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Open Access
8-Hydroxyquinolines: a review of their metal chelating properties and medicinal applications
(2013) Veda Prachayasittikul; Supaluk Prachayasittikul; Somsak Ruchirawat; Virapong Prachayasittikul; Center of Data Mining and Biomedical Informatics; Department of Clinical Microbiology and Applied Technology
Metal ions play an important role in biological processes and in metal homeostasis. Metal imbalance is the leading cause for many neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis. 8-Hydroxyquinoline (8HQ) is a small planar molecule with a lipophilic effect and a metal chelating ability. As a result, 8HQ and its derivatives hold medicinal properties such as antineurodegenerative, anticancer, antioxidant, antimicrobial, anti-inflammatory, and antidiabetic activities. Herein, diverse bioactivities of 8HQ and newly synthesized 8HQ-based compounds are discussed together with their mechanisms of actions and structure–activity relationships.
Open Access
Antimalarial and Antimicrobial Activities of 8-Aminoquinoline-Uracils Metal Complexes
(2015-12) Kamonrat Phopin; Nujarin Sinthupoom; Lertyot Treeratanapiboon; Sarun Kunwittaya; Supaluk Prachayasittikul; Somsak Ruchirawat; Virapong Prachayasittikul; Mahidol University. Faculty of Medical Technology. Department of Clinical Microbiology and Applied Technology
8-Aminoquinoline (8AQ) derivatives have been reported to have antimalarial, anticancer, and antioxidant activities. This study investigated the potency of 8AQ-5-substituted (iodo and nitro) uracils metal (Mn, Cu, Ni) complexes (1-6) as antimalarial and antimicrobial agents. Interestingly, all of these metal complexes (1-6) showed fair antimalarial activities. Moreover, Cu complexes 2 (8AQ-Cu-5Iu) and 5 (8AQ-Cu-5Nu) exerted antimicrobial activities against Gram-negative bacteria including P. shigelloides and S. dysenteriae. The results reveal application of 8AQ and its metal complexes as potential compounds to be further developed as novel antimalarial and antibacterial agents.
Open Access
Antimicrobial and cytotoxic acetogenin from Polyalthia debilis
(2015-03) Somchai Boonpangrak; Rungrot Cherdtrakulkiat; Ratchanok Pingaew; Patumporn Manam; Supaluk Prachayasittikul; Somsak Ruchirawat; Virapong Prachayasittikul; Mahidol University. Faculty of Medical Technology. Center for Innovation Development and Technology Transfer; Mahidol University. Faculty of Medical Technology. Department of Clinical Microbiology and Applied Technology; Mahidol University. Faculty of Medical Technology. Center of Data Mining and Biomedical Informatics
Objective: To isolate bioactive acetogenin compound and to investigate antimicrobial, antioxidant as well as cytotoxic activities of the isolate, fractions and extracts of Polyalthia debilis. Methods: The P. debilis (roots) extracts and isolated compound were tested for their antimicrobial (agar dilution method) against twenty-seven strains of microorganisms (gram positive and gram negative bacteria, and diploid fungus), antioxidant (DPPH assay) and cytotoxic activities. The plant extracts were isolated by column chromatography and structure of compound was confirmed by spectral data . Result: The plant extracts and isolated fractions exhibited antioxidant and cytotoxic activities. The isolated acetogenin 1 (debilisome E) displayed antimicrobial activity against Morexella catarrhalis with the MIC of 64 microgram/mL, Corynebacterium diphtheriae NCTC 10356 and Streptococcus pyogenes with partial inhibition (50-75%) at 128 microgram/mL. The compound 1 exerted cytotoxic activity against 5 cancer cells (HepG2, A549, HCC-S102,HL-60 and P388) with IC50 values 18.4 - 40.3 microgram/mL. Conclusion: The results demonstrate novel bioactivities of P. debilis as antimicrobials and anticancer agents.
