Shi-Lin Chen

Identification of Dendrobium Species by a Candidate DNA Barcode Sequence: The Chloroplast psbA-trnH Intergenic Region

DNA barcoding is a novel technology that uses a standard DNA sequence to facilitate species identification. Although a consensus has not been reached regarding which DNA sequences can be used as the best plant barcodes, the psbA-trnH spacer region has been tested extensively in recent years. In this study, we hypothesize that the psbA-trnH spacer regions are also effective barcodes for Dendrobium species. We have sequenced the chloroplast psbA-trnH intergenic spacers of 17 Dendrobium species to test this hypothesis. The sequences were found to be significantly different from those of other species, with percentages of variation ranging from 0.3 % to 2.3 % and an average of 1.2 %. In contrast, the intraspecific variation among the Dendrobium species studied ranged from 0 % to 0.1 %. The sequence difference between the psbA-trnH sequences of 17 Dendrobium species and one Bulbophyllum odoratissimum ranged from 2.0 % to 3.1 %, with an average of 2.5 %. Our results support the notion that the psbA-trnH intergenic spacer region could be used as a barcode to distinguish various Dendrobium species and to differentiate Dendrobium species from other adulterating species.

Xanthones with growth inhibition against HeLa cells from Garcinia xipshuanbannaensis.

Eight prenylated xanthones, bannaxanthones A-H (1-8), together with seven known compounds, were isolated from the acetone extract of the twigs of Garcinia xipshuanbannaensis. Their structures were elucidated by spectroscopic data interpretation. The cytotoxic activities of these compounds were evaluated using the MTT method. The results showed that xanthones with an unsaturated prenyl group had stronger cytotoxic activity against cancer cells, whereas those with hydroxylated prenyl groups had none.

Cytotoxic Polyprenylated Xanthones from the Resin of Garcinia hanburyi

Thirteen xanthones (1-13) were isolated from the resin of Garcinia hanburyi. Among them, two new compounds (namely gaudichaudic acid, and isogambogenic acid, 1, 2), and one new natural product (deoxygaudichaudione A, 3) were identified on the basis of extensive spectral evidence including detailed 2D NMR data. Ten of these xanthones were tested for their cytotoxicities against human leukemia K562 (K562/S) and doxorubicin-resistant K562 (K562/R) cell lines, and showed similar inhibitory effects on both cell lines, suggesting that this group of polyprenylated xanthones might not be multidrug resistance (MDR) substrates.

Comparative Physicochemical Characterization of Phospholipids Complex of Puerarin Formulated by Conventional and Supercritical Methods

PurposeThe aim of this work was to compare the physicochemical characteristics of the phospholipids complex of puerarin (Pur) prepared by traditional methods (solvent evaporation, freeze-drying and micronization) and a supercritical fluid (SCF) technology. The physicochemical properties of the pure drug and the corresponding products prepared by two different SCF methods were also compared.MethodsSolid-state characterization of particles included differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), solubility, dissolution rate and scanning electron microscopy (SEM) examinations. Besides puerarin phospholipids complex (PPC) by four different methods, the solid-state properties of unprocessed, gas antisolvent (GAS) crystallized and solution enhanced dispersion by supercritical fluid (SEDS) precipitated puerarin samples were also compared. Crystallinity was assessed using DSC and XRPD. Drug-phospholipids interactions were characterized using Fourier transform infrared spectroscopy (FTIR). SEM was used to determine any morphological changes. Pharmaceutical performance was assessed in dissolution rate and solubility tests.ResultThe results of the physical characterization attested a substantial correspondence of the solid state of the drug before and after treatment with GAS technique, whereas a pronounced change in size and morphology of the drug crystals was noticed. The GAS-processed puerarin exhibited a better crystal shape confirmed by DSC, XRPD and IR. Polymorphic change of puerarin during SEDS coupled with the dramatic reduction of the dimensions determined a remarkable enhancement of its solubility and in vitro dissolution rate. Phospholipids complex prepared using supercritical fluid technology showed similar properties of physical state, thermal stability and molecular interaction with phospholipids (PC) to those of corresponding systems prepared by other three conventional methods namely solvent evaporation, freeze-drying and micronization as proved by XRPD, DSC, and FTIR. The best dissolution rate was obtained by SEDS-prepared complex, while the highest solubility was obtained for solvent evaporation method.ConclusionSupercritical fluid technology for the preparation of puerarin and its phospholipids complex has been proven to have significant advantages over the solvent evaporation technique and other conventional methods.

