The formation of 3-monochloropropane-1,2-diol (3-MCPD) esters in refined palm oil during deodorisation is attributed to the intrinsic composition of crude palm oil. Utilising D-optimal design, the effects of the degumming and bleaching processes on the reduction in 3-MCPD ester formation in refined palm oil from poor-quality crude palm oil were studied relative to the palm oil minor components that are likely to be their precursors. Water degumming remarkably reduced 3-MCPD ester formation by up to 84%, from 9.79 mg/kg to 1.55 mg/kg. Bleaching with synthetic magnesium silicate caused a further 10% reduction, to 0.487 mg/kg. The reduction in 3-MCPD ester formation could be due to the removal of related precursors prior to the deodorisation step. The phosphorus content of bleached palm oil showed a significant correlation with 3-MCPD ester formation.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Some novel Schiff bases derived from 1-(2-ketoiminoethyl)piperazines were synthesized and characterized by mass spectroscopy, FTIR, UV-Visible, 1H and 13C-NMR. The compounds were tested for inhibitory activities on human acetylcholinesterase (hAChE), antioxidant activities, acute oral toxicity and further studied by molecular modeling techniques. The study identified the compound (DHP) to have the highest activity among the series in hAChE inhibition and DPPH assay while the compound LP revealed the highest activity in the FRAP assay. The hAChE inhibitory activity of DHP is comparable with that of propidium, a known AChE inhibitor. This high activity of DHP was checked by molecular modeling which showed that DHP could not be considered as a bivalent ligand due to its incapability to occupy the esteratic site (ES) region of the 3D crystal structure of hAChE. The antioxidant study unveiled varying results in 1,1-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. This indicates mechanistic variations of the compounds in the two assays. The potential therapeutic applications and safety of these compounds were suggested for use as human acetylcholinesterase inhibitors and antioxidants.
Ergosterol is the main component of the fungal membrane and is not found in plants or other microbial cells. Therefore, it can be a useful biomarker for the quantification of fungal biomass. We are now reporting the first isolation and characterisation of ergosterol from the mycelium of G. boninense. The ergosterol structure was detected by Thin Liquid Chromatography (TLC) and Ultra Performance Liquid Chromatography (UPLC) and confirmed with Gas Chromatography coupled with Mass Spectrometry (GCMS) and Nuclear Magnetic Resonance (NMR) analysis.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
A series of 1,3,5-triaryl-2-pyrazolines was synthesized by dissolving the corresponding 4-alkoxychalcones in glacial acetic acid containing a few drops of concentrated hydrochloric acid. This step was followed by the addition of (3,4-dimethylphenyl) hydrazaine hydrochloride. Finally the target compounds were precipitated by pouring the reaction mixture onto crushed ice. The structures of the synthesized compounds were established by physicochemical and spectroscopic methods. The 1,3,5-triaryl-2-pyrazolines bearing homologous alkoxy groups were found to possess fluorescence properties in the blue region of the visible spectrum when irradiated with ultraviolet radiation. The fluorescent behavior of these compounds was studied by UV-Vis and emission spectroscopy, performed at room temperature.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
In this work, crude oil biodegradation has been optimized in a solid-liquid two phase partitioning bioreactor (TPPB) by applying a response surface methodology based d-optimal design. Three key factors including phase ratio, substrate concentration in solid organic phase, and sodium chloride concentration in aqueous phase were taken as independent variables, while the efficiency of the biodegradation of absorbed crude oil on polymer beads was considered to be the dependent variable. Commercial thermoplastic polyurethane (Desmopan®) was used as the solid phase in the TPPB. The designed experiments were carried out batch wise using a mixed acclimatized bacterial consortium. Optimum combinations of key factors with a statistically significant cubic model were used to maximize biodegradation in the TPPB. The validity of the model was successfully verified by the good agreement between the model-predicted and experimental results. When applying the optimum parameters, gas chromatography-mass spectrometry showed a significant reduction in n-alkanes and low molecular weight polycyclic aromatic hydrocarbons. This consequently highlights the practical applicability of TPPB in crude oil biodegradation.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
The aim of this study was to optimize the antioxidant activity of Piper nigrum L. essential oil extracted using the supercritical carbon dioxide (SC-CO₂) technique. Response surface methodology was applied using a three-factor central composite design to evaluate the effects of three independent extraction variables: pressure of 15-30 MPa, temperature of 40-50 °C and dynamic extraction time of 40-80 min. The DPPH radical scavenging method was used to evaluate the antioxidant activity of the extracts. The results showed that the best antioxidant activity was achieved at 30 MPa, 40 °C and 40 min. The extracts were analyzed by GC-FID and GC-MS. The main components extracted using SC-CO₂ extraction in optimum conditions were β-caryophyllene (25.38 ± 0.62%), limonene (15.64 ± 0.15%), sabinene (13.63 ± 0.21%), 3-carene (9.34 ± 0.04%), β-pinene (7.27 ± 0.05%), and α-pinene (4.25 ± 0.06%). The essential oil obtained through this technique was compared with the essential oil obtained using hydro-distillation. For the essential oil obtained by hydro-distillation, the most abundant compounds were β-caryophyllene (18.64 ± 0.84%), limonene (14.95 ± 0.13%), sabinene (13.19 ± 0.17%), 3-carene (8.56 ± 0.11%), β-pinene (9.71 ± 0.12%), and α-pinene (7.96 ± 0.14%). Radical scavenging activity of the extracts obtained by SC-CO₂ and hydro-distillation showed an EC₅₀ of 103.28 and 316.27 µg mL(-1) respectively.
