Displaying publications 1 - 20 of 129 in total

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  1. Cytotoxic xanthones isolated from Calophyllum depressinervosum and Calophyllum buxifolium with antioxidant and cytotoxic activities
    Zamakshshari NH, Ee GCL, Ismail IS, Ibrahim Z, Mah SH
    Food Chem Toxicol, 2019 Nov;133:110800.
    PMID: 31479710 DOI: 10.1016/j.fct.2019.110800
    The stem bark of Calophyllum depressinervosum and Calophyllum buxifolium were extracted and examined for their antioxidant activities, together with cytotoxicity towards human cancer cells. The methanol extract of C. depressinervosum exhibited good DPPH and NO scavenging effects. The strongest BCB inhibition and FIC effects were shown by dichloromethane and ethyl acetate extracts of both species. Overall, DPPH, FRAP and FIC assays showed strong correlation with TPC. For cytotoxicity, hexane extract of C. depressinervosum possessed the strongest anti-proliferative activities towards SNU-1 cells while the hexane extract of C. buxifolium showed the strongest activity towards LS-174T and K562 cells with the IC50 values ranging from 7 to 17 μg/mL. The purification of plant extracts afforded eight xanthones, ananixanthone (1), caloxanthone B (2), caloxanthone I (3), caloxanthone J (4) xanthochymone B (5), thwaitesixanthone (6), 1,3,5,6-tetrahydroxyxanthone (7) and dombakinaxanthone (8). All the xanthones, except 1 were reported for the first time from both Calophyllum species. The xanthones were examined for their cytotoxic effect against K562 leukemic cells. Compounds 1 and 2 showed strong cytotoxicity with the IC50 values of 2.96 and 1.23 μg/mL, respectively. The molecular binding interaction of 2 was further investigated by performing molecular docking study with promising protein receptor Src kinase.
  2. Perturbations in Amino Acid Metabolism in Reserpine-Treated Zebrafish Brain Detected by 1H Nuclear Magnetic Resonance-Based Metabolomics
    Zakaria F, Akhtar MT, Wan Ibrahim WN, Abu Bakar N, Muhamad A, Shohaimi S, et al.
    Zebrafish, 2021 02;18(1):42-54.
    PMID: 33538644 DOI: 10.1089/zeb.2020.1895
    Depression is a complex and disabling psychiatric disorder, which is expected to be a leading cause for disability by 2030. According to World Health Organization, about 350 million people are suffering with mental health disorders around the globe, especially depression. However, the mechanisms involved in stress-induced depression have not been fully elucidated. In this study, a stress-like state was pharmacologically induced in zebrafish using reserpine, a drug widely used to mediate depression in experimental animal models. Zebrafish received single intraperitoneal (i.p.) injections of 20, 40, and 80 mg/kg body weight reserpine doses and were subjected to open-field test at 2, 24, 48, 72, and 96 h after the treatment. Along with observed changes in behavior and measurement of cortisol levels, the fish were further examined for perturbations in their brain metabolites by 1H nuclear magnetic resonance (NMR)-based metabolomics. We found a significant increase in freezing duration, whereas total distance travelled was decreased 24 h after single intraperitoneal injection of reserpine. Cortisol level was also found to be higher after 48 h of reserpine treatment. The 1H NMR data showed that the levels of metabolites such as glutamate, glutamine, histamine, valine, leucine and histidine, lactate, l-fucose, betaine and γ-amino butyric acid (GABA), β-hydroxyisovalerate, and glutathione were significantly decreased in the reserpine-treated group. This study provided some insights into the molecular nature of stress that could contribute toward a better understanding of depression disorder.
  3. Centella asiatica (L.) Urb. Extract ameliorates branched-chain amino acid (BCAA) metabolism in acute reserpine-induced stress zebrafish model via 1H Nuclear Magnetic Resonance (NMR)-based metabolomics approach
    Zakaria F, Akhtar MT, Wan Norhamidah WI, Noraini AB, Muhamad A, Shohaimi S, et al.
