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  1. Fulltext Vulnerability of financial markets in India: The contagious effect of COVID-19
    Rao P, Goyal N, Kumar S, Hassan MK, Shahimi S
    Res Int Bus Finance, 2021 Dec;58:101462.
    PMID: 36540343 DOI: 10.1016/j.ribaf.2021.101462
    This study aims to examine the impact of COVID-19 on financial markets, using emerging market data. Specifically, panel data regression is applied on 3200 observations for daily market returns during lockdown in India. The event study methodology is adopted to show abnormal returns registered in the lockdown period. A contrasting breakdown effect of COVID-19 on various Indian industries has been observed through sectoral analysis. The study also provides empirical evidence for lockdown measures taken by the government on stock market returns and post lockdown impact of COVID-19 on daily market returns for over 6550 observations.
  2. Valsalva haemorrhagic retinopathy after push-ups
    Hassan M, Tajunisah I
    Lancet, 2011 Feb 5;377(9764):504.
    PMID: 21255827 DOI: 10.1016/S0140-6736(10)60677-0
  3. Ultrasound mediated efficient synthesis of new 4-oxoquinazolin-3(4H)-yl)furan-2-carboxamides as potent tyrosinase inhibitors: Mechanistic approach through chemoinformatics and molecular docking studies
    Dige NC, Mahajan PG, Raza H, Hassan M, Vanjare BD, Hong H, et al.
    Bioorg Chem, 2019 11;92:103201.
    PMID: 31445195 DOI: 10.1016/j.bioorg.2019.103201
    We have carried out the synthesis of new 4-oxoquinazolin-3(4H)-yl)furan-2-carboxamide derivatives by the reaction between isatoic anhydride, 2-furoic hydrazide and substituted salicylaldehydes in ethanol: water (5:5 v/v) solvent system using p-TSA as a catalyst under ultrasound irradiation at room temperature. The structures of newly synthesized compounds were confirmed through spectral techniques such as IR, 1H NMR, 13C NMR, and LCMS. The important features of this protocol include simple and easy workup procedure, reaction carried out at ambient temperature, use of ultrasound and high yield of oxoquinazolin-3(4H)-yl)furan-2-carboxamides in short reaction time. The synthesized compounds 4a-4j were screened against tyrosinase enzyme and all these compounds found to be potent inhibitors with much lower IC50 value of 0.028 ± 0.016 to 1.775 ± 0.947 µM than the standard kojic acid (16.832 ± 1.162 µM). The kinetics mechanism for compound 4e was analyzed by Lineweaver-Burk plots which revealed that compound inhibited tyrosinase non-competitively by forming an enzyme-inhibitor complex. Along with this all the synthesized compounds (4a-4j) were scanned for their DPPH free radical scavenging ability. The outputs received through in vitro and in silico analysis are coherent to the each other with good binding energy values (kcal/mol) posed by synthesized ligands.
  4. Fulltext Toxicity and Sublethal Effect of Farnesyl Acetate on Diamondback Moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae)
    Yusoff N, Abd Ghani I, Othman NW, Aizat WM, Hassan M
    Insects, 2021 Jan 27;12(2).
    PMID: 33513706 DOI: 10.3390/insects12020109
    The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is the most important pest of cruciferous vegetables worldwide. In this study, we evaluated the properties of selected farnesyl derivative compounds against P. xylostella. The toxicity and sublethal concentration (LC50) of farnesyl acetate, farnesyl acetone, farnesyl bromide, farnesyl chloride, and hexahydrofarnesyl acetone were investigated for 96 h. The leaf-dip bioassays showed that farnesyl acetate had a high level of toxicity against P. xylostella compared to other tested farnesyl derivatives. The LC50 value was 56.41 mg/L on the second-instar larvae of P. xylostella. Then, the sublethal effects of farnesyl acetate on biological parameters of P. xylostella were assessed. Compared to the control group, the sublethal concentration of farnesyl acetate decreased pupation and emergence rates, pupal weight, fecundity, egg hatching rate, female ratio, and oviposition period. Furthermore, the developmental time of P. xylostella was extended after being exposed to farnesyl acetate. Moreover, the application of farnesyl acetate on P. xylostella induced morphogenetic abnormalities in larval-pupal intermediates, adults that emerged with twisted wings, or complete adults that could not emerge from the cocoon. These results suggested that farnesyl acetate was highly effective against P. xylostella. The sublethal concentration of farnesyl acetate could reduce the population of P. xylostella by increasing abnormal pupal and adults, and by delaying its development period.
