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Implantation of GLP-1 secreting cells fails to recapitulate effects of exogenous GLP-1 mimetics in mice

Vasu S, Hamid MH, McCluskey JT, Irwin N, Flatt PR

Regul. Pept., 2010 Sep 9;164(1):32.
PMID: 26009405 DOI: 10.1016/j.regpep.2010.07.075
Fulltext Impacts of tilapia aquaculture on native fish diversity at an ecologically important reservoir

Abd Hamid M, Md Sah ASR, Idris I, Mohd Nor SA, Mansor M

PeerJ, 2023;11:e15986.
PMID: 38144186 DOI: 10.7717/peerj.15986

BACKGROUND: The Temengor Reservoir is the second largest reservoir in Peninsular Malaysia. Located in the northwestern state of Perak, it was selected to develop a large-scale tilapia (Oreochromis niloticus) aquaculture facility within the Aquaculture Industrial Zone (AIZ) in 2008 due to its favourable environmental conditions. No record of tilapia has ever been reported in the natural waters prior to this. However, a post-establishment study recorded tilapia sightings in the natural waters of this lake. The cultured tilapia was easily recognizable with the elongated mouth and body, and long caudal fin. It is postulated that these were escapees from the floating cages that had invaded the natural waters and would negatively impact the native fish species. To test our hypothesis, we investigated the impact of the aquaculture facility on native fish diversity through a spatial design.
METHODS: The study was focused on assessing the impact of tilapia culture at sites nearer to the AIZ vs more distant sites, the former with a greater likelihood of receiving escapees. Two major sites were chosen; within 5 km (near-cage) and within 5-15 km (far-cage) radii from the AIZ. Fish sampling was conducted using multiple mesh sizes of gill nets (3.7, 5.1, 6.5, 7.6, and 10.2 cm) deployed at the littoral zone of the sampling points. Species diversity, abundance, dietary habits, and habitat preference were investigated.
RESULTS: The CPUE (individual/hour) of native fish species at the far-cage site of the AIZ Reservoir was found to be significantly higher (p < 0.05) than that at the near-cage site. Principal component analysis (PCA) based on diet and habitat preferences showed that the tilapia, O. niloticus had almost overlapping diet resources and habitat with native fish species.
CONCLUSION: We conclude that there is a correlation between the reduced catches of native species (based on CPUE) and the high presence of tilapia. Thus, appropriate actions must be implemented for strategic and effective planning in terms of native fish conservation.
Fulltext Immunological Analysis of the Hepatitis B Virus "a" Determinant Displayed on Chimeric Virus-Like Particles of Macrobrachium rosenbergii Nodavirus Capsid Protein Produced in Sf9 Cells

Ninyio NN, Ho KL, Ong HK, Yong CY, Chee HY, Hamid M, et al.

Vaccines (Basel), 2020 Jun 04;8(2).
PMID: 32512923 DOI: 10.3390/vaccines8020275

Chimeric virus-like particles (VLPs) have been widely exploited for various purposes including their use as vaccine candidates, particularly due to their ability to induce stronger immune responses than VLPs consisting of single viral proteins. In the present study, VLPs of the Macrobrachium rosenbergii nodavirus (MrNV) capsid protein (Nc) displaying the hepatitis B virus "a" determinant (aD) were produced in Spodoptera frugiperda (Sf9) insect cells. BALB/c mice immunised with the purified chimeric Nc-aD VLPs elicited a sustained titre of anti-aD antibody, which was significantly higher than that elicited by a commercially available hepatitis B vaccine and Escherichia coli-produced Nc-aD VLPs. Immunophenotyping showed that the Sf9-produced Nc-aD VLPs induced proliferation of cytotoxic T-lymphocytes and NK1.1 natural killer cells. Furthermore, enzyme-linked immunospot (ELISPOT)analysis showed the presence of antibody-secreting memory B cells in the mice splenocytes stimulated with the synthetic aD peptide. The significant humoral, natural killer cell and memory B cell immune responses induced by the Sf9-produced Nc-aD VLPs suggest that they present good prospects for use as a hepatitis B vaccine candidate.
Fulltext Identification of Antidiabetic Metabolites from Paederia foetida L. Twigs by Gas Chromatography-Mass Spectrometry-Based Metabolomics and Molecular Docking Study

