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Fulltext Assessing biofilm formation by Listeria monocytogenes

Fouladynezhad, N., Afsah-Hejri, L., Rukayadi, Y., Abdulkarim, S.M., Son, R., Marian, M.N.

International Food Research Journal, 2013;20(2):987-990.
MyJurnal

Listeria monocytogenes (L. monocytogenes) is a serious food-borne pathogen for immunocompromised individuals. L. monocytogenes is capable of producing biofilm on the surface of food processing lines and instruments. The biofilm transfers contamination to food products and impose risk to public health. Transfers contamination to food products, and impose risk hazard to public health. The aim of this study was to investigate biofilm producing ability of L. monocytogenes isolates. Microtitre assay was used to measure the amount of biofilm production by ten L. monocytogenes isolates from minced chicken / meat, sausages and burgers. Results showed that all 10 L. monocytogenes isolates were able to form biofilm after 24 h at 20˚C on polystyrene surface (the common surface in food industries). Some strains were capable of forming biofilm more than the others. All strains showed a slight raise in the quantities of attached cells over 48 and 72 h. L. monocytogenes strains isolated from minced chicken, minced meat and burgers were better biofilm-producers comparing to the strains isolated from sausages.
Fulltext Prevalence of Salmonella spp. in chicken and beef from retail outlets in Malaysia

Son, R., Shafini, A.B., Mahyudin, N.A., Rukayadi, Y., Tuan Zainazor, T.C.

International Food Research Journal, 2017;24(1):437-449.
MyJurnal

The prevalence of Salmonella in chicken and beef sold in retails outlets in Malaysia was
determined by analysing 312 raw beef and chicken meat samples including their processed
products. Samples purchased from supermarkets, butcher shops and wet market, which being
classified into raw, minced and processed chicken and beef. A total of 86 (27.6%) samples were
found positive for Salmonella spp., with chicken meat samples (40.4%) showed greater presence
compared to beef (15.4%). Highest presence of Salmonella were detected from wet market
samples (35.4%), followed by supermarket (26.9%) and butcher shop (21.3%). The prevalence
of Salmonella were higher in unpacked chicken meat (84.8%), followed by unpacked beef
(27.8%). Salmonella serovars were identified as S. Enteritidis, S. Hadar, S. Dublin, S. Anatum,
S. Stanley, S. Gallinarum, S. Choleraesuis and S. Typhimurium. Detection of 8 Salmonella
serovars showed possibilities of cross contamination in various sources either at slaughtering
house, processing plant or until storage at retails level. Improper cooking method on meats and
hygiene practices prior to consume should be avoided in order to ensure food safety before
ingestion.
Fulltext Distribution of bacteriophages in food and environment samples

Premarathne, J.M.K.J.K., Thung, T.Y., New, C.Y., Huat, J.T.Y., Basri, D.F., Rukayadi, Y., et al.

International Food Research Journal, 2017;24(2):888-896.
MyJurnal

Foodborne pathogens have become a constant threat to the consumer and food industry.
Reduce efficacy of antibiotics with emergence of resistant bacteria has limited the opportunities
for controlling pathogenic bacteria in food commodities and treating foodborne infections.
Bacteriophages can be a promising alternative for alleviate the risk of transmitting pathogenic
bacteria via food commodities. Therefore, this research was conducted to find distribution of
bacteriophages in diverse niches in order to identify suitable sources for isolating bacteriophages
to use controlling foodborne pathogens. Firstly bacterial strains were screened for lysogenic and
selected suitable host bacterial strains were used for isolating and determining bacteriophage titer
in fresh raw food and environmental samples. Eighteen different lytic bacteriophages effective
against Campylobacter, S. aureus, L. monocytogenes and E. coli were isolated from this study.
Bacteriophages titer was determined within range of 102
to 1010 PFU/mL and bacteriophages
were most frequently isolated from chicken (60%) samples. The isolated bacteriophages could
be potential candidates for controlling foodborne diseases.
Fulltext Antibacterial and Antispore Activities of Isolated Compounds from Piper cubeba L