Open Access
The association of Duffy binding protein region II polymorphisms and its antigenicity in Plasmodium vivax isolates from Thailand
(Mahidol University, 2014-08-07) Patchanee Chootonga; Jetsumon Sattabongkotd; Amy M. McHenryb; Francis B. Ntumngiac; John H. Adamsc; Mahidol University. Faculty of Medical Technology. Department of Clinical Microbiology and Applied Technology
Plasmodium vivax Duffy binding protein II (DBPII) plays an important role in reticulocyte invasion and is a potential vaccine candidate against vivax malaria. However, polymorphisms in DBPII are a challenge for the successful design of a broadly protective vaccine. In this study, the genetic diversity of DBPII among Thai isolates was analyzed from Plasmodium vivax-infected blood samples and polymorphism characters were defined with the MEGA4 program. Sequence analysis identified 12 variant residues that are common among Thai DBPII haplotypes with variant residues L333F, L424I, W437R and I503K having the highest frequency. Variant residue D384K occurs in combination with either E385K or K386N/Q. Additionally, variant residue L424I occurs in conjunction with W437R in most Thai DBPII alleles and these variants frequently occur in combination with the I503K variant. The polymorphic patterns of Thai isolates were defined into 9 haplotypes (Thai DBL-1, -2, -3, etc.…). Thai DBL-2, -5, -6 haplotypes are the most common DBPII variants in Thai residents. To study the association of these Thai DBPII polymorphisms with antigenic character, the functional inhibition of anti-DBPII monoclonal antibodies against a panel of Thai DBL variants was characterized by an in vitro erythrocyte binding inhibition assay. The functional inhibition of anti-DBPII monoclonal antibodies 3C9, 2D10 and 2C6 against Thai variants was significantly different, suggesting that polymorphisms of Thai DBPII variants alter the antigenic character of the target epitopes. In contrast, anti-DBPII monoclonal antibody 2H2 inhibited all Thai DBPII variants equally well. Our results suggest that the immune efficacy of a DBPII vaccine will depend on the specificity of the anti-DBPII antibodies induced and that it is preferable to optimize responses to conserved epitopes for broadly neutralizing protection against P. vivax.
Open Access
Bioactive azafluorenone alkaloids from polyalthia debilis (Pierre) finet and gagnep
(2009) Supaluk Prachayasittikul; Patumporn Manam; Maneekarn Chinworrungsee; Chartchalerm Isarankura-Na-Ayudhya; Somsak Ruchirawat; Virapong Prachayasittikul
This study investigated bioactive extracts of Polyalthia debilis (Annonaceae) with antimicrobial, antimalarial and cytotoxic activities. Extensive chromatographic isolations provided azafluorenone alkaloids; onychine (1) and 7-methoxyonychine (2) together with a mixture of β–sitosterol and stigmasterol. The two alkaloids were isolated from the P. debilis for the first time. Isolated fractions containing a mixture of triterpenoids (C7, C8 and C9) exhibited the most potent antimicrobial activity against many bacterial strains with minimum inhibitory concentration of 64 μg/mL. Fractions with antimalarial and cytotoxic activities were also observed. The findings suggest the potential use of P. debilis in medicinal applications.
Open Access
Bioactive metabolites from spilanthes acmella murr
(2009) Supaluk Prachayasittikul; Saowapa Suphapong; Apilak Worachartcheewan; Ratana Lawung; Somsak Ruchirawat; Virapong Prachayasittikul
Spilanthes acmella Murr. (Compositae) has been used as a traditional medicine for toothache, rheumatism and fever. Its extracts had been shown to exhibit vasorelaxant and antioxidant activities. Herein, its antimicrobial, antioxidant and cytotoxic activities were evaluated. Agar dilution method assays against 27 strains of microorganisms were performed. Results showed that fractions from the chloroform and methanol extracts inhibited the growth of many tested organisms, e.g. Corynebacterium diphtheriae NCTC 10356 with minimum inhibitory concentration (MIC) of 64-256 μg/mL and Bacillus subtilis ATCC 6633 with MIC of 128-256 μg/mL. The tested fractions all exhibited antioxidant properties in both DPPH and SOD assays. Potent radical scavenging activity was observed in the DPPH assay. No cytotoxic effects of the extracts against KB and HuCCA-1 cell lines were evident. Bioassay-guided isolation resulted in a diverse group of bioactive compounds such as phenolics [vanillic acid (2), trans-ferulic acid (5) and transisoferulic acid (6)], coumarin (scopoletin, 4) and triterpenoids like 3-acetylaleuritolic acid (1), β-sitostenone (3), stigmasterol and stigmasteryl-3-O- β-D-glucopyranosides, in addition to a mixture of stigmasteryl-and β-sitosteryl-3-O- β-D-glucopyranosides. The compounds 1–6 represent bioactive metabolites of S. acmella Murr. that were never previously reported. Our findings demonstrate for the first time the potential benefits of this medicinal plant as a rich source of high therapeutic value compounds for medicines, cosmetics, supplements and as a health food.
