Sains Malaysiana

PHYSICOCHEMICAL PROPERTIES OF RAW CLEANED (RC) EDIBLE BIRD’S NEST (EBN) AFTER DIFFERENT PRIMARY PROCESSING CLEANING METHODS INCLUDING A NEW DESIGN METHOD

Bee-Hui Yeo, Rakayadi Yaya, Shew-Fung Wong, Chin-Ping Tan, Oi-Ming Lai — Tue, 05 Nov 2024 00:00:00 +0000

Primary processing is the cleaning process of raw uncleaned (RUC) edible bird's nest (EBN) into raw clean (RC) bird's nest. In this study, three primary processing methods were used, including two methods commonly used in industry (semi-dry and wet methods) and a newly proposed method (semi-wet method). EBNs before and after primary processing were characterized by structural and chemical analysis. The RC EBN samples after initial processing were divided into two categories, with moulding (cup-shaped) and un-shaped. Scanning Electron Microscopy-Energy Dispersive X-ray Microanalysis (SEM-EDX) was used to study the morphology and element composition of EBN samples. The EBN sample were also tested on their colour, moisture content, water activity, nitrite content, nitrate content, total sialic acid content, total glycoprotein content, and total polysaccharide content. The semi-wet method yielded > 75 % cup- shaped RC EBN for six different batches of RUC EBN, outperforming wet cleaning method (68.76 – 82.92 %). Micrographs showed structural similarity between RC EBN samples even with different cleaning methods; but showed structural difference between RUC and RC EBN samples. Elements Na and Cl were significantly (P < 0.05) highest in RUC EBN. After cleaning, RC EBNs showed nitrite reduction at 34.78 – 60.72 %; and nitrate reduction at 33.62 – 72.35 %, respectively. No reduction of antioxidant activity, total sialic acid content, total glycoprotein content and total polysaccharide were observed for EBNs after primary processing. The nitrate and glycoprotein contents in EBNs after moulding were lower than those before moulding.

PRODUCTION OF GAMMA AMINOBUTYRIC ACID (GABA)- MISO USING Candida parapsilosis ISOLATED FROM A COMMERCIAL SOY SAUCE MOROMI

Wan Abd Al Qadr Imad Wan-Mohtar — Tue, 05 Nov 2024 00:00:00 +0000

A newly identified yeast, Candida parapsilosis strain KBC (CPSKBC) was tested for its GABA-producing potential in miso fermentation and consumer acceptability towards the GABA-miso was evaluated through sensory analysis. Three different formulations were used over one month to make the GABA-miso: formulation 1 (F1) used soybeans, rice koji, and miso starter; formulation 2 (F2) used soybeans, rice koji, and CPSKBC suspension; and formula 3 (F3) used soybeans, rice koji, miso starter, and CPSKBC suspension. High Performance Liquid Chromatography (HPLC) was used to measure the gamma-aminobutyric acid (GABA) concentration of the miso produced. F3 produced the highest GABA (36.73 mg/L), followed by F2 (34.54 mg/L) and F1 (28.42 mg/L). Sensory evaluation was conducted with 60 panelists using a 9-point hedonic scale. For all the sensory attributes evaluated (appearance, color, odor, taste and overall acceptability), the results showed no significant differences (p >0.05) between groups of miso (F1, F2, and F3) and commercial miso (C1). We can conclude that our products (F1, F2, and F3) matched with commercially produced miso in the market. This study demonstrated that CPSKBC was able to produce GABA-miso (F2 and F3) which is acceptable to the consumer

CHARACTERIZATION OF RECOMBINANT 3CLPROTEASE FROM SARS-CoV-2 PRODUCED IN E. coli BL21 (DE3) USING PEPTIDE SUBSTRATE LGSAVLQ-Rh110 FOR SCREENING CANDIDATES ANTI COVID DRUGS