Alqadeeri F, Rukayadi Y, Abbas F, Shaari K

Molecules, 2019 Aug 26;24(17).
PMID: 31454974 DOI: 10.3390/molecules24173095

Piper cubeba L. is the berry of a shrub that is indigenous to Java, Southern Borneo, Sumatra, and other islands in the Indian Ocean. The plant is usually used in folk traditional medicine and is an important ingredient in cooking. The purpose of this study was to isolate and purify the bioactive compounds from P. cubeba L. fractions. In addition, the isolated compounds were tested for their antibacterial and antispore activities against vegetative cells and spores of Bacilluscereus ATCC33019, B. subtilis ATCC6633, B.pumilus ATCC14884, and B.megaterium ATCC14581. The phytochemical investigation of the DCM fraction yielded two known compounds: β-asarone (1), and asaronaldehyde (2) were successfully isolated and identified from the methanol extract and its fractions of P. cubeba L. Results showed that exposing the vegetative cells of Bacillus sp. to isolated compounds resulted in an inhibition zone with a large diameter ranging between 7.21 to 9.61 mm. The range of the minimum inhibitory concentration (MIC) was between 63.0 to 125.0 µg/mL and had minimum bactericidal concentration (MBC) at 250.0 to 500.0 µg/mL against Bacillus sp. Isolated compounds at a concentration of 0.05% inactivated more than 3-Log10 (90.99%) of the spores of Bacillus sp. after an incubation period of four hours, and all the spores were killed at a concentration of 0.1%. The structures were recognizably elucidated based on 1D and 2D-NMR analyses (1H, 13C, COSY, HSQC, and HMBC) and mass spectrometry data. Compounds 1, and 2 were isolated for the first time from this plant. In conclusion, the two compounds show a promising potential of antibacterial and sporicidal activities against Bacillus sp. and thus can be developed as an anti-Bacillus agent.
Isolation and identification of biocellulose-producing bacterial strains from Malaysian acidic fruits

Voon WW, Rukayadi Y, Meor Hussin AS

Lett Appl Microbiol, 2016 May;62(5):428-33.
PMID: 27002476 DOI: 10.1111/lam.12568

Biocellulose (BC) is pure extracellular cellulose produced by several species of micro-organisms that has numerous applications in the food, biomedical and paper industries. However, the existing biocellulose-producing bacterial strain with high yield was limited. The aim of this study was to isolate and identify the potential biocellulose-producing bacterial isolates from Malaysian acidic fruits. One hundred and ninety-three bacterial isolates were obtained from 19 local acidic fruits collected in Malaysia and screened for their ability to produce BC. A total of 15 potential bacterial isolates were then cultured in standard Hestrin-Schramm (HS) medium statically at 30°C for 2 weeks to determine the BC production. The most potent bacterial isolates were identified using 16S rRNA gene sequence analysis, morphological and biochemical characteristics. Three new and potent biocellulose-producing bacterial strains were isolated from soursop fruit and identified as Stenotrophomonas maltophilia WAUPM42, Pantoea vagans WAUPM45 and Beijerinckia fluminensis WAUPM53. Stenotrophomonas maltophilia WAUPM42 was the most potent biocellulose-producing bacterial strain that produced the highest amount of BC 0·58 g l(-1) in standard HS medium. Whereas, the isolates P. vagans WAUPM45 and B. fluminensis WAUPM53 showed 0·50 and 0·52 g l(-1) of BC production, respectively.
Fulltext Detection of Klebsiella pneumoniae in raw vegetables using Most Probable Number-Polymerase Chain Reaction (MPN-PCR)

Puspanadan, S., Afsah-Hejri, L., Loo, Y.Y., Nillian, E., Kuan, C.H., Goh, S.G., et al.

