Tips and tricks: antibacterial assay of plant extracts

Antibacterial study of plant origin has brought tremendous breakthrough in various field vis. medicinal, pharmaceutical and food preservatives. The long and tedious process of identifying the capability of extracts due to the need of selecting of smaller sample particle size, maturity of sample, matrix interference, appropriate solvent polarity, substrate to solvent ratio, extraction technique, and sample storage and temperature promises high turnout of antibacterial capacity. Other consideration for instance extraction temperature, duration time, added process such as sonication, sample pretreatment affect the antibacterial extraction. Solvents used in extraction have bactericidal effect on pathogens tested. Agar diffusion and broth dilution are endpoint methods while descriptive methods involve turbidity assays and inhibition curves are used in antibacterial evaluation. Broth dilution method by spectroscopy instrument involves microscale and macroscale volume up to 250 μL and 1 mL respectively. Soluble concentration equivalent to lower concentration of non-polar extract reduces effect of precipitation in minimum inhibitory concentration (MIC) test. MIC is easily determined by polar extracts since it is immiscible with dimethyl sulfoxide (DMSO) and broth media. Minimum bactericidal concentration (MBC) is identified at higher concentration than MIC. Determination of MIC0, MIC50 and MIC100 can be obtained from turbidity assays. Lethality of pathogens can be established at concentration lower than MIC through inhibition on profile curves. Each test should include negative (solvent and DMSO) and positive (penicillin or tetracycline) measures to support the data analysis. Complementary antibacterial assays are recommended for confirmation of antibacterial properties from plant extracts

In vitro antibacterial activities and composition of Carica papaya cv. Sekaki/Hong Kong peel extracts

Ten solvents were used to extract phytochemicals from the peel of Carica papaya cv. Sekaki/Hong Kong to determine their antibacterial activities. Moderate to clear inhibition on Corynebacterium diphtheriae, Streptococcus pneumoniae, Bacillus subtilis and Clostridium perfringens were obtained from the disk diffusion test out of fourteen pathogens tested. Petroleum ether extract, the most potent extract, showed moderate inhibition towards C. diphtheria and S. pneumoniae at MIC of 5.63 mg/mL and 1.40 mg/mL. Polar solvents gave higher yield, total phenolic and total flavonoid contents than nonpolar solvents. Extract yields were 10.9 to 84.1 mg/g in polar solvents and 3.9 to 20.3 mg/g in non-polar solvents. Twenty eight compounds were identified in petroleum extracts through GC/MS analysis. Among the compounds identified were fatty acids, esters, alkane, tocopherols and sterols. 9,12,15-octadecatrienoic acid was the most abundant compound

A network analysis and support vector regression approaches for visualising and predicting the COVID-19 outbreak in Malaysia

This study aims to (1) correlate and visualise the Coronavirus disease 19 (COVID-19) pandemic spread via Spearman rank coefficients of network analysis (NA) and (2) predict the cumulative number of COVID-19 confirmed and death cases via support vector regression (SVR) based on COVID-19 dataset in Malaysia between July 2020 to June 2021. The NA indicated increasing connectivity between different states throughout the time frame, revealing the most complex network of COVID-19 transmission in the second quarter of 2021. The SVR model predicted future COVID-19 cases and deaths in Malaysia in the second half of 2021. The study demonstrated that the NA and SVR could provide relatively simple yet valuable artificial intelligence techniques for visualising the degree of connectivity and predicting pandemic risk based on confirmed COVID-19 cases and deaths. The Malaysian health authorities used the NA and SVR model results for preventive measures in highly populated states

Comparison of prediction model using spatial discriminant analysis for marine water quality index in mangrove estuarine zones

The prediction models of MWQI in mangrove and estuarine zones were constructed. The 2011–2015 data em- ployed in this study entailed 13 parameters from six monitoring stations in West Malaysia. Spatial discriminant analysis (SDA) had recommended seven significant parameters to develop the MWQI which were DO, TSS, O&G, PO4, Cd, Cr and Zn. These selected parameters were then used to develop prediction models for the MWQI using artificial neural network (ANN) and multiple linear regressions (MLR). The SDA-ANN model had higher R2 value for training (0.9044) and validation (0.7113) results than SDA-MLR model and was chosen as the best model in mangrove estuarine zone. The SDA-ANN model had also demonstrated lower RMSE (5.224) than the SDA-MLR (12.7755). In summary, this work suggested that ANN was an effective tool to compute the MWQ in mangrove estuarine zone and a powerful alternative prediction model as compared to the other modelling methods