Open Access
Bioactive triterpenoids, antimicrobial, antioxidant and cytotoxic activities of Eclipta prostrata Linn
(2015-03) Rungrot Cherdtrakulkiat; Somchai Boonpangrak; Somsak Ruchirawat; Ratchanok Pingaew; Virapong Prachayasittikul; Supaluk Prachayasittikul; Mahidol University. Faculty of Medical Technology. Department of Clinical Microbiology and Applied Technology; Mahidol University. Faculty of Medical Technology. Center for Innovation Development and Technology Transfer; Mahidol University. Faculty of Medical Technology. Center of Data Mining and Biomedical Informatics
Bioactive triterpenoids; 3-acetylaleuritolic acid, stigmasterol, a mixture of triterpenoids, fatty esters and aromatic components were isolated from the aerial parts of Eclipta prostrata by column chromatography. The plant extracts were investigated for their antimicrobial activity (agar dilution method) against twenty-eight strains of gram-positive and gram-negative bacteria, including diploid fungus. In addition, antioxidant and cytotoxic activities were also evaluated.The extracts and isolated fractions exhibited antimicrobial activity against Morexella catarrhalis, Corynebacterium diphtheriae NCTC 10356 and Streptococcus pyogenes with the MIC of 64 g/mL including Saccharomyces cerevisiae ATCC 2601 (MIC 256 g/mL). The ethyl acetate extract and isolated fractions displayed antioxidant effect. In addition, the plant extracts showed cytotoxic activity (ED50 > 100 g/mL) toward HuCCA-1 and KB cells. The results demonstrate beneficial effects of E. prostrata as the antimicrobials and bioactive compounds for medicinal usages.
Open Access
Characterization of Inhibitory Anti-Duffy Binding Protein II Immunity: Approach to Plasmodium vivax Vaccine Development in Thailand
(Mahidol University, 2012-04) Patchanee Chootong; Tasanee Panichakul; Chongrak Permmongkol; Samantha J. Barnes; Rachanee Udomsangpetch; John H. Adams; Department of Clinical Microbiology and Applied Technology
Plasmodium vivax Duffy binding protein region II (DBPII) is an important vaccine candidate for antibody-mediated immunity against vivax malaria. A significant challenge for vaccine development of DBPII is its highly polymorphic nature that alters sensitivity to neutralizing antibody responses. Here, we aim to characterize naturally-acquired neutralizing antibodies against DBPII in individual Thai residents to give insight into P. vivax vaccine development in Thailand. Anti-DBPII IgG significantly increased in acute vivax infections compared to uninfected residents and naive controls. Antibody titers and functional anti-DBPII inhibition varied widely and there was no association between titer and inhibition activity. Most high titer plasmas had only a moderate to no functional inhibitory effect on DBP binding to erythrocytes, indicating the protective immunity against DBPII binding is strain specific. Only 5 of 54 samples were highly inhibitory against DBP erythrocyte-binding function. Previously identified target epitopes of inhibitory anti-DBPPII IgG (H1, H2 and H3) were localized to the dimer interface that forms the DARC binding pocket. Amino acid polymorphisms (monomorphic or dimorphic) in H1 and H3 protective epitopes change sensitivity of immune inhibition by alteration of neutralizing antibody recognition. The present study indicates Thai variant H1.T1 (R308S), H3.T1 (D384G) and H3.T3 (K386N) are the most important variants for a DBPII candidate vaccine needed to protect P. vivax in Thai residents.