International Food Research Journal, 2012;19(4):1757-1762.
MyJurnal

Klebsiella pneumoniae (K. pneumoniae) is one of the most important members of Klebsiella genus in Enterobacteriacae family, which is responsible for pneumonia (the destructive lung inflammation disease). Vegetables are known as source of contamination with K. pneumonia. Raw vegetables are usually consumed in salads and other dishes. The aim of this study was to investigate the occurrence of K. pneumoniae in raw vegetables marketed in Malaysia. Two hundred commonly used salad vegetables (lettuces, parsley, cucumber, tomato and carrot) from hypermarkets and wet markets were investigated for presence of K. pneumoniae using Most Probable Number-Polymerase Chain Reaction (MPN-PCR). K. pneumoniae was found to be significantly more frequent (100%) and (82.5%) in lettuce and cucumbers, respectively. K. pneumoniae contamination was lowest in carrot samples (30%). All samples were contaminated with K. pneumoniae ranging from
Fulltext Quantification and antibiotic susceptibility of Salmonella spp., Salmonella Enteritidis and Salmonella Typhimurium in raw vegetables (ulam)

Najwa, M.S., Rukayadi, Y., Ubong, A., Loo, Y.Y., Chang, W.S., Lye, Y.L., et al.

International Food Research Journal, 2015;22(5):1761-1769.
MyJurnal

Salmonella has been reported to be presence both in raw and processed foods worldwide. In this study, the prevalence, quantification and antibiotic susceptibility of Salmonella isolated from raw vegetables or locally known as ulam such as asiatic pennywort (Centella asiatica (L) Urb), water dropwort (Oenanthe javanica (Blume) DC), long bean (Vigna sinensis EndL), and winged bean (Psophocarpus tetragonolobus (L) DC) obtained from retail markets in Selangor, Malaysia were carried out. From 96 samples tested, the overall prevalence of Salmonella spp. was 97.9%, Salmonella Enteritidis was 54.2% and Salmonella Typhimurium was 82.3% respectively. Samples were contaminated with Salmonella ranging from < 3 to 2400 MPN/g. Salmonella Enteritidis and Salmonella Typhimurium isolates obtained from the raw vegetables (ulam) were found to exhibit high resistance against ampicillin (100%), erythromycin (100%), amoxicillin/clavunic acid (81.3%), cephalothin (75%), streptomycin (50%) and ciprofloxacin (50%). All Salmonella isolates showed multi drug resistant (MDR) profile with each isolate being resistant to 3 or more antibiotics. The multiple antibiotic resistance (MAR) index of Salmonella isolates ranged from 0.27 to 0.55 for Salmonella Enteritidis and 0.27 to 0.82 for Salmonella Typhimurium. The presence of Salmonella on raw vegetables (ulam) and high antibiotic resistance isolates indicated that raw vegetables could be contaminated and thus imposes possible health risk to local consumers.
Fulltext Antibacterial Activity of Ethanolic Extract of Syzygium polyanthum L. (Salam) Leaves against Foodborne Pathogens and Application as Food Sanitizer

Ramli S, Radu S, Shaari K, Rukayadi Y

Biomed Res Int, 2017;2017:9024246.
PMID: 29410966 DOI: 10.1155/2017/9024246

The aim of this study was to determine antibacterial activity of S. polyanthum L. (salam) leaves extract foodborne pathogens. All the foodborne pathogens were inhibited after treating with extract in disk diffusion test with range 6.67 ± 0.58-9.67 ± 0.58 mm of inhibition zone. The range of MIC values was between 0.63 and 1.25 mg/mL whereas MBC values were in the range 0.63 mg/mL to 2.50 mg/mL. In time-kill curve, L. monocytogenes and P. aeruginosa were found completely killed after exposing to extract in 1 h incubation at 4x MIC. Four hours had been taken to completely kill E. coli, S. aureus, V. cholerae, and V. parahaemolyticus at 4x MIC. However, the population of K. pneumoniae, P. mirabilis, and S. typhimurium only reduced to 3 log CFU/mL. The treated cell showed cell rupture and leakage of the cell cytoplasm in SEM observation. The significant reduction of natural microflora in grapes fruit was started at 0.50% of extract at 5 min and this concentration also was parallel to sensory attributes acceptability where application of extract was accepted by the panellists until 5%. In conclusion, S. polyanthum extract exhibits antimicrobial activities and thus might be developed as natural sanitizer for washing raw food materials.
Fulltext Controlling vegetative cells and spores growth of Bacillus spp. using ethanolic Ketapang (Terminalia catappa L.) leaf extract