Basic Requirements of Laboratory Operation for Halal Analysis

Analysis of halal food requires that the laboratories conductive the tests adhere to international guidelines and standards. Common worldwide guidelines and standards for laboratory include the ‘International Organization for Standardization 17025’ (ISO 17025), the ‘Good Manufacturing Practice’ (GMP), and ‘Good Laboratory Practice’ (GLP). In halal analysis, the laboratory shall comply with ISO 17025, GMP, and ‘Good Hygiene Practice’ (GHP) as stated in the ‘Manual Procedure for Malaysia Halal Certification’ (MPPHM). This article discusses the basic requirements for laboratory practises, specifically for halal analysis. The study compares these international guidelines  with ‘Malaysia Halal Standards’ to demonstrate that these international standards are combined with Islamic practices to produce valid test results using globally recognized best-practices. This promotes confidence in the halal laboratory’s work both nationally and internationally, and will thus improve international trade. Keywords: Halal analysis, ISO 17025, GMP, GLP, laboratory operation

Recent advanced techniques in cysteine determination: a review

The utilization of cysteine in a wide variety of products especially bakery products has led to a huge concern of various groups of consumers especially those who restricted to religious-based dietary. It has become a major concern due to the raw materials are derived from arguable sources such as pig bristles and human hair. This review briefly elaborates cysteine as food additives with highlighted issues in halal perspective and toxicity in the food industry. This review also highlighted several analytical approaches used in direct determination of cysteine compound such as high performance liquid chromatography (HPLC), molecular imprinted polymers (MIPs), Raman spectroscopy, flow injection spectrophotometric, electrochemical biosensor and gold nanoparticles based calorimetric assa

Discrimination and authentication of lard blending with palm oil in cosmetic soap formulations

Background: The employment of Fourier transforms infrared (FT-IR) spectroscopy combined with chemometrics for determination and quantification of lard in a binary blend with palm oil in a cosmetic soap formulations. Objective: To determine and quantify lard as an adulterant in a binary blend with palm oil in a cosmetic soap formulations by FT-IR and multivariate analysis. Methods: Fatty acids in lard, palm oil and binary blends were extracted via liquid–liquid extraction and were subjected to FTIR spectrometry, combined with principal component analysis (PCA) and discriminant analysis (DA) for the classification of lard in cosmetic soap formulations via two DA models: Model A (percentage of lard in cosmetic soap) and Model B (porcine and non-porcine cosmetic soap). Linear regression (MLR), partial least square regression (PLS-R) and principal components regression (PCR) were used to assess the degree of adulteration of lard in the cosmetic soap. Findings: The FTIR spectrum of palm oil slightly differed from that of lard at the wavenumber range of 1453 cm−1 and 1415 cm−1 in palm oil and lard, respectively, indicating the bending vibrations of CH2 and CH3 aliphatic groups and OH carboxyl group respectively. Both of the DA models could accurately classify 100% of cosmetic soap formulations. Nevertheless, less than 100% of verification value was obtained when it was further used to predict the unknown cosmetic soap sample suspected of containing lard or a different percentage of lard. The PCA for Model A and Model B explained a similar cumulative variability (CV) of 92.86% for the whole dataset. MLR and PCR showed the highest determination coefficient (R2) of 0.996, and the lowest relative standard error (RSE) and mean square error (MSE), indicating that both regression models were effective in quantifying the lard adulterant in cosmetic soap. Conclusion: FTIR spectroscopy coupled with chemometrics with DA, PCA and MLR or PCR can be used to analyse the presence of lard and quantify its percentage in cosmetic soap formulation

The Effect of Maturity and Extraction Solvents on Bioactive Compounds and Antioxidant Activity of Mulberry (Morus alba) Fruits and Leaves