    Comp Biochem Physiol C Toxicol Pharmacol, 2023 Feb;264:109501.
    PMID: 36336330 DOI: 10.1016/j.cbpc.2022.109501
    Depression is a common mental disorder that can adversely affect psychosocial function and quality of life. However, the exact aetiology and pathogenesis of depression are still unclear. Stress plays a major role in the pathogenesis of depression. The use of currently prescribed antidepressants has many side effects. Centella asiatica (C. asiatica) has shown promising antidepressant activity in rodent models. Here, we developed a reserpine-induced zebrafish stress-like model and performed behavioural analysis, cortisol measurement and 1H-Nuclear Magnetic Resonance (1H NMR) spectroscopy-based metabolomics analysis to test the anti-stress activity of ethanolic extract of C. asiatica (RECA). A significant increase in total distance travelled (F(8,8) = 8.905, p = 0.0054) and a reduction in freezing duration (F(9, 9) = 10.38, p = 0.0018) were found in the open field test (OFT). Asiaticoside, one of tested C.asiatica's triterpenoid gives a significant increase in contact duration (F(5,5) = 142.3, (p = 0.0330) at 2.5 mg/kg). Eight biomarkers were found, i.e. ß-hydroxyisovaleric acid, leucine, threonine, scylloinositol, lactate, betaine, valine, choline and l-fucose, to be responsible for the class separation between stress and RECA-treated groups. Metabolic pathway alteration in zebrafish brain upon treatment with RECA was identified as valine, leucine and isoleucine biosynthesis, while alanine, aspartate, glutamate and glycerophospholipid metabolism was involved after fluoxetine treatment.
  4. 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).
  5. Predictors of ischaemic heart disease in a Malaysian population with the metabolic syndrome
    Yeow TP, Khir AS, Ismail AA, Ismail IS, Kamarul Imran M, Khalid BA, et al.
    Diabet Med, 2012 Nov;29(11):1378-84.
    PMID: 22803824 DOI: 10.1111/j.1464-5491.2012.03741.x
    AIMS: Cardiovascular disease is the foremost cause of mortality in Malaysia but little is known about the prevalence of the metabolic syndrome and its associations with other known cardiovascular risk markers. We undertook a population-based study to examine these.
    METHODS: For the study, 4341 subjects were selected using a multistage stratified sampling method. Subjects were interviewed for personal and past medical history. Biomedical markers and anthropometric indices were measured. The metabolic syndrome was defined using the harmonized criteria. The associations between the metabolic syndrome and cardiovascular risk markers, including high-sensitivity C-reactive protein, microalbuminuria and HbA(1c) were examined.
    RESULTS: The prevalence of the metabolic syndrome was 42.5%. Subjects with the metabolic syndrome are significantly more likely to have higher BMI (> 25 kg/m(2)), HbA(1c) [≥ 42 mmol/mol (6.0%)], LDL (≥ 2.6 mmol/l), elevated albumin:creatinine ratio (> 2.5 μg/mmol creatinine for men, 3.5 μg/mmol creatinine for women) and high-sensitivity C-reactive protein (> 3 mg/l); odds ratio 5.48, 6.14, 1.44, 3.68 and 1.84, respectively, P < 0.001. The presence of an elevated albumin:creatinine ratio and high-sensitivity C-reactive protein are strong predictors for the presence of a higher number of positive criteria of the metabolic syndrome. HbA(1c) > 48 mmol/mol (6.5%) is associated with increased relative risk of elevated albumin:creatinine ratio, high-sensitivity C-reactive protein and LDL (relative risk 3.10, 2.46 and 1.65 respectively, P < 0.001).