Tan DC, Kassim NK, Ismail IS, Hamid M, Ahamad Bustamam MS

Biomed Res Int, 2019;2019:7603125.
PMID: 31275982 DOI: 10.1155/2019/7603125

Paederia foetida L. (Rubiaceae) is a climber which is widely distributed in Asian countries including Malaysia. The plant is traditionally used to treat various diseases including diabetes. This study is to evaluate the enzymatic inhibition activity of Paederia foetida twigs extracts and to identify the metabolites responsible for the bioactivity by gas chromatography-mass spectrometry (GC-MS) metabolomics profiling. Three different twig extracts, namely, hexane (PFH), chloroform (PFC), and methanol (PFM), were submerged for their α-amylase and α-glucosidase inhibition potential in 5 replicates for each. Results obtained from the loading column scatter plot of orthogonal partial least square (OPLS) model revealed the presence of 12 bioactive compounds, namely, dl-α-tocopherol, n-hexadecanoic acid, 2-hexyl-1-decanol, stigmastanol, 2-nonadecanone, cholest-8(14)-en-3-ol, 4,4-dimethyl-, (3β,5α)-, stigmast-4-en-3-one, stigmasterol, 1-ethyl-1-tetradecyloxy-1-silacyclohexane, ɣ-sitosterol, stigmast-7-en-3-ol, (3β,5α,24S)-, and α-monostearin. In silico molecular docking was carried out using the crystal structure α-amylase (PDB ID: 4W93) and α-glucosidase (PDB ID: 3WY1). α-Amylase-n-hexadecanoic acid exhibited the lowest binding energy of -2.28 kcal/mol with two hydrogen bonds residue, namely, LYS178 and TYR174, along with hydrophobic interactions involving PRO140, TRP134, SER132, ASP135, and LYS172. The binding interactions of α-glucosidase-n-hexadecanoic acid complex ligand also showed the lowest binding energy among 5 major compounds with the energy value of -4.04 kcal/mol. The complex consists of one hydrogen bond interacting residue, ARG437, and hydrophobic interactions with ALA444, ASP141, GLN438, GLU432, GLY374, LEU373, LEU433, LYS352, PRO347, THR445, HIS348, and PRO351. The study provides informative data on the potential antidiabetic inhibitors identified in Paederia foetida twigs, indicating the plant has the therapeutic effect properties to manage diabetes.
Hypoglycemic effects of cocoa (Theobroma cacao L.) autolysates

Sarmadi B, Aminuddin F, Hamid M, Saari N, Abdul-Hamid A, Ismail A

Food Chem, 2012 Sep 15;134(2):905-11.
PMID: 23107706 DOI: 10.1016/j.foodchem.2012.02.202

Fat, alkaloid and polyphenol contents of two clones of cocoa (UIT1 and PBC 140) were removed and the remaining powder was autolyzed at pH 3.5 and 5.2. Based on the results, autolysates of UIT produced at pH 3.5 exhibited the highest ability to inhibit α-amylase activity. However, no α-glucosidase inhibition activity was observed under the conditions specified. Autolysates produced under pH 3.5 caused the highest amount of insulin secretion. In streptozotocin-diabetic rats, all cocoa autolysates significantly decreased blood glucose at 4h. To assure that the results from the assays were not due to the polyphenols of cocoa autolysates qualitative and quantitative tests were applied. According to their results cocoa autolysates were found to be free from polyphenols. Analysis of amino acid composition revealed that cocoa autolysates were abundant in hydrophobic amino acids. It can be suggested that besides other compounds of cocoa, its peptides and amino acids could contribute to its health benefits.
Genetic diversity of secreted protein with an altered thrombospondin repeat (SPATR) of Plasmodium knowlesi clinical isolates from Malaysia

Azlan UW, Lau YL, Hamid MHA, Jelip J, Ooi CH, Mudin RN, et al.

