Displaying publications 1201 - 1220 of 4699 in total

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  1. A review of bioretention components and nutrient removal under different climates-future directions for tropics
    Goh HW, Lem KS, Azizan NA, Chang CK, Talei A, Leow CS, et al.
    Environ Sci Pollut Res Int, 2019 May;26(15):14904-14919.
    PMID: 30977005 DOI: 10.1007/s11356-019-05041-0
    Bioretention systems have been implemented as stormwater best management practices (BMPs) worldwide to treat non-point sources pollution. Due to insufficient research, the design guidelines for bioretention systems in tropical countries are modeled after those of temperate countries. However, climatic factors and stormwater runoff characteristics are the two key factors affecting the capacity of bioretention system. This paper reviews and compares the stormwater runoff characteristics, bioretention components, pollutant removal requirements, and applications of bioretention systems in temperate and tropical countries. Suggestions are given for bioretention components in the tropics, including elimination of mulch layer and submerged zone. More research is required to identify suitable additives for filter media, study tropical shrubs application while avoiding using grass and sedges, explore function of soil faunas, and adopt final discharged pollutants concentration (mg/L) on top of percentage removal (%) in bioretention design guidelines.
    Matched MeSH terms: Nitrogen/isolation & purification; Phosphorus/isolation & purification
  2. Purification of recombinant antigen BmSXP used in panLF rapid kit for lymphatic filariasis
    Khoo TK, Noordin R, Santhanam A
    Indian J Exp Biol, 2012 Apr;50(4):256-64.
    PMID: 22611913
    A rapid antibody detection test is very useful for the detection of lymphatic filariasis, especially for certification and surveillance of post-mass drug administration. panLF Rapid kit is suitable for this purpose since it can detect all species of lymphatic filaria. It is based on the detection of anti-filarial IgG4 antibodies that react with recombinant B. malayi antigens, BmR1 and BmSXP. There is an increase demand for the test due to its attributes of being rapid, sensitive and specific results, as well as its field-applicability. The main aim of this paper is to obtain high recovery and purity of recombinant antigen BmSXP via a modified method of immobilized metal affinity chromatography (IMAC). The highest product yield of 11.82 mg/g dry cell weight (DCW) was obtained when IMAC was performed using the optimized protocol of 10 mM imidazole concentration in lysis buffer, 30 mM imidazole concentration in wash buffer, and 10 column volume wash buffer containing 300 mM salt concentration. This gave a 54% protein recovery improvement over the manufacturer's protocol which recorded a product yield of only 7.68 mg/g DCW. The recovered BmSXP recombinant antigen showed good western blot reactivity, high sensitivity (31/32, 97%) and specificity (32/32, 100%) in ELISA, thus attesting to its good purity and quality.
    Matched MeSH terms: Antigens, Helminth/isolation & purification; Recombinant Proteins/isolation & purification
  3. Fulltext Characterization of N-acylhomoserine lactone-degrading bacteria associated with the Zingiber officinale (ginger) rhizosphere: co-existence of quorum quenching and quorum sensing in Acinetobacter and Burkholderia
    Chan KG, Atkinson S, Mathee K, Sam CK, Chhabra SR, Cámara M, et al.
    BMC Microbiol, 2011 Mar 08;11:51.
    PMID: 21385437 DOI: 10.1186/1471-2180-11-51
    BACKGROUND: Cell-to-cell communication (quorum sensing (QS)) co-ordinates bacterial behaviour at a population level. Consequently the behaviour of a natural multi-species community is likely to depend at least in part on co-existing QS and quorum quenching (QQ) activities. Here we sought to discover novel N-acylhomoserine lactone (AHL)-dependent QS and QQ strains by investigating a bacterial community associated with the rhizosphere of ginger (Zingiber officinale) growing in the Malaysian rainforest.