Open Access
Classification of P-glycoprotein-interacting compounds using machine-learning methods
(2015-07) Watshara Shoombuatong; Apilak Worachartcheewan; Veda Prachayasittikul; Chanin Nantasenamat; Virapong Prachayasittikul; Mahidol University. Faculty of Medical Technology. Center of Data Mining and Biomedical Informatics
P-glycoprotein (Pgp) is a drug transporter that plays important roles in multidrug resistance and drug pharmacokinetics. The inhibition of Pgp has become a notable strategy for combating multidrug-resistant cancers and improving therapeutic outcomes. However, the polyspecific nature of Pgp, together with inconsistent results in experimental assays, renders the determination of endpoints for Pgp-interacting compounds a great challenge. In this study, the classification of a large set of 2,477 Pgp-interacting compounds (i.e., 1341 inhibitors, 913 non-inhibitors, 197 substrates and 26 non-substrates) was performed using several machine learning methods (i.e., decision tree induction, artificial neural network modelling and support vector machine) as a function of their physicochemical properties. The models provided good predictive performance, producing MCC values in the range of 0.739-1 for internal cross-validation and 0.665-1 for external validation. The study provided simple and interpretable models for important properties that influence the activity of Pgp-interacting compounds, which are potentially beneficial for screening and rational design of Pgp inhibitors that are of clinical importance.
Open Access
Cloning of a chitinase gene into Bacillus thuringiensis subsp. aizawai for enhanced insecticidal activity
(1997-12) Tantimavanich S; Pantuwatana S; Bhumiratana A; Panbangred W; Faculty of Science. Department of Biotechnology
Chitinase from a high producing strain (TP-1) of Bacillus licheniformis was used with B. thuringiensis subsp. aizawai (B.t.a.) in a combined larvicidal assay against the pest, Spodoptera exigua. With 10 mU of this chitinase, the LD(50) of B.t.a. was reduced by 7.6, 13.8 and 15 times on days 3, 5 and 7, respectively when compared to use of B.t.a. alone. In addition, a combination of chitinase (10 mU) and B.t.a. at a sub-lethal dose retarded growth and development of S. exigua. In preparation for transformation of B.t.a., the TP-1 chitinase gene was cloned in E. coli DH5alpha and sequenced to reveal a single open reading frame of 1,815 bp. This open reading frame encoded for a protein of 604 amino acids and a characteristic signal peptide sequence of 35 amino acids. The gene was subsequently introduced into B.t.a. where it was expressed constitutively. The transformed strain showed slightly improved activity against S. exigua when compared to the non-transformed strain. This was probably due to the low chitinase activity (15 mU/ml) of the transformant, which might be improved by further gene manipulation to overexpress enzyme production.
Open Access
Combining electrochemical sensors with miniaturized sample preparation for rapid detection in clinical samples
(2014-11-21) Natinan Bunyakul; Antje J. Baeumner; Mahidol University. Faculty of Medical Technology. Department of Clinical Chemistry
Clinical analyses benefit world-wide from rapid and reliable diagnostics tests. New tests are sought with greatest demand not only for new analytes, but also to reduce costs, complexity and lengthy analysis times of current techniques. Among the myriad of possibilities available today to develop new test systems, amperometric biosensors are prominent players-best represented by the ubiquitous amperometric-based glucose sensors. Electrochemical approaches in general require little and often enough only simple hardware components, are rugged and yet provide low limits of detection. They thus offer many of the desirable attributes for point-of-care/point-of-need tests. This review focuses on investigating the important integration of sample preparation with (primarily electrochemical) biosensors. Sample clean up requirements, miniaturized sample preparation strategies, and their potential integration with sensors will be discussed, focusing on clinical sample analyses.