    CONCLUSIONS: We confirmed the high prevalence of the metabolic syndrome in Malaysia. Our study revealed a strong relationship between risk markers of elevated BMI, HbA(1c), LDL, albumin:creatinine ratio and high-sensitivity C-reactive protein with the presence of the metabolic syndrome, putting them at a statistically high risk for cardiovascular mortality.
  6. Phenolic content of Terminalia catappa L. leaf and toxicity evaluation on red hybrid tilapia (Oreochromis sp.)
    Yakubu Y, Ahmad MT, Chong CM, Ismail IS, Shaari K
    J Fish Biol, 2023 Feb;102(2):358-372.
    PMID: 36333916 DOI: 10.1111/jfb.15266
    Despite the use of Terminalia catappa (TC) leaf by traditional fish farmers around the world to improve the health status of cultured fish, there is a paucity of information on comprehensive metabolite profile and the maximum safe dose of the plant. This study aims at profiling the methanol leaf extract of T. catappa, quantifying total phenolic content (TPC) as well as the total flavonoid content (TFC) and evaluating its acute toxicity on blood, plasma biochemical parameters and histopathology of some vital organs in red hybrid tilapia (Oreochromis sp.). The experimental fish were acclimatised for 2 weeks and divided into six groups. Group (1) served as a control group and was administered 0.2 ml,g-1 of phosphate buffer saline (PBS). Groups 2-6 were orally administered T. catappa leaf extracts (0.2 ml.50 g-1 ) in the following sequence; 31.25, 62.5, 125, 250 and 500 mg.kg-1 body weight. The metabolites identified in T. catappa using liquid chromatography-tandem mass electrospray ionisation spectrometry (LC-ESI-MS/MS) revealed the presence of organic acids, hydrolysable tannins, phenolic acids and flavonoids. Phenolic quantification revealed reasonable quantity of phenolic compounds (217.48 μg GAEmg-1 for TPC and 91.90 μg. QCEmg-1 for TFC). Furthermore, there was no significant difference in all the tested doses in terms of blood parameters and plasma biochemical analysis except for the packed cell volume (PCV) at 500 mg.kg-1 when compared to the control. Significant histopathological changes were observed in groups administered with the extract at 125, 250 and 500 mg.kg-1 doses. To a very large extent it is therefore safe to administer the extract at 31.25 and 62.5 mg.kg-1 in tilapia.
  7. A new pyranoxanthone from Garcinia nervosa
    Wong KW, Ee GCL, Ismail IS, Karunakaran T, Jong VYM
    Nat Prod Res, 2017 Nov;31(21):2513-2519.
    PMID: 28412841 DOI: 10.1080/14786419.2017.1315717
    Phytochemical studies on the stem bark of Garcinia nervosa has resulted in the discovery of one new pyranoxanthone derivative, garner xanthone (1) and five other compounds, 1,5-dihydroxyxanthone (2), 6-deoxyisojacareubin (3), 12b-hydroxy-des-D-garcigerrin A (4) stigmasterol (5), and β-sitosterol (6). The structures of these compounds were elucidated with the aid of spectroscopic techniques, such as NMR and MS. The crude extracts of the plant were assessed for their antimicrobial activity.
  8. Synthesis of benzylated amine-substituted xanthone derivatives and their antioxidant and anti-inflammatory activities
    Wong KW, Teh SS, Law KP, Ismail IS, Sato K, Mase N, et al.
    Arch Pharm (Weinheim), 2023 Jan;356(1):e2200418.
