A study was conducted on the chemical and biological properties of three different species of Mangifera i.e. Mangifera pajang, M. indica L., and M. kemanga leaves obtained from Pitas, Sabah. The aims of this study were to determine the presence of secondary metabolites as well as the antioxidative activities especially the catalase (CAT) and guiacol peroxidase specific activities (gPOD) in the leaves part of these three species. The extraction of these samples was carried out using three different polarities of solvents: hexane, ethyl acetate, and methanol. The total percentage of the crude extract of is 7.30% for M. pajang, 12.87% for M. indica and 7.98% for M. kemanga. Phytochemical screening was performed with various tests for each of the crude extracts. The results showed that these three species gave positive results for alkaloids, saponins, flavonoids, phenols, carbohydrates, phytosterols, and tannins metabolites. Based on the tests, CAT specific activities were significantly higher in the leaves of M. pajang with 4.35 ± 1.18 units/mg protein compared to M. indica L. and M. kemanga. The guaiacol peroxidase (gPOD) specific activities showed that M. indica L. has the highest activity with the value of 0.0047 ± 0.0004 units/mg protein.
Fine particulate matter (aerodynamic diameter ≤2.5 μm) (PM2.5) has become a major concern because it can adsorb chemicals e.g. polycyclic aromatic hydrocarbons (PAHs) onto its surface. Although PAHs are priority pollutants that can cause adverse health effect, there is still limited information concerning indoor exposures to PAHs in Malaysia. This study aimed to characterise the distribution of PAHs bounded to PM2.5in primary school environments. Indoor and outdoor PM2.5 were collected between May and July 2017 using low volume samplers (LVS) at three public primary schools in the Federal Territory of Kuala Lumpur. PAHs were extracted by ultrasonic extraction with Dichloromethane: n-Hexane (1:1, v/v) as the extraction solvent and analysed using gas chromatography coupled with mass spectrometer (GC-MS). Based on the results, the average total concentration of PAHs (∑PAHs) ranged from 3.8 to 10.1 ng m-3and 1.6 to 8.0 ng m-3for outdoors and indoors, respectively. PAHs in PM2.5samples indicated the potential contribution of combustion at high temperature and indoor sources and the infiltration of outdoor PAHs were the important sources for outdoor and indoor, respectively. In addition, the diagnostic ratio analysis showed that vehicular emissions were the most predominant sources of PAHs in school environments.
Background:Pseudomonas protein expression in E. coli is known to be a setback due to significant genetic variation and absence of several genetic elements in E. coli for regulation and activation of Pseudomonas proteins. Modifications in promoter/repressor system and shuttle plasmid maintenance have made the expression of stable and active Pseudomonas protein possible in both Pseudomonas sp. and E. coli. Objectives: Construction of shuttle expression vectors for regulation and overexpression of Pseudomonas proteins in Pseudomonas sp. and E. coli. Materials and Methods:Pseudomonas-Escherichia shuttle expression vectors, pCon2(3), pCon2(3)-Kan and pCon2(3)-Zeo as well as E. coli expression vectors of pCon4 and pCon5 were constructed from pUCP19-, pSS213-, pSTBlue-1- and pPICZαA-based vectors. Protein overexpression was measured using elastase strain K as passenger enzyme in elastinolytic activity assay. Results: The integration of two series of IPTG inducible expression cassettes in pCon2(3), pCon2(3)-Kan and pCon2(3)-Zeo, each carrying an E. coli lac-operon based promoter, Plac, and a tightly regulated T7(A1/O4/O3) promoter/repressor system was performed to facilitate overexpression study of the organic solvent-tolerant elastase strain K. These constructs have demonstrated an elastinolytic fold of as high as 1464.4 % in comparison to other published constructs. pCon4 and pCon5, on the other hand, are series of pCon2(3)-derived vectors harboring expression cassettes controlled by PT7(A1/O4/O3) promoter, which conferred tight regulation and repression of basal expression due to existence of respective double operator sites, O3 and O4, and lacIq. Conclusions: The constructs offered remarkable assistance for overexpression of heterogeneous genes in Pseudomonas sp. and E. coli for downstream applications such as in industries and structural biology study.
