Tingguo Kang

Dammarane-type saponins from Panax quinquefolium and their inhibition activity on human breast cancer MCF-7 cells

A new compound, named quinquefoloside-L(c) (1), together with nine known compounds, was isolated from leaves of Panax quinquefolium, and its structure was elucidated as 3beta,12beta, 20S-trihydroxy-25-methoxydammar-23-ene 3-O-beta-D-glucopyranosyl (1-->2)beta-D-glucopyranosyl-20-O-beta-D-xylopyanosyl (1-->6) beta-D-glucopyranoside (1), on the basis of MS, 1D-and 2D-NMR experiments as well as by chemical degradation. The cytotoxicity of these compounds against human breast cancer MCF-7 cell line was also tested by MTT method.

Studies on the anti-psoriasis constituents of Oplopanax elatus Nakai.

Seven compounds were isolated from roots and stems of Oplopanax elatus, of which compounds 3, 4, 5 and 6 were isolated for the first time from the title plant; compounds 1 and 2 are new compounds and characterised to be 3,3′-dimethoxy-4,9,9′-trihydroxy-4′,7-epoxy-5′8-lignan-4,9-bis-O-β-D-glucopyranoside and 5-methoxylariciresinol-4-O-β-D-glucopyranoside on the basis of NMR spectra and CD spectrum.

The anaphylactoid constituents in Xue-Sai-Tong injection.

Xue-Sai-Tong injection, a traditional Chinese medicine with total saponins of Sanqi ginseng as active ingredients, has been used for more than 500 years to treat coronary artery disease in China. Anaphylactoid reaction induced by Xue-Sai-Tong injection was one of the main adverse drug reactions which has occurred frequently in recent years. It is of importance to elucidate its anaphylactoid constituents. The in vivo anaphyalctoid tests indicated that the anaphylactoid mediators could be used as indexes to evaluate the anaphylactoid action. Further, the in vitro model based on determining the mediators release from the degranulation of mast cells and RBL-2H3 cells stimulated by Xue-Sai-Tong injection was explored. Mediators released from mast cells and RBL-2H3 cells caused by Xue-Sai-Tong injection were determined by comparison of the methods of fluorospectrophotometry, ELISA, and spectrophotometry, respectively, revealing that the histamine release induced by the Xue-Sai-Tong injection could not be assayed accurately by the method of fluorospectrophotometry because of the interference of saponins and unknown components in the injection. The rat peritoneal mast cell was also not an optimal cell model for determining histamine and β-hexosaminidase release due to the higher spontaneous release ratio during the cell collection. Thus, ELISA determination of the histamine release from RBL-2H3 cells is a suitable in vitro model to assay the anaphylactoid reaction of Xue-Sai-Tong injection. Previously, abnormal hemolysis in some batches of Xue-Sai-Tong injection was observed in the course of their HD₅₀ (half hemolytic dosage) determination. This study further found that injections which exhibited an abnormal hemolysis phenomenon also caused a higher release of the anaphylactoid mediators from RBL-2H3 cells, indicating the HD₅₀ could be an auxiliary index to evaluate anaphylactoid action of the herbal injection indirectly. Research for anaphylactoid components in Xue-Sai-Tong injection indicated that proteins with over 10 KDa of molecular weight, but not ginsenosides, could be the main constituents inducing the release of anaphylactoid mediators from RBL-2H3 cells. An HPLC method for protein determination in the Xue-Sai-Tong injection was established subsequently, and the content of proteins with molecular weights of over 10 KDa in the injections showed an obviously positive correlation with the histamine release induced by the injections. In addition, taking ginsenoside-Rd coupled with BSA as an example, the hapten property of ginsenosides was studied and the ratio of ginsenoside-Rd to BSA was determined to be 8:1 by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and the ginsenoside-BSA conjugate showed a stronger action to stimulate histamine release from the RBL-2H3 cells.

A new angeloylated triterpenoid saponin from the husks of Xanthoceras sorbifolia Bunge

A new angeloylated oleanane-type triterpenoid saponin, sorbifoliaside (1), and a known saponin, xanifolia O54, were isolated from the husks of Xanthoceras sorbifolia Bunge. Their chemical structures were elucidated on the basis of various spectroscopic analyses coupled with chemical degradation. To our knowledge, compound 1 is the first example of a naturally occurring triterpenoid saponin with an angeloyl group at C-2 of the sugar moiety.

Biotransformation of isoimperatorin by rat liver microsomes and its quantification by LC-MS/MS method.