Madhavan K, Rukayadi Y, Abdul-Mutalib NA

Heliyon, 2023 Aug;9(8):e18749.
PMID: 37600365 DOI: 10.1016/j.heliyon.2023.e18749

Terminalia catappa L. is a large, spreading type of tree which usually grows in tropical environment, especially at coastal area with sandy stones. The current study evaluated anti-Bacillus potential of the ethanolic ketapang (Terminalia catappa L.) leaf extract (EKLE) as antibacterial and sporicidal agent against vegetative cells and spores of Bacillus spp. The antibacterial activity of EKLE against Bacillus spp. (B. cereus ATCC33019, B. pumilus ATCC14884, B. subtilis ATCC6633 and B. megaterium ATCC14581) vegetative cells were determined by performing well diffusion assay (WDA), minimum inhibition concentration (MIC), minimum bacterial concentration (MBC) and time-kill curve analyses. The sporicidal activity was tested at different concentrations of EKLE. Then, the extract's stability in terms of antibacterial and sporicidal activities upon exposure to different temperatures and pHs were carried out. Results demonstrated inhibition zones of EKLE against Bacillus spp. was in the range of 9.25 ± 0.75 mm - 11.67 ± 0.47 mm. All vegetative cells of Bacillus spp. were inhibited with MIC values at 0.63-1.25 mg/mL and can be completely killed with MBC values of 0.63 - >5.00 mg/mL. Time-kill analysis showed all the Bacillus spp. tested can be completely killed at concentrations of 2.50-5.00 mg/mL from 1 to 4 h. EKLE concentration of 1% (w/v) completely killed all Bacillus spp. spores at different exposure time. The antibacterial and sporicidal activities of EKLE were not affected by exposure to different temperatures (4, 30, 50, 80 and 121 °C) and pHs (3, 7 and 10), revealing the stability of the extract against different conditions. In conclusion, Terminalia catappa L. leaf exhibits antibacterial and sporicidal activities against Bacillus spp., therefore, the extract can be developed as anti-Bacillus agent, paving the way for its utilization in food industry as a natural food preservative.
Fulltext Antioxidant Activity, α-Glucosidase Inhibition and UHPLC-ESI-MS/MS Profile of Shmar (Arbutus pavarii Pamp)

Buzgaia N, Lee SY, Rukayadi Y, Abas F, Shaari K

Plants (Basel), 2021 Aug 11;10(8).
PMID: 34451703 DOI: 10.3390/plants10081659

The genus Arbutus (Ericaceae) has been traditionally used in folk medicine due to its phytomedicinal properties, especially Arbutus pavarii Pamp. However, this plant has not been evaluated for its efficacy, quality, and consistency to support the traditional uses, potentially in treating diabetes. Despite previous studies that revealed the biological activities of A. pavarii as antioxidant and α-glucosidase inhibitory agents, scientific reports on the bioactive compounds that contribute to its health benefits are still scarce. Therefore, this research focused on the evaluation of antioxidant and α-glucosidase inhibitory activities of the methanol crude extracts and various fractions of the leaf and stem bark, as well as on metabolite profiling of the methanol crude extracts. The extracts and fractions were evaluated for total phenolic (TPC) and total flavonoid (TFC) contents, as well as the DPPH free radical scavenging, ferric reducing antioxidant power (FRAP), and α-glucosidase inhibitory activities. Methanol crude extracts of the leaf and stem bark were then subjected to UHPLC-ESI-MS/MS. To the best of our knowledge, the comparative evaluation of the antioxidant and α-glucosidase inhibitory activities of the leaf and stem bark of A. pavarii, as well as of the respective solvent fractions, is reported herein for the first time. Out of these extracts, the methanolic crude extracts and polar fractions (ethyl acetate and butanol fractions) showed significant bioactivities. The DPPH free radical and α-glucosidase inhibitions was highest in the leaf ethyl acetate fraction, with IC50 of 6.39 and 4.93 µg/mL, respectively, while the leaf methanol crude extract and butanol fraction exhibited the highest FRAP with 82.95 and 82.17 mmol Fe (II)/g extract. The UHPLC-ESI-MS/MS analysis resulted in the putative identification of a total of 76 compounds from the leaf and stem bark, comprising a large proportion of plant phenolics (flavonoids and phenolic acids), terpenoids, and fatty acid derivatives. Results from the present study showed that the different parts of A. pavarii had potent antioxidant and α-glucosidase inhibitory activities, which could potentially prevent oxidative damage or diabetes-related problems. These findings may strengthen the traditional claim on the medicinal value of A. pavarii.
Fulltext Quantitative detection and characterization of Shiga toxin-producing Escherichia coli O157 and non-O157 in raw vegetables by MPN-PCR in Malaysia