This study reports the caffeine content in seven locally available coffee. The caffeine was extracted with chloroform and analysed using Fourier Transform Infrared (FTIR). The method reports an average recovery of 101% with the limit of determination established at 0.1%. The absorption band at 1654 cm-1 was used to construct the calibration curve for quantification of caffeine where the regression was fitted with satisfactory linearity. An average of 0.55% of caffeine was detected in the seven coffee products with Arabica coffee demonstrating lower caffeine concentration. The study evidenced that caffeine content in coffee is determined by the coffee types. The caffeine content found in the local coffee products was relatively lower likely due to the solvent types, extraction procedure and analytical method used.
Small sized electrocatalysts, which can be obtained by rapid nucleation and high supersaturation are imperative for outstanding methanol oxidation reaction (MOR). Conventional microwave synthesis processes of electrocatalysts include ultrasonication, stirring, pH adjustment, and microwave irradiation of the precursor mixture. Ethylene glycol (EG), which serves as a reductant and solvent was added during the ultrasonication or stirring stage. However, this step and pH adjustment resulted in unintended multi-stage gradual nucleation. In this study, the microwave reduction approach was used to induce rapid nucleation and high supersaturation in order to fabricate small-sized reduced graphene oxide-supported palladium (Pd/rGO) electrocatalysts via the delayed addition of EG, elimination of the pH adjustment step, addition of sodium carbonate (Na₂CO₃), prior microwave irradiation of the EG mixed with Na₂CO₃, and addition of room temperature precursor mixture. Besides its role as a second reducing agent, the addition of Na₂CO₃ was primarily intended to generate an alkaline condition, which is essential for the high-performance of electrocatalysts. Moreover, the microwave irradiation of the EG and Na₂CO₃ mixture generated highly reactive free radicals that facilitate rapid nucleation. Meanwhile, the room temperature precursor mixture increased supersaturation. Results showed improved electrochemically active surface area (78.97 m² g-1, 23.79% larger), MOR (434.49 mA mg-1, 37.96% higher) and stability.
Introduction: Hygrocybe conica (HC), a wild mushroom commonly consumed by the indigenous people (Orang Asli) in Peninsular Malaysia, was assessed for its antioxidant content. Methods: The HC mushroom was extracted using distilled water and the crude extract partitioned using different solvents and open column chromatography to evaluate its potential antioxidant properties. The mushroom extract was partitioned using liquid-liquid extraction into the hexane (Fl), chloroform (F2), butanol (F3) and formic acid (F4) fractions. Based on solvent polarity, the water extract of the mushroom was fractionated into non-polar (FI), semi-polar (Fii), and polar fractions (Fiii) using open column chromato graphy. Antioxidant capacities were determined using DPPH, ABTS, and ferric reducing antioxidant power (FRAP) assays while Folin-Ciocalteu reagent assay was used to determine total phenolic content (TPC). Results: The HC extract had the highest TPC and DPPH scavenging capacity compared to its extract fractions. TE values (ABTS assay) of F2 and F4 were not significantly higher than the HC extract. Among the extract fractions of different polarities, Fiii had the highest antioxidant capacities (DPPH and FRAP) compared to FI and Fii while FRAP values of these fractions were not significantly lower than the FRAP value of HC extract. The HC extract had significantly lower antioxidant capacity than antioxidant standards (ascorbic acid and BHA). Tannie acid as the main bioactive component in HC mushroom was detected using HPLC method. The presence of phenolics in HC extract was also confirmed using TLC. Conclusion: Due to the presence of potent phenolic components, the mycelia of HC could be consumed for potential antioxidative benefits.