Trop Biomed, 2022 Dec 01;39(4):504-510.
PMID: 36602208 DOI: 10.47665/tb.39.4.006

The Plasmodium knowlesi secreted protein with an altered thrombospondin repeat (PkSPATR) is an important protein that helps in the parasite's invasion into the host cell. This protein has been regarded as one of the potential vaccine candidates against P. knowlesi infection. This study investigates the genetic diversity and natural selection of PkSPATR gene of P. knowlesi clinical isolates from Malaysia. PCR amplification of the full length PkSPATR gene was performed on 60 blood samples of infected P. knowlesi patients from Peninsular Malaysia and Malaysian Borneo. The amplified PCR products were cloned and sequenced. Sequence analysis of PkSPATR from Malaysia showed higher nucleotide diversity (CDS p: 0.01462) than previously reported Plasmodium vivax PvSPATR (p = 0.0003). PkSPATR from Peninsular Malaysia was observed to have slightly higher diversity (CDS p: 0.01307) than those from Malaysian Borneo (CDS p: 0.01212). Natural selection analysis on PkSPATR indicated significant purifying selection. Multiple amino acid sequence alignment revealed 69 polymorphic sites. The phylogenetic tree and haplotype network did not show any distinct clustering of PkSPATR. The low genetic diversity level, natural selection and absence of clustering implied functional constrains of the PkSPATR protein.
Fulltext Ficus deltoidea: A Potential Alternative Medicine for Diabetes Mellitus

Adam Z, Khamis S, Ismail A, Hamid M

Evid Based Complement Alternat Med, 2012;2012:632763.
PMID: 22701507 DOI: 10.1155/2012/632763

Ficus deltoidea from the Moraceae family has been scientifically proven to reduce hyperglycemia at different prandial states. In this study, we evaluate the mechanisms that underlie antihyperglycemic action of Ficus deltoidea. The results had shown that hot aqueous extract of Ficus deltoidea stimulated insulin secretion significantly with the highest magnitude of stimulation was 7.31-fold (P < 0.001). The insulin secretory actions of the hot aqueous extract involved K(+) (ATP) channel-dependent and K(+) (ATP)-channel-independent pathway. The extract also has the ability to induce the usage of intracellular Ca(2+) to trigger insulin release. The ethanolic and methanolic extracts enhanced basal and insulin-mediated glucose uptake into adipocytes cells. The extracts possess either insulin-mimetic or insulin-sensitizing property or combination of both properties during enhancing glucose uptake into such cells. Meanwhile, the hot aqueous and methanolic extracts augmented basal and insulin-stimulated adiponectin secretion from adipocytes cells. From this study, it is suggested that Ficus deltoidea has the potential to be developed as future oral antidiabetic agent.
Fulltext Evaluation of the α-glucosidase inhibitory and free radical scavenging activities of selected traditional medicine plant species used in treating diabetes

Wan-Nadilah, W.A., Khatib, A., Khozirah, S., Hamid, A.A., Hamid, M.

International Food Research Journal, 2019;26(1):75-85.
MyJurnal

Plants constitute a major ingredient in traditional or folk medicine. The therapeutic claims made on the use of these traditional medicinal plants range from simple conditions such as fevers and migraines, to more complex diseases such as cancer, metabolic syndrome and diabetes mellitus. The aqueous ethanolic extracts of five medicinal plant species; Cosmos caudatus, Leucaena leucocephala, Momordica charantia, Pereskia bleo and Averrhoa bilimbi were assessed for glucose lowering effect via the in vitro α-glucosidase inhibition assay. Their antioxidant potential, represented by their DPPH radical scavenging activity and total phenolic contents were also measured. The most potent α-glucosidase inhibitory activity was recorded for the leaf extract of C. caudatus with IC50 of 21.90 ± 3.60 μg/mL, followed by L. leucocephala with IC50 value of 30.80 ± 2.50 μg/mL. Momordica charantia, P. bleo and A. bilimbi did not show any significant inhibition of α-glucosidase. Meanwhile C. caudatus also gave the highest DPPH radical scavenging activity with IC50 value of 272.46 ± 8.98 μg/mL, and the highest total phenolic content with a value of 0.263 ± 0.02 g GAE/g DW. The present work provides a priority list of interesting plants for further study with respect to the treatment of diabetes.
Enzyme immunoassay for the detection of porcine gelatine in edible bird's nests

