Displaying publications 81 - 100 of 355 in total

Abstract:
Sort:
  1. An optical biosensor for dichlovos using stacked sol-gel films containing acetylcholinesterase and a lipophilic chromoionophore
    Wong FC, Ahmad M, Heng LY, Peng LB
    Talanta, 2006 Jun 15;69(4):888-93.
    PMID: 18970653 DOI: 10.1016/j.talanta.2005.11.034
    An optical biosensor consisting of a chromoionophore (ETH5294) (CM) doped sol-gel film interfaced with another sol-gel film immobilized with acetylcholinesterase (AChE) was employed to detect the insecticide dichlorvos. The main advantage of this optical biosensor is the use of a sol-gel layer with immobilized CM that possesses lipophilic property. The highly lipophilic nature of the CM and its compatibility with the sol-gel matrix has prevented leaching, which is frequently a problem in optical sensor construction based on pH indicator dyes. The immobilization of the indicator and enzyme was simple and need no chemical modification. The CM layer is pH sensitive and detects the pH changes of the acetylcholine chloride (AChCl) substrate when hydrolyzed by AChE layer deposited above. In the absence of the AChE layer, the pH response of the CM layer is linear from pH 6 to 8 (R(2)=0.98, n=3) and it showed no leaching of the lipophilic chromoionophore. When the AChE layer is deposited on top, the optical biosensor responds to AChCl with a linear dynamic range of 40-90mM AChCl (R(2)=0.984, n=6). The response time of the biosensor is 12min. Based on the optimum incubation time of 15min, a linear calibration curve of dichlorvos against the percentage inhibition of AChE was obtained from 0.5 to 7mg/L of dichlorvos (17-85% inhibition, R(2)=0.991, n=9). The detection limit for dichlorvos was 0.5mg/L. The results of the analysis of 1.7-6.0mg/L of dichlorvos using this optical biosensor agreed well with a gas chromatography-mass spectrometry detection method.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  2. Chemotaxonomical markers in essential oil of Murraya koenigii
    Nagappan T, Ramasamy P, Vairappan CS
    Nat Prod Commun, 2012 Oct;7(10):1375-8.
    PMID: 23157015
    The composition of the essential oils of Murraya koenigii (L.) Spreng, cultivated at six locations in Peninsula Malaysia and Borneo are presented. The oils were obtained from fresh leaves by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS); 61 compounds were identified, of which eleven were present in all the specimens analyzed. The two major volatile metabolites were identified as beta-caryophyllene (16.6-26.6%) and alpha-humulene (15.2-26.7%) along with nine minor compounds identified as beta-elemene (0.3-1.3%), aromadendrene (0.5-1.5%), beta-selinene (3.8-6.5%), spathulenol (0.6-2.7%), caryophyllene oxide (0.7-3.6%), viridiflorol (1.5-5.5%), 2-naphthalenemethanol (0.7-4.8%), trivertal (0.1-1.0%) and juniper camphor (2.6-8.3%). The results suggest that beta-caryophyllene and alpha-humulene could be used as chemotaxonomical markers for Malaysian M. koenigii, hence these specimens could be of the same stock and different from the ones in India, Thailand and China.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  3. An assessment of the concentrations of particulate polycyclic aromatic hydrocarbons (PAHs) in the aftermath of a chemical store fire incident
    Abas MR, Omar NY, Maah MJ
    J Environ Sci (China), 2004;16(5):751-4.