    PMID: 36285691 DOI: 10.1002/ardp.202200418
    Oxidative stress and its constant companion, inflammation, play a critical part in the pathogenesis of many acute and chronic illnesses. The discovery of new multi-targeted drug candidates with antioxidant and anti-inflammatory properties is deemed necessary. Thus, a series of novel xanthone derivatives with halogenated benzyl (4b-4d, 4f-4h) and methoxylated benzyl groups (4e) attached to the butoxy amine substituent were synthesized in this study. The synthesized xanthone derivatives exhibited stronger antioxidant activity against H2 O2 scavenging than the standard drug, α-tocopherol, but weaker towards DPPH scavenging and ferrous ion chelation. Besides that, 4b-4d, 4f-4h demonstrated good anti-inflammatory activities through NO production inhibition towards lipopolysaccharide (LPS)-induced RAW 264.7 cells and showed 2-4 times stronger effects than the standard drug, diclofenac sodium. Moreover, compound 4b with two brominated benzyl groups attached to the butoxy amine substituent suppressed the production of pro-inflammatory cytokines, TNF-α and IL-1β, significantly. Structure-activity relationship elucidated that the halogenated benzylamine substituent plays an important role in contributing the antioxidant and anti-inflammatory activities of xanthones. In summary, xanthone 4b was identified as a potential lead compound to be further developed into antioxidant and anti-inflammatory drugs. Thus, further studies on the related mechanisms of action of 4b are recommended.
  9. Fulltext Prevalence of overweight and obesity among adult Malaysians: an update
    Wan Nazaimoon WM, Musa KI, Md Khir AS, Ismail AA, Ismail IS, Khalid BAK, et al.
    Asia Pac J Clin Nutr, 2011;20(1):35-41.
    PMID: 21393108
    A total of 4428 adults (>18 years old) from 5 different selected regions in Peninsular and East Malaysia participated in this health survey. Using World Health Organization recommendations for body mass index (BMI), the prevalence of overweight and obesity were found to be 33.6% (95% CI= 32.2, 35.0) and 19.5% (95% CI= 18.3, 20.7) respectively. There were more females who were obese (22.5%, 95% CI=20.9, 24.0) compared to males (14.1%, 95% CI=12.3, 15.9). Highest prevalence of obesity were among the Indians (24.6%, 95% CI=20.3, 29.3), followed closely by the Malays (23.2%, 95% CI=21.6, 24.8%) and lowest prevalence was among the Chinese subjects (8.2%, 95% CI=6.2, 10.6). More than 43% of the 531 younger subjects (<30 years old) were either overweight (20%, 95% CI=16.6, 23.6) or obese (13.9%, 95% CI=11.1, 17.2%). All subjects who claimed to be non-diabetes were required to undergo 75 g glucose tolerance test. Compared to subjects with normal BMI (18.5-24.9 kg/m2), there was a 3- and 2-folds increase in the prevalence of newly diagnosed diabetes and impaired glucose tolerance respectively, among obese subjects (BMI>30 kg/m2) who initially claimed to have no diabetes. This study highlights a need for more active, inter-sectoral participation advocating a health-promoting environment in order to combat obesity in this country.
  10. Prevalence of diabetes in Malaysia and usefulness of HbA1c as a diagnostic criterion
    Wan Nazaimoon WM, Md Isa SH, Wan Mohamad WB, Khir AS, Kamaruddin NA, Kamarul IM, et al.
    Diabet Med, 2013 Jul;30(7):825-8.
    PMID: 23413941 DOI: 10.1111/dme.12161
    AIM: The prevalence of diabetes mellitus among Malaysians aged ≥ 30 years of age has increased by more than twofold over a 20-year period. This study aimed to determine the current status and to evaluate the diagnostic usefulness of the HbA(1c) cut-off point of 48 mmol/mol (6.5%).
    METHODS: Using a two-stage stratified sampling design, participants aged ≥ 18 years were recruited from five zones selected to represent Malaysia. An oral glucose tolerance test was performed on all those not known to have diabetes.
    RESULTS: A total of 4341 subjects were recruited. By World Health Organization criteria, the prevalence of diabetes mellitus was 22.9%; of that percentage, 10.8% was known diabetes and 12.1% was newly diagnosed diabetes. Diabetes was most prevalent amongst Indians (37.9%) and Malays (23.8%). Prevalence of new diabetes mellitus was only 5.5% (95% CI 4.9-6.3) when based on the HbA(1c) diagnostic criteria of 48 mmol/mol (6.5%) and, although the cut-off point was highly specific (98.1%), it was less sensitive (36.7%) compared with 45 mmol/mol (6.3%), which showed the optimal sum of sensitivity (42.5%) and specificity (97.4%) in identifying new diabetes mellitus.