Tukiran NA, Ismail A, Mustafa S, Hamid M

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2015;32(7):1023-8.
PMID: 25861981 DOI: 10.1080/19440049.2015.1039605

Porcine gelatine is a common adulterant found in edible bird's nests (EBNs) used to increase the net weight prior to sale. This study aimed to develop indirect enzyme-linked immunosorbent assays (ELISAs) for porcine gelatine adulteration using anti-peptide polyclonal antibodies. Three indirect ELISAs were developed (PAB1, 2 and 3), which had limits of detection (LODs) of 0.12, 0.10 and 0.11 µg g(-1), respectively. When applied to standard solutions of porcine gelatine, the inter- and intra-assays showed coefficients of variation (CVs) less than 20% and were able to detect at least 0.5 ng µg(-1) (0.05%) porcine gelatine in spiked samples. The proposed ELISA offers attractions for quality control in the EBN industry.
Encephalitis and retarded growth of chicks caused by Sitiawan virus, a new isolate belonging to the genus Flavivirus

Kono Y, Tsukamoto K, Abd Hamid M, Darus A, Lian TC, Sam LS, et al.

Am J Trop Med Hyg, 2001 5 19;63(1-2):94-101.
PMID: 11358004

A new virus named Sitiawan virus (SV) was isolated from sick broiler chicks in chicken embryos. The virus replicated well with cytopathogenic effect (CPE) in the chicken B-lymphocyte cell line LSCC-BK3. The virus was an enveloped RNA virus of approximately 41 nm in size with hemagglutinating activity (HA) to goose erythrocytes. It was cross-reactive with Japanese encephalitis virus (JEV), a member of flaviviruses by HA inhibition tests but not by cross-virus neutralization tests. The cDNA fragment of NS5 gene was amplified with primers corresponding to NS5 gene of flaviviruses. The nucleotide sequences were 92% homologous to Tembusu virus, a member of the mosquito-borne virus cluster of the genus Flavivirus. In cross-neutralization tests with Tembusu virus, antiserum to SV did not neutralize Tembusu virus, and antiserum to Tembusu virus neutralized more weakly to SV than against homologous virus. These results indicate that SV is a new virus which can be differentiated serologically from Tembusu virus but is otherwise similar with respect to nucleotide sequence. The virus causes encephalitis, growth retardation, and increased blood glucose levels in inoculated chicks.
Effects of cocoa extract on glucometabolism, oxidative stress, and antioxidant enzymes in obese-diabetic (Ob-db) rats

Jalil AM, Ismail A, Pei CP, Hamid M, Kamaruddin SH

J Agric Food Chem, 2008 Sep 10;56(17):7877-84.
PMID: 18702467 DOI: 10.1021/jf8015915

In this present study, we investigated the effects of cocoa extract containing polyphenols and methylxanthines prepared from cocoa powder on the biochemical parameters of obese-diabetic (Ob-db) rats. Obese-diabetic (Ob-db) rats were developed using a high-fat diet (49% fat, 32% carbohydrate, and 19% protein from total energy, kcal) for 3 months, followed by a low dose (35 mg/kg body weight) streptozotocin (STZ) injection. Cocoa extract (600 mg/kg body weight/day) was given to the rats for 4 weeks. The results indicated that there were no significant differences in fasting plasma glucose and insulin level after 4 weeks of cocoa extract administration. Oral glucose tolerance test revealed that cocoa supplementation in Ob-db rats significantly (p < 0.05) reduced plasma glucose at 60 and 90 min compared to unsupplemented Ob-db rats. Plasma free fatty acid and oxidative stress biomarker (8-isoprostane) were significantly (p < 0.05) reduced after cocoa supplementation. Superoxide dismutase activity was enhanced in Ob-db compared to that in nonsupplemented rats. However, no change was observed in catalase activity. The results showed that cocoa supplementation had an effect on postprandial glucose control but not for long term (4 weeks). Moreover, cocoa supplementation could reduce circulating plasma free fatty acid and 8-isoprostane and may enhance the antioxidant defense system.
Fulltext Effects of Flower and Fruit Extracts of Melastoma malabathricum Linn. on Growth of Pathogenic Bacteria: Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, and Salmonella typhimurium