We report the isolation of N-acyl homoserine lactone-producing Enterobacter sp. isolate T1-1 from the posterior dorsal surfaces of the tongue of a healthy individual. Spent supernatants extract from Enterobacter sp. isolate T1-1 activated the biosensor Agrobacterium tumefaciens NTL4(pZLR4), suggesting production of long chain AHLs by these isolates. High resolution mass spectrometry analysis of these extracts confirmed that Enterobacter sp. isolate T1-1 produced a long chain N-acyl homoserine lactone, namely N-dodecanoyl-homoserine lactone (C12-HSL). To the best of our knowledge, this is the first isolation of Enterobacter sp., strain T1-1 from the posterior dorsal surface of the human tongue and N-acyl homoserine lactones production by this bacterium.
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
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
IgE-mediated allergic reaction to squid is one of the most frequent molluscan shellfish allergies. Previously, we have detected a 36 kDa protein as the major allergen of Loligo edulis (white squid) by immunoblotting using sera from patients with squid allergy. The aim of this present study was to further identify this major allergen using a proteomics approach. The major allergen was identified by a combination of two-dimensional electrophoresis (2-DE), immunoblotting, mass spectrometry and bioinformatics tools. The 2-DE gel fractionated the cooked white squid proteins to more than 50 different protein spots between 10 to 38 kDa and isoelectric point (pI) from 3.0 to 10.0. A highly reactive protein spot of a molecular mass of 36 kDa and pI of 4.55 was observed in all of the patients' serum samples tested. Mass spectrometry analysis led to identification of this allergen as tropomyosin. This finding can contribute to advancement in component-based diagnosis, management of squid allergic patients, to the development of immunotherapy and to the standardization of allergenic test products as tools in molecular allergology.
Calamansi juices from three countries (Malaysia, the Philippines and Vietnam) were characterised through measuring volatiles, physicochemical properties and non-volatiles (sugars, organic acids and phenolic acids). The volatile components of manually squeezed calamansi juices were extracted using dichloromethane and headspace solid-phase microextraction, and then analysed using gas chromatography-mass spectrometry/flame ionisation detector, respectively. A total of 60 volatile compounds were identified. The results indicated that the Vietnam calamansi juice contained the highest amount of volatiles. Two principal components obtained from principal component analysis (PCA) represented 89.65% of the cumulative total variations of the volatiles. Among the non-volatile components, these three calamansi juices could be, to some extent, differentiated according to fructose and glucose concentrations. Hence, this study of calamansi juices could lead to a better understanding of calamansi fruits.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Sixteen trace elements found in 309 street heroin samples, piped water and contaminated water were determined using inductively coupled plasma-mass spectrometry. All the street heroin samples were found to contain high levels of sodium, a reflection of the use of sodium bicarbonate during heroin synthesis. Additionally, this element was also found to be one of the potential contaminants acquired from the piped water. Calcium could be derived from lime while iron, aluminum and zinc could have come from the metallic container used in the processing/cutting stage. The levels of these elements remained low in the heroin and it could be due to the dilution effects from the addition of adulterants. Statistical validation was performed with six links of related heroin samples using principal component analysis to find the best pretreatment for sample classification. It was obtained that normalization followed by fourth root showed promising results with 8% errors in the sample clustering. The technique was then applied to the case samples. Finally, the result suggested that the case samples could have originated from at least two major groups respectively showing unique elemental profiles at the street level.