Open Access
A comparative study of natural immune responses against Plasmodium vivax C-terminal merozoite surface protein-1 (PvMSP-1) and apical membrane antigen-1 (PvAMA-1) in two endemic settings
(2015-08-06) Hui Xia; Qiang Fang; Kulachart Jangpatarapongsa; Tao Zhiyong; Liwang Cui; Baiqing Li; Rachanee Udomsangpetch; Mahidol University. Faculty of Medical Technology. Center for Research and Innovation; Mahidol University. Faculty of Medical Technology. Department of Clinical Microbiology and Applied Technology
The mechanisms of cellular and humoral immune responses against P. vivax parasite remain poorly understood. Several malaria immunological studies have been conducted in endemic regions where both P. falciparum and P. vivax parasites co-exist. In this study, a comparative analysis of immunity to Plasmodium vivax antigens in different geography and incidence of Plasmodium spp. infection was performed. We characterised antibodies against two P. vivax antigens, PvMSP-1 and PvAMA-1, and the cross-reactivity between these antigens using plasma from acute malaria infected patients living in the central region of China and in the western border of Thailand. P. vivax endemicity is found in central China whereas both P. vivax and P. falciparum are endemic in Thailand. There was an increased level of anti-PvMSP-1/anti-PvAMA-1 in both populations. An elevated level of antibodies to total P. vivax proteins and low level of antibodies to total P. falciparum proteins was found in acute P. vivax infected Chinese, suggesting antibody cross-reactivity between the two species. P. vivax infected Thai patients had both anti-P. vivax and anti-P. falciparum antibodies as expected since both species are present in Thailand. More information on humoral and cell mediated immunity during acute P. vivax-infection in the area where only single P. vivax species existed is of great interest in the relation of building up anti-disease severity caused by P. falciparum. This knowledge will support vaccine development in the future. © 2015, Leibniz Research Centre for Working Environment and Human Factors. All rights reserved.
Open Access
Computational identification of miRNAs that modulate the differentiation of mesenchymal stem cells to osteoblasts
(2016-04) Kanokwan Seenprachawong; Pornlada Nuchnoi; Chanin Nantasenamat; Aungkura Supokawej; Mahidol University. Faculty of Medical Technology. Center of Data Mining and Biomedical Informatics; Mahidol University. Faculty of Medical Technology. Department of Clinical Microscopy
MicroRNAs (miRNAs) are small endogenous noncoding RNAs that play an instrumental role in post-transcriptional modulation of gene expression. Genes related to osteogenesis (i.e. RUNX2, COL1A1 and OSX) is important in controlling the differentiation of mesenchymal stem cells (MSCs) to bone tissues. The regulated expression level of miRNAs is critically important for the differentiation of MSCs to preosteoblasts. The understanding of miRNA regulation in osteogenesis could be applied for future applications in bone defects. Therefore, this study aims to shed light on the mechanistic pathway underlying osteogenesis by predicting miRNAs that may modulate this pathway. This study investigates RUNX2, which is a major transcription factor for osteogenesis that drives MSCs into preosteoblasts. Three different prediction tools were employed for identifying miRNAs related to osteogenesis using the 3’UTR of RUNX2 as the target gene. Of the 1,023 miRNAs, 70 miRNAs were found by at least two of the tools. Candidate miRNAs were then selected based on their free energy values, followed by assessing the probability of target accessibility. The results showed that miRNAs 23b, 23a, 30b, 143, 203, 217, and 221 could regulate the RUNX2 gene during the differentiation of MSCs to preosteoblasts.