    PMID: 15559805
    PM10 airborne particles and soot deposit collected after a fire incident at a chemical store were analyzed in order to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs). The samples were extracted with 1:1 hexane-dichloromethane by ultrasonic agitation. The extracts were then subjected to gas chromatography-mass spectrometric (GC-MS) analysis. The total PAHs concentrations in airborne particles and soot deposit were found to be 3.27 +/- 1.55 ng/m3 and 12.81 +/- 24.37 microg/g, respectively. Based on the molecular distributions of PAHs and the interpretation of their diagnostic ratios such as PHEN/(PHEN + ANTH), FLT/(FLT + PYR) and BeP/(BeP + BaP), PAHs in both airborne particles and soot deposit may be inferred to be from the same source. The difference in the value of IP/(IP + BgP) for these samples indicated that benzo[g, h, i] perylene and coronene tend to be attached to finer particles and reside in the air for longer periods. Comparison between the molecular distributions of PAHs and their diagnostic ratios observed in the current study with those reported for urban atmospheric and roadside soil particles revealed that they are of different sources.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  4. Identification of naphthalene metabolism by white rot fungus Pleurotus eryngii
    Hadibarata T, Teh ZC, Rubiyatno, Zubir MM, Khudhair AB, Yusoff AR, et al.
    Bioprocess Biosyst Eng, 2013 Oct;36(10):1455-61.
    PMID: 23334282 DOI: 10.1007/s00449-013-0884-8
    The use of biomaterials or microorganisms in PAHs degradation had presented an eye-catching performance. Pleurotus eryngii is a white rot fungus, which is easily isolated from the decayed woods in the tropical rain forest, used to determine the capability to utilize naphthalene, a two-ring polycyclic aromatic hydrocarbon as source of carbon and energy. In the meantime, biotransformation of naphthalene to intermediates and other by-products during degradation was investigated in this study. Pleurotus eryngii had been incubated in liquid medium formulated with naphthalene for 14 days. The presence of metabolites of naphthalene suggests that Pleurotus eryngii begin the ring cleavage by dioxygenation on C1 and C4 position to give 1,4-naphthaquinone. 1,4-Naphthaquinone was further degraded to benzoic acid, where the proposed terepthalic acid is absent in the cultured extract. Further degradation of benzoic acid by Pleurotus eryngii shows the existence of catechol as a result of the combination of decarboxylation and hydroxylation process. Unfortunately, phthalic acid was not detected in this study. Several enzymes, including manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase and 2,3-dioxygenase are enzymes responsible for naphthalene degradation. Reduction of naphthalene and the presence of metabolites in liquid medium showed the ability of Pleurotus eryngii to utilize naphthalene as carbon source instead of a limited glucose amount.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  5. Optimization of palm oil physical refining process for reduction of 3-monochloropropane-1,2-diol (3-MCPD) ester formation
    Zulkurnain M, Lai OM, Tan SC, Abdul Latip R, Tan CP
    J Agric Food Chem, 2013 Apr 3;61(13):3341-9.
    PMID: 23464796 DOI: 10.1021/jf4009185
    The reduction of 3-monochloropropane-1,2-diol (3-MCPD) ester formation in refined palm oil was achieved by incorporation of additional processing steps in the physical refining process to remove chloroester precursors prior to the deodorization step. The modified refining process was optimized for the least 3-MCPD ester formation and acceptable refined palm oil quality using response surface methodology (RSM) with five processing parameters: water dosage, phosphoric acid dosage, degumming temperature, activated clay dosage, and deodorization temperature. The removal of chloroester precursors was largely accomplished by increasing the water dosage, while the reduction of 3-MCPD esters was a compromise in oxidative stability and color of the refined palm oil because some factors such as acid dosage, degumming temperature, and deodorization temperature showed contradictory effects. The optimization resulted in 87.2% reduction of 3-MCPD esters from 2.9 mg/kg in the conventional refining process to 0.4 mg/kg, with color and oil stability index values of 2.4 R and 14.3 h, respectively.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  6. GC-MS fingerprint of Pogostemon cablin in China
    Hu LF, Li SP, Cao H, Liu JJ, Gao JL, Yang FQ, et al.
    J Pharm Biomed Anal, 2006 Sep 18;42(2):200-6.