    CONCLUSION: This study recorded an overall diabetes prevalence of 22.6%, almost a twofold increase from 11.6% reported in 2006. This was likely attributable to the higher prevalence of new diabetes (12.1%) diagnosed following an oral glucose tolerance test. An HbA(1c) of 45 mmol/mol (6.3%) was found to be a better predictive cut-off point for detecting new diabetes in our multi-ethnic population.
  11. Systolic hypertension and duration of diabetes mellitus are important determinants of retinopathy and microalbuminuria in young diabetics
    Wan Nazaimoon WM, Letchuman R, Noraini N, Ropilah AR, Zainal M, Ismail IS, et al.
    Diabetes Res Clin Pract, 1999 Dec;46(3):213-21.
    PMID: 10624787 DOI: 10.1016/s0168-8227(99)00095-9
    This cross-sectional study looked at the prevalence of microalbuminuria and retinopathy in a cohort of 926 young, Type 1 and Type 2 diabetes mellitus (DM) patients, and determined the factors which were associated with these microvascular complications. The prevalence of microalbuminuria, defined as the albumin:creatinine ratio > or = 2.5 (for males) or > or = 3.5 mg/mmol (for females), was 13.4% in Type 1 DM, 69.5% in insulin-requiring Type 2 DM and 16% in Type 2 DM treated only with oral hypoglycemic agents. Compared to those with normal renal functions, these patients were older (P < or = 0.01), had significantly elevated blood pressures (P < 0.01 or P = 0.0001), and in the case of Type 1 DM, with a higher body mass index (P = 0.0001) and waist-hip ratio (P < 0.01). The prevalence of diabetic retinopathy in Type 1 DM was found to increase with the duration of diabetes, from 1.4% in the newly-onset (< 5 years), to 9.9% in those with 5-10 years disease, to 35% among patients with more than 10 years of diabetes (P < 0.0001). In this study, it was also observed that 10% of the Type 2 DM patients already had retinopathy within 5 years of diagnosis, and the prevalence increased significantly to 42.9% (P < 0.0001) among patients who had been diabetics for more than 10 years. Stepwise multiple regression analysis showed that besides the disease duration, systolic blood pressure was the most common and significant determinant for both microalbuminuria and retinopathy in both types of DM, thus implying that in order to reduce the risk of microvascular complications in diabetes mellitus, systolic and not just the diastolic blood pressure, should be effectively controlled.
  12. Prevalence of glutamic acid decarboxylase antibodies amongst young Malaysian diabetics
    Wan Nazaimoon WM, Faridah I, Singaraveloo M, Ismail IS, Wan Mohamad WB, Letchuman R, et al.
    Diabetes Res Clin Pract, 1999 Jan;43(1):59-66.
    PMID: 10199589 DOI: 10.1016/s0168-8227(98)00108-9
    This study determined the prevalence of glutamic acid decarboxylase antibodies (GAD Ab) in a group of 926 young Malaysian diabetics of three ethnic groups, Malay, Chinese, and Indian. Patients were clinically diagnosed to be Type 1 or Type 2 before the age of 40 years. The overall GAD Ab positivity was 17.4% (161/926), significantly higher in the Type 1 than the Type 2 diabetics (35.5%, 116/329 vs. 7.5%, 45/597, P=0.0001). Compared to GAD Ab negative patients, seropositive diabetics were diagnosed at younger age (21.2+/-0.9 vs. 27.4+/-0.3 y, P=0.0001), had lower fasting (289+/-27.4 vs. 640+/-17.6 pmol/l, P=0.0001) and post-glucagon C-peptide levels (527+/-51.8 vs. 1030+/-28.9 pmol/l, P=0.0001). There were no racial differences in the prevalence of GAD Ab; of the total Type 1, 30.8, 36.4, and 39.4% were Malay, Chinese, and Indian diabetics, respectively and of the total Type 2, 8.8, 8.2, and 4.4% were Malay, Chinese, and Indian diabetics respectively. There was a curvilinear relationship between GAD Ab and the post-glucagon C-peptide levels, suggesting that GAD Ab do play a role in the beta-cells destruction and could be an important immune marker for the LADA group. This study reconfirmed previous reports that the autoimmune mechanisms in the Type 1 Asian diabetics are indeed different from the Caucasians, and further investigations should be carried out to explain the differences.