  5. Fulltext Towards health monitoring using remote heart rate measurement using digital camera: A feasibility study
    Hassan MA, Malik AS, Fofi D, Karasfi B, Meriaudeau F
    Measurement : journal of the International Measurement Confederation, 2020 Jan;149:106804.
    PMID: 32287815 DOI: 10.1016/j.measurement.2019.07.032
    The paper presents a feasibility study for heart rate measurement using a digital camera to perform health monitoring. The feasibility study investigates the reliability of the state of the art heart rate measuring methods in realistic situations. Therefore, an experiment was designed and carried out on 45 subjects to investigate the effects caused by illumination, motion, skin tone, and distance variance. The experiment was conducted for two main scenarios; human-computer interaction scenario and health monitoring scenario. The human-computer scenario investigated the effects caused by illumination variance, motion variance, and skin tone variance. The health monitoring scenario investigates the feasibility of health monitoring at public spaces (i.e. airports, subways, malls). Five state of the art heart rate measuring methods were re-implemented and tested with the feasibility study database. The results were compared with ground truth to estimate the heart rate measurement error. The heart rate measurement error was analyzed using mean error, standard deviation; root means square error and Pearson correlation coefficient. The findings of this experiment inferred promising results for health monitoring of subjects standing at a distance of 500 cm.
  6. Three new species of Acanthocephala from Acanthogyrus (Acanthosentis) (Acanthocephala: Quadrigyridae) from tinfoil barb fish, Barbonymus schwanenfeldii in Lake Kenyir, Terengganu, Malaysia
    Mohd-Agos S, Mohd-Husin N, Zakariah MI, Yusoff NAH, Wahab W, Jones JB, et al.
    Trop Biomed, 2021 Sep 01;38(3):387-395.
    PMID: 34608112 DOI: 10.47665/tb.38.3.064
    This study was carried out in order to identify acanthocephalan species complexes, based on morphological variability, infecting Barbonymus schwanenfeldii from Lake Kenyir, Terengganu, Malaysia. Acanthocephala were fixed in ethanol, stained with aceto-carmine and studied morphologically by using a light microscope. Variation in morphological traits such as proboscis, proboscis receptacle, egg, testes shape and location, number of hooks and cement gland has been traditionally used to diagnose the acanthocephalans species but the delimitations between closely related species are still confusing and are always questionable among taxonomists. Molecular analysis was used for support the identification. Morphological variability prospecting reveals the presence of three different new species complexes from the subgenus Acanthosentis by referring published taxonomic keys. These new species may be distinguished from the other 46 described species of Acanthosentis by having six unique structures: the presence of an anterior parareceptacle structure (PRS); vaginal sleeve structure; a paired lateral, cone-shaped, muscular jacket surrounding the vagina; alternating pattern and size of proboscis hooks, variation in proboscis size and shape; the presence of the circular collar ring around the neck between the proboscis and trunk and lastly the presence of a muscular-like structure attached to the collar ring on the proboscis. These acanthocephalans found in the intestine of B. schwanenfeldii in Kenyir Lake Malaysia represent new species, named Acanthogyrus ( Acanthosentis) kenyirensis n.sp., A. ( A.) terengganuensis n.sp. and A. ( A.) tembatensis n. sp.
  7. Fulltext Three new pancreatic cancer susceptibility signals identified on chromosomes 1q32.1, 5p15.33 and 8q24.21
    Zhang M, Wang Z, Obazee O, Jia J, Childs EJ, Hoskins J, et al.