Loo, Y. Y., Puspanadan, S., Goh, S. G., Kuan, C. H., Chang, W. S., Lye, Y. L., et al.

International Food Research Journal, 2013;20(6):3313-3317.
MyJurnal

Foodborne diseases are mainly caused by bacterial contamination which can lead to severe diarrhea. This study aimed to detect the presence of Shiga toxin-Producing Escherichia coli O157, Escherichia coli non-O157 and virulence gene in raw vegetables. The samples were purchased from wet market and hypermarket in Selangor. The detections were carried out by using the combination methods of Most Probable Number-Polymerase Chain Reaction (MPNPCR). A total of 37(18.5%) samples were found to be contaminated by STEC. Out of these 37 isolates, four (10.8%) of the isolates were E. coli O157 while 33(89.2%) were E. coli nonO157. However, there was no E. coli O157:H7 detected in all the samples. The occurrence of Shiga toxin-Producing E. coli in edible raw vegetables samples suggests the importance of this pathogen in vegetables. Therefore, more studies are required to remove this pathogen from vegetables.
Fulltext Characterization of extended-spectrum ß -lactamases (ESBLs) producers in Klebsiella pneumoniae by genotypic and phenotypic method

Puspanadan, S., Afsah-Hejri, L., Rukayadi, Y., Loo, Y.Y., Nillian, E., Kuan, C.H., et al.

International Food Research Journal, 2013;20(3):1479-1483.
MyJurnal

This study aims to determine the presence of extended-spectrum (ESBL) in Klebsiella pneumoniae isolated from raw vegetables by genotypic and phenotypic method. Fifty-three K. pneumoniae isolates that were obtained by plating method were confirmed by PCR. Isolates obtained were screened for their resistance to selected antibiotics. Phenotypic tests for ESBL detection is basically to confirm production of ESBL, in this study two types of antibiotics used which were amoxycillin/clavulanic Acid (AMC, 30 µg) and ceftazidime (CAZ, 30 µg), The resistance were 5/53 (9.4%) and 1/53 (1.9%), respectively. However, it was interesting to observe that none of the K. pneumoniae isolates demonstrated the presence of any of the bla genes by using genotypic method except blaTEM gene has been detected in two isolates out of 53 isolates of K. pneumoniae in this research.
Fulltext Quantification of Escherichia coli O157:H7 in organic vegetables and chickens

Chang, W.S., Afsah-Hejri, L., Rukayadi, Y., Khatib, A., Lye, Y.L., Loo, Y.Y., et al.

International Food Research Journal, 2013;20(2):1023-1029.
MyJurnal

The organic foods’ market is becoming one of the rapidly growing sections in agricultural economies in the world. During the last two decades, food-borne outbreaks associated with fresh produce have rapidly increased. E. coli O57:H7, the caustic agent of acute hemorrhagic diarrhea and abdominal cramps, is mainly associated with meat and poultry product outbreaks but frequent outbreaks linked to the consumption of vegetables have been reported. The aim of this study was to investigate prevalence of E. coli O157:H7 in some organic foods. A total of 230 organic food samples including four-winged bean, tomato, white radish, red cabbage, chinese cabbage, lettuce, cucumber and chicken form retailed groceries and supermarkets in Malaysia were investigated. Low prevalence of E. coli O157:H7 was detected in organic vegetables and chickens. The estimated quantity of E. coli O157:H7 in all samples ranged from 2400 MPN/g. The overall MPN/g estimate of E. coli O157:H7 in the samples from organic groceries was higher than supermarket with the maximum of >2400 MPN/g. Most of the samples from supermarket showed a minimum of
Fulltext Risk of Escherichia coli O157:H7 transmission linked to the consumption of raw milk

Lye, Y.L., Afsah-Hejri, L., Chang, W.S., Loo, Y.Y., Puspanadan, S., Kuan, C.H., et al.