    RESULTS: By using a basal growth medium containing N-(3-oxohexanoyl)homoserine lactone (3-oxo-C6-HSL) as the sole source of carbon and nitrogen, the ginger rhizosphere associated bacteria were enriched for strains with AHL-degrading capabilities. Three isolates belonging to the genera Acinetobacter (GG2), Burkholderia (GG4) and Klebsiella (Se14) were identified and selected for further study. Strains GG2 and Se14 exhibited the broadest spectrum of AHL-degrading activities via lactonolysis while GG4 reduced 3-oxo-AHLs to the corresponding 3-hydroxy compounds. In GG2 and GG4, QQ was found to co-exist with AHL-dependent QS and GG2 was shown to inactivate both self-generated and exogenously supplied AHLs. GG2, GG4 and Se14 were each able to attenuate virulence factor production in both human and plant pathogens.

    CONCLUSIONS: Collectively our data show that ginger rhizosphere bacteria which make and degrade a wide range of AHLs are likely to play a collective role in determining the QS-dependent phenotype of a polymicrobial community.

    Matched MeSH terms: Acinetobacter/isolation & purification; Burkholderia/isolation & purification
  4. Characterisation of fucoidan extracted from Malaysian Sargassum binderi
    Lim SJ, Wan Aida WM, Maskat MY, Latip J, Badri KH, Hassan O, et al.
    Food Chem, 2016 Oct 15;209:267-73.
    PMID: 27173562 DOI: 10.1016/j.foodchem.2016.04.058
    Fucoidan is a sulphated polysaccharide that consists mainly of fucose, normally found in brown seaweeds. In this study, fucoidan was extracted from Sargassum binderi (Fsar) from Malaysia and subsequently characterised. The chemical characteristics of Fsar were found to be different than those of commercial food grade fucoidan (Fysk) and those of previously studied fucoidans. NMR analysis proposed that the main structure of Fsar is →3)fuc-2-OSO3(-)(1→3)fuc(1→. The molecular weight (47.87kDa) and degree of sulphation (0.20) of Fsar were higher than those of Fysk, at 27.98kDa and 0.15, respectively. However, Fsar's polydispersity index (1.12) and fucose content (34.50%) were lower than those of Fysk, at 1.88 and 43.30%, respectively. Both Fsar and Fysk showed similar thermo-gravimetric properties with four mass losses, amorphous in nature and negative optical rotations. Results show that Fsar has fundamental characteristics of fucoidan with different structural conformation i.e. variation in glycosidic linkages and sulphate group orientation.
    Matched MeSH terms: Fucose/isolation & purification*; Polysaccharides/isolation & purification*
  5. Study of optimal temperature, pH and stability of dragon fruit (Hylocereus polyrhizus) peel for use as potential natural colorant
    Harivaindaran KV, Rebecca OP, Chandran S
    Pak J Biol Sci, 2008 Sep 15;11(18):2259-63.
    PMID: 19137837
    The peel of Hylocereus polyrhizus is often regarded as a waste hence this study was aimed at exploring the feasibility of using the peel as a natural colorant using simple water extraction method. Samples were subjected to a series of temperatures: Room temperature (RT), 50, 80 and 100 degrees C; varied length of heating time from 1, 2, 3, 4, 5 and 10 min and a varied range of pH using 1 M of citric acid solution. The best condition to obtain highest betacyanin content was heating samples at 100 degrees C for 5 min in a pH 5 citric acid solution. The next part of this study involved the stability test of the pigments obtained through the best method determined earlier. The pigments were dried and resuspended in distilled water. The samples were then exposed to light to monitor pigment changes. Initial resuspension of the dried pigments yielded a comparable high content of betacyanins to its juice counterpart. The results showed that resuspended pigments had high pigment retention and were stable up to 7 days. These initial findings must be further studied in more controlled conditions to understand the stability of betacyanin. Nevertheless, the results show that betacyanin obtained from the peel of dragon fruit has a high potential to be used as a natural dye.
    Matched MeSH terms: Carbocyanines/isolation & purification; Food Coloring Agents/isolation & purification
  6. Plaque formation in vero cell cultures by some Malaysian viruses
    Rudnick A, Dewey RW
    Southeast Asian J Trop Med Public Health, 1973 Jun;4(2):272-3.