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
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
Polycyclic aromatic hydrocarbons (PAHs) in a sediment core collected from Langkawi Island of the Andaman Sea, Malaysia were determined by GC/MS, the vertical variations of concentration and distributions of PAHs were investigated. In combining with 210Pb-dating, the PAHs sedimentary record in the last 100 years was reconstructed and their possible sources were also discussed. The sigmaPAH concentration ranged from 13.2-60.1 ng x g(-1) in the whole sedimentary section (0-56 cm) with the dominant compounds of phenanthrene, naphthalene and perylene. The sediments contaminated to a lesser extent comparing with the surrounding waters. Before the 1920s, the concentrations of PAHs were considered to be the background level, which was implied from the natural inputs. The historical records of PAHs in the core showed that two distinct peaks which represented the input time of 1960s and 1980s, respectively, inferred that there were some relatively dramatically land-based inputs, and human activities leaded a clear impact to these waters during these periods. Furthermore, PAHs diagnostic ratios indicated that PAHs in the core sediments were mainly of pyrolytic origin (combustion), accompanied with minor petroleum origin. These were related with agriculture, industry, ocean import and export, and shipping activities in the surrounding regions. Meanwhile as the vital communication line, the marine transportation of the Strait of Malacca had influenced the environmental quality of the Andaman Sea. Meanwhile, based on the sedimentary record, PAHs concentrations were found to correlate positively with humanism activities and socioeconomic development (Gross Domestic Production) in the surrounding regions.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
Polycyclic aromatic hydrocarbons (PAHs) occur as contaminants in different types of food predominantly from environmental pollution, food packaging and food processing and the levels found depend on the source of the contamination. PAHs emissions from automobile traffic and industry activities were shown to influence the PAHs levels and profiles in vegetables and fruits grown nearby. The present study was carried out to determine the levels of PAHs in samples of tomato, cabbage and apple, collected from six different places of urban and rural areas of plantation in Dhaka city. Eight PAHs listed in the priority pollutant of US Environment Protection Agency and regarded as carcinogens were analyzed in this study. The analytical method involved saponification with methanolic KOH, liquid-liquid extraction with cyclohexane, clean-up on silica gel column and determination by Gas chromatography and mass spectrometry. The mean levels of total PAHs were 9.50 μg/kg in tomato, 8.86 μg/kg in cabbage and 4.05 μg/kg in apple. Of the carcinogenic PAHs, benzo(a)anthracene was the most representative, being found in 89% of all samples analysed. Chrysene was not detected in any sample.
Matched MeSH terms: Gas Chromatography-Mass Spectrometry
The leaves of Melicope ptelefolia (Rutaceae) afforded a new acetophenone named 2,4,6-trihydroxy-3-geranylacetophenone. The structure of the compound was established by mass and NMR spectroscopy.
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
The sequential extraction procedure proposed by the European Standard, Measurements and Testing (SM&T) program, formerly the Community Bureau of Reference (BCR), was applied for partitioning of heavy metals (HMs) in river sediments collected along the course of Sungai Buloh and the Straits of Malacca in Selangor, Malaysia. Eight elements (V, Pb, Cd, Cr, Co, Ni, Cu and Zn) from seven stations (S1-S7) and at different depths were analyzed using the modified BCR Sequential Extraction Procedure (SEP) in combination with ICP-MS to obtain the metal distribution patterns in this region. The results showed that heavy metal contaminations at S2 and S3 was more severe than at other sampling sites, especially for Zn, Cu, Ni and Pb. Nevertheless, the element concentrations from top to bottom layers decreased predominantly. The samples from the Straits of Malacca (S4-S7) the highest contamination factors obtained were for Co, Zn and Pb while the lowest were found for V and Cr, similar to Sungai Buloh sediments. The sediments showed a low risk for V, Cr, Cu and Pb with RAC values of less than 10%, but medium risk for Co, Zn (except S3), Cd at S1 and S2 and Ni at S1, S3 and S5. Zn at S3 and Cd at S3-S7 showed high risk to our sediment samples. There is not any element of very high risk conditions in the selected samples.
Mouthbrooding is an elaborate form of parental care displayed by many teleost species. While the direct benefits of mouthbrooding such as protection and transportation of offsprings are known, it is unclear if mouthbrooding offers additional benefits to embryos during incubation. In addition, mouthbrooding could incur negative costs on parental fish, due to limited feeding opportunities. Parental tilapia fish (Oreochromis spp.) display an elaborated form of parental care by incubating newly hatched embryos in oral buccal cavity until the complete adsorption of yolk sac. In order to understand the functional aspects of mouthbrooding, we undertake a proteomics approach to compare oral mucus sampled from mouthbrooders and non-mouthbrooders, respectively. Majority of the identified proteins have also been previously identified in other biological fluids or mucus-rich organs in different organisms. We also showed the upregulation of 22 proteins and down regulation of 3 proteins in mucus collected from mouthbrooders. Anterior gradient protein, hemoglobin beta-A chain and alpha-2 globin levels were lower in mouthbrooder samples. Mouthbrooder oral mucus collectively showed increase levels of proteins related to cytoskeletal properties, glycolytic pathway and mediation of oxidative stress. Overall the findings suggest cellular stress response, probably to support production of mucus during mouthbrooding phase.