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Fulltext 2-[4-Acetyl-5-(biphenyl-4-yl)-4,5-dihydro-1,3,4-oxadiazol-2-yl]phenyl acetate

Yehye WA, Ariffin A, Rahman NA, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2010 Mar 20;66(Pt 4):o878.

PMID: 21580697 DOI: 10.1107/S1600536810009621

In the title mol-ecule, C(24)H(20)N(2)O(4), the five-membered oxadiazole ring is nearly planar (r.m.s. deviation = 0.053 Å) and the phenyl ring of the biphenyl unit attached to it forms a dihedral angle of 73.2 (1)°; the other phenyl ring is close to coplanar with the oxadiazole ring [dihedral angle = 6.2 (2)°].

Fulltext 2-Sulfanyl-idene-1,2-dihydro-pyridine-3-carbohydrazide

Mansor S, Yehye WA, Ariffin A, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 10):o2516.

PMID: 21587510 DOI: 10.1107/S160053681003521X

All non-H atoms of the title compound, C(6)H(7)N(3)OS, which exists in the thione form, lie in a common plane (r.m.s. of non-H atoms = 0.08 Å). The amino group of the -NH-NH(2) substituent forms an intra-molecular hydrogen bond to the S atom. The terminal -NH(2) group is pyramidally coordinated; it forms a weak N-H⋯O and a weak N-H⋯S hydrogen bond. Furthermore, the N atom is an acceptor for a C-H⋯N contact. The amino group of the ring is a hydrogen-bond donor to the carbonyl O atom of an adjacent mol-ecule, this inter-action giving rise to a linear chain motif running along the b axis.

Fulltext N'-[(Biphenyl-4-yl)methyl-ene]-2-[(3,5-di-tert-butyl-4-hydroxy-benz-yl)sulfan-yl]acetohydrazide

Yehye WA, Ariffin A, Rahman NA, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2010;66(Pt 4):o734.

PMID: 21580580 DOI: 10.1107/S1600536810006884

In the title compound, C(30)H(36)N(2)O(2)S, the dihedral angle between the two aromatic rings of the biphenyl residue is 31.2 (1)°. The two methyl-ene C atoms subtend an angle of 99.9 (1)° at the S atom. In the crystal, mol-ecules form inversion dimers linked by pairs of N-H⋯O hydrogen bonds. The hydroxyl group is shielded by the tert-butyl residues and is therefore not involved in any hydrogen bonding.

Fulltext Dipyridinium 2,2'-dithio-dinicotinate

Yehye WA, Ariffin A, Rahman NA, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 5):o1068.

PMID: 21583884 DOI: 10.1107/S1600536809013543

The dianion of the title salt, 2C(5)H(6)N(+)·C(12)H(6)N(2)O(4)S(2) (2-), lies on a special position of 2 site symmetry that relates one thio-nicotinate part to the other, and the dihedral angle between the niotinate planes is 89.2 (2)°. The pyridinium cations are hydrogen bonded to the carboxyl-ate group by way of N-H⋯O links.

Fulltext 2-[(3,5-Di-tert-butyl-4-hydroxy-benz-yl)-sulfan-yl]-N'-isopropyl-ideneaceto-hydrazide

Yehye WA, Ariffin A, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 4):o730.

PMID: 21582464 DOI: 10.1107/S1600536809007843

The title compound, C(20)H(32)N(2)O(2)S, the condensation product of a thio-acetohydrazine and acetone, has a two-coordinate S atom and the angle at this atom is 100.7 (1)°. The (CH(3))C=N-NH-C(O)- substituent engages in N-H⋯O hydrogen-bonding inter-actions with the substituent of an adjacent mol-ecule across a center of inversion, generating a dimeric structure.

Fulltext 2-(3,5-Di-tert-butyl-4-hydroxy-benzyl-sulfan-yl)-N'-(3-methoxy-benzyl-idene)acetohydrazide

Yehye WA, Ariffin A, Rahman NA, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2009;65(Pt 9):o2112.

PMID: 21577527 DOI: 10.1107/S1600536809030645

The title compound, C(25)H(34)N(2)O(3)S, is a derivative of N'-benzyl-ideneacetohydrazide having substituents on the acetyl and benzylidenyl parts, and displays a planar C(carbon-yl)-NH-NC(anis-yl) fragment [torsion angle = 174.9 (3)°]. The -NH- unit forms an N-H⋯O hydrogen bond with the carbonyl O atom of an inversion-related mol-ecule.