    PMID: 4201359
    Matched MeSH terms: Insect Viruses/isolation & purification; Viruses/isolation & purification
  7. Isospora hylomysis and Eimeria bentongi n. spp. (Protozoa: Eimeriidae) from the lesser gymnure Hylomys suillus Müller, 1839 in Malaysia
    Colley FC, Mullin SW
    Southeast Asian J Trop Med Public Health, 1971 Sep;2(3):289-91.
    PMID: 5168250
    Matched MeSH terms: Eimeria/isolation & purification; Isospora/isolation & purification
  8. Characterization of the Synergistic Effect of Fungal Isolates in Suppressing Ganoderma boninense and Enhancing Oil Palm Growth
    Anuar MSK, Hashim AM, Sundram S, Rahman SRA, Ho CL, Wong MY, et al.
    J Basic Microbiol, 2025 Jan;65(1):e2400312.
    PMID: 39304989 DOI: 10.1002/jobm.202400312
    The globally vital oil palm, a major oil producer, confronts productivity challenges due to Ganoderma boninense (Gb), causing output decline. Chemical control efforts have proven ineffective, prompting exploration of microbial-based biocontrol. While single fungal biocontrol research exists, the impact of employing multiple biocontrols concurrently to combat Ganoderma and enhance oil palm growth remains uncharted. This study examined four soil-derived fungal isolates for their ability to antagonize Gb PER71 in vitro. Molecular identification categorized them as Talaromyces spp. and Penicillium sp. Moreover, all isolates were revealed to have at least three plant growth-promoting (PGP) traits and were shown to have phosphoric hydrolase, ester hydrolase, peptide hydrolase, and glycosidase activities which are essential for plant growth. Furthermore, the synergistic evaluation of fungal isolates was tested against Gb PER71. One out of six combinations of fungal isolates showed a synergistic effect in vitro, and two showed a synergistic effect in planta. The application of single and combined fungal isolates tested in planta also suppressed Gb PER71 and enhanced oil palm growth compared to control groups. The findings indicate the promising potential of these isolates as biocontrol agents (BCAs) and bioformulations against Gb in oil palm cultivation.
    Matched MeSH terms: Penicillium/isolation & purification; Talaromyces/isolation & purification
  9. Benzofurans and dibenzofurans from galls on twigs of the endangered Chinese endemic tree Parrotia subaequalis and their inhibitory properties against Staphylococcus aureus and ATP-citrate lyase
    Zhou PJ, Wu XY, Zhao ZY, Zang Y, Sun ZS, Li YL, et al.
    Phytochemistry, 2025 Jan;229:114309.
    PMID: 39427693 DOI: 10.1016/j.phytochem.2024.114309
    Parrotia subaequalis, an endangered Tertiary relict tree native to China and a member of the Hamamelidaceae family, is one of several host plant species in this family that exhibit unique ecological habits, such as gall formation. Tree galls are the results of complex interactions between gall-inducing insects and their host plant organs. The formation of galls may serve to protect other regions of the plant from potential damage, often through the production of phytoalexins. In this study, a preliminary investigation was carried out on the metabolites of the 90% MeOH extract derived from the closed spherical galls on the twigs of P. subaequalis. Consequently, nine previously undescribed benzofuran-type and dibenzofuran-type phytoalexins (parrotiagallols A-I, 1-9, respectively) were isolated and characterized, along with several known miscellaneous metabolites (10-17). Their chemical structures and absolute configurations were elucidated using spectroscopic methods, a combination of calculated and experimental electronic circular dichroism data, and single crystal X-ray diffraction analyses. Among these compounds, 1 and 2 are identified as neolignan derivatives, while compounds 3-5 are classified as 9,10-dinorneolignans. Compound 6 represents a rare 2,3-seco-neolignan, and compounds 7-9 are dihydroxy-dimethyl-dibenzofuran derivatives. Parrotiagallol A (1) showed considerable antibacterial activity against Staphylococcus aureus, with an MIC value of 14 μM. Additionally, parrotiagallol E (5) and methyl gallate (17) exhibited inhibitory effects against ATP-citrate lyase (ACL), a potential therapeutic target for hyperlipidemia, with IC50 values of 5.1 and 9.8 μM, respectively. The findings underscore that galls not only serve as physical defense barriers but also benefit from the chemical defense system of the host plants. These insights provide avenues for exploring potential new therapeutic agents for S. aureus infections and ACL-related diseases, while also promoting scientific conservation strategies for P. subaequalis.