  13. Steroids from Dysoxylum grande (Meliaceae) leaves
    Wah LK, Abas F, Cordell GA, Ito H, Ismail IS
    Steroids, 2013 Feb;78(2):210-9.
    PMID: 23178158 DOI: 10.1016/j.steroids.2012.09.011
    Seven new 23-oxo-cholestane derivatives named as grandol A (1), B (2), C (3), D (4), E (5), F (6), and G (7) were isolated from Dysoxylum grande leaves alongside with a new 3,4-secodammar-4(28)-en-3-oic acid derivative (8). The structures of the compounds were elucidated based on the interpretation of spectroscopic data, and their relative configurations were established by NOESY 2D NMR data. All of the isolates were tested for anti-acetylcholinesterase activity using thin layer chromatography (TLC)-bioautography with fast blue B salt. Only grandol A (1) and B (2) showed positive results, with clear discoloration at a concentration of 12.5 ppm. However, the obtained IC(50) values for grandol A and B, when using Ellman's method, were not significant (>200 μg/ml).
  14. Fulltext Production and differential activity of recombinant human wild-type G6PD and G6PDViangchan
    Vengidasan L, Yunus MA, Yusoff NM, Yahaya BH, Ismail IS
    Asian Biomed (Res Rev News), 2020 Aug;14(4):159-167.
    PMID: 37551388 DOI: 10.1515/abm-2020-0023
    BACKGROUND: Glucose-6-phosphate dehydrogenase (G6PD) is essential to produce reduced nicotinamide adenine dinucleotide phosphate, which is required to protect cells against oxidative stress. G6PD deficiency is a genetic variation that may lead to hemolysis with potential consequences, such as kidney failure, and patients often experience low quality of life.

    OBJECTIVES: To establish a simple, efficient, and optimized method to produce a G6PDViangchan variant and characterize the phenotypes of recombinant human wild-type G6PD and G6PDViangchan.

    METHODS: G6PD was amplified by polymerase chain reaction (PCR) from a human cDNA plasmid, and the gene for G6PDViangchan was amplified by initiating a mutation at location 871 (G>A) through site-directed mutagenesis. Protein expression and western blotting were conducted after successful cloning. The enzymatic activity of both proteins was assessed spectrophotometrically after purification.

    RESULTS: Both amplicons were successfully cloned into a pET26b(+) expression vector and transformed into Escherichia coli BL21 (DE3) cells for overexpression as C-terminally histidine-tagged recombinant proteins. Western blotting confirmed that both proteins were successfully produced at similar levels. The enzymes were purified by immobilized metal (Co) affinity chromatography. Postpurification assay of enzyme activity revealed about 2-fold differences in the levels of specific activity between the wild-type G6PD (155.88 U/mg) and G6PDViangchan (81.85 U/mg), which is consistent with earlier reports. Analysis in silico showed that the coding change in G6PDViangchan has a substantial effect on protein folding structure.

    CONCLUSIONS: We successfully cloned, expressed, and purified both wild-type G6PD and G6PDViangchan proteins. Such a protocol may be useful for creating a model system to study G6PD deficiency disease.