Open Access
Copper Complexes of Nicotinic-Aromatic Carboxylic Acids as Superoxide Dismutase Mimetics
(Mahidol University, 2008) Thummaruk Suksrichavalit; Supaluk Prachayasittikul; Theeraphon Piacham; Chartchalerm Isarankura-Na-Ayudhya; Chanin Nantasenamat; Virapong Prachayasittikul
Nicotinic acid (also known as vitamin B3) is a dietary element essential for physiological and antihyperlipidemic functions. This study reports the synthesis of novel mixed ligand complexes of copper with nicotinic and other select carboxylic acids (phthalic, salicylic and anthranilic acids). The tested copper complexes exhibited superoxide dismutase (SOD) mimetic activity and antimicrobial activity against Bacillus subtilis ATCC 6633, with a minimum inhibition concentration of 256 μg/mL. Copper complex of nicotinic-phthalic acids (CuNA/Ph) was the most potent with a SOD mimetic activity of IC50 34.42 μM. The SOD activities were observed to correlate well with the theoretical parameters as calculated using density functional theory (DFT) at the B3LYP/LANL2DZ level of theory. Interestingly, the SOD activity of the copper complex CuNA/Ph was positively correlated with the electron affinity (EA) value. The two quantum chemical parameters, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), were shown to be appropriate for understanding the mechanism of the metal complexes as their calculated energies show good correlation with the SOD activity. Moreover, copper complex with the highest SOD activity were shown to possess the lowest HOMO energy. These findings demonstrate a great potential for the development of value-added metallovitamin-based therapeutics.
Open Access
Cucurbitacin B causes increased radiation sensitivity of human breast cancer cells via G2/M cell cycle arrest
(Mahidol University. Faculty of Medical Technology, 2013-06-17) Suwit Duangmano; Phorntip Sae-lim; Apichart Suksamrarn; Pimpichaya Patmasiriwat; Frederick E. Domann
Purpose. To explore the effects of cucurbitacin B on the radiation survival of human breast cancer cells and to elucidate the cellular mechanism of radiosensitization if any. Materials and Methods. Human breast carcinoma cell lines were treated with cucurbitacin B before irradiation with 0–10Gy of 137Cs gamma rays. The effect of cucurbitacin B on cell-survival following irradiation was evaluated by colony-forming assay. Cell cycle distributions were investigated using flow cytometry. Real-time PCR and western blots were performed to investigate the expression of cell cycle checkpoints. Results. Cucurbitacin B inhibited breast cancer cell proliferation in a dose-dependent manner. Only MDA-MB-231 and MCF7:5C cells but not SKBR-3 cells were radiosensitized by cucurbitacin B. Flow cytometric analysis for DNA content indicated that cucurbitacin B resulted in G2/M arrest in MDA-MB-231 andMCF7:5C but not SKBR-3 cells.Moreover, Real-time PCR and western blot analysis demonstrated upregulated p21 expression before irradiation, a likely cause of the cell cycle arrest. Conclusion. Taken together, these findings suggest that cucurbitacin B causes radiosensitization of some breast cancer cells, and that cucurbitacin B induced G2/M arrest is an importantmechanism. Therefore, combinations of cucurbitacin B with radiotherapy may be appropriate for experimental breast cancer treatment.
Open Access
Cucurbitacin B inhibits human breast cancer cell proliferation through disruption of microtubule polymerization and nucleophosmin/B23 translocation
(2012) Suwit Duangmano; Phorntip Sae-lim; Apichart Suksamrarn; Frederick E Domann; Pimpicha Patmasiriwat; Mahidol University. Faculty of Medical Technology
Background: Cucurbitacin B, an oxygenated tetracyclic triterpenoid compound extracted from the Thai medicinal plant Trichosanthes cucumerina L., has been reported to have several biological activities including anti-inflammatory, antimicrobial and anticancer. Cucurbitacin B is great of interest because of its biological activity. This agent inhibits growth of various types of human cancer cells lines. Methods: In this study, we explored the novel molecular response of cucurbitacin B in human breast cancer cells, MCF-7 and MDA-MB-231. The growth inhibitory effect of cucurbitacin B on breast cancer cells was assessed by MTT assay. The effects of cucurbitacin B on microtubules morphological structure and tubulin polymerization were analyzed using immunofluorescence technique and tubulin polymerization assay kit, respectively. Proteomic analysis was used to identify the target-specific proteins that involved in cucurbitacin B treatment. Some of the differentially expressed genes and protein products were validated by real-time RT-PCR and western blot analysis. Cell cycle distributions and apoptosis were investigated using flow cytometry. Results: Cucurbitacin B exhibited strong antiproliferative effects against breast cancer cells in a dose-dependent manner. We show that cucurbitacin B prominently alters the cytoskeletal network of breast cancer cells, inducing rapid morphologic changes and improper polymerization of the microtubule network. Moreover, the results of 2D-PAGE, real-time RT-PCR, and western blot analysis revealed that the expression of nucleophosmin/B23 and c-Myc decreased markedly after cucurbitacin B treatment. Immunofluorescence microscopy showed that cucurbitacin B induced translocation of nucleophosmin/B23 from the nucleolus to nucleoplasm. Treatment with cucurbitacin B resulted in cell cycle arrest at G2/M phase and the enhancement of apoptosis. Conclusions: Our findings suggest that cucurbitacin B may inhibit the proliferation of human breast cancer cells through disruption of the microtubule network and down-regulation of c-Myc and nucleophosmin/B23 as well as the perturbation in nucleophosmin/B23 trafficking from the nucleolus to nucleoplasm, resulting in G2/M arrest.