    Matched MeSH terms: Enzyme Inhibitors/isolation & purification; Dibenzofurans/isolation & purification
  10. The appearance of a second genotype of Japanese encephalitis virus in the Australasian region
    Pyke AT, Williams DT, Nisbet DJ, van den Hurk AF, Taylor CT, Johansen CA, et al.
    Am J Trop Med Hyg, 2001 Dec;65(6):747-53.
    PMID: 11791969
    In mid-January 2000, the reappearance of Japanese encephalitis (JE) virus activity in the Australasian region was first demonstrated by the isolation of JE virus from 3 sentinel pigs on Badu Island in the Torres Strait. Further evidence of JE virus activity was revealed through the isolation of JE virus from Culex gelidus mosquitoes collected on Badu Island and the detection of specific JE virus neutralizing antibodies in 3 pigs from Saint Pauls community on Moa Island. Nucleotide sequencing and phylogenetic analyses of the premembrane and envelope genes were performed which showed that both the pig and mosquito JE virus isolates (TS00 and TS4152, respectively) clustered in genotype I, along with northern Thai, Cambodian, and Korean isolates. All previous Australasian JE virus isolates belong to genotype II, along with Malaysian and Indonesian isolates. Therefore, for the first time, the appearance and transmission of a second genotype of JE virus in the Australasian region has been demonstrated.
    Matched MeSH terms: Encephalitis Virus, Japanese/isolation & purification; RNA, Viral/isolation & purification
  11. Detection of Persistent Chikungunya Virus RNA but not Infectious Virus in Experimental Vertical Transmission in Aedes aegypti from Malaysia
    Wong HV, Vythilingam I, Sulaiman WY, Lulla A, Merits A, Chan YF, et al.
    Am J Trop Med Hyg, 2016 Jan;94(1):182-6.
    PMID: 26598564 DOI: 10.4269/ajtmh.15-0318
    Vertical transmission may contribute to the maintenance of arthropod-borne viruses, but its existence in chikungunya virus (CHIKV) is unclear. Experimental vertical transmission of infectious clones of CHIKV in Aedes aegypti mosquitoes from Malaysia was investigated. Eggs and adult progeny from the second gonotrophic cycles of infected parental mosquitoes were tested. Using polymerase chain reaction (PCR), 56.3% of pooled eggs and 10% of adult progeny had detectable CHIKV RNA, but no samples had detectable infectious virus by plaque assay. Transfected CHIKV RNA from PCR-positive eggs did not yield infectious virus in BHK-21 cells. Thus, vertical transmission of viable CHIKV was not demonstrated. Noninfectious CHIKV RNA persists in eggs and progeny of infected Ae. aegypti, but the mechanism and significance are unknown. There is insufficient evidence to conclude that vertical transmission exists in CHIKV, as positive results reported in previous studies were almost exclusively based only on viral RNA detection.
    Matched MeSH terms: Chikungunya virus/isolation & purification*; RNA, Viral/isolation & purification*
  12. Fulltext Rapid Detection of Plasmodium knowlesi by Isothermal Recombinase Polymerase Amplification Assay
    Lai MY, Ooi CH, Lau YL
    Am J Trop Med Hyg, 2017 Nov;97(5):1597-1599.
