Hainan Medical University

Haikou, China
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Yu K.,CAS Shanghai Institute of Materia Medica | Chen F.,CAS Shanghai Institute of Materia Medica | Chen F.,Hainan Medical University | Li C.,CAS Shanghai Institute of Materia Medica
Current Drug Metabolism | Year: 2012

Saponins are a group of amphiphilic glycosides containing one or more sugar chains linked to a nonpolar triterpene or steroid aglycone skeleton, which are believed to be responsible for the pharmacological activities of many Chinese medicinal herbs. The purpose of this paper is to summarize the contemporary knowledge of the absorption, disposition, and pharmacokinetics of some important saponins, including ginsenosides, licorice saponins, dioscorea saponins, astragalosides, and saikosaponins. Poor intestinal absorption of saponins is mainly due to their unfavorable physicochemical traits, such as large molecular mass (>500 Da), high hydrogen-bonding capacity (>12), and high molecular flexibility (>10), that underlie poor membrane permeability. Rapid and extensive biliary excretion is another primary factor that limits the oral bioavailability of most saponins. However, several saponins, including ginsenosides Ra 3, Rb 1, Rc, and Rd, and dioscin, are excreted slowly into the bile and in turn have significantly long elimination half lives (7-25 h in rats). These longcirculating saponins may be used as pharmacokinetic markers to substantiate systemic exposure to the ingested herb extracts. In addition to biliary excretion for elimination of most saponins unchanged, renal excretion may also be important for certain saponins. Saponins can be hydrolyzed by the colonic microflora. After absorption, the deglycosylated aglycones undergo phase I and/or II metabolism by the host. In line with the poor permeability, saponin concentrations in most rat tissues are lower than the concurrent plasma level and the brain level is usually very low. However, the liver concentrations of many saponins, as well as the kidney levels of certain saponins, can be quite high, which involves transporter-mediated uptake mechanisms. Repeated p.o. ingestion of glycyrrhizin appears to be able to induce CYP3A in rodents and humans, while several deglycosylated products of ginsenosides can moderately inhibit CYP activities in vitro with IC 50 values of 10-50 μM. More research is required for elucidation of the absorption, disposition, and pharmacokinetics of multiple saponins to enhance understanding which saponins are most likely to exert pharmacological effects in vivo, as well as influence of complex herb matrix. In addition, research is also needed to characterize the microbiotal deglycosylation and the subsequent aglycone metabolism by the host for a broader range of saponins, as well as the hepatobiliary transporter phenotyping for and the interaction with saponins. Furthermore, in vitro and in vivo studies of saponin-based herb-drug interactions are also warranted. © 2012 Bentham Science Publishers.

Wiwanitkit S.,Wiwanitkit House | Wiwanitkit V.,Hainan Medical University
Asian Pacific Journal of Tropical Biomedicine | Year: 2015

Ebola virus outbreak in Africa in 2014 is a big global issue. The vaccine is the hope for management of the present outbreak of Ebola virus infection. There are several ongoing researches on new Ebola vaccine. In this short manuscript, we discuss and put forward specific remained problems to be answered on this specific issue. Lack for complete knowledge on the new emerging virus, concern from pharmaceutical company and good trial of new vaccine candidates are the remained problem to be further discussed in vaccinology. © 2015 by the Asian Pacific Journal of Tropical Biomedicine.

Zeng N.-K.,CAS Kunming Institute of Botany | Zeng N.-K.,Hainan Medical University | Cai Q.,CAS Kunming Institute of Botany | Yang Z.L.,CAS Kunming Institute of Botany
Mycologia | Year: 2012

Corneroboletus was erected in the Boletaceae to accommodate Boletus indecorus originally described from southeastern Asia. The mucilaginous surface of the basidioma, the ixohyphoepithelium pileipellis and the irregularly warty to irregularly bacillate ornamentation of basidiospores distinguish this fungus from other described species in Boletaceae. Phylogenetic placement of this fungus was investigated further with molecular data including LSU rRNA and concatenated alignment of nrLSU, 5.8S rRNA and rpb2 genes, and an independent lineage among existing genera of Boletaceae was suggested by our phylogenetic results. Consequently a description, illustrations and a comparison of Corneroboletus with allied taxa are presented. © 2012 by The Mycological Society of America.

Jiao Y.,Hainan Medical University | Huang B.W.,Information Technology Center
Applied Mechanics and Materials | Year: 2014

In image processing, removal of noise without blurring the image edges is a difficult problem. Aiming at orthogonal wavelet transform and traditional threshold’s shortage, a new wavelet packet transform adaptive threshold image de-noising method which is based on edge detection is proposed. By edge detection method, the wavelet packet coefficients corresponding to edge which is detected and other non-edge wavelet packet coefficients are treated by different threshold. Using the relativity among wavelet packet coefficients and neighbor dependency relation, at the same time, adopting the new variance neighbor estimate method and then the adaptive threshold is produced. From the experiment result, we see that compared with traditional methods, this method can not only effectively eliminate noise, but can also well keep original image’s information and the quality after image de-noising is very well. © (2014) Trans Tech Publications, Switzerland.

Wen Y.,CAS Yantai Institute of Coastal Zone Research | Wen Y.,Hainan Medical University | Wen Y.,University of Chinese Academy of Sciences | Chen L.,CAS Yantai Institute of Coastal Zone Research | And 3 more authors.
TrAC - Trends in Analytical Chemistry | Year: 2014

Sample preparation is a crucial bottleneck in the whole analytical process. Solid. -phase sorbents (SPSs) have aroused increasing interest in research on sample preparation, as they have key roles in obtaining high clean-up and enrichment efficiency in the analysis of trace targets present in complex matrices. The objective of this review is to provide a broad overview of the recent advances and applications of SPSs in sample preparation prior to chromatographic analysis, during the period 2008-13. We include SPSs, such as molecularly-imprinted polymers, carbon nanomaterials, metallic nanoparticles and metal organic frameworks, focusing on solid-phase extraction, solid-phase microextraction, matrix solid-phase dispersion and stir-bar sorptive extraction of typical pollutants in environmental, biological, food and pharmaceutical samples. We propose remaining challenges and future perspectives to improve development of new SPSs and to apply them further. © 2014 Elsevier B.V.