Tue, 05 Nov 2024 00:00:00 +0000

The prediction that the pandemic is in progress to turning into an endemic does not change the fact that COVID-19 can be fatal for those with weak immune systems. Therefore, anti-COVID drugs are still needed, even when the disease becomes endemic. With regards to SARS-CoV-2, the roles of two proteases, 3CLprotease, and PLprotease, are crucial in the formation of new virus particles. Therefore, inhibiting the function of these viral proteases will directly prevent viral replication in the human body. In this study, we report the production of a recombinant 3CLprotease -which has not been extensively studied in Indonesia- from SARS-CoV-2 in E. coli BL21 (DE3), its purification as highly soluble and functionally active protease, and characterization of the recombinant enzyme with LGSAVLQ-Rh110 substrate. We found that our recombinant 3CLprotease was unstable under the presence of a DMSO concentration above 10%. Using LGSAVLQ-Rh110 substrate we found that our enzyme had Km of 46.1 µM and Vmax of 0.43 RFU/s; the IC₅₀ of the GC376 was 13.35 nM. We also tested three bioactive compounds (catechin, emodin, and 1,4-naphthoquinone) using this protease as a protein target, and 1,4-naphthoquinone was the most promising bioactive compound in inhibiting the SARS-CoV-2 virus.

RAND PROTEASE THERMOSTABILITY: THE ROLE OF CALCIUM-BINDING SITE AND THE EFFECTIVENESS ON LEATHER DEHAIRING

Noor Dina Muhd Noor — Tue, 05 Nov 2024 00:00:00 +0000

Bacillus subtilis produces a number of proteases, which are highly demanded in various industries, especially the thermostable one. Rand protease, originally isolated from B. subtilis, also has thermostability and other remarkable properties such as organic solvent tolerance and pH stability. However, its vulnerability to instability-induced degradation has limited its applications. As Rand protease contains two calcium ions for folding, activation, and, most importantly, stability and past research has shown that boosting the calcium-binding affinity improves stability. Therefore, Rand protease’s susceptibility to degradation could be remedied by discovering the targeted calcium-binding site for further calcium-binding affinity improvement. This was done with an in silico mutagenesis approach whereby one calcium-binding site was mutated to alanine and evaluated either the RMSD, the deviation of the mutated configuration from the original configuration using YASARA, or stability in terms of kcal/mol using HotSpot Wizard. The result found that the desired calcium-binding sites were Leu75 from YASARA and Tyr171 from HotSpot Wizard, while the improved stability mutation was Asp41. This result was also validated using Pymol, ExPASy ProtParam, and Molprobity. Additionally, Rand protease-chemical formulation dehairs leather best without additional metal ions at pH 7.0 and for 18 hours. It also produced higher-quality leather with smaller pores, and softer leather than chemical formulations. In contrast, hair breakage was observed in calcium treatment, which is compatible with the low dehairing activity achieved. In conclusion, Leu75 and Tyr171 are vital for calcium stabilization, and this enzyme has demonstrated its crucial efficacy in the leather dehairing industry.

USING CIRCUIT THEORY, CONNECTIVITY ANALYSIS AND LEAST-COST PATH TO MODEL THE POTENTIAL ECOLOGICAL CORRIDORS OF MALAYAN TAPIR (TAPIRUS INDICUS) AT CHINI-BERA FOREST COMPLEX IN PAHANG, PENINSULAR MALAYSIA

Amal Najihah Muhamad Nor, Nur Hairunnisa Rafaai, Saiful Arif Abdullah — Tue, 05 Nov 2024 00:00:00 +0000

In Peninsular Malaysia, the Master Plan of Ecological Linkages has proposed ecological corridors at Chini-Bera forests complex to connect the forest patches. However, the proposed corridors have been determined arbitrarily without evaluating the reliability of the landscape structure which may cause liability in conservation effort. Therefore, the objective of this study was to determine potential ecological corridors by considering the reliability of landscape structure in Chini-Bera forests complex using Malayan tapir (Tapirus indicus) as a focal species. The tapir was chosen because it is one of the target large mammals in the master plan. In this study, three landscape structures, i.e patch size, patch distance and landscape resistance were used as parameters in modelling the potential ecological corridors for tapirs. In the modelling, circuit theory, connectivity analysis and least-cost path were integrated using the geographic information systems and remote sensing platforms. The model has identified a total of 35 potential ecological corridors for tapir of which over 50% connect the large core areas while the other 25% connect the small core areas. Meanwhile, four corridors can be considered as priority corridor as their effective resistance below 1000 which indicate easy movement and high connectivity. The findings revealed the importance to consider the reliability of the patch size, patch distance dan landscape resistance in determining the potential corridors of wildlife to avoid liability in conservation effort. In addition, the integrated modelling approach contributes to a more concrete assessment of ecological corridors for effective wildlife conservation planning.