Fulltext Biphenyl-4-carbaldehyde azine

Yehye WA, Ariffin A, Rahman NA, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 12):o2444.

PMID: 21581412 DOI: 10.1107/S1600536808038622

The complete mol-ecule of the title compound, C(26)H(20)N(2), is generated by crystallographic inversion symmetry. The terminal phenyl ring is twisted by 19.2 (1)° with respect to the adjacent phenyl-ene ring.

Fulltext N'-(3-Bromo-5-chloro-2-hydroxy-benzyl-idine)-2-hydroxy-benzohydrazide

Yehye WA, Ariffin A, Rahman NA, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 12):o2438.

PMID: 21581406 DOI: 10.1107/S1600536808038634

In the approximately planar title mol-ecule, C(14)H(10)BrClN(3)O(2), the dihedral angle between the aromatic ring planes is 5.79 (12)°. The conformation is stabilized by intra-molecular O-H⋯N and N-H⋯O hydrogen bonds and an inter-molecular O-H⋯O link leads to chains in the crystal propagating in [001].

Fulltext N'-(3,5-Di-tert-butyl-4-hydroxy-benzyl-idene)-2-hydroxy-benzohydrazide methanol solvate

Yehye WA, Ariffin A, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 8):o1452.

PMID: 21203167 DOI: 10.1107/S1600536808020746

The asymmetric unit of the title compound, C(22)H(28)N(2)O(3)·CH(4)O, consists of two independent Schiff base mol-ecules and two independent methanol solvent mol-ecules. In one Schiff base mol-ecule, the 2-hydr-oxy group forms an intra-molecular hydrogen bond with the amide O atom, whereas in the other Schiff base mol-ecule, the 2-hydr-oxy-substituted benzene ring is oriented so that the 2-hydr-oxy group serves as hydrogen-bond acceptor for the amide NH group. In the crystal structure, Schiff base mol-ecules inter-act with methanol solvent to furnish a hydrogen-bonded chain.

Fulltext 2-(3,5-Di-tert-butyl-4-hydroxy-benzyl-sulfan-yl)nicotinic acid

Mansor S, Yehye WA, Ariffin A, Rahman NA, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 9):o1778.

PMID: 21201758 DOI: 10.1107/S1600536808026056

Two mol-ecules of the title compound, C(21)H(27)NO(3)S, are disposed about a center of inversion, generating an O-H⋯O hydrogen-bonded dimer.

Fulltext Di-n-butyl-ammonium 2-(3,5-di-tert-butyl-4-hydroxy-benzyl-sulfan-yl)nicotinate

Mansor S, Yehye WA, Ariffin A, Rahman NA, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 9):o1799.

PMID: 21201778 DOI: 10.1107/S1600536808026202

The asymmetric unit of the title compound, C(8)H(20)N(+)·C(21)H(26)NO(3)S(-), contains two indpendent ion pairs which are disposed about a psuedo-inversion center, generating an ammonium-carboxylate N-H⋯O hydrogen-bonded four-component cluster. In the crystal structure, adjacent clusters are linked by hydr-oxy-carboxylate O-H⋯O hydrogen bonds, forming a chain.

Fulltext (2,4-Dimethoxy-benzyl-idene)-2-hydroxy-benzohydrazide ethanol solvate

Yehye WA, Ariffin A, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2008 May 03;64(Pt 6):o961.

PMID: 21202691 DOI: 10.1107/S1600536808011768

In the planar title mol-ecule, C(16)H(16)N(2)O(4)·C(2)H(6)O, the planar Schiff base molecule is linked to the ethanol solvent mol-ecule by a hydr-oxy-amide hydrogen bond. The hydr-oxy group of the ethanol mol-ecule is a hydrogen-bond donor to the double-bonded N atom of an adjacent Sciff base, pairs of interactions taking place across a center of symmetry and giving rise to a hydrogen-bonded dimer.

Fulltext 2-Hydr-oxy-(2-methyl-1H-indol-3-ylmethyl-idene)benzohydrazide ethanol solvate

Yehye WA, Ariffin A, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2008;64(Pt 6):o960.