This study examined the tunneling activity and the behaviour of two subterranean termites, Globitermes sulphurues and Coptotermes gestroi treated with four plant extracts, namely Pyllanthus niruri, Azadirachta indica, Leucaena leucocephala and Andrographis paniculata. All plants were extracted with three different solvents (methanol, hexane and water) and were diluted into three concentrations (500, 5,000 and 10,000 ppm). A group of 50 workers and 2 soldiers were tested and observed daily during the exposure in order to determine their survivorship and behaviour. Both sections were scored to determine their tunneling activities after seven days. There was a significant difference of tunneling activities of C. gestroi on sand treated with plant extracts (X2(2) = 31.790, p < 0.0001) with a mean rank of 8.50 for methanolic extracts and 32.50 for both hexane and water extracts. Meanwhile, no significant difference was observed on tunneling activity of G. sulphureus on treated sand (X2(2) = 2.200, p = 0.333) with a mean rank of 20.72 for methanolic extracts, 26.31 for water extracts and 26.47 for hexane extracts. Results showed that plants extracted with methanol demonstrated strong repellent properties with 0 tunneling activity on the treated sand and low survivorship of both termites. Moreover, both termites did not survive (0%) when they were treated with methanolic extracts at 10,000 ppm. They also displayed a different behaviour post-exposure such as avoidance, gradually losing the ability to walk and low feeding consumption. These results indicate that there is a strong termiticidal activity of plants extracted with methanol against C. gestroi and G. sulphureus.
Antibacterial activity of indigenous Dayak onion (Eleutherine palmifolia (L.) Merr) was investigated. The Dayak onion was solvent extracted with n-hexane, ethyl acetate, and ethanol 96% consecutively. Each extract was tested its antibacterial activity towards methicillin-resistant Staphylococcus aureus (MRSA), Bacillus cereus, Shigella sp., and Pseudomonas aeruginosa using disc diffusion method. The test results showed that the n-hexane, ethyl acetate, and ethanol 96% extracts positively inhibited the growth of MRSA, B. cereus, Shigella sp., and P. aeruginosa. The highest inhibition activity of each extract was obtained with 10 mg/mL of extract concentration; whereas the minimum inhibitory concentration (MIC) of each extract was 2 mg/mL. Extract with the highest inhibition activity was ethyl acetate extract against B. cereus (139.58%). TLC evaluation of ethyl acetate extract showed four spots and bioautography indicated that ethyl acetate extract contained four types of compounds with inhibition activity against B. cereus, in which two compounds have higher antibacterial activity than the other two.
Basal stem rot (BSR) is a devastating disease to Malaysian oil palm. Current techniques employed for BSR disease detection on oil palm are laborious, time consuming, costly, and subjected to accuracy limitations. An ergosterol detection method was developed, whereby it correlated well with the degree of infection in oil palm. This current study was designed to study the relationship between Ganoderma biomass, ergosterol concentration, BSR disease progress and to validate the efficiency of microwave assisted extraction (MAE) method for extraction of ergosterol compound. In addition, testing on the sensitivity of thin layer chromatography (TLC) analysis for detection of ergosterol was also the aim of this study. The optimised procedure involved extracting a small amount of Ganoderma-infected oil palm root tissues suspended in low volumes of solvent followed by irradiation in a conventional microwave oven at 70°C and medium high power for 30 s, resulting in simultaneous extraction and saponification. Based on the results obtained, MAE method may be effective in extracting low to high yields of ergosterol from infected oil palm roots demonstrating disease scale 2, 3 and 4. Positive relationship was observed between ergosterol content and inoculation period starting day 3 in the inoculated oil palm seedlings and hour 6 in germinated seeds. TLC analysis demonstrated a good correlation with high performance liquid chromatography (HPLC) quantification. Therefore, a semi-quantitative TLC analysis may be applied for handling a large amount of samples during onset field survey.
