidine (1), was isolated from the flowers of Plumeria rubra L. cv. Acutifolia. Its structure was elucidated by spectroscopic evidence and confirmed by X-ray diffraction crystallography. Its anticancer and antiviral activities were evaluated, but found to be insignificant.
[Show abstract][Hide abstract] ABSTRACT: A rapid, sensitive, and specific high-performance liquid chromatography (HPLC), diode-array detection, and mass-spectrometry techniques were developed for an identification of the constituents of Cortex Phellodendri and their metabolites in rat urine. The dose of 10 ml/kg of Cortex Phellodendri decoction was used for rats' oral administration. 0-24-h Urine was purified using a C18 solid-phase extraction cartridge, and then analyzed by an on-line MS detector. A total of 13 characteristic HPLC peaks were detected in the urine samples. Nine of them, including five alkaloids and four of their metabolites, were tentatively elucidated as magnoflorine (1), the glucuronide conjugate of demethy-leneberberine (2), menisperine (3), jatrorrhizine 3-O-glucuronide (4), berberubine 9-O-glucuronide (5), jatrorrhizine (6), the monomethyl and monohydroxy catabolite of berberubine (7), palmatine (8), and berberine (9). Identification and structural elucidation of the metabolites were performed by comparing their MSn spectra data with those reported.
[Show abstract][Hide abstract] ABSTRACT: Two new iridoid diastereoisomers (1, 2), together with five known compounds, were isolated from the flowers of Plumerian rubra L. cv. acutifolia. Their structures were elucidated by the means of in-depth spectroscopic and mass-spectrometric analyses, particularly 1D and 2D NMR spectroscopy.
Magnetic Resonance in Chemistry 12/2008; 46(12):1195-7. DOI:10.1002/mrc.2331 · 1.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: By the guidance of bioassay, one new cytotoxic triterpenoid saponin, 3-O-[beta-D-galactopyranosyl-(1-->2)-beta-D-glucuronopyranosyl] quillaic acid 28-O-beta-D-glucopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->2)-[beta-D-fucopyranosyl-(1-->4)]-beta-D-fucopyranoside (1), and five known cytotoxic triterpenoid saponins, vaccaroside E (2), vaccaroside G (3), vaccaroside B (4), segetoside H (5) and segetoside I (6), were isolated from Vaccaria segetalis. Their structures were established on the basis of ESI-MS, IR, extensive NMR ((1)H NMR, (13)C NMR, TOCSY, (1)H-(1)H COSY, DEPT, HMQC, HMBC and ROESY) analyses, chemical degradation, and by comparing with previously reported data. Compounds 1-6 showed moderate cytotoxic activities against LNcap, P-388 and A-549 cell lines with IC(50) values in the range 0.1-12.9 microM.
Journal of Asian Natural Products Research 02/2008; 10(1-2):177-84. DOI:10.1080/10286020701394381 · 0.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Four metabolites of mangiferin were firstly isolated and identified from rat urine. The structures of the four metabolites were determined to be 1,3,7-trihydroxyxanthone (M-1), 1,3,6,7-tetrahydroxyxanthone (M-2), 1,3,6-trihydroxy-7-methoxyxanthone (M-3) and 1,7-dihydroxyxanthone (M-4), respectively. A simple and specific analytical method for determination of the four metabolites in rat urine was developed by high performance liquid chromatography (HPLC). Quercetin was employed as an internal standard. The correlation coefficients of the calibration curves were higher than 0.997, both intra- and inter-day precision of four metabolites were determined and their R.S.D. did not exceed 10%. The accuracy and linear range had been investigated in detail. The cumulative urinary excretions of the four metabolites were measured and the possible metabolic pathway of the metabolites was discussed.
Journal of Pharmaceutical and Biomedical Analysis 01/2008; 45(5):793-8. DOI:10.1016/j.jpba.2007.07.019 · 2.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A reversed-phase high-performance liquid chromatographic (HPLC) assay for calycosin-7-O-beta-D-glucopyranoside in rat plasma and urine with solid-phase extraction (SPE) was developed. Rutin was employed as an internal standard. The mobile phase consisted of acetonitrile-water (16:84, v/v) at a flow rate of 1.0 mL/min. Detection was set at 280 nm. The limit of quantitation of calycosin-7-O-beta-D-glucopyranoside was 0.2 microg/mL in both plasma and urine. The standard curve was linear from 0.2 to 10.0 microg/mL in plasma, and 0.2 to 5.0 microg/mL in urine. Both intra- and inter-day precision of the calycosin-7-O-beta-d-glucopyranoside were determined and their RSD did not exceed 10%. The method was successfully applied to the analysis of samples obtained from a basic pharmacokinetic study, in which calycosin-7-O-beta-d-glucopyranoside was administered orally to rats.
[Show abstract][Hide abstract] ABSTRACT: Anti-DHBV (duck hepatitis B virus) activity was found in the aqueous extracts of Sophora flavescens Ait. in vivo. Liquid chromatography/electrospray ionization ion trap mass spectrometry was applied to characterize the components in duck serum after oral administration of S. flavescens extract. Oxymatrine (1), sophoranol (2), sophoridine (3) and matrine (4) were identified in the serum. Further research on the four compounds was evaluated for their antiviral activity against HBV (hepatitis B virus) in cell culture. The results suggested that oxymatrine, sophoranol and matrine were the efficacy substances for anti-HBV activity in aqueous extracts of S. flavescens Ait.
[Show abstract][Hide abstract] ABSTRACT: A high-performance liquid chromatographic method with UV detection has been developed for the determination of saikosaponin a in rat plasma. Saikosaponin a and internal standard jujuboside A were isolated from plasma samples by solid-phase extraction. The chromatographic separation was achieved on a reversed-phase C(18) column with the mobile phase of acetonitrile-water (35:65, v/v) at a flow rate of 1 mL/min and UV detection was set at 205 nm. The standard curve for saikosaponin a was linear over the concentration range 0.25-10 microg/mL and the limit of detection was 0.05 microg/mL. The absolute recovery was greater than 82%. The precision and accuracy ranged from 3.05 to 9.59% and 95.61 to 110.00%, respectively. The validated method was used to determine saikosaponin a in plasma samples in a pharmacokinetic study of saikosaponin a administered to Sprague-Dawley rats.
[Show abstract][Hide abstract] ABSTRACT: A novel sesquiterpene glycoside was isolated from the whole plant of Ixeris sonchifolia. The structure was established as 1(10)E-4Z-3alpha-hydroxy-germacra-1(10),4,11(13)-trien-6, 12-olide-14-O-beta-D-glucopyranoside (1) on the basis of spectroscopic techniques and chemical analysis.
Magnetic Resonance in Chemistry 04/2007; 45(4):362-3. DOI:10.1002/mrc.1960 · 1.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ellagic acid derivatives were isolated from Dipentodon sinicus and their structures were identified as 3,3′,4′-tri-O-methylellagic acid (1), 3,3′-di-O-methylellagic acid (2), 4,4′-di-O-methylellagic acid (3), 3,3′-di-O-methylellagic acid-4′-O-α-L-rhamnopyranoside (4), 3,3′,4′-tri-O-methylellagic acid-4′-O-β-D-glucopyranoside (5), 3,3′-di-O-methylellagic acid-4′-O-β-D-glucopyranoside (6), and ellagic acid (7). All the compounds were isolated for the first time from the title plant.