Cultivation location, maturity levels, and extraction solvents could affect the bioactive compounds and biological activities of mulberry (Morus alba Linnaeus). The lack of study on Malaysia grown mulberry causes its underutilization. This study investigated the bioactive compound content and the antioxidant activity of Sabah-grown mulberry at two different maturity stages (fruits: red mature and black fully ripe; leaves: young and mature) extracted using 70% (v/v) methanol, 60% (v/v) ethanol, and 65% (v/v) acetone. Analyses showed that mulberry fruits demonstrated maturity dependent increment (except UHPLC-DAD quantification), while the leaves revealed maturity dependent reduction. Principal component analysis (PCA) displayed 65% (v/v) acetone black fully ripe fruits as the best phenolics and antioxidant sources. However, the 60% (v/v) ethanol black fully ripe fruits contained 20.08–68.43% higher total anthocyanins. Meanwhile, the 65% (v/v) acetone and 70% (v/v) methanol red mature fruits were higher in chlorogenic acid (27.53–47.12%) and rutin (31.42–35.92%) than other fruit extracts, respectively. For leaves, 65% (v/v) acetone young leaves were the best phenolics and antioxidant sources. However, the 60% (v/v) ethanol young leaves possessed greater chlorogenic acid (19.56–74.11%) than other leaf extracts. Overall, Malaysia-grown mulberry is rich in phenolics and antioxidants, suggesting its potential application in food and pharmaceutical products

Variability on particulate matter and meteorology dataset during the hazy period in eastern region of Peninsular Malaysia

This paper provides detail on sequence analysis of hazy days based on eight monitoring stations from three states (Kelantan, Ter- engganu and Pahang) in the eastern region of Peninsular Malaysia. The dataset comprises of 1502 daily mean hazy days that had been measured for a decade. The meteorology data namely wind speed, wind direction, air temperature, relative humidity and particulate matter (PM10) were used to comprehend the variability, and the relationship existed amongst variables. The final dataset consists of a summary descriptive analysis and a boxplot, where all five var- iables were involved, including the minimum, maximum, mean, 1st quartile, median, 3rd quartile and standard deviation are pre- sented. Apart from descriptive analysis, the normality test and histogram were performed as well

Characterization, antibacterial and anti-Inflammatory activities of electrospun poly (vinyl alcohol) (PVA) containing Aquilaria Malaccencis Leaf Extract (ALEX) nanofibers

Plant-based electrospun nanofibers are widely fabricated as wound dressing in recent years primarily due to the presence of bioactive compounds which can facilitate the wound healing effects. In this study, poly(vinyl alcohol) (PVA) fibre mats containing Aquilaria malaccensis leaf extract (ALEX) [5, 10 and 15 %(w/w)] were fabricated by electrospinning method as potential wound dressing material. The nanofibers were uniform, beadless and randomly oriented with average diameters ranged between 195.27 – 281.20 nm. The presence of ALEX in the PVA nanofibers were evaluated by Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and differential scanning calorimetry (DSC). The mechanical properties, swelling degree and weight loss of nanofiber mats were also determined. ALEX was rapidly released from the ALEX-loaded PVA nanofibers in the first 12 hours and increased gradually afterwards. The released rate of ALEX was dependent on the ALEX content in the PVA nanofibers. This result is also contributed by the swelling degree and porosity of the nanofibers where the results were found to be between 241.66 – 305.86% and 64.53 – 30.81%, respectively. Meanwhile, the tensile stress and maximum elongation at break for all electrospun nanofiber mats were in the range of 8.56 – 2.68 MPa and 205.94 – 166.31%, respectively. The nanofiber mats inhibited growth of Escherichia coli, Vibrio vulnificus, Bacillus subtilis and Staphylococcus aureus with zone of inhibition of 7.5 - 15.0 mm for gram positive bacteria and 6.1 - 11.7 mm for gram negative bacteria. ALEX-loaded PVA nanofibers also showed potent anti-inflammatory activity against lipoxygenase with percentage of inhibition between 80.887 – 86.977%. Taken together, the results of this study suggest that ALEX-loaded PVA nanofibers have the desired properties of bioactive wound dressing