    PMID: 16242880
    Pogostemon cablin, originating in Malaysia and India, is cultivated in southern China including Guangdong and Hainan Province, which was called GuangHuoXiang to differentiate it from the HuoXiang of the north, the species Agastache rugosa, that it resembles. Essential oil of P. cablin mainly contributes to the pharmacological activities and the therapeutic properties of the essential oils are directly correlated with their qualitative and quantitative composition. For controlling the quality, standard fingerprint of P. cablin collected from different regions was developed by using GC-MS. Nine compounds including beta-patchoulene, caryophyllene, alpha-guaiene, seychellene, beta-guaiene, delta-guaiene, spathulenol, patchouli alcohol and pogostone were identified among 10 main peaks in P. cablin. Hierarchical clustering analysis based on characteristics of 10 investigated peaks in GC profiles showed that 18 samples were divided into three main clusters, patchouliol-type, pogostone-type and an interim-type, which was the one between the two chemotypes. The simulative mean chromatogram for the three types P. cablin was generated using the Computer Aided Similarity Evaluation System. The fingerprint can help to distinguish the substitute or adulterant, and further assess the differences of P. cablin grown in various areas of China.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  7. Fulltext Aphid-induced Defences in Chilli Affect Preferences of the Whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae)
    Saad KA, Mohamad Roff MN, Hallett RH, Idris AB
    Sci Rep, 2015;5:13697.
    PMID: 26334135 DOI: 10.1038/srep13697
    The sweetpotato whitefly (WF), Bemisia tabaci, is a major pest that damages a wide range of vegetable crops in Malaysia. WF infestation is influenced by a variety of factors, including previous infestation of the host plant by other insect pests. This study investigated the effects of previous infestation of host chilli plants by the green peach aphid (Myzus persicae) on the olfactory behavioural response of B. tabaci, using free-choice bioassay with a Y-tube olfactometer. We analysed volatile organic compounds (VOCs) emitted by non-infested and M. persicae-infested chilli plants using solid-phase microextraction and gas chromatography-mass spectrometry. Our results showed that female WFs preferred non-infested to pre-infested plants. Collection and analysis of volatile compounds emitted by infested plants confirmed that there were significant increases in the production of monoterpenes (cymene; 1,8-cineole), sesquiterpenes (β-cadinene, α-copaene), and methyl salicylate (MeSA) compared to non-infested plants. Our results suggest that host plant infestation by aphids may induce production of secondary metabolites that deter B. tabaci from settling on its host plants. These results provide important information for understanding WF host selection and dispersal among crops, and also for manipulating WF behaviour to improve IPM in chilli.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  8. One pot synthesis, molecular structure and spectroscopic studies (X-ray, IR, NMR, UV-Vis) of novel 2-(4,6-dimethoxy-1,3,5-triazin-2-yl) amino acid ester derivatives
    El-Faham A, Soliman SM, Osman SM, Ghabbour HA, Siddiqui MR, Fun HK, et al.
    Spectrochim Acta A Mol Biomol Spectrosc, 2016 Apr 15;159:184-98.
    PMID: 26845586 DOI: 10.1016/j.saa.2016.01.051
    Novel series of 2-(4,6-dimethoxy,1,3,5-triazin-2-yl) amino acid ester derivatives were synthesized using simple one pot method in methanol. The products were obtained in high yields and purities as observed from their spectral data, elemental analyses, GC-MS and X-ray crystallographic analysis. The B3LYP/6-311G(d,p) calculated molecular structures are well correlated with the geometrical parameters obtained from the X-ray analyses. The spectroscopic properties such as IR vibrational modes, NMR chemical shifts and UV-Vis electronic transitions were discussed both experimentally and theoretically. The IR vibrational frequencies showed good correlations with the experimental data (R(2)=0.9961-0.9995). The electronic spectra were assigned based on the TD-DFT results. Intense electronic transition band is calculated at 198.1nm (f=0.1389), 204.2nm (f=0.2053), 205.0 (f=0.1704) and 205.7 (0.2971) for compounds 6a-i, respectively. The molecular orbital energy levels contributed in the longest wavelength transition band were explained. For all compounds, the experimental wavelengths showed red shifts compared to the calculations due to the solvent effect. The NMR chemical shifts were calculated using GIAO method. The NBO analyses were performed to predict the stabilization energies due to the electron delocalization processes occur in the studied systems.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  9. Fulltext Evaluation of in-vitro antioxidant and antibacterial properties of Commelina nudiflora L. extracts prepared by different polar solvents
    Kuppusamy P, Yusoff MM, Parine NR, Govindan N
    Saudi J Biol Sci, 2015 May;22(3):293-301.