    Oncotarget, 2016 Oct 11;7(41):66328-66343.
    PMID: 27579533 DOI: 10.18632/oncotarget.11041
    Genome-wide association studies (GWAS) have identified common pancreatic cancer susceptibility variants at 13 chromosomal loci in individuals of European descent. To identify new susceptibility variants, we performed imputation based on 1000 Genomes (1000G) Project data and association analysis using 5,107 case and 8,845 control subjects from 27 cohort and case-control studies that participated in the PanScan I-III GWAS. This analysis, in combination with a two-staged replication in an additional 6,076 case and 7,555 control subjects from the PANcreatic Disease ReseArch (PANDoRA) and Pancreatic Cancer Case-Control (PanC4) Consortia uncovered 3 new pancreatic cancer risk signals marked by single nucleotide polymorphisms (SNPs) rs2816938 at chromosome 1q32.1 (per allele odds ratio (OR) = 1.20, P = 4.88x10 -15), rs10094872 at 8q24.21 (OR = 1.15, P = 3.22x10 -9) and rs35226131 at 5p15.33 (OR = 0.71, P = 1.70x10 -8). These SNPs represent independent risk variants at previously identified pancreatic cancer risk loci on chr1q32.1 ( NR5A2), chr8q24.21 ( MYC) and chr5p15.33 ( CLPTM1L- TERT) as per analyses conditioned on previously reported susceptibility variants. We assessed expression of candidate genes at the three risk loci in histologically normal ( n = 10) and tumor ( n = 8) derived pancreatic tissue samples and observed a marked reduction of NR5A2 expression (chr1q32.1) in the tumors (fold change -7.6, P = 5.7x10 -8). This finding was validated in a second set of paired ( n = 20) histologically normal and tumor derived pancreatic tissue samples (average fold change for three NR5A2 isoforms -31.3 to -95.7, P = 7.5x10 -4-2.0x10 -3). Our study has identified new susceptibility variants independently conferring pancreatic cancer risk that merit functional follow-up to identify target genes and explain the underlying biology.
  8. The prevalence of gestational diabetes, associated factors and feto-maternal outcome among antenatal women attending health clinics in Terengganu
    Abd Latif R, Yusof NA, Yahya R, Muda Z, Tengku Lih TB, Mohamed K, et al.
    Malays Fam Physician, 2022 Nov 30;17(3):43-52.
    PMID: 36606162 DOI: 10.51866/oal302
    INTRODUCTION: Gestational diabetes mellitus (GDM) is a known risk factor for diabetes mellitus (DM). The rising prevalence of GDM in the Asian population (11.7%) may explain the increasing incidence of DM in women. This study examined the prevalence of GDM, its associated factors and the foeto-maternal outcomes of women with GDM in Terengganu.

    METHOD: A cross-sectional study was conducted between April and September 2019 using secondary data from antenatal records in 40 health clinics in Terengganu for 2018. All pregnant women aged 25 years and above with or without risk factors for GDM were included in the study. Those with pre-existing type 1 or 2 DM were excluded. A total of 270 respondents were included. The prevalence of GDM and its associated factors were determined using descriptive statistics followed by multiple logistic regression.

    RESULTS: The prevalence of GDM in Terengganu was 27.3% (n=72). Logistic regression analysis found that BMI at booking (adjusted OR=4.51, 95% CI 2.13-9.55, p<0.001), history of GDM (adjusted OR=5.31, 95% CI 2.17-12.99, p<0.001) and family history of DM (adjusted OR=4.24, 95% CI 2.23-8.05, p<0.001) were the significant associated risk factors. Of women with GDM, 17.7% (n=11) had postpartum pre-diabetes based on modified oral glucose tolerance at 6 weeks postpartum. Univariate analysis using chi-square tests showed a significant association of neonatal jaundice and hypoglycaemia with GDM.

    CONCLUSION: Because the prevalence of GDM in Terengganu is high, surveillance of GDM in highrisk pregnancies and effective glycaemic management should be emphasised to prevent adverse foeto-maternal outcomes.