The aim of the present research was to establish a comprehensive strategy to identify the metabolites of isoimperatorin after biotransformation with rat liver microsomes in vitro, and further describe metabolic kinetic characteristics of isoimperatorin and its main metabolites. Utilizing liquid chromatography with time of flight mass spectrometry (LC-TOF-MS), 18 metabolites (M 1-18) were characterized according to the typical fragment ions and literature data. Among them, M-2, 3, 5, 9, 10, and 15 were new compounds. To further verify structures of the metabolites, five main metabolites were obtained from the magnifying biotransformation incubation system, and their chemical structures were elucidated as 8-hydroxyoxypeucedanin (M-3), hydroxypeucedanin hydrate (M-4), E-5-(4-hydroxy-3-methyl-2-alkenyloxy)-psoralen (M-11), Z-5-(4-hydroxy-3-methyl-2-alkenyloxy)-psoralen (M-12), and oxypeucedanin (M-16) by various spectroscopy methods including IR, MS and NMR. A simple new liquid chromatography with triple quadrupole tandem mass spectrometry (LC-QqQ-MS) method was developed for the simultaneous determination of isoimperatorin and its main metabolites. The analysis was performed on a Diamonsil™ ODS C18 column with acetonitrile-water containing 0.1% formic acid as mobile phase. Total run time was 20.0 min. The results suggested that the method we exhibited was successfully applied for analysis of isoimperatorin and its metabolites. The study provides essential data for proposing metabolite pathway and further pharmacological study of isoimperatorin.

Protective effect of arctigenin against MPP+ and MPTP-induced neurotoxicity.

The potential protective effects of arctigenin on 1-methyl-4-phenylpyridinium ion and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyride-induced neurotoxicity were examined, and the results indicated that arctigenin could improve the movement behaviors and upregulate dopamine and γ-aminobutyric acid levels in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyride-induced neurotoxicity mouse model. A further in vitro experiment showed that the pretreatment with arctigenin on cultured human neuroblastoma SH-SY5Y cells could obviously attenuate the decrease of cell survival rates caused by treatment with 1-methyl-4-phenylpyridinium ion by way of acting against cell apoptosis through the decrease of Bax/Bcl-2 and caspase-3, and by antioxidative action through reduction of the surplus reactive oxygen species production and downregulation of mitochondrial membrane potential. It is for the first time that a neuroprotective activity of arctigenin in both in vitro and in vivo experiments was reported, enlightening that arctigenin could be useful as a potential therapeutic agent for Parkinsons disease.

Pharmacokinetic study of arctigenin in rat plasma and organ tissue by RP-HPLC method

A high-performance liquid chromatography (HPLC) technique was developed for the determination of arctigenin in plasma and various organs of rats after the oral administration of 30, 50 and 70 mgkg−1 of arctigenin to the Sprague–Dawley rats. Results showed that the validated HPLC method was simple, fast, reproducible and suitable to the determination of arctigenin in rat plasma and organ tissue and one-compartmental model with zero-order absorption process can well describe the changes of arctigenin concentration in the plasma. The concentration of compound was highest in the spleen, less in the liver and the least in the lung.

Simultaneous determination of three polyphenols in rat plasma after orally administering hawthorn leaves extract by the HPLC method.

A simple and sensitive HPLC method was developed to simultaneously determine three active compounds, vitexin-4″-O-glucoside (VG), vitexin-2″-O-rhamnoside (VR) and hyperoside (HP), in rat plasma after administering the hawthorn leaves extract (HLE). An HPLC assay with baicalin as the internal standard 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 linear over the range of 2.5–500, 0.2–25 and 0.25–12.5 µg mL–1 for VG, VR and HP, respectively. The method was reproducible and reliable, with relative standard deviations of the intra- and inter-day precision between 1.2% and 13.2% for the analysis of the three analytes. The validated HPLC method herein described was successfully applied to the pharmacokinetic study of VG, VR and HP after oral administration of HLE to rats over the dose range of 2.5–10 mL kg–1.

A rapid method for chemical fingerprint analysis of Pan Panax notoginseng powders by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

A method coupling ultra-performance liquid chromatography (UPLC) with quadrupole time-of-flight mass spectrometer (Qtof MS) using the electrospray ionization (ESI) source was developed for the identification of the major saponins from Panax notoginseng powder (PNP). Ten different PNP samples were analyzed and evaluated for their quality by similarity evaluation and principle component analysis (PCA). Based on the accurate mass, summarized characteristic fragmentation behaviors, retention times of different types of saponins, related botanical biogenesis, and reported chromatographic behavior of saponins, fifty-one common peaks were effectively separated and identified, including 28 protopanaxadiol saponins and 18 protopanaxatriol saponins. Simultaneously, 15 significant discrepancy compounds were identified from the disqualified PNP samples. The established UPLC/Qtof MS fingerprint method was successfully applied for profiling and identifying the major saponins of PNP, providing a fast quality evaluation tool for distinguishing the authentic PNP and the adulterated products.

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

Abstract 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 μgċ 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.