    PMID: 25972750 DOI: 10.1016/j.sjbs.2014.09.016
    The study explored on the commonly available weed plant Commelina nudiflora which has potential in-vitro antioxidant and antimicrobial activity. The different polar solvents such as ethanol, chloroform, dichloromethane, hexane and aqueous were used for the soxhlet extraction. The extracts were identified pharmacologically as important bioactive compounds and their potential free radical scavenging activities, and antimicrobial properties were studied. C. nudiflora extracts were monitored on their in-vitro antioxidant ability by DPPH and ABTS radical scavenging assay. Aqueous extract shows significant free radical scavenging activity of 63.4 mg/GAE and 49.10 mg/g in DPPH and ABTS respectively. Furthermore, the aqueous crude extract was used in antibacterial studies, which shows the highest inhibitory activity against Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Among all the extracts, aqueous extract of C. nudiflora has significant control over free radical scavenging activity and inhibition of the growth of food pathogenic bacteria. Also, the aqueous extract contains abundance of phenolics and flavonoids higher than other extracts. This study explored weed plant C. nudiflora as a potential source of antioxidant and antibacterial efficacy and identified various therapeutic value bioactive compounds from GC-MS analysis.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  10. Feasibility study of biodiesel production using lipids of Hermetia illucens larva fed with organic waste
    Leong SY, Kutty SR, Malakahmad A, Tan CK
    Waste Manag, 2016 Jan;47(Pt A):84-90.
    PMID: 25872864 DOI: 10.1016/j.wasman.2015.03.030
    Hermetia illucens larvae by nature are a decomposer which fed on organic wastes. This study explores the potential of producing biodiesel using lipids from H. illucens larvae. Three types of organic wastes (sewage sludge, fruit waste and palm decanter cake from oil palm mill) were selected based on considerable generation and disposal concern in the area of study as well as lack of investigations as feed for Hermetia illucens larvae in current literatures. Growth rate of the larvae was determined with studying the changes in the biomass per day. H. illucens larvae fed with fruit waste and palm decanter cake have shown growth rates of 0.52±0.02 and 0.23±0.09 g d(-1), respectively. No positive sign of growth were observed in the larvae fed with treated sewage sludge (-0.04±0.01 g d(-1)). Biodiesel as fatty acid methyl ester (FAME) was synthesized by transesterification of the larvae lipid using sulphuric acid as catalyst in methanol. FAME produced was ascertained using ATR-FTIR spectroscopy and GC-MS. The main compositions of fatty acid were found to be C12:0, C16:0 and C18:1n9c. Fatty acid composition of C12:0 fed with fruit waste, sewage sludge and palm decanter was found to be most abundant in the larvae lipid. The amount of C12:0 obtained was 76.13%, 58.31% and 48.06%, respectively. In addition, fatty acid of C16:0 was attained at 16.48% and 25.48% fed with sewage sludge and palm decanter, respectively. Based on the findings, FAME derived from larvae lipids is feasible to be used for biodiesel production.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  11. Quantitative application of fecal sterols using gas chromatography-mass spectrometry to investigate fecal pollution in tropical waters: western Malaysia and Mekong Delta, Vietnam
    Isobe KO, Tarao M, Zakaria MP, Chiem NH, Minh le Y, Takada H
    Environ Sci Technol, 2002 Nov 1;36(21):4497-507.