  9. The prevalence and intensity of Amblyomma javanense infestation on Malayan pangolins (Manis javanica Desmarest) from Peninsular Malaysia
    Hassan M, Sulaiman MH, Lian CJ
    Acta Trop, 2013 May;126(2):142-5.
    PMID: 23416121 DOI: 10.1016/j.actatropica.2013.02.001
    A parasitological survey of 16 pangolins, confiscated from the Department of Wildlife and Nature Park Peninsular Malaysia (DWNP) at Kelantan and Pulau Pinang, Malaysia was conducted in 2011. Amblyomma javanense (family: Ixodidae) was the only ectoparasite found on the pangolins. The prevalence, intensity and life cycle of A. javanense were observed together with the respective pangolins' age and sex. It was found that 68.8% of the pangolins were infected, and significant difference, χ(2)(1, N=16)=4.02, p=0.05 were observed with males higher in infestation (88.9%) as compared to the females (42.9%). However, the mean intensity was higher on females (72) as compared to males (31.6). In addition, significant difference, χ(2) (2, N=16)=6.73, p=0.05 was recorded between adults and juveniles with juveniles found to be 100% infected as compared to adult (63.6%). Nevertheless, the mean intensity was slightly higher on adults (47) than juveniles (35). Adult ticks were found in higher numbers as compared to the nymph and larvae with number of male ticks higher (236) as compared to the females (53). Similarly, a high significant difference χ(2)(2, N=469)=203.47, p=0.05 was recorded in the composition of the tick's life stages with a higher number of adult ticks (61.6%) followed by nymph (30.3%) and larvae (8.1%). As such, the results of this study revealed a picture of the A. javanense life cycle which is related to the age and gender of the Malayan Pangolin.
  10. The organisation of the Department of Veterinary Services in Malaysia
    Mohd Nor MN, Abu Mustapa AJ, Abu Hassan MA, Chang KW
    Rev. - Off. Int. Epizoot., 2003 Aug;22(2):485-97.
    PMID: 15884584
    The Department of Veterinary Services (DVS) in Malaysia was established in 1888 as an agency to control exotic and domestic animal diseases. Over the years, the structure and functions of the organisation have evolved to meet the growing demand for veterinary services. The responsibilities of the Veterinary Services are enshrined in the Constitution of Malaysia. The current organisation of the DVS is structured to achieve the following objectives:---to prevent, control and eradicate animal and zoonotic diseases--to facilitate the growth and development of a strong animal industry--to ensure that animal products for human consumption are wholesome, clean, safe and suitable to be consumed--to facilitate the growth and development of the animal feed industry--to ensure the welfare and well-being of all animals. To meet these objectives the DVS has nine different divisions, as follows: Planning and Evaluation, Epidemiology and Veterinary Medicine, Veterinary Public Health, Research and Development, Industry Development, Production and Development of Genetic Resources, Human Resource Development (HRD), Enforcement, and Administration. The development of the animal industry is managed through national development policies, including the Third National Agriculture Policy. The basis for current programmes for disease control and animal industry development is the Eighth Development Plan (2001-2005). Over the period of this Plan, Malaysia will address the need for sanitary and phytosanitary measures by developing specific programmes covering all fields of the animal industry. This is just one way in which Malaysia is meeting the challenges of the increased liberalisation of trade created by the World Trade Organization and the Association of Southeast Asian Nations Free Trade Area. The development of the industry is focused on the major commodities, namely, beef, mutton, poultry meat, eggs, pork and milk. Other commodities receive support if it is considered economically viable. All support services are being strengthened, particularly the HRD division. The organisation and functions of the DVS are constantly being reviewed in accordance with changes in the animal industry and the nature of the services in demand.
  11. The nonlinear elastic and viscoelastic passive properties of left ventricular papillary muscle of a guinea pig heart
    Hassan MA, Hamdi M, Noma A
    J Mech Behav Biomed Mater, 2012 Jan;5(1):99-109.
