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Chiang Mai, Thailand

Hongthong S.,Mahidol University | Kuhakarn C.,Mahidol University | Jaipetch T.,Mahidol University | Prabpai S.,Mahidol University | And 8 more authors.
Fitoterapia | Year: 2015

Six new naturally occurring polyoxygenated cyclohexene derivatives together with eight related known derivatives, two known alkaloids, and two known flavonoid derivatives were isolated from bioassay-guided fractionation of the ethyl acetate extract of the leaves and twigs of Dasymaschalon sootepense. The structure elucidation and determination of absolute configurations were established by various spectroscopic methods, X-ray diffraction techniques as well as comparison with the literature data. Several isolated compounds were evaluated for their cytotoxic, anti-HIV-1 RT and anti-inflammatory activities. © 2015 Elsevier B.V. All rights reserved.

Phanichphant S.,Chiang Mai UniversityChiang Mai | Nakaruk A.,Naresuan UniversityPhitsanulok | Nakaruk A.,Naresuan UniversityPhitsanulok | Channei D.,Naresuan UniversityPhitsanulok
Applied Surface Science | Year: 2016

In this study, CeO2 photocatalyst was modified by composite with SiO2 to increase efficiency and improve photocatalytic activity. The as-prepared SiO2 particles have been incorporated into the precursor mixture of CeO2 by homogeneous precipitation and subsequent calcination process. The phase compositions of CeO2 before and after compositing with SiO2 were identified by X-ray diffraction (XRD). The morphology and particle size of CeO2/SiO2 composite was analyzed by high resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). The results showed SiO2 spheres with the particle size approximately 100–120 nm, and a uniform layer of CeO2 nanoparticles with a diameter of about 5–7 nm that were fully composite to the surfaces of SiO2. The X-ray photoelectron spectroscopy (XPS) technique was carried out in order to characterize the change in valence state and composite characteristic by shifted peaks of binding energies. The photocatalytic activity was studied through the degradation of Rhodamine B in aqueous solution under visible light exposure. The highest photocatalytic efficiency of CeO2/SiO2 composite was also obtained. To explain the high photocatalytic efficiency of CeO2/SiO2 composite, the proposed mechanism involves the high surface properties of the CeO2/SiO2 composite, as measured by Brunauer-Emmett-Teller (BET) method. © 2016 Elsevier B.V.

Pientong C.,Khon Kaen UniversityKhon Kaen | Wongwarissara P.,Khon Kaen UniversityKhon Kaen | Ekalaksananan T.,Khon Kaen UniversityKhon Kaen | Swangphon P.,Khon Kaen UniversityKhon Kaen | And 5 more authors.
Virology Journal | Year: 2013

Background: The variation of human papillomavirus (HPV) genes or HPV variants demonstrates different risks of cervical cancer. Mutation in the long control region (LCR) at YY1-motifs is one of the mechanisms for enhancing viral oncogene expression during the course of cancer cell progression. In Thai women, cervical cancers are almost always associated with HPV16 variant sub-lineage Asian (HPV16As); however, the mechanism involved remains elusive. The aim of this study was to understand further the oncogenic potential of HPV16As. Methods: A total of 82 HPV16-positive specimens from Thai women were selected from formalin-fixed paraffin-embedded cervical tissues, and the full length E6 gene of each specimen was amplified and sequenced. LCRs of the HPV16As-positive cases were amplified and sequenced to analyze their polymorphisms. Transcriptional activities of the HPV16As LCRs were then compared with sub-lineage European (EUR), sub-lineage Asian-American 1 (AA1) and HPV16 prototype by insertion of the LCRs into the pGL3-Basic vector. Results: The HPV16 DNA sequences were classified as HPV16 prototype (18.3%), Asian (As, 61%), Asian American-1 (AA1, 8.5%), European (EUR, 7.3%), Asian African-2 (AFR2, 3.7%) and Java-135C (J135C, 1.2%). The prevalence of HPV16As was 30% in low-grade squamous intraepithelial lesion (LSIL), while that in high-grade squamous intraepithelial lesion (HSIL) and squamous cell cervical carcinoma (SCC) were 63.9% and 66.7%, respectively, which demonstrates a significant association of HPV16As with the disease severity. LCR polymorphisms from 43 HPV16As positive cases were analyzed by PCR-sequencing. Thirty-eight nucleotide variation positions spanned nucleotide positions 7157-82. Ten new mutations found in the HPV16As LCRs were located predominantly at the enhancer and proximal to the 3'-end of the early promoter. The LCRs of the common HPV16As, EUR and AA1 showed 5, 13 and 23-fold higher activity than the HPV16 prototype LCR, while those of the new nucleotide variations of As showed 19 (As-sv1) and 30 (As-sv14) -fold higher activity than the HPV16 prototype. Conclusions: HPV16As DNA sequence variation, especially at the proximal to early promoter in the LCR, enhances transcriptional activity. This could be one of the possible mechanisms for HPV16As-associated cervical cancer development. © 2013 Pientong et al; licensee BioMed Central Ltd.