Gene Expression, Growth Performance and Body Composition of Labeo rohita Fingerlings Fed on Polyphenols Supplement

Tue, 05 Nov 2024 00:00:00 +0000

The aim of this research was to check the impacts of polyphenols-supplemented diet on growth, body composition and gene expressions of insulin-like growth factor (IGF) and growth hormone (GH) in Labeo rohita fingerlings fed canola meal based diets. Two plants extract; Salvadora persica and Salvadora oleoides were used to assess the efficacy of polyphenols. Ten test diets including control (no supplementation) and supplemented with S. persica, S. oleoides and thereafter their mixture at the levels of 200, 400 and 800 mg/kg were formulated. The gene expression of insulin like growth factors and growth hormone was observed to be regulated significantly (p< 0.05) in the liver tissue of fingerlings when fed with supplemented diet. The highest expression of growth hormone was observed at 200 mg/kg mixture diet. The results of growth performance showed that at 200 mg/kg mixture diet, maximum weight gain% (215%) and SGR (1.63) was recorded. The results of carcass analysis showed that the body composition was significantly influenced by supplemented diet when compared with control diet. Conclusively, the results revealed that rohu fingerlings showed the best results of gene expression, growth performance and body composition when fed on mixture of S. persica and S. oleoides at 200 mg/kg.

SEDIMENTOLOGICAL ANALYSIS OF THIN-BEDDED SEQUENCE OF EASTERN PART OF WEST CROCKER FORMATION, NORTHWEST SABAH

Nurul Afifah Mohd Radzir — Tue, 05 Nov 2024 00:00:00 +0000

It has been suggested that the eastern part of the West Crocker Formation is the slope to the inner fan of a deep-water system. Detailed sedimentological examination of eight outcrops of this formation in this study identified four types of facies: interbedded sandstone and mudstone facies (F1), chaotic facies (F2), and mudstone facies (F3). The immature textures and deformations with rolled-over sandstone block deposits occur as infers due to the presence of an angle of loose sediments, while the repeated thinly bedded sandstones and mudstones were recognized as levee-channel complexes. The overbank was identified as thick mudstone deposits. The sandstone deposits are synonymous with strong energy carried by the head of the turbidity current, while the fine to very fine sediment grains are typical of sediments that are carried by the body and tail of turbidity current and may deposited far away from the first deposition of sand. All the characteristics present in the environment of slope are to the inner fan of a deep-water system with deformed structures. This deformed slope is believed to be part of a late Eocene accretionary complex formed during the Sabah orogeny.

Relationship Between Obesity and Infertility among Women with Polycystic Ovarian Syndrome Treated at The National Population And Family Development Board (NPFDB) Malaysia

Tue, 05 Nov 2024 00:00:00 +0000

Polycystic ovarian syndrome (PCOS) is a metabolic dysfunction and is closely related to infertility in women. Obesity has an impact on the clinical manifestations of PCOS. This study was designed to determine the relationship between obesity and infertility among women with PCOS treated at the National Population and Family Development Board (NPFDB) Malaysia. This is a cross-sectional study with a simple random sampling technique involving infertile women attending NPFDB Subfertility Clinic. Clinical and menstrual history were obtained, and subjects underwent physical examination by a medical doctor. Subjects were diagnosed to have PCOS based on Rotterdam criteria, A total of 179 infertile women completed the study, and 84 (47%) were diagnosed with PCOS. FSH was higher, and progesterone hormone was lower significantly (p<0.05) in PCOS women compared to non-PCOS women. A total of 44% of PCOS women were found to be obese, and they have higher blood pressure and triglyceride but lower high-density lipoprotein (HDL) significantly (p<0.05). Chi-square (χ2) showed PCOS women with obesity significantly experienced ovulatory dysfunction shown by oligo and amenorrhea compared to non-obese PCOS women. Meanwhile, an independent t-test showed that the levels of testosterone were significantly higher (p<0.05), and progesterone was lower in obese PCOS women. This study revealed that PCOS women with obesity had more prominent ovulatory dysfunction and reproductive hormonal imbalance than non-obese PCOS women. These findings suggest that PCOS women with obesity are more prone to develop infertility.