    PMID: 12433157
    This is the first report on fecal pollution using molecular markers in Southeast Asia where serious sewage pollution has occurred. A simple and sensitive analytical method using gas chromatography-mass spectrometry for 10 sterols in various environmental samples was developed to monitor extensive areas of tropical Asia. First, the method was applied to wastewater to confirm that >95% of sterols existed in the particulate phase. Then the approach was applied to a tropical Asian region, Malaysia and Vietnam, with a selection of 59 sampling stations in total. River water and sediment samples were collected and analyzed for chemical markers (coprostanol and other sterols) and microbiological markers (fecal coliforms and fecal streptococci). Particulate coprostanol concentrations ranged from <0.0001 to 13.47 microg/L in tropical river and estuarine waters, indicating severe fecal pollution in populous areas. Coprostanol concentrations in the sediments ranged from 0.005 to 15.5 microg/g-dry. The sedimentary coprostanol concentrations were lower than those reported in some urban areas of industrialized countries. This is probably because frequent heavy rain induces intensive input of eroded soil, which dilutes fecal material in river sediments. The relationship between the concentrations of fecal sterols and bacterial indicators was examined in an attempt to develop public health criteria for coprostanol levels applicable to the tropical region. Coprostanol concentrations of 30-100 ng/L or percent coprostanol levels of 2% corresponded to approximately 1000 fecal coliforms per 100 mL, which is set for secondary contact limit in many countries. These coprostanol concentrations were lower than those proposed as criteria in temperate countries, probably owing to greater survival of bacteria in warmer tropical waters. On the basis of these criteria, extensive monitoring of sediments suggests that poor sanitary conditions exist in most of the urbanized area of Malaysia and in several urban and rural sites in Vietnam.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  12. Distribution of oil and grease and petroleum hydrocarbons in the Straits of Johor, peninsular Malaysia
    Abdullah AR, Woon WC, Bakar RA
    Bull Environ Contam Toxicol, 1996 Jul;57(1):155-62.
    PMID: 8661474
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  13. Leaching of bisphenol A from new and old babies' bottles, and new babies' feeding teats
    Tan BL, Mustafa AM
    Asia Pac J Public Health, 2003;15(2):118-23.
    PMID: 15038686
    Bisphenol A is the monomer used in the manufacture of polycarbonate. Bisphenol A is also known to mimic the female hormone estrogen. In this study, the possibility of the leaching of bisphenol A from polycarbonate babies' bottles and feeding teats was investigated. Bisphenol A was extracted from water samples exposed to the bottles and teats using liquid-liquid extraction. Bisphenol A was analysed by gas chromatograph-mass spectrometer with quadrapole detector in selected ion monitoring mode. Mean leaching of bisphenol A from 100 used babies' bottles when filled with water at 25 degrees C and 80 degrees C were 0.71 +/- 1.65 ng/cm2 (mean +/- standard deviation) and 3.37 +/- 5.68 ng/cm2 respectively. Mean leaching of bisphenol A from 30 new babies' bottles when filled with water at 25 degrees C and 80 degrees C were 0.03 +/- 0.02 ng/cm2 and 0.18 degrees 0.30 ng/cm2 respectively. Bisphenol A was observed to have leached from babies' feeding teats into 37 degrees C water ranged from non-detectable to 22.86 ng/g. The technique employed in this study is fast, reliable and economical.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  14. Fulltext Optimization of headspace solid phase microextraction (HS-SPME) for the extraction of volatile organic compounds (VOCs) in MD2 pineapple
    Syaidatul Faraha Zainuddin, Siti Raihan Zakaria, Norashikin Saim, Rossuriati Dol Hamid, Rozita Osman
    Science Letters, 2020;14(2):58-70.