Naksuriya O.,Chiang Mai University | Shi Y.,University Utrecht | Van Nostrum C.F.,University Utrecht | Anuchapreeda S.,Chiang Mai UniversityChiang Mai | And 2 more authors.
European Journal of Pharmaceutics and Biopharmaceutics | Year: 2015

Abstract Curcumin (CM) has been reported as a potential anticancer agent. However, its pharmaceutical applications as therapeutic agent are hampered because of its poor aqueous solubility. The present study explores the advantages of polymeric micelles composed of block copolymers of methoxypoly(ethylene glycol) (mPEG) and N-(2-hydroxypropyl) methacrylamide (HPMA) modified with monolactate, dilactate and benzoyl side groups to enhance CM solubility and inhibitory activity against cancer cells. Amphiphilic block copolymers, ω-methoxypoly(ethylene glycol)-b-(N-(2-benzoyloxypropyl) methacrylamide) (PEG-HPMA-Bz) were synthesized and characterized by 1H NMR and GPC. One polymer with a molecular weight of 28,000 Da was used to formulate CM and compared with other aromatic substituted polymers. CM was loaded by a fast heating method (PEG-HPMA-DL and PEG-HPMA-Bz-L) and a nanoprecipitation method (PEG-HPMA-Bz). Physicochemical characteristics and cytotoxicity/cytocompatibility of the CM loaded polymeric micelles were evaluated. It was found that HPMA-based polymeric micelles significantly enhanced the solubility of CM. The PEG-HPMA-Bz micelles showed the best solubilization properties. CM loaded polymeric micelles showed sustained release of the loading CM for more than 20 days. All of CM loaded polymeric micelles formulations showed a significantly potent cytotoxic effect against three cancer cell lines. HPMA-based polymeric micelles are therefore promising nanodelivery systems of CM for cancer therapy. © 2015 Elsevier B.V.

Jarulertwathana B.,Chiang Mai University | Sarakonsri T.,Chiang Mai University | Sarakonsri T.,Chiang Mai UniversityChiang Mai
Journal of Ceramic Processing Research | Year: 2014

Silica/copper (SiO2/Cu) composites were prepared in nano-dimensions for use as anode materials in lithium-ion batteries. Modified Stöber and microwave-assisted methods were used to prepare of SiO2 and Cu, respectively. The composites were prepared with different tetraethyl orthosilicate (TEOS) concentrations and mole ratios of TEOS to Cu2+ reactants. Cu was observed as the main phase in the products, which agglomerated into large particles, with some of them dispersed on the SiO2 particles. SiO2 appeared in the composites was amorphous phase and spherical in shape. Decreasing the TEOS concentration decreased the size of the SiO2. © 2014, Journal of Ceramic Processing Research. All Rights Reserved.

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