CYTOTOXIC AND ANTIBACTERIAL PROPERTIES OF PIPER BETLE COMBINED WITH SELECTED ROOT CANAL SEALER

Wei Qi Chen, Dr Huwaina Abd Ghani, Dr. Suharni Mohamad — Tue, 05 Nov 2024 00:00:00 +0000

A root canal sealer with antibacterial properties continues the elimination of infectious microorganisms as last medicament. Antibiotics with sealer was used as the efficacy is significant but can cause antibacterial resistance if inappropriately used. Hence, Piper betle (PB), can serve as alternative treatment regime as it has antibacterial properties against Enterococcus faecalis (E. faecalis) and is not cytotoxic toward periradicular tissues. This study aims to research on the cytotoxicity, and antibacterial effects of ethanolic extract of PB in combination with AH Plus (AH) and BioRoot RCS (BR) and sealers alone. Four tested materials were used; AH; PB and AH plus (PBAH); BR; and PB and BioRoot RCS (PBBR). At 24, 48, and 72 hours, MTT assay on HPdLF was performed to measure the cytotoxicity. Antibacterial effect was evaluated with modified direct contact test (MDCT) against E. faecalis at fresh, day-1-set and day-7-set state. Data were analysed with SPSS with Tukey’s post-test at the level of significance of P = 0.05. Results showed PBAH has significantly lower cytotoxicity compared to AH (P = 0.028), with 26.35% more mean cell viability compared to AH. Besides, PB reduces the antibacterial effect of BR all the time at a significant level (P = 0.000, 0.014, 0.032). Conclusion, at 24 and 48 hours, PBBR was cytotoxic to HPdLF. AH and PBAH both demonstrated antibacterial activity against E. faecalis, followed by BR and PBBR. PBAH has potential to be an improved root canal sealer, more research may be done to completely uncover its remarkable characteristics.

Molecular Mechanism of DLBS3233 Bioactive Fraction in Type 2 Diabetes Mellitus: Network Pharmacology and Docking Study

Raymond Rubianto Tjandrawinata, Santi Tan, Vivitri Dewi Prasasty — Tue, 05 Nov 2024 00:00:00 +0000

Although several antidiabetic agents are currently available, they commonly have undesirable effects and are not fully effective in reducing blood glucose. Therefore, since a long time ago, some Indonesians have preferred herbal medicine to cure and prevent diseases such as Lagerstroemia speciosa (L.) Pers. and Cinnamomum burmanni (Nees & T.Nees) Blume, plants from Indonesia, are believed to be able to treat type 2 diabetes mellitus (T2DM). Both herbs are present in DLBS3233 bioactive fraction, a standardized herbal extract that acts as an insulin sensitizer like thiazolidinediones (TZDs). However, the molecular mechanisms, the bioactive compounds, and the target proteins involved remain unclear. To understand more about the potential molecular mechanism of DLBS3233 in treating T2DM, this network pharmacology study is conducted for the first time. Quercetin, kaempferol, and ellagic acid were discovered to have antidiabetic effects in this study as selected compounds of DLBS3233, primarily on eight core target proteins, including AKT1, EGFR, GSK3B, IL6, PTK2, RELA, SRC, and VEGFA. We also found that they exhibited ligand-receptor binding activity comparable to pioglitazone in the molecular docking study. Concisely, as a reference for furthering the development of this bioactive fraction, this study provides novel information on DLBS3233 in T2DM treatment that was not revealed in prior studies.

Keywords: DLBS3233; Lagerstroemia speciosa (L.) Pers.; Cinnamomum burmanni (Nees & T.Nees) Blume; type 2 diabetes mellitus; network pharmacology

Zerumbone: A Potent Emerging Phytochemical with Anticancer Therapeutic Potential

Tue, 05 Nov 2024 00:00:00 +0000

Breast cancer is a prevalent cause of global mortality, characterised by abnormal cell growth within the breast. These cells can spread to distant sites in the body through metastasis and one of the mechanisms that breast cancer cells use to metastasise is via invadopodia formation. Accumulated evidences have explained pathways that may contribute to the breast cancer cells metastasis including the ERK, SMAD-3, STAT3 and NF-κB pathways. The hypoxic conditions within tumours enhance their metastatic ability through HIF-1α upregulation. Despite advanced treatments including chemotherapy and radiotherapy, these approaches are expensive and sometimes lack efficacy. Zerumbone, a compound extracted from Zingiber zerumbet, is known for its anti-cancer properties. It counteracts cancer cell metastasis by reducing cell migration, invasion and proliferation by acting upon multiple signalling pathways. This review recapitulates the metastasis of breast cancer and its biomarkers. In addition, our review also will explore the impact of zerumbone, therapeutic roles and its mechanism of action in reducing breast cancer metastasis.