Open Access
Derivatives (halogen, nitro and amino) of 8-hydroxyquinoline with highly potent antimicrobial and antioxidant activities
(2016-07) Rungrot Cherdtrakulkiat; Somchai Boonpangrak; Nujarin Sinthupoom; Supaluk Prachayasittikul; Somsak Ruchirawat; Virapong Prachayasittikul; Mahidol University. Faculty of Medical Technology. Department of Clinical Microbiology and Applied Technology; Mahidol University. Faculty of Medical Technology. Center for Innovation Development and Technology Transfer; Mahidol University. Faculty of Medical Technology. Center of Data Mining and Biomedical Informatics
8-Hydroxyquinoline (8HQ) compounds have been reported to possess diverse bioactivities. In recent years, drug repositioning has gained considerable attention in drug discovery and development. Herein, 8HQ (1) and its derivatives (2-9) bearing various substituents (amino, nitro, cyano and halogen) were investigated for their antimicrobial against 27 microorganisms (agar dilution method) and antioxidant (DPPH method) activities. The parent 8HQ (1) exerted a highly potent antimicrobial activity against Gram-positive bacteria including diploid fungi and yeast with MIC values in the range of 3.44-13.78 μM. Moreover, the halogenated 8HQ, especially 7-bromo-8HQ (4) and clioquinol (6), displayed a high antigrowth activity against Gram-negative bacteria compared with the parent compound (1). Apparently, the derivatives with a relatively high safely index, e.g., nitroxoline (2), exhibited strong antibacterial activity against Aeromonas hydrophila (MIC=5.26 μM) and selectively inhibited the growth of P. aeruginosa with the MIC value of 84.14 μM; cloxyquin (3) showed a strong activity against L. monocytogenes and P. shigelloides with MIC values of 5.57 and 11.14 μM, respectively. Most compounds displayed an antioxidant activity. Specifically, 5-amino-8HQ (8) was shown to be the most potent antioxidant (IC50=8.70 μM) compared with the positive control (α-tocopherol) with IC50 of 13.47 μM. The findings reveal that 8HQ derivatives are potential candidates to be further developed as antimicrobial and antioxidant agents.
Open Access
Detection of non-amplified mycobacterium tuberculosis genomic DNA using piezoelectric DNA-based biosensors
(2010) Thongchai Kaewphinit; Somchai Santiwatanakul; Chamras Promptmas; Kosum Chansiri
Piezoelectric DNA-based biosensor technology was developed as a new method for detection of M. tuberculosis. This method consists of immobilizing a thiol-modified oligonucleotide probe on the gold electrode surface of a quartz crystal, using a selfassembled monolayer method. The advantage of this study is that a non-amplified genomic bacterial DNA target was used. Instead, the genomic DNA was digested by restriction enzyme to obtain DNA fragments containing the target sequence. The fabricated biosensor was evaluated through an examination of 200 samples. No cross hybridization were observed against M. avium complex and other microorganisms. This target DNA preparation, without PCR amplification, will reduce time, costs, and the tedious step of amplification.