    MyJurnal
    Headspace solid phase microextraction (HS-SPME) was employed for the extraction of volatile organic compounds (VOCs) in MD2 pineapple (Ananas comosus L. var. comosus cv. MD2). Optimisation of HS-SPME operating parameters was conducted using three-factor, three-level Box–Behnken response surface experimental design to evaluate the interactive effects of temperature (30 – 50 ºC), extraction time (10 – 30 min) and salting effect (1 – 3 g of salt addition) on the amount of selected VOCs. Determination of VOCs was done using gas chromatography with spectrometry detector (GC-MSD). Extraction temperature was found to be significant (p < 0.05) in increasing the amount of selected VOCs (ethyl acetate, methyl isobutyrate and butanoic acid methyl ester). Based on the maximum amount of these VOCs, the optimum operating extraction conditions for HS-SPME were set up at temperature of 30 °C, time of 29 min and salt addition of 1 g. The optimized HS-SPME conditions were employed for the extraction of VOCs from pineapple of different varieties.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  15. Fulltext Antinociceptive activity of methanolic extract of melastoma malabathricum l.leaves and mechanisms of action in experimentalanimals
    Erman Shah Jaios, Suzanah Abdul Rahman, Mooi, Ching Siew, Arifah Abdul Kadir, Mohd Nasir Mohd Desa, Zainul Amirudin Zakaria
    International Journal of Allied Health Sciences, 2017;1(1):1-1.
    MyJurnal
    Objectives/Research Problem:Melastoma malabathricum L., (Melastomaceae) is a medicinally important plant known as “Senduduk”. Traditionally, the leaves are used to relieve diverse pain-related ailments. Present study aims to examine the antinociceptive activity of methanolic extract of M. malabathricum (MEMM) leaves and its fractions via in vivo models of nociception.

    Materials and Method: Extracts (100, 250, 500 mg/kg) were administered orally 60 minutes prior to subjection to the respective test, n=6/group. Evaluation of MEMM antinociceptive activity; chemically (acetic acid-induced abdominal constriction; ACT, formalin-induced paw licking test; FT) and thermally (hot plate test; HT) models of nociception and elucidation of mechanisms of action involved; role of opioid, vanilloid receptors, glutamatergic system and NO/cGMP pathway were determined. Continuously, MEMM, partitioned into three fractions: petroleum ether (PEMM), ethyl acetate (EAMM), and aqueous (AQMM) extracts and determine the most potent fraction. Therefore, experiment ED50 and its 95% confidence intervals (CI) values were conducted, and ACT was used to screen. Calculation, obtained, PEMM, the most effective was further used to assess the antinociceptive properties. Phytochemical screening, HPLC and GC-MS analysis were performed.

    Results and Discussion: First stage, MEMM exhibited significant (P
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  16. Fulltext Inhibition of Quorum Sensing and Biofilm Formation in Chromobacterium violaceum by Fruit Extracts of Passiflora edulis
    Venkatramanan M, Sankar Ganesh P, Senthil R, Akshay J, Veera Ravi A, Langeswaran K, et al.
    ACS Omega, 2020 Oct 13;5(40):25605-25616.
    PMID: 33073086 DOI: 10.1021/acsomega.0c02483
    Chromobacterium violaceum (C. violaceum) is a Gram-negative, rod-shaped facultatively anaerobic bacterium implicated with recalcitrant human infections. Here, we evaluated the anti-QS and antibiofilm activities of ethyl acetate extracts of Passiflora edulis (P. edulis) on the likely inactivation of acyl-homoserine lactone (AHL)-regulated molecules in C. violaceum both by in vitro and in silico analyses. Our investigations showed that the sub-MIC levels were 2, 1, and 0.5 mg/mL, and the concentrations showed a marked reduction in violacein pigment production by 75.8, 64.6, and 35.2%. AHL quantification showed 72.5, 52.2, and 35.9% inhibitions, inhibitions of EPS production (72.8, 36.5, and 25.9%), and reductions in biofilm formation (90.7, 69.4, and 51.8%) as compared to a control. Light microscopy and CLSM analysis revealed dramatic reduction in the treated biofilm group as compared to the control. GC-MS analysis showed 20 major peaks whose chemical structures were docked as the CviR ligand. The highest docking score was observed for hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester bonds in the active site of CviR with a binding energy of -8.825 kcal/mol. Together, we found that hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester remarkably interacted with CviR to inhibit the QS system. Hence, we concluded that hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl) ethyl ester of P. edulis could likely be evaluated for treating C. violaceum infections.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  17. Fulltext Dual bioactivities of laurus nobilis essential oil
    Nur Afiqah Saparin, Mohd Muzamir Mahat, Muhd Fauzi Safian, Shahrul Hisham Zainal Ariffin, Nor Azah Mohamad Ali, Zaidah Zainal Ariffin
    Science Letters, 2020;14(1):62-67.
