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Efficient heterogeneous catalytic hydrogenation of acetone to isopropanol on semihollow and porous palladium nanocatalyst

Balouch A, Ali Umar A, Shah AA, Mat Salleh M, Oyama M

ACS Appl Mater Interfaces, 2013 Oct 9;5(19):9843-9.
PMID: 24025235 DOI: 10.1021/am403087m

Highly efficient and remarkable selective acetone conversion to isopropanol has been achieved via a heterogeneous catalytic hydrogenation of acetone by NaBH4 in the presence of semihollow palladium nanoparticles (PdNPs) grown on ITO substrate. PdNPs with high surface defect grown on an indium tin oxide (ITO) surface were prepared via a simple immersion of the substrate into a solution containing K2PdCl6, sodium dodecyl sulphate (SDS), and formic acid for 2 h at room temperature. The sample showed remarkably high heterogeneous catalytic efficiency by producing 99.8% of isopropanol within 6 min using only 0.28 μg of PdNPs on the ITO surface. The present system exhibits heterogenenous catalytic hydrogenation efficiency 1 × 10(6) time higher than using the conventional Raney Ni system.
Removal of organochlorine pesticides using zerovalent iron supported on biochar nanocomposite from Nephelium lappaceum (Rambutan) fruit peel waste

Batool S, Shah AA, Abu Bakar AF, Maah MJ, Abu Bakar NK

Chemosphere, 2022 Feb;289:133011.
PMID: 34863732 DOI: 10.1016/j.chemosphere.2021.133011

Unique zerovalent iron (Fe0) supported on biochar nanocomposite (Fe0-BRtP) was synthesized from Nephelium lappaceum (Rambutan) fruit peel waste and were applied for the simultaneous removal of 6 selected organochlorine pesticides (OCPs) from aqueous medium. During facile synthesis of Fe0-BRtP, Rambutan peel extract was used as the green reducing mediator to reduce Fe2+ to zerovalent iron (Fe0), instead of toxic sodium borohydride which were used for chemical synthesis. For comparison, chemically synthesized Fe0-BChe nanocomposite was also prepared in this work. Characterization study confirmed the successful synthesis and dispersion of Fe0 nanoparticles on biochar surface. Batch experiments revealed that Fe0-BRtP and Fe0-BChe nanocomposites combine the advantage of adsorption and dechlorination of OCPs in aqueous medium and up to 96-99% and 83-91% removal was obtained within 120 and 150 min, respectively at initial pH 4. Nevertheless, the reactivity of Fe0-BChe nanocomposite decreased 2 folds after being aged in air for one month, whilst Fe0-BRtP almost remained the same. Adsorption isotherm of OCPs were fitted well to Langmuir isotherm and then to Freundlich isotherm. The experimental kinetic data were fitted first to pseudo-second-order adsorption kinetic model and then to pseudo-first-order reduction kinetic model. The adsorption mechanism involves π-π electron-donor-acceptor interaction and adsorption is facilitated by the hydrophobic sorption and pore filling. After being reused five times, the removal efficiency of regenerated Fe0-BChe and Fe0-BRtP was 5-13% and 89-92%, respectively. The application of this Fe0-BRtP nanocomposite could represent a green and low-cost potential material for adsorption and subsequent reduction of OCPs in aquatic system.
Fulltext Solution Processed PVB/Mica Flake Coatings for the Encapsulation of Organic Solar Cells

Channa IA, Chandio AD, Rizwan M, Shah AA, Bhatti J, Shah AK, et al.

Materials (Basel), 2021 May 12;14(10).
PMID: 34065936 DOI: 10.3390/ma14102496

Organic photovoltaics (OPVs) die due to their interactions with environmental gases, i.e., moisture and oxygen, the latter being the most dangerous, especially under illumination, due to the fact that most of the active layers used in OPVs are extremely sensitive to oxygen. In this work we demonstrate solution-based effective barrier coatings based on composite of poly(vinyl butyral) (PVB) and mica flakes for the protection of poly (3-hexylthiophene) (P3HT)-based organic solar cells (OSCs) against photobleaching under illumination conditions. In the first step we developed a protective layer with cost effective and environmentally friendly methods and optimized its properties in terms of transparency, barrier improvement factor, and bendability. The developed protective layer maintained a high transparency in the visible region and improved oxygen and moisture barrier quality by the factor of ~7. The resultant protective layers showed ultra-flexibility, as no significant degradation in protective characteristics were observed after 10 K bending cycles. In the second step, a PVB/mica composite layer was applied on top of the P3HT film and subjected to photo-degradation. The P3HT films coated with PVB/mica composite showed improved stability under constant light irradiation and exhibited a loss of <20% of the initial optical density over the period of 150 h. Finally, optimized barrier layers were used as encapsulation for organic solar cell (OSC) devices. The lifetime results confirmed that the stability of the OSCs was extended from few hours to over 240 h in a sun test (65 °C, ambient RH%) which corresponds to an enhanced lifetime by a factor of 9 compared to devices encapsulated with pristine PVB.
Cytotoxicity of Anchusa arvensis Against HepG-2 Cell Lines: Mechanistic and Computational Approaches

Hussain S, Ullah F, Sadiq A, Ayaz M, Shah AA, Ali Shah SA, et al.