DIFFERENTIALLY EXPRESSED GENES (DEGs) ANALYSIS INDICATING 6-SHOGAOL ANTICANCER ACTIVITY AGAINST HCT-116 CELLS PERFORMED PRIMARILY BY AFFECTING GENES IN COMMON (SHARED-DEGs) OF APOPTOTIC AND P53 SIGNALING PATHWAYS

Kusmardi Kusmardi — Tue, 05 Nov 2024 00:00:00 +0000

Ginger have strong anti-inflammatory and antioxidant properties that can inhibit growth and trigger apoptosis of colorectal cancer cells. Dried ginger containing the main bioactive compound 6-shogaol is widely used for practical reasons in storage. In this study, the mechanism of 6-shogaol apoptosis was tried to be explained by looking at the Differentially Expressed Genes (DEGs) changes in HCT-116 cells. The results of DEG analysis on Gene Expression Omnibus (GEO) data which contained gene expression data for the HCT-116 cell group treated with 6-shogaol and the control group showed that there were 142 DEGs of the apoptotic pathway with 9 (nine) of them being share-DEGs of the apoptotic pathway with other pathways related to apoptosis such as MAPK signaling pathway, p53 signalling pathway, and protein processing in endoplasmic reticulum pathways. Based on the regulation of the 9 share-DEGs, it was also explained that the apoptotic activity of 6-shogaol mainly occurs through the p53 signalling pathway which involves up-regulation of BAX, BBC3, GADD45G, and TNFRSF10A.

Keywords: 6-shogaol, HCT-116, apoptosis, Differentially Expressed Genes (DEG), p53 signaling pathway

Pyranocycloartobilixanthone A Suppressed Metastasis Ovarian Cancer Cells Via S Phase Cell Cycle Arrest and Apoptosis

Mashitoh Abd Rahman — Tue, 05 Nov 2024 00:00:00 +0000

Ovarian cancer is a devastating disease with a poor prognosis, highlighting the urgent need for novel treatments. Pyranocycloartobiloxanthone A (PA), an exceptional xanthone compound has gained attention due to its various medicinal properties. This study aimed to investigate the anticancer properties of PA on metastatic ovarian cancer SKOV-3 cells. Cytotoxicity was evaluated using an MTT assay, while apoptotic changes and mechanisms were determined using AOPI double staining, annexin V-fluorescein isothiocyanate, multiple cytotoxicity-3, ROS production, caspases, Real-time PCR, western blot, human apoptosis protein profile array and cell cycle analysis. PA inhibited SKOV-3 cell proliferation in a time-dependent manner, with an IC₅₀ of 7.0±0.5 µg/mL and a selectivity index of 13.2 after 72 hours of treatment. PA induced apoptosis through the intrinsic apoptotic pathway and arrested the cell cycle at the S phase. PA stimulated ROS production and disrupted the mitochondrial membrane potential, releasing cytochrome c from mitochondria to the cytosol. Additionally, results from human apoptotic protein profile indicated that 21 proteins were upregulated while 22 proteins were downregulated including Bcl-2, survivin, and HSP70. These findings suggest that PA has the potential as a lead molecule in developing a chemotherapy drug for ovarian cancer. However, further research is necessary to evaluate the safety and efficacy of PA in preclinical and clinical settings.

ESTIMATION OF POPULATION SIZE BASED ON ONE-INFLATED, ZERO-TRUNCATED COUNT DISTRIBUTION WITH COVARIATE INFORMATION

Tita Jongsomjit, Rattana Lerdsuwansri — Tue, 05 Nov 2024 00:00:00 +0000

To estimate the unknown size of the population that is difficult or hidden to enumerate, the capture-recapture method is widely used for this purpose. We propose the one-inflated, zero-truncated geometric (OIZTG) model to deal with three important characteristics of some capture–recapture data: zero-truncation, one-inflation, and observed heterogeneity. The OIZTG model is generated by two distinct processes, one from a zero-truncated geometric (ZTG) process, and the other one-count producing process. To explain heterogeneity at an individual level, the OIZTG model provides a simple way to link the covariate information. The new estimator was proposed based on the OIZTG distributions through the modified Horvitz-Thomson approach, and the parameters of the OIZTG distributions are estimated by using a maximum likelihood estimator (MLE). With regard to making inferences about the unknown size of the population, confidence interval estimations are proposed where variance estimate of population size estimator is achieved by using conditional expectation technique. All of these are assessed through simulation studies. The real data sets are provided for understanding the methodologies.