PMID: 21202690 DOI: 10.1107/S1600536808011756

In the title compound, C(17)H(15)N(3)O(2)·C(2)H(6)O, Schiff base molecules are linked by a hydr-oxy-amido hydrogen bond into a helical chain running along the b axis. This chain is consolidated by two other hydrogen bonds; the ethanol solvent mol-ecule is a hydrogen-bond donor to the amide group and a hydrogen-bond acceptor for the indolyl NH group of an adjacent Schiff base mol-ecule.

Fulltext N-Acetyl-2-hydroxy-N'-[methoxy(1-methylindol-2-yl)methyl]benzohydrazide

Yehye WA, Rahman NA, Ariffin A, Ng SW

Acta Crystallogr Sect E Struct Rep Online, 2008 Aug 23;64(Pt 9):o1824.

PMID: 21201799 DOI: 10.1107/S1600536808026846

In the crystal structure of the title Schiff-base, C(20)H(21)N(3)O(4), the amino group forms an N-H⋯O hydrogen bond to the acetyl group of an adjacent mol-ecule, forming a zigzag chain. The 2-hydr-oxy group is inter-nally hydrogen bonded to the amido group though an O-H⋯O hydrogen bond.

Antioxidant, cytotoxic activities, and structure-activity relationship of gallic acid-based indole derivatives

Khaledi H, Alhadi AA, Yehye WA, Ali HM, Abdulla MA, Hassandarvish P

Arch Pharm (Weinheim), 2011 Nov;344(11):703-9.

PMID: 21953995 DOI: 10.1002/ardp.201000223

A new series of gallic hydrazones containing an indole moiety was synthesized through the reaction of gallic hydrazide and different indole carboxaldehydes. Their antioxidant activities were determined on DPPH radical scavenging and inhibition of lipid peroxidation. The in-vitro cytotoxic activities of the compounds were evaluated against HCT-116 (human colon cancer cell line) and MCF-7 (estrogen-dependent human breast cancer cell line) by the MTT method. An attempt to correlate the biological results with their structural characteristics has been done. A limited positive structure activity relationship was found between cytotoxic and antioxidant activities.

Fulltext Discovery of potential anti-infectives against Staphylococcus aureus using a Caenorhabditis elegans infection model

Kong C, Yehye WA, Abd Rahman N, Tan MW, Nathan S

BMC Complement Altern Med, 2014;14:4.

PMID: 24393217 DOI: 10.1186/1472-6882-14-4

The limited antibiotic options for effective control of methicillin-resistant Staphylococcus aureus infections has led to calls for new therapeutic approaches to combat this human pathogen. An alternative approach to control MRSA is through the use of anti-infective agents that selectively disrupt virulence-mediated pathways without affecting microbial cell viability or by modulating the host natural immune defenses to combat the pathogen.

Fulltext PASS-predicted Vitex negundo activity: antioxidant and antiproliferative properties on human hepatoma cells--an in vitro study

Kadir FA, Kassim NM, Abdulla MA, Yehye WA

BMC Complement Altern Med, 2013;13:343.

PMID: 24305067 DOI: 10.1186/1472-6882-13-343

Hepatocellular carcinoma is a common type of tumour worldwide with a high mortality rate and with low response to current cytotoxic and chemotherapeutic drugs. The prediction of activity spectra for the substances (PASS) software, which predicted that more than 300 pharmacological effects, biological and biochemical mechanisms based on the structural formula of the substance was efficiently used in this study to reveal new multitalented actions for Vitex negundo (VN) constituents.

Fulltext Effect of oral administration of ethanolic extract of Vitex negundo on thioacetamide-induced nephrotoxicity in rats

Kadir FA, Kassim NM, Abdulla MA, Yehye WA

BMC Complement Altern Med, 2013 Oct 30;13:294.

PMID: 24499255 DOI: 10.1186/1472-6882-13-294

BACKGROUND: Oxidative stress due to abnormal induction of reactive oxygen species (ROS) molecules is believed to be involved in the etiology of many diseases. Evidences suggest that ROS is involved in nephrotoxicity through frequent exposure to industrial toxic agents such as thioacetamide (TAA). The current investigation was designed to explore the possible protective effects of the leaves of Vitex negundo(VN) extract against TAA-induced nephrotoxicity in rats.

METHODS: Twenty four Sprague Dawleyrats were divided into four groups: (A) Normal control, (B) TAA (0.03% w/v in drinking water), (C) VN100 (VN 100 mg/kg + TAA) and (D) VN300 (VN 300 mg/kg + TAA). Blood urea and serum creatinine levels were measured,supraoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) levels of renal tissue were assayed. Histopathological analysis together with the oxidative stress nicotinamide adenine dinucleotide phosphate (NADPH) oxidase p22phox in kidney sections were examined in all experimental groups.