    PMID: 28820700 DOI: 10.4269/ajtmh.17-0427
    In this study, we developed a recombinase polymerase amplification (RPA) assay for specific diagnosis of Plasmodium knowlesi. Genomic DNA was extracted from whole blood samples using a commercial kit. With incubation at 37°C, the samples were successfully amplified within 20 minutes. The end product of RPA was further examined by loading onto agarose gel and a specific band was observed with a size of 128 bp. The RPA assay exhibited high sensitivity with limits of detection down to one copy of the plasmid. From the specificity experiments, it was demonstrated that all P. knowlesi samples (N = 45) were positive while other Plasmodium spp. (N = 42) and negative samples (N = 6) were negative. Therefore, the RPA assay is a highly promising approach with the potential to be used in resource-limited settings. This assay can be further optimized for bedside and on field application.
    Matched MeSH terms: DNA, Protozoan/isolation & purification*; Plasmodium knowlesi/isolation & purification*
  13. A longitudinal study of malaria antibodies in a Malaysian population. I. Group responses
    Mathews HM, Dondero TJ
    Am J Trop Med Hyg, 1982 Jan;31(1):14-8.
    PMID: 7036766
    The indirect hemagglutination test was used to measure malaria antibody levels in residents of an endemic area of Malaysia. Blood specimens were collected at 4-week intervals for a year. Seropositivity rates increased with age and number of episodes of malaria in young children. Although antibody levels were variable, titers tended to rise with parasitemia and fall in the absence of detected parasites. In general, the serologic indices tended to reflect the parasitologic findings.
    Matched MeSH terms: Plasmodium falciparum/isolation & purification; Plasmodium vivax/isolation & purification
  14. Fulltext Fatal co-infection--melioidosis and leptospirosis
    Hin HS, Ramalingam R, Chunn KY, Ahmad N, Ab Rahman J, Mohamed MS
    Am J Trop Med Hyg, 2012 Oct;87(4):737-40.
    PMID: 22826499 DOI: 10.4269/ajtmh.2012.12-0165
    Co-infection of melioidosis and leptospirosis is uncommon. We report here four such cases, confirmed by blood culture for melioidosis and blood polymerase-chain reaction for leptospirosis, which occurred among rescuers involved in a search and rescue operation for a young man who was suspected to have drowned in Lubuk Yu, a recreational forest in Pahang, Malaysia. Despite treatment, three of the patients died from the co-infection.
    Matched MeSH terms: Leptospira/isolation & purification*; Burkholderia pseudomallei/isolation & purification*
  15. A rapid sporozoite ELISA using 3,3',5,5'-tetramethylbenzidine as the substrate chromogen
    Lee M, Harrison BA, Lewis GE
    Am J Trop Med Hyg, 1990 Apr;42(4):314-9.
    PMID: 2184690 DOI: 10.4269/ajtmh.1990.42.314
    A modified version of the standard 2-site sporozoite enzyme-linked immunosorbent assay (ELISA) using 3,3',5,5'-tetramethylbenzidine (TMB) as the substrate chromogen solution was adapted for rapid detection and identification of Plasmodium falciparum and P. vivax circumsporozoite (CS) proteins. The TMB-ELISA was evaluated using sporozoites from experimentally infected mosquitoes and laboratory colonized uninfected mosquitoes. Our data indicate comparable sensitivity levels between the TMB-ELISA and the standard ELISA, i.e., 50 P. falciparum or P. vivax sporozoites/50 microliters of test solution. Reactions inherent to the method were specific and background reactivity was minimal. The TMB-ELISA is rapid (1 hr), simple, uses a minimal amount of monoclonal antibodies, and is suitable for use in a wide range of laboratories.
    Matched MeSH terms: Plasmodium falciparum/isolation & purification*; Plasmodium vivax/isolation & purification*
  16. Fulltext Isolation, Characterization, and Unlocking the Potential of Mimir124 Phage for Personalized Treatment of Difficult, Multidrug-Resistant Uropathogenic E. coli Strain
    Golomidova A, Kupriyanov Y, Gabdrakhmanov R, Gurkova M, Kulikov E, Belalov I, et al.
    Int J Mol Sci, 2024 Nov 27;25(23).