Che Omar SN, Ong Abdullah J, Khairoji KA, Chin Chin S, Hamid M

Evid Based Complement Alternat Med, 2013;2013:459089.
PMID: 23662136 DOI: 10.1155/2013/459089

Melastoma malabathricum Linn. is a shrub that comes with beautiful pink or purple flowers and has berries-like fruits rich in anthocyanins. This study was carried out with the aim to evaluate the inhibitory activities of different concentrations of the M. malabathricum Linn. flower and fruit crude extracts against Listeria monocytogenes IMR L55, Staphylococcus aureus IMR S244, Escherichia coli IMR E30, and Salmonella typhimurium IMR S100 using the disc diffusion method. The lowest concentrations of the extracts producing inhibition zones against the test microorganisms were used to determine their minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). In addition, the growth of Listeria monocytogenes IMR L55 and Staphylococcus aureus IMR S244 grown in medium supplemented with the respective extracts at different temperatures (4°C, 25°C, and 37°C) and pHs (4, 6, 7, and 8) was determined.
Effect of Ipomoea aquatica ethanolic extract in streptozotocin (STZ) induced diabetic rats via1H NMR-based metabolomics approach

Abu Bakar Sajak A, Mediani A, Maulidiani, Mohd Dom NS, Machap C, Hamid M, et al.

Phytomedicine, 2017 Dec 01;36:201-209.
PMID: 29157816 DOI: 10.1016/j.phymed.2017.10.011

BACKGROUND: Ipomoea aquatica (locally known as "kangkung") has previously been reported to have hypoglycemic activities on glucose level in diabetes patients. However, the effect of I. aquatica ethanolic extract on the metabolites in the body has remained unknown.
PURPOSE: This study provides new insights on the changes of endogenous metabolites caused by I. aquatica ethanolic extract and improves the understanding on the therapeutic efficacy and mechanism of I. aquatica ethanolic extract.
METHODS: By using a combination of 1H nuclear magnetic resonance (NMR) with multivariate analysis (MVDA), the changes of metabolites due to I. aquatica ethanolic extract administration in obese diabetic-induced Sprague Dawley rats (OB+STZ+IA) were identified.
RESULTS: The results suggested 19 potential biomarkers with variable importance projections (VIP) above 0.5, which include creatine/creatinine, glucose, creatinine, citrate, carnitine, 2-oxoglutarate, succinate, hippurate, leucine, 1-methylnicotinamice (MNA), taurine, 3-hydroxybutyrate (3-HB), tryptophan, lysine, trigonelline, allantoin, formiate, acetoacetate (AcAc) and dimethylamine. From the changes in the metabolites, the affected pathways and aspects of metabolism were identified.
CONCLUSION: I. aquatica ethanolic extract increases metabolite levels such as creatinine/creatine, carnitine, MNA, trigonelline, leucine, lysine, 3-HB and decreases metabolite levels, including glucose and tricarboxylic acid (TCA) intermediates. This implies capabilities of I. aquatica ethanolic extract promoting glycolysis, gut microbiota and nicotinate/nicotinamide metabolism, improving the glomerular filtration rate (GFR) and reducing the β-oxidation rate. However, the administration of I. aquatica ethanolic extract has several drawbacks, such as unimproved changes in amino acid metabolism, especially in reducing branched chain amino acid (BCAA) synthesis pathways and lipid metabolism.
Fulltext Echocardiography and strain analysis in Malaysian elite athletes versus young healthy adults

Roslan A, Stanislaus R, Yee Sin T, Aris FA, Ashari A, Shaparudin AA, et al.