Apoptotic effects of polyprenylated benzoylphloroglucinol derivatives from the twigs of Garcinia multiflora.

With bioassay-guided fractionation, five new polyprenylated benzoylphloroglucinol derivatives, garcimultiflorone D (1), 18-hydroxygarcimultiflorone D (2), garcimultiflorone E (3), garcimultiflorone F (4), and isogarcimultiflorone F (5), and five known compounds, guttiferone E (6), guttiferone F (7), aristophenone A (8), isoxanthochymol (9), and morelloflavone (10), were isolated from the acetone extract of the twigs of Garcinia multiflora. The compounds were evaluated for their apoptotic effects against HeLa-C3 cells, which have been genetically engineered to produce a fluorescent biosensor capable of detecting caspase-3 activation. Compounds 1 and 3-9 activate caspase-3 in HeLa-C3 cells within 72 h after treatment at a concentration of 100 microM or lower. In particular, compounds 6, 8, and 9 showed strong apoptosis-inducing effects at a concentration of 25 microM.

Process parameters and morphology in puerarin, phospholipids and their complex microparticles generation by supercritical antisolvent precipitation

The aim of the study was to develop and evaluate a new method for the production of puerarin phospholipids complex (PPC) microparticles. The advanced particle formation method, solution enhanced dispersion by supercritical fluids (SEDS), was used for the preparation of puerarin (Pur), phospholipids (PC) and their complex particles for the first time. Evaluation of the processing variables on PPC particle characteristics was also conducted. The processing variables included temperature, pressure, solution concentration, the flow rate of supercritical carbon dioxide (SC-CO2) and the relative flow rate of drug solution to CO2. The morphology, particle size and size distribution of the particles were determined. Meanwhile Pur and phospholipids were separately prepared by gas antisolvent precipitation (GAS) method and solid characterization of particles by the two supercritical methods was also compared. Pur formed by GAS was more orderly, purer crystal, whereas amorphous Pur particles between 0.5 and 1microm were formed by SEDS. The complex was successfully obtained by SEDS exhibiting amorphous, partially agglomerated spheres comprised of particles sized only about 1microm. SEDS method may be useful for the processing of other pharmaceutical preparations besides phospholipids complex particles. Furthermore adopting a GAS process to recrystallize pharmaceuticals will provide a highly versatile methodology to generate new polymorphs of drugs in addition to conventional techniques.

Identification and evaluation of apoptotic compounds from Garcinia paucinervis.

Four new compounds, paucinervins A-D (1-4), and 15 known ones were isolated from the leaves of Garcinia paucinervis. The structures of the new compounds were elucidated by spectroscopic evidences. All of the 19 compounds were evaluated for their apoptosis-inducing effects using HeLa-C3 cells which have been genetically engineered to possess a fluorescent biosensor capable of detecting caspase-3 activation. Eight of them were found to activate caspase-3 in HeLa-C3 cells within 72 h at the concentration of 25 microM. Moreover, the values of IC50 were measured for all four new compounds on HeLa cells using the MTT assay. Among them, compound 2 (paucinervin B) had the lowest IC50 value of 9.5 microM, while the other three new compounds had much higher IC50 values of 29.5, 52.5, and 95.6 microM, respectively. This result shows that paucinervin B has the strongest inhibitory effect against HeLa cell growth among these four newly identified paucinervins and it may have the potential to be developed into a new anticancer candidate.

The effect of puerarin on serum nitric oxide concentration and myocardial eNOS expression in rats with myocardial infarction