    PMID: 39684465 DOI: 10.3390/ijms252312755
    Escherichia coli and its bacteriophages are among the most studied model microorganisms. Bacteriophages for various E. coli strains can typically be easily isolated from environmental sources, and many of these viruses can be harnessed to combat E. coli infections in humans and animals. However, some relatively rare E. coli strains pose significant challenges in finding suitable phages. The uropathogenic strain E. coli UPEC124, isolated from a patient suffering from neurogenic bladder dysfunction, was found to be resistant to all coliphages in our collections, and initial attempts to isolate new phages failed. Using an improved procedure for phage enrichment, we isolated the N4-related phage Mimir124, belonging to the Gamaleyavirus genus, which was able to lyse this "difficult" E. coli strain. Although Mimir124 is a narrow-spectrum phage, it was effective in the individualized treatment of the patient, leading to pathogen eradication. The primary receptor of Mimir124 was the O antigen of the O101 type; consequently, Mimir124-resistant clones were rough (having lost the O antigen). These clones, however, gained sensitivity to some phages that recognize outer membrane proteins as receptors. Despite the presence of nine potential antiviral systems in the genome of the UPEC124 strain, the difficulty in finding effective phages was largely due to the efficient, non-specific cell surface protection provided by the O antigen. These results highlight the importance of an individualized approach to phage therapy, where narrow host-range phages-typically avoided in pre-fabricated phage cocktails-may be instrumental. Furthermore, this study illustrates how integrating genomic, structural, and functional insights can guide the development of innovative therapeutic strategies, paving the way for broader applications of phage therapy in combating multidrug-resistant bacterial pathogens.
    Matched MeSH terms: Bacteriophages/isolation & purification; Coliphages/isolation & purification
  17. Investigation of Phytochemical Composition, Radical Scavenging Potential, Anti-Obesogenic Effects, and Anti-Diabetic Activities of Kaempferia parviflora Rhizomes
    Prabakaran S, Saad HM, Tan CH, Syed Abdul Rahman SN, Sim KS
    Chem Biodivers, 2025 Jan;22(1):e202401086.
    PMID: 39289837 DOI: 10.1002/cbdv.202401086
    Kaempferia parviflora or commonly known as "Kunyit hitam" by locals, is an edible plant, native to tropical regions, has been extensively utilized for culinary and medicinal applications. The present study aimed to investigate the phytochemical composition and biological activities of the rhizomes of K. parviflora. The ethanol crude and fractionated extracts (hexane and chloroform) of the rhizomes were evaluated for their total phenolic content, total steroidal content, as well as antioxidant, anti-obesogenic, and anti-diabetic activities. The chloroform extract demonstrated the highest concentration of plant sterols (432±0.23 mg BSE/g extract) and a substantial amount of phenolic compounds (1.19×103±0.41 mg GAE/g extract). Gas chromatography-mass spectrometry (GC/MS) analysis revealed that the chloroform extract of the rhizomes is predominantly composed of bioactive flavonoids including tectochrysin (1), 5,7-dimethoxyflavone (2), 3,5,7-trimethoxyflavone (3), 3,4',5,7-tetramethoxyflavone (4), and 4',5,7-trimethoxyflavone (5). Furthermore, the chloroform extract exhibited the highest overall radical scavenging and α-glucosidase inhibitory activities, which can be attributed to the presence of compounds 1-5 in the extract. Collectively, these findings suggest that the chloroform extract of the rhizomes of K. parviflora is a potentially valuable source of bioactive compounds with antioxidant, anti-obesogenic, and anti-diabetic properties, with potential application in therapeutics and functional foods.
    Matched MeSH terms: Antioxidants/isolation & purification; Glycoside Hydrolase Inhibitors/isolation & purification
  18. Fulltext Salivary cariogenic bacteria counts are associated with obesity in student women at a Malaysian university
    Yeo WZ, Lim SP, Say YH
    Asia Pac J Clin Nutr, 2017 12 10;27(1):99-106.
    PMID: 29222886 DOI: 10.6133/apjcn.032017.14
    BACKGROUND AND OBJECTIVES: The counts of cariogenic bacteria lactobacilli and mutans streptococci have been studied and correlated with sugar intake. This study was to investigate the association between salivary lactobacilli and mutans streptococci counts with sweet food eating behavior and sweet sensitivity among 120 Malaysian women (101 ethnic Chinese, 19 ethnic Indians), while taking into account anthropometric and menstruation variables.