International Food Research Journal, 2013;20(2):1001-1005.
MyJurnal

E. coli O157:H7 is associated with life threatening diseases such as hemorrhagic colitis (HC), hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Raw milk is considered a high risk food as it is highly nutritious and serves as an ideal medium for bacterial growth. The aim of this study was to investigate the prevalence of E. coli O157:H7 in raw cow, goat and buffalo milk samples. MPN-PCR method targeting the major virulence rfbE gene and fliCH7gene of E. coli O157:H7 was used. Total of 177 raw milk samples were collected from local dairy farms in the state of Selangor, Malaysia. The highest prevalence of E. coli O157:H7 was found in raw cow milk (18.75%). E. coli O157:H7 was detected in 7.32% and 3.57% of raw goat and buffalo milk, respectively. The estimated quantity of E. coli O157:H7 in raw cow, goat and buffalo milk ranged from
Fulltext Antimicrobial resistance of Listeria monocytogenes and Salmonella Enteritidis isolated from vegetable farms and retail markets in Malaysia

Kuan, C.H., Rukayadi, Y., Ahmad, S. H., Wan Mohamed Radzi, C.W.J., Kuan, C.S., Yeo, S.K., et al.

International Food Research Journal, 2017;24(4):1831-1839.
MyJurnal

Listeriosis and salmonellosis are the major foodborne illnesses worldwide. Over the last decade,
increasing reports about the antibiotic resistance of Listeria monocytogenes and Salmonella from diverse sources have prompted public health concerns, especially in developing countries with over reliance or misuse of antibiotic drugs in the treatment of humans and animals. In this study, antibiotic susceptibility profiles of 58 L. monocytogenes and 12 Salmonella Enteritidis strains from vegetable farms and retail markets in Malaysia were testedby the standard disk diffusion method. Listeria monocytogenes isolates were found to exhibit 100% resistance to penicillin G. Also, high resistance patterns were observed for meropenem (70.7%) and rifampicin (41.4%). The multiple antibiotic resistance (MAR) index of L. monocytogenes isolates ranged from 0.11 to 0.56. Besides, the antibiogram results revealed that multidrugresistant (MDR) S. Enteritidis were detected and all the S. Enteritidis isolates demonstrated resistance to at least four antibiotics. Ampicillin, amoxicillin, and trimethoprim failed to inhibit all the S. Enteritidis strains. Salmonella Enteritidis isolates also displayed high resistance to nalidixic acid (75.0%), trimethoprim-sulfamethoxazole (75.0%), and chloramphenicol (66.7%). Findings in this study indicated that vegetables could be potential sources of multidrug resistance of L. monocytogenes and S. Enteritidis, which can be a serious issue and a major concern for public health. Thus, there is a great need for surveillance programs in Malaysia to continuously monitor the antibiotic resistance profiles of important pathogens.
Proposed molecular mechanism of non-competitive inhibition using molecular dynamics simulations between α-glucosidase enzyme and mangostin compound as antidiabetic

Maulana AF, Maksum IP, Sriwidodo S, Rukayadi Y

J Mol Model, 2024 Apr 18;30(5):136.
PMID: 38634946 DOI: 10.1007/s00894-024-05934-z