    PMID: 22100084 DOI: 10.1016/j.jmbbm.2011.08.011
    The mechanical behavior of the heart muscle tissues is the central problem in finite element simulation of the heart contraction, excitation propagation and development of an artificial heart. Nonlinear elastic and viscoelastic passive material properties of the left ventricular papillary muscle of a guinea pig heart were determined based on in-vitro precise uniaxial and relaxation tests. The nonlinear elastic behavior was modeled by a hypoelastic model and different hyperelastic strain energy functions such as Ogden and Mooney-Rivlin. Nonlinear least square fitting and constrained optimization were conducted under MATLAB and MSC.MARC in order to obtain the model material parameters. The experimental tensile data was used to get the nonlinear elastic mechanical behavior of the heart muscle. However, stress relaxation data was used to determine the relaxation behavior as well as viscosity of the tissues. Viscohyperelastic behavior was constructed by a multiplicative decomposition of a standard Ogden strain energy function, W, for instantaneous deformation and a relaxation function, R(t), in a Prony series form. The study reveals that hypoelastic and hyperelastic (Ogden) models fit the tissue mechanical behaviors well and can be safely used for heart mechanics simulation. Since the characteristic relaxation time (900 s) of heart muscle tissues is very large compared with the actual time of heart beating cycle (800 ms), the effect of viscosity can be reasonably ignored. The amount and type of experimental data has a strong effect on the Ogden parameters. The in vitro passive mechanical properties are good initial values to start running the biosimulation codes for heart mechanics. However, an optimization algorithm is developed, based on clinical intact heart measurements, to estimate and re-correct the material parameters in order to get the in vivo mechanical properties, needed for very accurate bio-simulation and for the development of new materials for the artificial heart.
  12. The filariasis campaign in Kedah
    HASSAN MY
    Med J Malaya, 1959 Sep;14:36-46.
    PMID: 13851977
  13. The application of a computerised recording system to smallholder dairy extension in Malaysia
    Abu Hassan MA, Kamaruddin MI, Pharo HJ
    Acta Vet Scand Suppl, 1988;84:110-2.
    PMID: 3232593
  14. Fulltext The Relationship amongst Intervertebral Disc Vertical Diameter, Lateral Foramen Diameter and Nerve Root Impingement in Lumbar Vertebra
    Yusof MI, Hassan MN, Abdullah MS
    Malays Orthop J, 2018 Mar;12(1):21-25.
    PMID: 29725508 MyJurnal DOI: 10.5704/MOJ.1803.004
    Introduction: The vertical diameter of the foramen is dependent upon the vertical diameter of the corresponding intervertebral disc. A decrease in disc vertical diameter has direct anatomic consequences to the foraminal diameter and area available for the nerve root passing through it. This study is to establish the relationship amongst the intervertebral disc vertical diameter, lateral foramen diameters and nerve root compression in the lumbar vertebra. Materials and Methods: Measurements of the study parameters were performed using sagittal MRI images. The parameters studied were: intervertebral disc vertical diameter (DVD), foraminal vertical diameter (FVD), foraminal transverse diameter (FTD) and nerve root diameter (NRD) of both sides. The relationship between the measured parameters were then analyzed. Results: A total of 62 MRI images were available for this study. Statistical analysis showed moderate to strong correlation between DVD and FVD at all the lumbar levels except at left L23 and L5S1 and right L3L4 and L4L5. Correlation between DVD and FTD were not significant at all lumbar levels. Regression analysis showed that a decrease of 1mm of DVD was associated with 1.3, 1.7, 3.3, 3.3 and 1.3mm reduction of FVD at L1L2, L2L3, L3L4, L4L5 and L5S1 respectively. Conclusion: Reduction of DVD was associated with reduction of FVD. However, FVD was relatively wide for the nerve root even with complete loss of DVD. FTD was much narrower than the FVD making it more likely to cause nerve root compression at the exit foramina. These anatomical details should be given consideration in treating patients with lateral canal stenosis.