An Efficient Method of Identification of Influential Observations in Multiple Linear Regression and Its Application to Real Data

habshah midi — Tue, 05 Nov 2024 00:00:00 +0000

Influential observations (IOs) are those observations which either alone or together with several other observations have detrimental effect on the computed values of various estimates. As such, it is very important to detect their presence. Several methods have been proposed to identify IOs that include the fast improvised influential distance (FIID). The FIID method has been shown to be more efficient than some existing methods. Nonetheless, the shortcoming of the FIID method is that, it is computationally not stable, still suffers from masking and swamping effects, time consuming issues and not using proper cut-off point. As a solution to this problem, a new robust version of influential distance method (RFIID) which is based on Reweighted Fast Consistent and High Breakdown (RFCH) estimator is proposed. The results of real data and Monte Carlo simulation study indicate that the RFIID able to correctly separate the IOs from the rest of data with the least computational running times, least swamping effect and no masking effect compared to the other methods in this study.

QUANTIFYING HAZE EFFECT USING AIR POLLUTION INDEX DATA

Razik Ridzuan Mohd Tajuddin, Nurulkamal Masseran — Tue, 05 Nov 2024 00:00:00 +0000

Malaysia has been misfortunate with intermittent haze episodes since 1997 which affect the air quality tremendously. In Malaysia, an instrument named as air pollution index (API) is utilized in determining the quality of air, which is influenced by the presence of haze. API values are calculated by considering the concentration of harmful particles in haze. So, any haze episode heavily affects the API values and can be considered as a determining factor. Since Malaysia is prone to haze, it is crucial to identify and quantify the haze effect on the API values. Therefore, a regression model with autoregressive integrated moving average errors (ARIMAX) is employed. It is found that ARIMAX with non-zero mean is the best model in describing the API data with presence of haze as external regressor based on the smallest adequacy and error measures for training and test datasets. In conclusion, the effect of haze is significant in describing the API values and thus, proper health managements are required during haze episodes.

DEVELOPMENT OF ENZYME-LINKED IMMUNOSORBENT ASSAY METHOD TO DETECT DIOXIN CONTAMINATION IN VIETNAM

Tue, 05 Nov 2024 00:00:00 +0000

Dioxins are a group of chemical compounds that cause environmental pollution and many harmful effects on human health. HRGC/HRMS is the standard method for the determination of dioxin concentration in soil samples with the most accurate results. However, this method is time-consuming, high cost and requires modern equipment. Currently, competitive ELISA is a reliable method used for dioxin detecting analysis with fast implementation time and low cost. This study presented optimized conditions for ELISA method to detect dioxin with an IC₅₀ of 8500 pg/well and a detection limit of 2.02 pg/well. Although there is a difference between the analytical results of the two methods, the well correlated results show the potential of the ELISA method in detecting and screening for dioxin contamination before performing confirmative analysis with HRGC/HRMS.

Synthesis, antimalarial activities of secondary amine-substituted eugenol compounds against Plasmodium falciparum and in silico molecular docking analysis

Jufrizal Syahri, Meidita Kemala Sari, Neni Frimayanti — Tue, 05 Nov 2024 00:00:00 +0000