  15. Fulltext Induction of Apoptosis in MCF-7 Cells via Oxidative Stress Generation, Mitochondria-Dependent and Caspase-Independent Pathway by Ethyl Acetate Extract of Dillenia suffruticosa and Its Chemical Profile
    Tor YS, Yazan LS, Foo JB, Wibowo A, Ismail N, Cheah YK, et al.
    PLoS One, 2015;10(6):e0127441.
    PMID: 26047480 DOI: 10.1371/journal.pone.0127441
    Dillenia suffruticosa, which is locally known as Simpoh air, has been traditionally used to treat cancerous growth. The ethyl acetate extract of D. suffruticosa (EADs) has been shown to induce apoptosis in MCF-7 breast cancer cells in our previous study. The present study aimed to elucidate the molecular mechanisms involved in EADs-induced apoptosis and to identify the major compounds in the extract. EADs was found to promote oxidative stress in MCF-7 cells that led to cell death because the pre-treatment with antioxidants α-tocopherol and ascorbic acid significantly reduced the cytotoxicity of the extract (P<0.05). DCFH-DA assay revealed that treatment with EADs attenuated the generation of intracellular ROS. Apoptosis induced by EADs was not inhibited by the use of caspase-inhibitor Z-VAD-FMK, suggesting that the cell death is caspase-independent. The use of JC-1 dye reflected that EADs caused disruption in the mitochondrial membrane potential. The related molecular pathways involved in EADs-induced apoptosis were determined by GeXP multiplex system and Western blot analysis. EADs is postulated to induce cell cycle arrest that is p53- and p21-dependent based on the upregulated expression of p53 and p21 (P<0.05). The expression of Bax was upregulated with downregulation of Bcl-2 following treatment with EADs. The elevated Bax/Bcl-2 ratio and the depolarization of mitochondrial membrane potential suggest that EADs-induced apoptosis is mitochondria-dependent. The expression of oxidative stress-related AKT, p-AKT, ERK, and p-ERK was downregulated with upregulation of JNK and p-JNK. The data indicate that induction of oxidative-stress related apoptosis by EADs was mediated by inhibition of AKT and ERK, and activation of JNK. The isolation of compounds in EADs was carried out using column chromatography and elucidated using the nuclear resonance magnetic analysis producing a total of six compounds including 3-epimaslinic acid, kaempferol, kaempferide, protocatechuic acid, gallic acid and β-sitosterol-3-O-β-D-glucopyranoside. The cytotoxicity of the isolated compounds was determined using MTT assay. Gallic acid was found to be most cytotoxic against MCF-7 cell line compared to others, with IC50 of 36 ± 1.7 μg/mL (P<0.05). In summary, EADs generated oxidative stress, induced cell cycle arrest and apoptosis in MCF-7 cells by regulating numerous genes and proteins that are involved in the apoptotic signal transduction pathway. Therefore, EADs has the potential to be developed as an anti-cancer agent against breast cancer.
  16. A new coumarin from stem bark of Calophyllum wallichianum
    Tee KH, Ee GCL, Ismail IS, Karunakaran T, Teh SS, Jong VYM, et al.
    Nat Prod Res, 2018 Nov;32(21):2565-2570.
    PMID: 29355031 DOI: 10.1080/14786419.2018.1428588
    A phytochemical study carried out on the plant, Calophyllum wallichianum has led to the isolation of a new coumarin, wallimarin T (1) and a known coumarin, calanolide E (2) along with two common triterpenes, friedelin (3) and stigmasterol (4). The structures of these compounds were elucidated with the aid of spectroscopic analyses such as FT-IR, GC-MS, and NMR. MIC assay against the Bacillus bacteria were conducted on the extracts and this gave MIC values ranging from 0.313 to 1.25 mg/mL. Compound 2 was weakly inhibitory towards the Bacilli strains with MIC values ranging from 0.25-0.50 mg/mL. Wallimarin T (1) was not active towards all four bacteria. Overall, the extracts exhibited weak bactericidal properties whereas compound 2 was not bactericidal on the tested bacteria. The hexane and chloroform extracts of the plant were found to be inhibitors to the growth of Bacillus megaterium, Bacillus cereus, Bacillus pumilus and Bacillus subtilis.