  15. The Gulf Achievement of Cholesterol Targets in Out-Patients Study (GULF ACTION): Design, Rationale, and Preliminary Results
    Albackr HB, Al Waili K, Almahmeed W, Jarallah MA, Amin MI, Alrasadi K, et al.
    Curr Vasc Pharmacol, 2023;21(4):285-292.
    PMID: 37431901 DOI: 10.2174/1570161121666230710145604
    AIM: To assess the current dyslipidemia management in the Arabian Gulf region by describing the demographics, study design, and preliminary results of out-patients who achieved low-density lipoprotein cholesterol (LDL-C) goals at the time of the survey.

    BACKGROUND: The Arabian Gulf population is at high risk for atherosclerotic cardiovascular disease at younger ages. There is no up-to-date study regarding dyslipidemia management in this region, especially given the recent guideline-recommended LDL-C targets.

    OBJECTIVE: Up-to-date comprehensive assessment of the current dyslipidemia management in the Arabian Gulf region, particularly in view of the recent evidence of the additive beneficial effects of ezetimibe and proprotein convertase subtilisin/kexin-9 (PCSK-9) inhibitors on LDL-C levels and cardiovascular outcomes.

    METHODS: The Gulf Achievement of Cholesterol Targets in Out-Patients (GULF ACTION) is an ongoing national observational longitudinal registry of 3000 patients. In this study, adults ≥18 years on lipidlowering drugs for over three months from out-patients of five Gulf countries were enrolled between January 2020 and May 2022 with planned six-month and one-year follow-ups.

    RESULTS: Of the 1015 patients enrolled, 71% were male, aged 57.9±12 years. In addition, 68% had atherosclerotic cardiovascular disease (ASCVD), 25% of these patients achieved the LDL-C target, and 26% of the cohort were treated using combined lipid-lowering drugs, including statins.

    CONCLUSION: The preliminary results of this cohort revealed that only one-fourth of ASCVD patients achieved LDL-C targets. Therefore, GULF ACTION shall improve our understanding of current dyslipidemia management and "guideline gaps" in the Arabian Gulf region.

  16. The Annealing Impact on Properties of CN- 85 Polymer NTD
    Al-Ta'ii HMJ, Rmadhan EJ
    Appl Radiat Isot, 2021 Dec;178:109933.
    PMID: 34537565 DOI: 10.1016/j.apradiso.2021.109933
    Samples of cellulose nitrate polymer (CN-85) were annealed at 100 °C, 120 °C, and 140 °C for 15 min before and after irradiation with alpha particles emitted from a241Am source. Irradiation was performed at room temperature for 5 min. The changes in the optical and structural properties of CN-85 NTD, due to annealing and irradiation, were studied by using ultraviolet-visible spectroscopy (UV-VIS), and Fourier transform infrared spectroscopy (FTIR). Direct and indirect energy gap values, the number of carbon atoms, carbon clusters, and Urbach's energy values were determined. The UV-VIS analysis showed a shift in the absorption edge of the CN-85 polymer toward long wavelengths. The FTIR results revealed the changes in some bonds and the structural decomposition of CN-85 due to irradiation. The direct band gap energy was slightly decreased from 4.13 eV to 4.09 eV when the pristine samples were heated to 140 °C and irradiated. The indirect band gap energy was decreased from 3.9 eV to 3.8 eV under the same conditions. The Urbach's energy values showed a fluctuating rise with increasing annealing temperature for the irradiated and heated samples. When the pristine samples irradiated and heated, the band gap energy is reduced from 4.13 eV to 4.06 eV and from 3.90 eV to 3.84 eV for the direct and indirect transition, respectively. In conclusion, this technique showed promising benefits for a wide range of applications such as optoelectronics and microelectronic devices.
  17. Synthesis, molecular docking, dynamic simulations, kinetic mechanism, cytotoxicity evaluation of N-(substituted-phenyl)-4-{(4-[(E)-3-phenyl-2-propenyl]-1-piperazinyl} butanamides as tyrosinase and melanin inhibitors: In vitro, in vivo and in silico approaches
    Raza H, Abbasi MA, Aziz-Ur-Rehman, Siddiqui SZ, Hassan M, Abbas Q, et al.