    MyJurnal
    The evolution of cosmetic products results in the growing demands for cosmetics that are preservatives free. Plant essential oils were found to be a promising antimicrobial and also antioxidant agent. In this study, Cymbopogon citratus (lemongrass), Laurus nobilis (bay leaf) and Backhousia citriodora (lemon myrtle) essential oils were selected and evaluated for their antimicrobial properties. It was found that Laurus nobilis exhibited strong antimicrobial activity against the selected bacteria Streptococcus saprophyticus (ATCC 49619), Streptococcus aureus (ATCC 22923), Streptococcus pyogenes (ATCC 29436), Pseudomonas aeruginosa (ATCC 13048), Klebsiella pneumoniae (ATCC 700603), Escherichia coli (ATCC 22922) with MIC ranging between 7.8 ug/mL to 250 μg/mL. The antioxidant activity of selected essential oils was determined by antioxidant assays which were 1,1-Diphenyl-2-picrylhydrazyl assay (DPPH), determination of ferric reducing antioxidant power assay (FRAP) and β-Carotene/linoleic acid bleaching assay. Backhousia citriodora and Laurus nobilis showed the highest antioxidant activity.
    n-Octanal and β-Selinene were identified to be the major components with peak area of 26.37 % and 13.92 % respectively in secondary metabolites analysis by Gas Chromatography-Mass Spectrometry (GCMS).
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  18. Fulltext Microbial Biodegradation of Paraffin Wax in Malaysian Crude Oil Mediated by Degradative Enzymes
    Adlan NA, Sabri S, Masomian M, Ali MSM, Rahman RNZRA
    Front Microbiol, 2020;11:565608.
    PMID: 33013795 DOI: 10.3389/fmicb.2020.565608
    The deposition of paraffin wax in crude oil is a problem faced by the oil and gas industry during extraction, transportation, and refining of crude oil. Most of the commercialized chemical additives to prevent wax are expensive and toxic. As an environmentally friendly alternative, this study aims to find a novel thermophilic bacterial strain capable of degrading paraffin wax in crude oil to control wax deposition. To achieve this, the biodegradation of crude oil paraffin wax by 11 bacteria isolated from seawater and oil-contaminated soil samples was investigated at 70°C. The bacteria were identified as Geobacillus kaustophilus N3A7, NFA23, DFY1, Geobacillus jurassicus MK7, Geobacillus thermocatenulatus T7, Parageobacillus caldoxylosilyticus DFY3 and AZ72, Anoxybacillus geothermalis D9, Geobacillus stearothermophilus SA36, AD11, and AD24. The GCMS analysis showed that strains N3A7, MK7, DFY1, AD11, and AD24 achieved more than 70% biodegradation efficiency of crude oil in a short period (3 days). Notably, most of the strains could completely degrade C37-C40 and increase the ratio of C14-C18, especially during the initial 2 days incubation. In addition, the degradation of crude oil also resulted in changes in the pH of the medium. The degradation of crude oil is associated with the production of degradative enzymes such as alkane monooxygenase, alcohol dehydrogenase, lipase, and esterase. Among the 11 strains, the highest activities of alkane monooxygenase were recorded in strain AD24. A comparatively higher overall alcohol dehydrogenase, lipase, and esterase activities were observed in strains N3A7, MK7, DFY1, AD11, and AD24. Thus, there is a potential to use these strains in oil reservoirs, crude oil processing, and recovery to control wax deposition. Their ability to withstand high temperature and produce degradative enzymes for long-chain hydrocarbon degradation led to an increase in the short-chain hydrocarbon ratio, and subsequently, improving the quality of the oil.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  19. Fulltext Classification of different pineapple varieties grown in Malaysia based on volatile fingerprinting and sensory analysis
    Lasekan O, Hussein FK
    Chem Cent J, 2018 Dec 19;12(1):140.