  17. Fulltext Potency of Selected Berries, Grapes, and Citrus Fruit as Neuroprotective Agents
    Tan SJ, Ismail IS
    Evid Based Complement Alternat Med, 2020;2020:3582947.
    PMID: 32565853 DOI: 10.1155/2020/3582947
    A healthy diet should nourish the brain with essential nutrients, including bioactive compounds, for normal brain functioning and to protect it from the negative effects of inflammation and oxidative stress. In this review, a concise summation of the protective effects of selected fruits, namely, berries, grapes, and citrus fruits, against neurological disorder is presented. The focus is on the neuroprotective potential of these fruits against neurodegenerative and mental disorders. The fruits selection was based on the vast reported pharmacological studies on their neuroprotection efficacies. Hence, the respective knowledge and limitations are discussed based on the biological and pharmacological evidence compiled from the previously reported laboratory, epidemiology, and intervention trials.
  18. Gamma-glutamyltransferase, alanine transaminase and aspartate transaminase levels and the diagnosis of gestational diabetes mellitus
    Tan PC, Aziz AZ, Ismail IS, Omar SZ
    Clin Biochem, 2012 Oct;45(15):1192-6.
    PMID: 22659058 DOI: 10.1016/j.clinbiochem.2012.05.025
    OBJECTIVES: To evaluate gamma-glutamyltransferase (GGT), alanine transaminases (ALT) and aspartate transaminases (AST) levels and prevalent gestational diabetes mellitus (GDM).
    DESIGN AND METHODS: Random plasma glucose, GGT, ALT and AST and the 50-g glucose challenge test were done on antenatal women followed by diagnostic 3-point 75-g oral glucose tolerance test within two weeks. GDM was diagnosed by ADA (2011) criteria.
    RESULTS: The GDM rate was 12.2% (319/2610). Mean GGT level was higher in GDM women, 18 ± 12 vs. 16 ± 11 IU/L; P=0.03. The risk for GDM was higher for women in the highest GGT quartile band compared to the lowest: RR 1.35 95%CI 1.0-1.8; P=0.04. However, after adjustment for confounders, GGT was no longer associated with GDM. There was no correlation between ALT and AST levels and GDM.
    CONCLUSIONS: Liver transaminases do not predict GDM in contrast to type 2 diabetes.
  19. Fulltext Rapid Quantification and Validation of Biomarker Scopoletin in Paederia foetida by qNMR and UV-Vis for Herbal Preparation
    Tan DC, Quek A, Kassim NK, Ismail IS, Lee JJ
    Molecules, 2020 Nov 06;25(21).
    PMID: 33171900 DOI: 10.3390/molecules25215162
    Scopoletin has previously been reported as a biomarker for the standardization of Paederia foetida twigs. This study is the first report on the determination and quantification of scopoletin using quantitative nuclear magnetic resonance (qNMR) in the different extracts of Paederia foetida twigs. The validated qNMR method showed a good linearity (r2 = 0.9999), limit of detection (LOD) (0.009 mg/mL), and quantification (LOQ) (0.029 mg/mL), together with high stability (relative standard deviation (RSD) = 0.022%), high precision (RSD < 1%), and good recovery (94.08-108.45%). The quantification results of scopoletin concentration in chloroform extract using qNMR and microplate ultraviolet-visible (UV-vis) spectrophotometer was almost comparable. Therefore, the qNMR method is deemed accurate and reliable for quality control of Paederia foetida and other medicinal plants without extensive sample preparation.
  20. 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.
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