Curr Top Med Chem, 2019;19(30):2805-2813.
PMID: 31702502 DOI: 10.2174/1568026619666191105103801

BACKGROUND: Liver cancer is a devastating cancer with increasing incidence and mortality rates worldwide. Plants possess numerous therapeutic properties, therefore the search for novel, naturally occurring cytotoxic compounds is urgently needed.
METHODS: The anticancer activity of plant extracts and isolated compounds from Anchusa arvensis (A. arvensis) were studied against the cell culture of HepG-2 (human hepatocellular carcinoma cell lines) using 3-(4,5-Dimethylthiazol-yl)-diphenyl tetrazoliumbromide (MTT) assay. Apoptosis was investigated by performing Acridine orange -ethidium bromide staining, styox green assay and DNA interaction study. We also used tools for computational chemistry studies of isolated compounds with the tyrosine kinase.
RESULTS: In MTT assay, the crude extract caused a significant cytotoxic effect with IC50 of 34.14 ± 0.9 μg/ml against HepG-2 cell lines. Upon fractionation, chloroform fraction (Aa.Chm) exhibited the highest antiproliferative activity with IC50 6.55 ± 1.2 μg/ml followed by ethyl acetate (Aa.Et) fraction (IC50, 24.59 ± 0.85 μg/ml) and n-hexane (Aa.Hex) fraction (IC50 29.53 ± 1.5μg/ml). However, the aqueous (Aa.Aq) fraction did not show any anti-proliferative activity. Bioactivity-guided isolation led to the isolation of two compounds which were characterized as para-methoxycatechol (1) and decane (2) through various spectroscopic techniques. Against HepG-2 cells, compound 1 showed marked potency with IC50 6.03 ± 0.75 μg/ml followed by 2 with IC50 18.52 ± 1.9 μg/ml. DMSO was used as a negative control and doxorubicin as a reference standard (IC50 1.3 ± 0.21 μg/ml). It was observed that compounds 1-2 caused apoptotic cell death evaluated by Acridine orange -ethidium bromide staining, styox green assay and DNA interaction study, therefore both compounds were tested for molecular docking studies against tyrosine kinase to support cytotoxic activity.
CONCLUSION: This study revealed that the plant extracts and isolated compounds possess promising antiproliferative activity against HepG-2 cell lines via apoptotic cell death.
Synthesis, in vitro biological screening and docking study of benzo[d]oxazole bis Schiff base derivatives as a potent anti-Alzheimer agent

Taha M, Rahim F, Zaman K, Anouar EH, Uddin N, Nawaz F, et al.

J Biomol Struct Dyn, 2023 Mar;41(5):1649-1664.
PMID: 34989316 DOI: 10.1080/07391102.2021.2023640

We have synthesized benzo[d]oxazole derivatives (1-21) through a multistep reaction. Alteration in the structure of derivatives was brought in the last step via using various substituted aromatic aldehydes. In search of an anti-Alzheimer agent, all derivatives were evaluated against acetylcholinesterase and butyrylcholinesterase enzyme under positive control of standard drug donepezil (IC50 = 0.016 ± 0.12 and 4.5 ± 0.11 µM) respectively. In case of acetylcholinesterase enzyme inhibition, derivatives 8, 9 and 18 (IC50 = 0.50 ± 0.01, 0.90 ± 0.05 and 0.3 ± 0.05 µM) showed very promising inhibitory potentials. While in case of butyrylcholinesterase enzyme inhibition, most of the derivatives like 6, 8, 9, 13, 15, 18 and 19 (IC50 = 2.70 ± 0.10, 2.60 ± 0.10, 2.20 ± 0.10, 4.25 ± 0.10, 3.30 ± 0.10, 0.96 ± 0.05 and 3.20 ± 0.10 µM) displayed better inhibitory potential than donepezil. Moreover, derivative 18 is the most potent one among the series in both inhibitions. The binding interaction of derivatives with the active gorge of the enzyme was confirmed via a docking study. Furthermore, the binding interaction between derivatives and the active site of enzymes was correlated through the SAR study. Structures of all derivatives were confirmed through spectroscopic techniques such as 1H-NMR, 13C-NMR and HREI-MS, respectively.Communicated by Ramaswamy H. Sarma.