Crystallinity plays a vital role in the pharmaceutical industry. It affects drug manufacturing, development processes, and the stability of pharmaceutical dosage forms. An objective of this study was to measure and analyze the carbamazepine (CBZ) crystallinity before and after formulation. Moreover, it intended to determine the extent to which the crystallinity of CBZ would affect the drug loading, the particle size, and the release of CBZ from the microparticles. The CBZ microparticles were prepared by encapsulating CBZ in ethyl cellulose (EC) polymer using a solvent evaporation method. EC was used here as a release modifier polymer and polyvinyl alcohol (PVA) as an aqueous phase stabilizer. Factorial design was used to prepare the CBZ microparticle formulations, including polymer concentration, solvent (dichloromethane, ethyl acetate), PVA concentrations factor, the homogenization time, and homogenization speed. The crystallinity of CBZ was calculated utilizing differential scanning calorimetry (DSC) thermal analysis. The crystallinity was calculated from the enthalpy of CBZ. Enthalpy was analyzed from the area under the curve peak of CBZ standard and CBZ-loaded microparticles. DSC and ATR-FTIR assessed the possible interaction between CBZ and excipients in the microparticle. The prepared CBZ microparticles showed various changes in the crystallinity rate of CBZ. The changes in the rate of CBZ crystallinity had different effects on the particle size, the drug loading, and the release of CBZ from the polymer. Statistically, all studied factors significantly affected the crystallinity of CBZ after formulation to microparticles.
Omega-3 fatty acids have been shown to reduce the risk of chronic diseases like cardiovascular disease and cancer as well as promote brain development among infants and children. This study was carried out to compare total protein, fat and omega-3 fatty acids content of raw and pressurized fish of P. pangasius (yellowtail catfish) and H. macrura (long tail shad). The fish was cooked using pressure cooker for six minute to be pressurized. The protein content was determined by using Kjedahl method while total fat was determined using solvent extraction using chloroform and methanol. Fatty acid methyl esters (FAME) were prepared by a direct transesterification method, and quantified by gas chromatography using external standard. Results showed that marine fish H. macrura (long tail shad) had higher content (p < 0.05) of protein (18.30 ± 0.040 g/100 g), fat (10.965 ± 1.610 g/100 g), EPA (11.83 ± 0.02 g/100 g) and DHA (5.96 ± 0.31 g/100 g) compared to freshwater fish P. pangasius (yellowtail catfish). The protein content of pressurized fish was higher compare to raw fish, but there was no difference in total fat and omega-3 fatty acids content between raw and pressurized of freshwater fish P. pangasius and marine fish, H. macrura. In conclusion, marine fish are better source of protein, fat and omega-3 content, while pressurized fish shown to have comparable amount of protein, fat and omega-3 fatty acids content with raw fish. The result obtained assist the consumers to prepare a healthy menu in order to retain the protein and omega-3 fatty acids content of fish through healthy way of cooking.
The translation of stacking techniques used in capillary electrophoresis (CE) to microchip CE (MCE) in order to improve concentration sensitivity is an important area of study. The success in stacking relies on the generation and control of the stacking boundaries which is a challenge in MCE because the manipulation of solutions is not as straightforward as in CE with a single channel. Here, a simple and rapid on-line sample concentration (stacking strategy) in a battery operated nonaqueous MCE device with a commercially available double T-junction glass chip is presented. A multi-stacking approach was developed in order to circumvent the issues for stacking in nonaqueous MCE. The cationic analytes from the two loading channels were injected under field-enhanced conditions and were focused by micelle-to-solvent stacking. This was achieved by the application of high electric fields along the two loading channels and a low electric field in the separation channel, with one ground electrode in the reservoir closest to the junction. At the junction, the stacked zones were re-stacked under field-enhanced conditions and then injected into the separation channels. The multi-stacking was verified under a fluorescence microscope using Rhodamine 6G as the analyte, revealing a sensitivity enhancement factor (SEF) of 110. The stacking approach was also implemented in the nonaqueous MCE with contactless conductivity detection of the anticancer drug tamoxifen as well as its metabolites. The multi-stacking and analysis time was 40 s and 110 s, respectively, the limit of detections was from 10 to 35 ng/mL, and the SEFs were 20 to 50. The method was able to quantify the target analytes from breast cancer patients.