Yu C.,CAS Yantai Institute of Coastal Zone Research | Yu C.,University of Chinese Academy of Sciences | Zhang J.,Hainan Medical University | Wang R.,CAS Yantai Institute of Coastal Zone Research | Chen L.,CAS Yantai Institute of Coastal Zone Research
Organic and Biomolecular Chemistry | Year: 2010

A new probe for Cu2+ based on the Cu2+- induced reversible ring-opening mechanism of the rhodamine spirolactam was described. It displayed a highly selective and sensitive "turn-on" fluorescent and colorimetric response toward Cu2+. © 2010 The Royal Society of Chemistry.

Zhang J.,Hainan Medical University | Yu C.,Hainan Medical University | Qian S.,Hainan Medical University | Lu G.,Hainan Medical University | Chen J.,Hainan Medical University
Dyes and Pigments | Year: 2012

A chemosensor based on rhodamine B with 1, 2, 4-triazole as subunit was synthesized and characterized. It exhibits high selectivity and sensitivity for Cu2+ in ethanol/water (6:4, v:v) of pH 7.0 HEPES buffer solution and undergoes ring opening mechanism, and a 2:1 metal-ligand complex is formed. The chemosensor displays a linear response to Cu2+ in the range between 1.0 × 10-7 M and 1.0 × 10-6 M with a detection limit of 4.5 × 10-8 M. Its capability of biological application was also evaluated and the results show that this chemosensor could be successfully employed as a Cu2+-selective chemosensor in the fluorescence imaging of living cells. © 2011 Elsevier Ltd. All rights reserved.

Jia C.,Hainan Medical University
Expert Review of Gastroenterology and Hepatology | Year: 2011

Liver regeneration is known to be a process involving highly organized and ordered tissue growth triggered by the loss of liver tissue, and remains a fascinating topic. A large number of genes are involved in this process, and there exists a sequence of stages that results in liver regeneration, while at the same time inhibitors control the size of the regenerated liver. The initiation step is characterized by priming of quiescent hepatocytes by factors such as TNF-α, IL-6 and nitric oxide. The proliferation step is the step during which hepatocytes enter into the cell cycle's G1 phase and are stimulated by complete mitogens including HGF, TGF-α and EGF. Hepatic stimulator substance, glucagon, insulin, TNF-α, IL-1 and IL-6 have also been implicated in regulating the regeneration process. Inhibitors and stop signals of hepatic regeneration are not well known and only limited information is available. Furthermore, the effects of other factors such as VEGF, PDGF, hypothyroidism, proliferating cell nuclear antigen, heat shock proteins, ischemic-reperfusion injury, steatosis and granulocyte colony-stimulating factor on liver regeneration are also systematically reviewed in this article. A tissue engineering approach using isolated hepatocytes for in vitro tissue generation and heterotopic transplantation of liver cells has been established. The use of stem cells might also be very attractive to overcome the limitation of donor liver tissue. Liver-specific differentiation of embryonic, fetal or adult stem cells is currently under investigation. © 2011 Expert Reviews Ltd.

Xie Y.-Q.,Hainan Medical University | Wu X.-B.,Chengdu University of Traditional Chinese Medicine | Tang S.-Q.,Chengdu University of Traditional Chinese Medicine
International Journal of Clinical and Experimental Medicine | Year: 2014

Curcumin, a plant phenol, has been used for centuries in traditional medicines for its anti-inflammatory and anti-neoplastic properties. The compound is believed to act on a range of proteins involved in cell cycle regulation. In this study, the effect of curcumin on ERK-1/2 pathway protein expression and on proliferation of nasopharyngeal carcinoma cells was investigated. CNE-2Z nasopharyngeal carcinoma cells were cultured with 10, 20, 40, or 80 μM curcumin for 24 h before proliferation was assessed by MTT colorimetry. Cell proliferation was increasingly inhibited as the concentration of curcumin increased (P<0.005). Additionally, Western blotting revealed that expression of p-ERK-1/2, MMP-9, and TIMP-1 was altered following curcumin treatment, also in a dose-dependent manner. Expression of p-ERK-1/2 and MMP-9 decreased, while expression of TIMP-1 increased (P<0.05). Finally, CNE-2Z cells were xenografted under the skin of 18 nude mice. Mice were treated with vehicle only (control), 24 mg/kg curcumin (low-dose group), or 50 mg/kg curcumin (high-dose group) every other day for 40 days beginning 24 h after xenografting. Compared to tumors from the control group, the volume and weight of xenograft tumors was significantly lower in both curcumin groups, with a higher magnitude of difference in the high-dose curcumin group (P<0.05). These results indicate that curcumin treatment can inhibit proliferation of nasopharyngeal carcinoma cells and alter expression of proteins in the ERK-1/2 signaling pathway. Therefore, curcumin warrants further investigation as a potential treatment for nasopharyngeal cancer.

Wiwanitkit V.,Hainan Medical University
Asian Pacific Journal of Tropical Biomedicine | Year: 2016

Rift Valley fever is an important viral infection that is rarely reported in Asia. The recent emergence of this infection in China is a big global interest. In this short article, the author reviewed and presented important information on this disease. © 2016 Hainan Medical University

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