    METHODS AND STUDY DESIGN: Demographics, anthropometric measurements and menstrual history were taken. Hedonic preference, intake frequency of a list of sweet foods, intensity perception and pleasantness ratings of sweet stimuli were assessed. Saliva was collected for lactobacilli and mutans streptococci culture.

    RESULTS: We found that centrally obese subjects (high waist circumference and waist-hip ratio) had significantly higher salivary lactobacilli and mutans streptococci counts (all p<0.05), while overweight and high total body fat subjects had significantly higher salivary mutans streptococci counts (p<0.001). The sweetness intensity perception of chocolate malt drinks was significantly lower in women who were in their pre-menstrual (post-ovulation) phase. However, menstruation variables (menstrual phases, regularity and pre-menstrual syndromes) did not play a role in determining compulsive eating, sweets/chocolate craving and salivary lactobacilli and mutans streptococci counts.

    CONCLUSIONS: Taken together, salivary lactobacilli and mutans streptococci counts of the Malaysian women are associated with central obesity, but not sweet food eating behaviour, sweet sensitivity and menstruation variables. Salivary microbiome analysis could be useful as a potential diagnostic indicator of diseases such as obesity.

    Matched MeSH terms: Lactobacillus/isolation & purification*; Streptococcus mutans/isolation & purification*
  19. Development, validation and determination of multiclass pesticide residues in cocoa beans using gas chromatography and liquid chromatography tandem mass spectrometry
    Zainudin BH, Salleh S, Mohamed R, Yap KC, Muhamad H
    Food Chem, 2015 Apr 1;172:585-95.
    PMID: 25442595 DOI: 10.1016/j.foodchem.2014.09.123
    An efficient and rapid method for the analysis of pesticide residues in cocoa beans using gas and liquid chromatography-tandem mass spectrometry was developed, validated and applied to imported and domestic cocoa beans samples collected over 2 years from smallholders and Malaysian ports. The method was based on solvent extraction method and covers 26 pesticides (insecticides, fungicides, and herbicides) of different chemical classes. The recoveries for all pesticides at 10 and 50 μg/kg were in the range of 70-120% with relative standard deviations of less than 20%. Good selectivity and sensitivity were obtained with method limit of quantification of 10 μg/kg. The expanded uncertainty measurements were in the range of 4-25%. Finally, the proposed method was successfully applied for the routine analysis of pesticide residues in cocoa beans via a monitoring study where 10% of them was found positive for chlorpyrifos, ametryn and metalaxyl.
    Matched MeSH terms: Alanine/isolation & purification; Chlorpyrifos/isolation & purification; Pesticide Residues/isolation & purification; Triazines/isolation & purification
  20. Cytotoxic vobasine, tacaman, and corynanthe-tryptamine bisindole alkaloids from Tabernaemontana and structure revision of tronoharine
    Sim DS, Chong KW, Nge CE, Low YY, Sim KS, Kam TS
    J Nat Prod, 2014 Nov 26;77(11):2504-12.
    PMID: 25333996 DOI: 10.1021/np500589u
    Seven new indole alkaloids (1-7) comprising four vobasine, two tacaman, and one corynanthe-tryptamine bisindole alkaloid were isolated from the stem-bark extract of a Malayan Tabernaemontana. Two of the new vobasine alkaloids (1, 3), as well as 16-epivobasine (15) and 16-epivobasenal (17), showed appreciable cytotoxicity toward KB cells (IC50 ca. 5 μg/mL). The structure of the known Tabernaemontana alkaloid tronoharine (8) was revised based on newly acquired NMR data, as well as X-ray diffraction analysis.
    Matched MeSH terms: Antineoplastic Agents, Phytogenic/isolation & purification*; Indoles/isolation & purification; Tryptamines/isolation & purification; Indole Alkaloids/isolation & purification*
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