Thin films of cerium oxide (CeO2) were prepared on silicon (Si) substrate by metal organic decomposition route. 0.25 M of cerium (III) acetylacetonate (acac) was used as starting materials with the addition of methanol and acetic acid as solvents. Oxide conversion of the film by thermal treatment was conducted at temperature ranging from 400 o C to 1000 o C for 15 min in argon ambient. X-ray diffraction (XRD) analysis utilizing Cukα radiation (Model Brukker’s Diffrac Plus ), Filmetrics system measurement, field emission scanning electron microscope (FE-SEM) (Model Zeiss Supra 35VP FE-SEM) and atomic force microscopy (AFM) (Model SII Nanonavi) were employed to characterize the phase formed and morphologies of the film produced.
Bioactive compounds from Quercus Infectoria (manjakani) were extracted with six different types of solvents: 100% methanol, ethanol, acetone, aqueous and 70% methanol and ethanol. High Performance liquid chromatography (HPLC) was used to identify and quantify the active compounds, namely gallic acid and tannic acid. Total phenolics content were determined by Folin-Ciocalteu while antioxidant and antibacterial activity were tested using DPPH free radicals scavenging and disc diffusion assay. The result revealed that aqueous extract contained the highest concentration of bioactive compounds compared to other types of solvents which are 51.14 mg/g sample and 1332.88 mg/g sample of gallic acid and tannic acid respectively.. The highest level of phenolic compound was found in 100% acetone extract (121 mg GAE/g). The results demonstrated that aqueous extract gives the highest antioxidant activity approximately 94.55% while acetone extract gives the largest inhibition zone for disc diffusion assay which is 19.00 mm respectively. The results revealed rich sources of gallic acid and tannic acid in Q. infectoria which might provide a novel source of these natural antioxidant and antibacterial activity.
Six new Pd(II) and Ni(II) metal complexes of N, O-bidentate (L1, L2) and ONNO-tetradentate (L3) Schiff base ligands have been synthesized. The compounds were characterized via various physicochemical and spectroscopic techniques namely elemental analysis (CHN), FT-IR, 1H and 13C NMR as well as magnetic susceptibility measurement. All complexes showed diamagnetism indicating that they are square planar complexes. Catalytic performance of Pd(L1)2 and Pd(L2)2 were investigated for Heck cross-coupling reaction under optimum operating parameters, monitored using GC-FID for 6 h of reaction time in inert conditions. High catalytic activities of up to 90% were observed in the presence of triethylamine as base and DMA as solvent at 100oC with 1 mmol% catalyst loading. The mechanism of catalyzed Heck reaction is proposed to go through a series of conversion of Pd(0)/Pd(II).
Plants, particularly fruits and vegetables, have many phytochemicals that possess various bioactivities, including antioxidant and anticancer properties. In this study, the aim was to investigate the antiproliferative properties of Syzygium fruits, namely water apple (Syzygium aqueum), milk apple (Syzygium malaccense), and malay apple (Syzygium malaccense L.) against two types of cancer-origin cells, namely MCF-7 (hormone dependent breast cancer cell line) and MDA-MB-231 (nonhormone-dependent breast cancer cell line). Two solvent methods were prepared using aqueous and methanol extraction. Antiproliferation activities of these extracts were evaluated by employing colorimetric MTT (3-(4,5-dimethylthiazol-2-yl)2,5 diphenyltetrazolium bromide) assay through time periods of 24, 48, and 72 hours. The result showed that extracts from the three fruits had no significant effects for 24 and 48 hours time periods (p >0.05) but extracts of Water apple and Malay apple displayed antiproliferation effects on MCF-7 cell lines (p
The peels of pomelo contribute 30% of the fruit weight and yet it has been dump without recognizing the possible nutritional value of the peels. Study has been carried out to identify flavonoid content of the peels and analysed the activity of the flavonoid towards inhibition of lipid peroxidation. Optimization of flavonoid extraction was conducted using aqueous solvent (methanol and ethanol), extraction time (1-3 h) and extraction temperature (50°C-80°) via water bath extraction. The total content of flavonoids was quantitatively determined by using coloration methods with chromogenic system of NaNO2–Al (NO3)3–NaOH and and it was found that the extraction at 65ºC for 2 h in aqueous ethanol was the optimized condition for maximum flavonoids i.e. 190.42mg/L. A spectrophometric analysis was performed to evaluate flavonoid activity towards lipid peroxidation in the fish tissue. There was reduction in Peroxide value (PV) indicated the inhibition of lipid peroxidation in fish treated with pomelo peel as evidence of concurrency of positive flavonoid activity.