    Bioorg Chem, 2020 01;94:103445.
    PMID: 31826809 DOI: 10.1016/j.bioorg.2019.103445
    In the current research work, different N-(substituted-phenyl)-4-{(4-[(E)-3-phenyl-2-propenyl]-1-piperazinyl}butanamides have been synthesized according to the protocol described in scheme 1. The synthesis was initiated by reacting various substituted anilines (1a-e) with 4-chlorobutanoyl chloride (2) in aqueous basic medium to give various electrophiles, 4-chloro-N-(substituted-phenyl)butanamides (3a-e). These electrophiles were then coupled with 1-[(E)-3-phenyl-2-propenyl]piperazine (4) in polar aprotic medium to attain the targeted N-(substituted-phenyl)-4-{(4-[(E)-3-phenyl-2-propenyl]-1-piperazinyl}butanamides (5a-e). The structures of all derivatives were identified and characterized by proton-nuclear magnetic resonance (1H NMR), carbon-nuclear magnetic resonance (13C NMR) and Infra-Red (IR) spectral data along with CHN analysis. The in vitro inhibitory potential of these butanamides was evaluated against Mushroom tyrosinase, whereby all compounds were found to be biologically active. Among them, 5b exhibited highest inhibitory potential with IC50 value of 0.013 ± 0.001 µM. The same compound 5b was also assayed through in vivo approach, and it was explored that it significantly reduced the pigments in zebrafish. The in silico studies were also in agreement with aforesaid results. Moreover, these molecules were profiled for their cytotoxicity through hemolytic activity, and it was found that except 5e, all other compounds showed minimal toxicity. The compound 5a also exhibited comparable results. Hence, some of these compounds might be worthy candidates for the formulation and development of depigmentation drugs with minimum side effects.
  18. Synthesis, in vitro and in silico studies of novel potent urease inhibitors: N-[4-({5-[(3-Un/substituted-anilino-3-oxopropyl)sulfanyl]-1,3,4-oxadiazol-2-yl}methyl)-1,3-thiazol-2-yl]benzamides
    Abbasi MA, Hassan M, Aziz-Ur-Rehman, Siddiqui SZ, Raza H, Shah SAA, et al.
    Bioorg Med Chem, 2018 07 30;26(13):3791-3804.
    PMID: 29903414 DOI: 10.1016/j.bmc.2018.06.005
    The present article describes the synthesis, in vitro urease inhibition and in silico molecular docking studies of a novel series of bi-heterocyclic bi-amides. The synthesis of title compounds was initiated by benzoylation, with benzoyl chloride (1), of the key starter ethyl 2-(2-amino-1,3-thiazol-4-yl)acetate (2) in weak basic aqueous medium followed by hydrazide formation, 4, and cyclization with CS2 to reach the parent bi-heterocyclic nucleophile, N-{4-[(5-sulfanyl-1,3,4-oxadiazol-2-yl)methyl]-1,3-thiazol-2-yl}benzamide (5). Various electrophiles, 8a-l, were synthesized by a two-step process and these were finally coupled with 5 to yield the targeted bi-heterocyclic bi-amide molecules, 9a-l. The structures of the newly synthesized products were corroborated by IR, 1H NMR, 13C NMR, EI-MS and elemental analysis. The in vitro screening of these molecules against urease explored that most of the compounds exhibit potent inhibitory potential against this enzyme. The compound 9j, with IC50 value of 2.58 ± 0.02 µM, exhibited most promising inhibitory activity among the series, relative to standard thiourea having IC50 value of 21.11 ± 0.12 µM. In silico studies fully augmented the experimental enzyme inhibition results. Chemo-informatics analysis showed that synthesized compounds (9a-l) mostly obeyed the Lipinski's rule. Molecular docking study suggested that ligand 9j exhibited good binding energy value (-7.10 kcal/mol) and binds within the active region of target protein. So, on the basis of present investigation, it was inferred that 9j may serve as a novel scaffold for designing more potent urease inhibitors.