Int J Cardiol Heart Vasc, 2023 Aug;47:101242.
PMID: 37576081 DOI: 10.1016/j.ijcha.2023.101242

BACKGROUND: Athletes have changes that can mimic pathological cardiomyopathy.
METHODS: Echocardiographic study of 50 male, female athletes (MA, FA) and non-athletes (MNA, FNA) age 18 to 30 years. These athletes participate in sports with predominantly endurance component. All participants exhibit no known medical illnesses or symptoms.
RESULTS: MA have thicker wall (IVSd) than MNA. No MA have IVSd > 1.2 cm and no FA have IVSd > 1.0 cm. Left ventricle internal dimension (LVIDd), left ventricle end diastolic volume index (LVEDVi) is bigger in athletes. None have LVIDd > 5.8 cm. Right ventricle fractional area change (FAC) is lower in athletes. (MA vs MNA, p = 0.013, FA vs FNA, p = 0.025). Athletes have higher septal and lateral e' (Septal e'; MA 13.57 ± 2.66 cm/s vs MNA 11.46 ± 2.93 cm/s, p 1.2 cm and/or LVIDd > 5.8 cm. There is no difference in GLS, RVFWS and GCS but athletes have smaller LArS and LAbS.
EVIPNet: translating the spirit of Mexico

Hamid M, Bustamante-Manaog T, Truong VD, Akkhavong K, Fu H, Ma Y, et al.

Lancet, 2005 Nov 19;366(9499):1758-60.
PMID: 16298204 DOI: 10.1016/S0140-6736(05)67709-4
Drying kinetics and stabilization of sewage sludge in lagoon in hot climate

Idris A, Yen OB, Hamid MH, Baki AM

Water Sci Technol, 2002;46(9):279-86.
PMID: 12448479

A sludge lagoon has been adopted as a simple and cost effective method for dewatering of sludge. The processes occurring in a sludge lagoon include thickening, dewatering, storage and stabilization; all happening simultaneously. The objective of this study is to determine the dewatering and drying rates at pilot-scale which occur in a lagoon having different design configurations. Two types of sludge lagoons with different initial sludge depth (0.75 m and 0.375 m) were investigated to measure the drying behavior and drying efficiency. The first design is a sludge lagoon with a clay bottom where the dewatering mechanisms are decanting supernatant and evaporation. The second design is a sludge lagoon installed with a sand and underdrains system, where the dewatering mechanisms are filtration or draining and evaporation. Sludge drying kinetic models with high fitness were plotted to describe the sludge drying behavior. Drying of sludge in a sludge lagoon with a clay bottom can best be described by an exponential function. Whereas, drying of sludge in a sludge lagoon with sand and underdrains system followed a logarithmic function. A lagoon designed with sand and underdrains system and having shallower sludge depth was the most efficient. The reduction in volatile solids was lower than 4% during the study period. The drying process proceeded with an increase in dryness and decline in pH value.
Fulltext Development and characterization of novel porous 3D alginate-cockle shell powder nanobiocomposite bone scaffold

Bharatham BH, Abu Bakar MZ, Perimal EK, Yusof LM, Hamid M

Biomed Res Int, 2014;2014:146723.
PMID: 25110655 DOI: 10.1155/2014/146723

A novel porous three-dimensional bone scaffold was developed using a natural polymer (alginate/Alg) in combination with a naturally obtained biomineral (nano cockle shell powder/nCP) through lyophilization techniques. The scaffold was developed in varying composition mixture of Alg-nCP and characterized using various evaluation techniques as well as preliminary in vitro studies on MG63 human osteoblast cells. Morphological observations using SEM revealed variations in structures with the use of different Alg-nCP composition ratios. All the developed scaffolds showed a porous structure with pore sizes ideal for facilitating new bone growth; however, not all combination mixtures showed subsequent favorable characteristics to be used for biological applications. Scaffolds produced using the combination mixture of 40% Alg and 60% nCP produced significantly promising results in terms of mechanical strength, degradation rate, and increased cell proliferation rates making it potentially the optimum composition mixture of Alg-nCP with future application prospects.
Fulltext Design and Development of an Ergonomic Trolley-Lifter for Sheet Metal Handling Task: A Preliminary Study

Radin Umar RZ, Ahmad N, Halim I, Lee PY, Hamid M

Saf Health Work, 2019 Sep;10(3):327-335.
PMID: 31497329 DOI: 10.1016/j.shaw.2019.06.006