Although Malaysia is one of the important pineapple fruit producing and exporting country, the production of MD-2 pineapple fruit only started in 2009. Pineapple fruit has been harvested at different ripening stages for different markets. The information on Malaysian grown MD-2 pineapple fruit quality is lacking. Therefore this work was carried out with the aim to determine physicochemical quality, antioxidant compounds and activity of MD-2 pineapple fruit at five ripening stages. Ripening stage affected physicochemical quality of MD-2 pineapple fruit. Soluble solids concentration of MD-2 pineapple fruit increased from 15.41 to 18.02% SSC when fruit ripened from stage 1 to 4 and no significant difference was found in fruit between stage 4 and 5. The ascorbic acid content decreased while total carotenoids content increased as ripening stage advanced. The total phenolic content of both 80% methanol and water extraction solvents increased significantly as fruit ripened from stage 1 to 3 and reduced as fruit ripened to stage 5. The antioxidant activity of MD-2 pineapple fruit as assayed using DPPH, FRAP and ABTS showed similar trend as total phenolic content. These results suggest that ripening stage affect MD-2 pineapple fruit quality and nutritional values.
The application of magnetized graphene (G) layers synthesized on the carbon nanofibers (CNFs) (m-G/CNF) was investigated as novel adsorbent for the magnetic solid-phase extraction (MSPE) of polycyclic aromatic hydrocarbons (PAHs) in water samples followed by gas chromatography-flame ionization detector (GC-FID). Six important parameters, affecting the extraction efficiency of PAHs, including: amount of adsorbent, adsorption and desorption times, type and volume of the eluent solvent and salt content of the sample were evaluated. The optimum extraction conditions were obtained as: 5min for extraction time, 20mg for sorbent amount, dichloromethane as desorption solvent, 1mL for desorption solvent volume, 5min for desorption time and 15% (w/v) for NaCl concentration. Good performance data were obtained at the optimized conditions. The calibration curves were linear over the concentration ranges from 0.012 to 100ngmL(-1) with correlation coefficients (r) between 0.9950 and 0.9967 for all the analytes. The limits of detection (LODs, S/N=3) of the proposed method for the studied PAHs were 0.004-0.03ngmL(-1). The relative standard deviations (RSDs) for five replicates at two concentration levels (0.1 and 50ngmL(-1)) of PAHs were ranged from 3.4 to 5.7%. Appropriate relative recovery values, in the range of 95.5-99.9%, were also obtained for the real water sample analysis.
The demand for novel antimicrobial agents from natural resources has been increased worldwide for food conservation purpose. In this study antimicrobial activity of musk lime, key lime and lemon were evaluated against various food borne pathogens and spoilage bacteria using disc diffusion test. Type of extraction solvent and concentration level significantly influenced the antibacterial activity of all the extracts. Ethanol extracts of musk lime, key lime and lemon exhibited significant broadest inhibitory activity at 100% concentration level (pure extract) compared to water and juice extracts. 100% ethanol extracts of musk lime (39.7 mm), key lime (26.7 mm) and lemon (32.0 mm) exhibited the largest diameter of inhibition zone (DIZ) against Aeromonas veronii. 100% water extracts of musk lime (25.3 mm), key lime juice extract (23.3 mm) and water extracts of lemon (23.7 mm) was most effective against food spoilage bacteria, A. veronii. The prominent results of the antimicrobial activity from lime, key lime and lemon extracts may attribute them as potential natural food preservatives and could be used in pharmaceuticals field.