CONTEXT: Further understanding of the molecular mechanisms is necessary since it is important for designing new drugs. This study aimed to understand the molecular mechanisms involved in the design of drugs that are inhibitors of the α-glucosidase enzyme. This research aims to gain further understanding of the molecular mechanisms underlying antidiabetic drug design. The molecular docking process yielded 4 compounds with the best affinity energy, including γ-Mangostin, 1,6-dimethyl-ester-3-isomangostin, 1,3,6-trimethyl-ester-α-mangostin, and 3,6,7-trimethyl-ester-γ-mangostin. Free energy calculation with molecular mechanics with generalized born and surface area solvation indicated that the 3,6,7-trimethyl-γ-mangostin had a better free energy value compared to acarbose and simulated maltose together with 3,6,7-trimethyl-γ-mangostin compound. Based on the analysis of electrostatic, van der Waals, and intermolecular hydrogen interactions, 3,6,7-trimethyl-γ-mangostin adopts a noncompetitive inhibition mechanism, whereas acarbose adopts a competitive inhibition mechanism. Consequently, 3,6,7-trimethyl-ester-γ-mangostin, which is a derivative of γ-mangostin, can provide better activity in silico with molecular docking approaches and molecular dynamics simulations.
METHOD: This research commenced with retrieving protein structures from the RCSB database, generating the formation of ligands using the ChemDraw Professional software, conducting molecular docking with the Autodock Vina software, and performing molecular dynamics simulations using the Amber software, along with the evaluation of RMSD values and intermolecular hydrogen bonds. Free energy, electrostatic interactions, and Van der Waals interaction were calculated using MM/GBSA. Acarbose, used as a positive control, and maltose are simulated together with test compound that has the best free energy. The forcefields used for molecular dynamics simulations are ff19SB, gaff2, and tip3p.
Fulltext Solvent Extraction and Identification of Active Anticariogenic Metabolites in Piper cubeba L. through ¹H-NMR-Based Metabolomics Approach

Raja Mazlan RNA, Rukayadi Y, Maulidiani M, Ismail IS

Molecules, 2018 Jul 16;23(7).
PMID: 30012946 DOI: 10.3390/molecules23071730

The aim of this study was to determine the effects of different solvents for extraction, liquid⁻liquid partition, and concentrations of extracts and fractions of Piper cubeba L. on anticariogenic; antibacterial and anti-inflammatory activity against oral bacteria. Furthermore, ¹H-Nuclear Magnetic Resonance (NMR) coupled with multivariate data analysis (MVDA) was applied to discriminate between the extracts and fractions and examine the metabolites that correlate to the bioactivities. All tested bacteria were susceptible to Piper cubeba L. extracts and fractions. Different solvents extraction, liquid⁻liquid partition and concentrations of extracts and fractions have partially influenced the antibacterial activity. MTT assay showed that P. cubeba L. extracts and fractions were not toxic to RAW 264.7 cells at selected concentrations. Anti-inflammatory activity evaluated by nitric oxide (NO) production in lipopolysaccharide (LPS) stimulated cells showed a reduction in NO production in cells treated with P. cubeba L. extracts and fractions, compared to those without treatment. Twelve putative metabolites have been identified, which are (1) cubebin, (2) yatein, (3) hinokinin, (4) dihydrocubebin, (5) dihydroclusin, (6) cubebinin, (7) magnosalin, (8) p-cymene, (9) piperidine, (10) cubebol, (11) d-germacrene and (12) ledol. Different extraction and liquid⁻liquid partition solvents caused separation in principal component analysis (PCA) models. The partial least squares (PLS) models showed that higher anticariogenic activity was related more to the polar solvents, despite some of the active metabolites also present in the non-polar solvents. Hence, P. cubeba L. extracts and fractions exhibited antibacterial and anti-inflammatory activity and have potential to be developed as the anticariogenic agent.
Fulltext Antibacterial potential of silver nanoparticles (SP-AgNPs) synthesized from Syzygium polyanthum (Wight) Walp. against selected foodborne pathogens

Khan S, Rukayadi Y, Jaafar AH, Ahmad NH

Heliyon, 2023 Dec;9(12):e22771.
PMID: 38125456 DOI: 10.1016/j.heliyon.2023.e22771