Open Access
Determination of Heavy Metal Residues in Tropical Fruits near Industrial Estates in Rayong Province, Thailand: A Risk Assessment Study
(2023) Amara Apilux; Thitiporn Thongkam; Thitaporn Tusai; Phasit Petisiwaveth; Sumana Kladsomboon
This study determined the extent of heavy metal contamination of local fruit in Rayong, Thailand, an area where an industrial base is adjacent to agricultural areas. Dietary exposure to agricultural products grown in contaminated areas can cause multiple adverse effects to the human body. In order to avoid such undesirable effects, concentrations of heavy metals [arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), and zinc (Zn)] were investigated in popular tropical fruits from three districts of Rayong, namely Wang Chan, Klang and Mueang. The levels of heavy metals were determined by inductively coupled plasma-mass spectrometry (ICP-MS) and cold vapor-atomic absorption spectrometry (CV-AAS). Levels of the six heavy metals in sampled fruits (durian, jackfruit, pineapple, rambutan, long kong, and mangosteen) were in the range of 0.0004-6.7095 mg/kg; 16.7% of fruit samples exceeded maximum permissible limits of Pb. Based on health risk assessments, values of estimated daily intake (EDI) were less than those of maximum tolerable daily intake. However, for non-carcinogenic risks, high hazard index (HI) values were found in some markets while for carcinogenic risks (CRs), CR values of three fruits (durian, jackfruit, and mangosteen) exceeded acceptable levels. Therefore, long-term fruit consumption could impact health of local consumers. These results provided insight into the need for regular monitoring of heavy metal concentrations in potentially contaminated fruits and for prevention of its potential effects.
Open Access
Determining a new formula for calculating low-density lipoprotein cholesterol:data mining approach
(2015-01-26) Prabhop Dansethakul; Lalin Thapanathamchai; Sarawut Saichanma; Phannee Pidetcha; Apilak Worachartcheewan; Excellence Service Center For Medical Technology and Quality Improvement; Center of Medical Laboratory Services; Department of Clinical Chemistry
Low-density lipoprotein cholesterol (LDL-C) is a risk factor of coronary heart diseases. The estimation of LDL- C (LDL-Cal) level was performed using Friedewald’s equation for triglyceride (TG) level less than 400 mg/dL. Therefore, the aim of this study is to generate a new formula for LDL-Cal and validate the correlation coefficient between LDL-Cal and LDL-C directly measured (LDL-Direct). A data set of 1786 individuals receiving annual medical check-ups from the Faculty of Medical Technology, Mahidol University, Thailand in 2008 was used in this study. Lipid profiles including total cholesterol (TC), TG, high-density lipoprotein cholesterol (HDL-C) and LDL-C were determined using Roche/Hitachi modular system analyzer. The estimated LDL-C was obtained us- ing Friedewald’s equation and the homogenous enzymatic method. The level of TG was divided into 6 groups (TG<200, <300, <400, <500, <600 and < 1000 mg/dL) for constructing the LDL-Cal formula. The pace regres- sion model was used to construct the candidate formula for the LDL-Cal and determine the correlation coeffi- cient (r) with the LDL-Direct. The candidate LDL-Cal formula was generated for 6 groups of TG levels that dis- played well correlation between LDL-Cal and LDL-Direct. Interestingly, The TG level was less than 1000 mg/dL, the regression model was able to generate the equation as shown as strong r of 0.9769 with LDL-Direct. Furthermore, external data set (n = 666) with TG measurement (36-1480 mg/dL) was used to validate new for- mula which displayed high r of 0.971 between LDL-Cal and LDL-direct. This study explored a new formula for LDL-Cal which exhibited higher r of 0.9769 and far beyond the limitation of TG more than 1000 mg/dL and po- tential used for estimating LDL-C in routine clinical laboratories.