Multi-resistance cases with antimalarial drugs had been developed in over the years. One of the ways of developing antimalarial drugs is to focus on searching for the potential antifolate inhibitors against Plasmodium sp. from synthetic or natural products. The aims of this research is to synthesis secondary amine-substituted eugenol compounds through the Mannich reaction for antimalarial evaluation using Plasmodium falciparum 3D7. The compounds were also evaluated on Plasmodium falciparum dihydrofolate reductase-thymidylate synthase (PfDHFR-TS) as a protein target and the compounds’ drug-likeness properties were determined. Five secondary amine-substituted eugenol compounds (1a-e) were synthesized via substitution of the secondary amine i.e. pyrrolidine, piperidine, methyl piperidine, and morpholine in the eugenol structures. The plasmodium lactate dehydrogenase assay (pLDH) showed that 1a and 1c had good antimalarial effects against P. falciparum 3D7 with the IC₅₀s values of 0.89 mM and 0.62 mM, respectively. The molecular docking analysis revealed that 1a and 1c had perfect interaction with PfDHFR-TS (PDB ID: 1J3I) with strong hydrogen bond interactions occurring with PfDHFR-TS protein. The eugenol derivatives 1a and 1c exerted CDOCKER binding energies of -6.1407 and -6.6536 kcal/mol, respectively. Based on this research, it was found that PfDHFR-TS is a plausible protein target for the synthesized secondary amine-substituted eugenol in P. falciparum infection. The substitution of a secondary amine group for eugenol significantly enhanced the antimalarial properties of the compounds. Thus, eugenol derivatives are potential compounds to be pursued to combat folate resistance in malarial infection.

Keywords : antimalarial activities; eugenol; Mannich reaction; Plasmodium falciparum 3D7; PfDHFR-TS;

A CORAL-LIKE MO2C/TiO2 PHOTOELECTRODE FOR PHOTOELECTROCHEMICAL WATER SPLITTING

Tue, 05 Nov 2024 00:00:00 +0000

In photoelectrochemical hydrogen (H₂) production, creating efficient photocatalysts with effective charge transfer and separation is a key problem. Titanium dioxide (TiO₂), one of the most explored photocatalyst materials, has a bandgap of 3.2 eV, which restricts its energy absorption to UV light, and the photoexcited electrons and holes swiftly recombine. Thus, alteration of the band structure, such as by adding materials as cocatalysts, is needed. In particular, 2D molybdenum carbide (Mo₂C) has been researched extensively as an excellent non-noble cocatalyst owing to its Pt-like H⁺ adsorption capacity and high conductivity. In this work, composites of TiO₂ and Mo₂C with four different compositions were produced using the sol-gel method, and their photoelectrochemical activity for water splitting was assessed. The composites were spin-coated onto FTO conducting glass, and FESEM analysis indicated that TiO₂nanoparticles are widely disseminated across Mo₂C to form coral-like structures. Analysis via X-ray diffraction verified the existence of peaks composed of TiO₂ and Mo₂C. The sample containing 3% Mo₂C had the greatest increase in photocurrent density, which was approximately 1.56 mA cm^-2 at a potential of 1.0 V against Ag/AgCl (1.59 vs. RHE), which is five times that of bare TiO₂. In addition, the composite's onset potential moved to a lower potential. Our findings suggest that adding Mo₂C increases the photoelectrochemical performance of the TiO₂ photoelectrode. This work indicates the feasibility of employing Mo₂C as a cocatalyst to improve the performance of TiO₂ for photoelectrochemical H₂ production.

THE GEOMETRICAL PROPERTIES OF ROUND BAMBOO OF GIGANTOCHLOA LEVIS AND THEIR EFFECTS ON CONSTRUCTION DESIGN

Mohd Jamil Abdul Wahab — Tue, 05 Nov 2024 00:00:00 +0000

Round bamboo is reviewed as a highly potential material for building components. However, the assessable data of the geometrical variability of Malaysian bamboos proposed as structural members are greatly lacking. A study was conducted to establish the geometric properties of bamboo culms and to derive the important parameters that will affect engineering design. A total of thirty culms of Gigantochloa levis were selected for this assessment. The evaluations were based on the internode length, culm diameter, wall thickness, and the second moment of area with respect to the height of the culm. The correlation between the internode length and culm height was generally erratic. Most internode sections measured between 35 to 50 cm. The findings have demonstrated that an internodal crack could severely change the cross-sectional geometry of the culm. There were two major factors concerning culm diameter that need to be considered in the design, i.e. diameter shrinkage and taper rate. The diameter of a culm was fairly equal within the height of 1 to 5 m and decreased from 5 m onwards. Upon drying, the culm of the larger diameter tended to shrink more than the smaller one. Thickness irregularity around the circumference of the internode wall was minor. The shrinkage of the internode wall was within 20%, with a very high probability of a lower percentage for thinner walls. The study indicates that the selection of culms for construction is best between the height of 1 to 5 m whereby the internodal length is more consistent.