Foodborne diseases continue to pose a significant global health concern, causing a considerable number of deaths worldwide. In response to concerns surrounding bacterial resistance and the limitations of traditional antibiotics, there is a growing interest in exploring natural antibacterial agents as potential alternatives for addressing foodborne pathogens. Nowadays efforts are being made on exploring the potential of natural antibacterial agents against foodborne pathogens. In this study, the antibacterial efficacy of silver nanoparticles synthesized using S. polyanthum leaves extract (SP-AgNPs) against selected Gram-negative and Gram-positive foodborne pathogens was investigated by using multiple assays, including the well diffusion assay (WDA), minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill assay. The well diffusion assay demonstrated the inhibitory potential of SP-AgNPs against all tested foodborne pathogens, with inhibition zones ranging from 10.16 + 1.25 to 13.16 + 1.52 mm. Furthermore, the MIC values ranged from 0.008 to 0.125 mg/mL, indicating the potent antibacterial activity of SP-AgNPs across a broad spectrum of foodborne pathogens. The MBC values, ranging from 0.008 to 0.250 mg/mL, further confirming the bactericidal ability of SP-AgNPs against these pathogens. In the time-kill experiment, most foodborne pathogens were entirely killed after 4 h of incubation at 4 × MIC concentration. However, only E. coli, K. pneumoniae, and S. Typhimurium showed a reduction in population to 3 Log10 CFU/mL, indicating a strong bactericidal effect of SP-AgNPs on most tested pathogens. In conclusion, this study provides compelling evidence that SP-AgNPs exhibit potent antibacterial activity against selected foodborne pathogens. The findings suggest that SP-AgNPs synthesized using S. polyanthum leaves extract hold great promise as a novel antibacterial agent for effectively controlling foodborne pathogens. These findings contribute to continuing efforts in developing alternative strategies to prevent foodborne diseases and enhance food safety.
Optimization of Culture Medium for the Growth of Candida sp. and Blastobotrys sp. as Starter Culture in Fermentation of Cocoa Beans (Theobroma cacao) Using Response Surface Methodology (RSM)

Mahazar NH, Zakuan Z, Norhayati H, MeorHussin AS, Rukayadi Y

Pak J Biol Sci, 2017;20(3):154-159.
PMID: 29023007 DOI: 10.3923/pjbs.2017.154.159

BACKGROUND AND OBJECTIVE: Inoculation of starter culture in cocoa bean fermentation produces consistent, predictable and high quality of fermented cocoa beans. It is important to produce healthy inoculum in cocoa bean fermentation for better fermented products. Inoculum could minimize the length of the lag phase in fermentation. The purpose of this study was to optimize the component of culture medium for the maximum cultivation of Candida sp. and Blastobotrys sp.
MATERIALS AND METHODS: Molasses and yeast extract were chosen as medium composition and Response Surface Methodology (RSM) was then employed to optimize the molasses and yeast extract.
RESULTS: Maximum growth of Candida sp. (7.63 log CFU mL-1) and Blastobotrys sp. (8.30 log CFU mL-1) were obtained from the fermentation. Optimum culture media for the growth of Candida sp., consist of 10% (w/v) molasses and 2% (w/v) yeast extract, while for Blastobotrys sp., were 1.94% (w/v) molasses and 2% (w/v) yeast extract.
CONCLUSION: This study shows that culture medium consists of molasses and yeast extract were able to produce maximum growth of Candida sp. and Blastobotrys sp., as a starter culture for cocoa bean fermentation.
Infrared-metabolomics approach in detecting changes in Andrographis paniculata metabolites due to different harvesting ages and times

Yusof NA, Isha A, Ismail IS, Khatib A, Shaari K, Abas F, et al.

J Sci Food Agric, 2015 Sep;95(12):2533-43.
PMID: 25371390 DOI: 10.1002/jsfa.6987

The metabolite changes in three germplasm accessions of Malaysia Andrographis paniculata (Burm. F.) Nees, viz. 11265 (H), 11341 (P) and 11248 (T), due to their different harvesting ages and times were successfully evaluated by attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy and translated through multivariate data analysis of principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA). This present study revealed the feasibility of ATR-FTIR in detecting the trend changes of the major metabolites - andrographolide and neoandrographolide - functional groups in A. paniculata leaves of different accessions. The harvesting parameter was set at three different ages of 120, 150 and 180 days after transplanting (DAT) and at two different time sessions of morning (7:30-10:30 am) and evening (2:30-5.30 pm).

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