Puerarin (1) is a major effective ingredient extracted from the traditional Chinese medicine Ge-gen (Radix Puerariae, RP). Recently, puerarin has been used to treat patients with coronary artery diseases (CAD). However, the mechanisms of puerarin on CAD are still not very clear. In this study, we investigated the role of puerarin on serum nitric oxide (NO) concentration, myocardial endothelial nitric oxide synthase (eNOS) gene expression, the protein expression of eNOS and inducible nitric oxide synthase (iNOS), as well as the level of protein kinase B (Akt/PKB) phosphorylation in rats with myocardial infarction. We found that puerarin (120 mg/kg/day, i.p.) could increase serum nitrite concentration in rat with myocardial ischemia (MI). It also induced the gene expression or activation of eNOS, protein expression of eNOS, and the Akt/PKB phosphorylation. From these results, we suggested that puerarin could increase serum nitric oxide level of rat with myocardial infarction, which should be one of the mechanisms of the therapeutic effect of puerarin on CAD. The increased expression of eNOS and the Akt/PKB pathway may be the underlying mechanism by which puerarin stimulates NO production.Two new lanostane triterpenoids, 29-hydroxypolyporenic acid C (4) and 25-hydroxypachymic acid (5), together with three known compounds, ergosta-7,22-dien-3beta-ol (1), polyporenic acid C (2) and pachymic acid (3), were isolated from the 95% ethanolic extract of the sclerotium of Poria cocos (Schw.) Wolf. Their structures were determined by extensive spectroscopic analyses, including IR, UV, ESITOF-MS, HRESI-MS, 1D and 2D NMR data (1H NMR, 13C NMR, 1H-1H COSY, NOESY, HSQC and HMBC).

Maturation of Murine Bone Marrow-Derived Dendritic Cells Induced by Radix Glycyrrhizae Polysaccharide

Radix Glycyrrhizae polysaccharide (GP), the most important component of Radix Glycyrrhizae, has been reported to have many immunopharmacological activities. However, the mechanism by which GP affects dendritic cells (DCs) has not been elucidated. In this study, we investigated the effect of GP on murine bone marrow-derived DCs and the potential pathway through which GP exerts this effect. Mononuclear cells (MNCs) were isolated from murine bone marrow and induced to become DCs by culturing with GM-CSF and IL-4. Six days later, DCs were divided into three groups: control group, GP group and LPS group. After 48 h of treatment, phenotypic figures and antigen uptake ability were determined by FACS analysis. The proliferation of DC-stimulated allogenic CD3+ T cells was detected by WST-1. IL-12 p70 and IFN-γ, which are secreted by DCs and CD3+ T cells respectively, were quantified by ELISA. Additionally, IL-12 p40 mRNA expression was determined by real-time PCR. Alterations in TLR4-related signaling pathways were examined by performing an antibody neutralization experiment. Treatment of DCs with GP resulted in the enhanced expression of the cell surface molecules CD80, CD86 and MHC I-A/I-E. GP also increased the production of IL-12 p70 by DCs in a time-dependent manner. The endocytosis of FITC-dextran by DCs was suppressed by GP administration. Furthermore, GP-treated DCs enhanced both the proliferation and IFN-γ secretion of allogenic CD3+ T cells. Finally, the effects of GP on DCs were partially reduced by using inhibitors of TLR4, NF-κB, p38 MAPK or JNK. In conclusion, GP can induce the maturation of DCs, and does so, in part, by regulating a TLR4-related signaling pathway.

The effect of triptolide on CD4+ and CD8+ cells in the Peyer's patch of DA rats with collagen induced arthritis.

Triptolide is a purified component from a traditional Chinese herb Tripterygium wilfordii Hook F. It has been shown to have anti-inflammatory and immunosuppressive activities by its inhibitory effect on T-cells. But the effect of triptolide on enteric mucosal immune responses is not well known. The enteric mucosal immune system, especially the Peyers patch, is regarded as one of the sites for inducing immunity tolerance, and this intolerance effect has been used to induce oral tolerance, which can considerably reduce arthritis severity in several models of experimental polyarthritis and rheumatoid arthritis (RA) patients. In this study, we investigated the effect of triptolide on the CD4+ and CD8+ cell distribution in Peyers patch cells and periphery lymphocytes and TGF-β and IFN-γ levels in periphery in collagen induced arthritis (CIA) in DA rats. CIA in the rat is a widely studied animal model of inflammatory polyarthritis, with similarities to RA, and the DA rat is one of most susceptible strains for CIA. Our data show that triptolide could lower the arthritic scores of CIA. The more CD8+ cells in the Peyers patch, the more CD4+ cells in periphery. High level IFN-γ and low level TGF-β in periphery are observed in CIA rats, while the less CD4+ and CD8+ cells in the Peyers patch, the less CD4+ cells in periphery. Low level IFN-γ and high level TGF-β in periphery are shown in triptolide-treated rats. The dose dependency of triptolide was observed in periphery CD4 cells and in the arthritic score. Therefore, the effect of triptolide on Peyers patch immune cells might partially explain some of the immunosuppressive activities of triptolide.