    PMID: 30569201 DOI: 10.1186/s13065-018-0505-3
    BACKGROUND: Pineapple is highly relished for its attractive sweet flavour and it is widely consumed in both fresh and canned forms. Pineapple flavour is a blend of a number of volatile and non-volatile compounds that are present in small amounts and in complex mixtures. The aroma compounds composition may be used for purposes of quality control as well as for authentication and classification of pineapple varieties.

    RESULTS: The key volatile compounds and aroma profile of six pineapple varieties grown in Malaysia were investigated by gas chromatography-olfactometry (GC-O), gas-chromatography-mass spectrometry and qualitative descriptive sensory analysis. A total of 59 compounds were determined by GC-O and aroma extract dilution analysis. Among these compounds, methyl-2-methylbutanoate, methyl hexanoate, methyl-3-(methylthiol)-propanoate, methyl octanoate, 2,5-dimethyl-4-methoxy-3(2H)-furanone, δ-octalactone, 2-methoxy-4-vinyl phenol, and δ-undecalactone contributed greatly to the aroma quality of the pineapple varieties, due to their high flavour dilution factor. The aroma of the pineapples was described by seven sensory terms as sweet, floral, fruity, fresh, green, woody and apple-like.

    CONCLUSION: Inter-relationship between the aroma-active compounds and the pineapples revealed that 'Moris' and 'MD2' covaried majorly with the fruity esters, and the other varieties correlated with lesser numbers of the fruity esters. Hierarchical cluster analysis (HCA) was used to establish similarities among the pineapples and the results revealed three main groups of pineapples.

    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
  20. Quantification of VOCs and the development of odour wheels for rubber processing
    Kamarulzaman NH, Le-Minh N, Fisher RM, Stuetz RM
    Sci Total Environ, 2019 Mar 20;657:154-168.
    PMID: 30543968 DOI: 10.1016/j.scitotenv.2018.11.451
    The impacts of rubber variations (clonal, seasonal, and pre-treatment) were investigated to assess changes in the composition of volatile organic compounds (VOCs) emitted during rubber processing. VOC emissions from 14 different rubber types were evaluated by headspace micro-chamber (μ-TEC) extraction coupled with gas chromatography-mass spectrometry (GC-MS). Headspace extracted at 120 °C, which is equivalent to the drying temperature during rubber processing, revealed a significant number of odorants in terms of concentrations as well as odorant type. Volatile fatty acids (VFAs) such as acetic, propanoic, butanoic, pentanoic and hexanoic acids, were frequently detected at concentrations greater than their odour detection thresholds. Other odorous compounds including trimethylamine, p-cresol, butanone, indole, and phenol, were also detected. Emissions collected at ambient conditions represent odorants released during material storage (or maturation) and were dominated by benzene derivatives followed by ketones, aldehydes, esters, and acids. Emission composition during storage appeared to be governed by specific rubber properties such as protein and rubber moisture content. Seasonal variations revealed greater impacts on the concentration of VOCs for all studied clones, compared to pre-treatment variations, suggesting that the VOCs composition was seasonally dependent and may represents the 'potential' emissions from rubber as they are processed. A combination of sensorial and analytical measurements were used to produce odour wheels which may be used as tool to identify key malodours in onsite rubber processing. The linking of odours and odorants can facilitate communication between receptors (the public) and plant operators inorder to minimise odour impact and develop effective abatement and on-site management practices.
    Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Related Terms
Filters
Contact Us

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links