BACKGROUND: There have been some concerns related to manual handling of large items in industry. Manual handling operations of large sheet metal may expose workers to risks related to efficiency as well as occupational safety and health. Large sheet metals are difficult to move and burdensome to lift/transfer, and handling the sharp sheet edges may result in contact stress and/or cut injuries on the workers.
METHODS: Through observation, interview, and immersive simulation activities, a few problems related to current handling of sheet metals were identified. A sheet metal trolley-lifter was then designed and fabricated to address these issues. A pilot study on the use of the developed trolley-lifter for handling sheet metals was conducted to compare between the new and traditional handling methods.
RESULTS: The pilot study of the trolley-lifter showed promising results in terms of improving the cycle time, manpower utilization, and working postures compared with the traditional handling method.
CONCLUSION: The trolley-lifter offers an alternative solution to automation and a mechanized assistive device by providing a simple mechanism to assist the handling of sheet metals effectively and safely.
Fulltext Depigmenting effect of Kojic acid esters in hyperpigmented B16F1 melanoma cells

Lajis AF, Hamid M, Ariff AB

J Biomed Biotechnol, 2012;2012:952452.
PMID: 23091364 DOI: 10.1155/2012/952452

The depigmenting effect of kojic acid esters synthesized by the esterification of kojic acid using Rhizomucor miehei immobilized lipase was investigated in B16F1 melanoma cells. The depigmenting effect of kojic acid and kojic acid esters was evaluated by the inhibitory effect of melanin formation and tyrosinase activity on alpha-stimulating hormone- (α-MSH-) induced melanin synthesis in B16F1 melanoma cells. The cellular tyrosinase inhibitory effect of kojic acid monooleate, kojic acid monolaurate, and kojic acid monopalmitate was found similar to kojic acid at nontoxic doses ranging from 1.95 to 62.5 μg/mL. However, kojic acid monopalmitate gave slightly higher inhibition to melanin formation compared to other inhibitors at doses ranging from 15.63 to 62.5 μg/mL. Kojic acid and kojic acid esters also show antioxidant activity that will enhance the depigmenting effect. The cytotoxicity of kojic acid esters in B16F1 melanoma cells was significantly lower than kojic acid at high doses, ranging from 125 and 500 μg/mL. Since kojic acid esters have lower cytotoxic effect than kojic acid, it is suggested that kojic acid esters can be used as alternatives for a safe skin whitening agent and potential depigmenting agents to treat hyperpigmentation.
DNA damage evaluation of hydroxyapatite on fibroblast cell L929 using the single cell gel electrophoresis assay

Rajab NF, Yaakob TA, Ong BY, Hamid M, Ali AM, Annuar BO, et al.

Med J Malaysia, 2004 May;59 Suppl B:170-1.
PMID: 15468872

Hydroxyapatite is the main component of the bone which is a potential biomaterial substance that can be applied in orthopaedics. In this study, the biocompatibility of this biomaterial was assessed using an in vitro technique. The cytotoxicity and genotoxicity effect of HA2 and HA3 against L929 fibroblast cell was evaluated using the MTT Assay and Alkaline Comet Assay respectively. Both HA2 and HA3 compound showed low cytotoxicity effect as determined using MTT Assay. Cells viability following 72 hours incubation at maximum concentration of both HA2 and HA3 (200 mg/ml) were 75.3 +/- 8.8% and 86.7 +/- 13.1% respectively. However, the cytotoxicity effect of ZnSO4.7H2O as a positive control showed an IC50 values of 46 mg/ml (160 microM). On the other hand, both HA2 and HA3 compound showed a slight genotoxicity effect as determined using the Alkaline Comet Assay following incubation at the concentration 200 mg/ml for 72 hours. This assay has been widely used in genetic toxicology to detect DNA strand breaks and alkali-labile site. The percentage of the cells with DNA damage for both substance was 27.7 +/- 1.3% and 15.6 +/- 1.0% for HA2 and HA3 respectively. Incubation of the cells for 24 hours with 38 microg/ml (IC25) of positive control showed an increase in percentage of cells with DNA damage (67.5 +/- 0.7%). In conclusion, our study indicated that both hydroxyapatite compounds showed a good biocompatibility in fibroblast cells.

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