RESULTS: Blood urea and serum creatinine levels were increased in TAA group as a result of the nephrotoxicity compared to the VN100 and VN300 groups where, the levels were significantly decreased (p

Graphene oxide and gold nanoparticle based dual platform with short DNA probe for the PCR free DNA biosensing using surface-enhanced Raman scattering

Khalil I, Yehye WA, Julkapli NM, Rahmati S, Sina AA, Basirun WJ, et al.

Biosens Bioelectron, 2019 Apr 15;131:214-223.

PMID: 30844598 DOI: 10.1016/j.bios.2019.02.028

Surface-enhanced Raman scattering (SERS) based DNA biosensors have considered as excellent, fast and ultrasensitive sensing technique which relies on the fingerprinting ability to produce molecule specific distinct spectra. Unlike conventional fluorescence based strategies SERS provides narrow spectral bandwidths, fluorescence quenching and multiplexing ability, and fitting attribute with short length probe DNA sequences. Herein, we report a novel and PCR free SERS based DNA detection strategy involving dual platforms and short DNA probes for the detection of endangered species, Malayan box turtle (MBT) (Cuora amboinensis). In this biosensing feature, the detection is based on the covalent linking of the two platforms involving graphene oxide-gold nanoparticles (GO-AuNPs) functionalized with capture probe 1 and gold nanoparticles (AuNPs) modified with capture probe 2 and Raman dye (Cy3) via hybridization with the corresponding target sequences. Coupling of the two platforms generates locally enhanced electromagnetic field 'hot spot', formed at the junctions and interstitial crevices of the nanostructures and consequently provide significant amplification of the SERS signal. Therefore, employing the two SERS active substrates and short-length probe DNA sequences, we have managed to improve the sensitivity of the biosensors to achieve a lowest limit of detection (LOD) as low as 10 fM. Furthermore, the fabricated biosensor exhibited sensitivity even for single nucleotide base-mismatch in the target DNA as well as showed excellent performance to discriminate closely related six non-target DNA sequences. Although the developed SERS biosensor would be an attractive platform for the authentication of MBT from diverse samples including forensic and/or archaeological specimens, it could have universal application for detecting gene specific biomarkers for many diseases including cancer.

PASS-assisted design, synthesis and antioxidant evaluation of new butylated hydroxytoluene derivatives

Ariffin A, Rahman NA, Yehye WA, Alhadi AA, Kadir FA

Eur J Med Chem, 2014 Nov 24;87:564-77.

PMID: 25299680 DOI: 10.1016/j.ejmech.2014.10.001

New multipotent antioxidants (MPAOs), namely 1,3,4-thiadiazoles and 1,2,4-triazoles bearing the well-known free radical scavenger butylated hydroxytoluene (BHT), were designed and synthesized using an acid-(base-) catalyzed intramolecular dehydrative cyclization reaction of the corresponding 1-acylthiosemicarbazides. The structure-activity relationship (SAR) of the designed antioxidants was performed along with the prediction of activity spectra for substances (PASS) training set. Experimental studies based on antioxidant activity using DPPH and lipid peroxidation assays verified the predictions obtained by the PASS-assisted design strategy. Compounds 4a-b, 5a-b and 6a-b showed an inhibition of stable DPPH free radicals at a 10(-4) M more than the well-known standard antioxidant BHT. Compounds with p-methoxy substituents (4b, 5b and 6b) were more active than o-methoxy substituents (4a, 5a and 6a). With an IC50 of 2.85 ± 1.09 μM, compound 6b exhibited the most promising in vitro inhibition of lipid peroxidation, inhibiting Fe(2+)-induced lipid peroxidation of essential oils derived from the egg yolk-based lipid-rich medium by 86.4%. The parameters for the drug-likeness of these BHT derivatives were also evaluated according to Lipinski's 'rule-of-five'. All of the BHT derivatives were found to violate one of Lipinski's parameters (Log P ≥ 5) even though they have been found to be soluble in protic solvents. The predictive TPSA and %ABS data allow for the conclusion that these compounds could have a good capacity for penetrating cell membranes. Therefore, these novel MPAOs containing lipophilic and hydrophilic groups can be proposed as potential antioxidants for tackling oxidative stress and lipid peroxidation processes.

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