  19. Fulltext Synthesis, enzyme inhibitory kinetics mechanism and computational study of N-(4-methoxyphenethyl)-N-(substituted)-4-methylbenzenesulfonamides as novel therapeutic agents for Alzheimer's disease
    Abbasi MA, Hassan M, Aziz-Ur-Rehman, Siddiqui SZ, Shah SAA, Raza H, et al.
    PeerJ, 2018;6:e4962.
    PMID: 29967717 DOI: 10.7717/peerj.4962
    The present study comprises the synthesis of a new series of sulfonamides derived from 4-methoxyphenethylamine (1). The synthesis was initiated by the reaction of 1 with 4-methylbenzenesulfonyl chloride (2) in aqueous sodium carbonate solution at pH 9 to yield N-(4-methoxyphenethyl)-4-methylbenzensulfonamide (3).This parent molecule 3 was subsequently treated with various alkyl/aralkyl halides, (4a-j), using N,N-dimethylformamide (DMF) as solvent and LiH as activator to produce a series of new N-(4-methoxyphenethyl)-N-(substituted)-4-methylbenzenesulfonamides (5a-j). The structural characterization of these derivatives was carried out by spectroscopic techniques like IR, 1H-NMR, and 13C-NMR. The elemental analysis data was also coherent with spectral data of these molecules. The inhibitory effects on acetylcholinesterase and DPPH were evaluated and it was observed that N-(4-Methoxyphenethyl)-4-methyl-N-(2-propyl)benzensulfonamide (5c) showed acetylcholinesterase inhibitory activity 0.075 ± 0.001 (IC50 0.075 ± 0.001 µM) comparable to Neostigmine methylsulfate (IC50 2.038 ± 0.039 µM).The docking studies of synthesized ligands 5a-j were also carried out against acetylcholinesterase (PDBID 4PQE) to compare the binding affinities with IC50 values. The kinetic mechanism analyzed by Lineweaver-Burk plots demonstrated that compound (5c) inhibits the acetylcholinesterase competitively to form an enzyme inhibitor complex. The inhibition constants Ki calculated from Dixon plots for compound (5c) is 2.5 µM. It was also found from kinetic analysis that derivative 5c irreversible enzyme inhibitor complex. It is proposed on the basis of our investigation that title compound 5c may serve as lead structure for the design of more potent acetylcholinesterase inhibitors.
  20. Fulltext Synthesis, Kinetics, Binding Conformations and Structure-activity Relationship of Potent Tyrosinase Inhibitors: Aralkylated 2-aminothiazole-ethyltriazole Hybrids
    Sadiq Butt AR, Abbasi MA, Rehman AU, Siddiqui SZ, Raza H, Hassan M, et al.
    Iran J Pharm Res, 2021;20(2):206-228.
    PMID: 34567157 DOI: 10.22037/ijpr.2020.15521.13145
    Considering the diversified pharmacological importance of thiazole and triazole heterocyclic moieties, a unique series of S-aralkylated bi-heterocyclic hybrids, 7a-l, was synthesized in a convergent manner. The structures of newly synthesized compounds were characterized by 1H-NMR, 13C-NMR, IR, and EI-MS spectral studies. The structure-activity relationship of these compounds was envisaged by analyzing their inhibitory effects against tyrosinase, whereby all these molecules exhibited potent inhibitory potentials relative to the standard used. The Kinetics mechanism was ascertained by Lineweaver-Burk plots, which revealed that 7g inhibited tyrosinase non-competitively by forming an enzyme-inhibitor complex. The inhibition constants Ki calculated from Dixon plots for this compound was 0.0057µM. These bi-heterocyclic molecules also disclosed good binding energy values (kcal /mol) when assessed computationally. So, these molecules can be considered promising medicinal scaffolds for the treatment of skin disorders.
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