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Norditerpenoid alkaloids of Delphinium denudatum as cholinesterase inhibitors

Ahmad H, Ahmad S, Ali M, Latif A, Shah SAA, Naz H, et al.

Bioorg Chem, 2018 08;78:427-435.
PMID: 29698893 DOI: 10.1016/j.bioorg.2018.04.008

Three new norditerpenoids alkaloids, 1β-hydroxy,14β-acetyl condelphine (1), jadwarine-A (2), jadwarine-B (3) along with two known alkaloids isotalatizidine hydrate (4) and dihydropentagynine (5) were isolated from medicinal plant Delphinium denudatum. The structures of natural products 1-5 were established on the basis of HR-EIMS, 1H and 13C NMR (1D & 2D) spectroscopic data as well as by comparison from literature data. The structures of compound 1 and 4 were also confirmed by single crystal X-ray diffraction studies. In-vitro AChE and BChE enzyme inhibitory activities of compounds 1-5 and molecular docking studies were performed to investigate the possible molecular inhibitory mechanism of the isolated natural products. Compound 2, 4 and 5 showed competitive inhibitory effects by inhibiting AChE and BChE, respectively, while 1 and 3 showed non-competitive inhibition. This work is the first report that provides a supporting evidence about the use of constituents of Delphinium denudatum in cerebral dementia and Alzheimer diseases.
2-{[5-(Substituted-phenyl)-1,3,4-oxadiazol-2-yl]sulfanyl}-N-(1,3-thiazol-2-yl)acetamides: New bi-heterocycles as possible therapeutic agents

Ramzan MS, Abbasi MA, Rehman A, Siddiqui SZ, Shah SAA, Ashraf M, et al.

Pak J Pharm Sci, 2018 May;31(3(Supplementary)):1051-1059.
PMID: 29731443

An electrophile, N-(1,3-thiazol-2-yl)-2-bromoacetamide (3), was synthesized by the reaction of 1,3-thiazole-2-amine (1) and 2-bromoethanoyl bromide (2) in an aqueous medium. A series of carboxylic acids, 7a-j, were converted into 1,3,4-oxadiazole heterocyclic core, through a series of three steps. The final compounds, 8a-j, were synthesized by stirring 7a-j and 3 in an aprotic polar solvent. The structural elucidation of the synthesized compounds was supported by IR, EI-MS, 1H-NMR, and 13C-NMR spectral data. Title compounds were evaluated for enzyme inhibition against cholinesterases and α-glucosidase enzymes and their cytotoxic behavior was monitored using brine shrimp assay. The enzyme inhibitor potential of compounds was supported by molecular docking studies.
Conventional versus microwave assisted synthesis, molecular docking and enzyme inhibitory activities of new 3,4,5-trisubstituted-1,2,4-triazole analogues

Virk NA, Rehman A, Abbasi MA, Siddiqui SZ, Rashid U, Iqbal J, et al.

Pak J Pharm Sci, 2018 Jul;31(4(Supplementary)):1501-1510.
PMID: 30058542

N-(Substituted)-5-(1-(4-methoxyphenylsulfonyl)piperidin-4-yl)-4H-1,2,4-triazol-3-ylthio) acetamide were synthesized by following conventional as well as microwave assisted protocol through five consecutive steps under the impact of various reaction conditions to control the reaction time and the yield of product. Starting from 4-methoxybenzenesulfonyl chloride and ethyl isonipecotate, product 3 was obtained which was converted into product 4 by treating with hydrazine hydrate. In step 3, the product 4 was refluxed with methyl isothiocyanate and KOH to yield compound 5 which was finally treated with variety of N-substituted acetamides to yield an array of different new compounds (8a-k). These synthesized compounds were evaluated for their inhibition potential against bovine carbonic anhydrase (bCA-II), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Compound 8g demonstrated good activity against bCA-II, AChE and BChE with IC50 values of 8.69 ± 0.38 μM, 11.87±0.19 μM and 26.01±0.55 μM respectively. SAR studies assisted with molecular docking were carried out to explore the mode of binding of the compounds against the studied enzymes.
Synthesis, Antioxidant and In-Silico Studies of Potent Urease Inhibitors: N-(4-{[(4-Methoxyphenethyl)-(substituted)amino]sulfonyl}phenyl)acetamides

Abbasi MA, Raza H, Rehman AU, Siddiqui SZ, Nazir M, Mumtaz A, et al.

Drug Res (Stuttg), 2019 Feb;69(2):111-120.
PMID: 30086567 DOI: 10.1055/a-0654-5074

In this study, a new series of sulfonamides derivatives was synthesized and their inhibitory effects on DPPH and jack bean urease were evaluated. The in silico studies were also applied to ascertain the interactions of these molecules with active site of the enzyme. Synthesis was initiated by the nucleophilic substitution reaction of 2-(4-methoxyphenyl)-1-ethanamine (1: ) with 4-(acetylamino)benzenesulfonyl chloride (2): in aqueous sodium carbonate at pH 9. Precipitates collected were washed and dried to obtain the parent molecule, N-(4-{[(4-methoxyphenethyl)amino]sulfonyl}phenyl)acetamide (3): . Then, this parent was reacted with different alkyl/aralkyl halides, (4A-M: ), using dimethylformamide (DMF) as solvent and LiH as an activator to produce a series of new N-(4-{[(4-methoxyphenethyl)-(substituted)amino]sulfonyl}phenyl)acetamides (5A-M: ). All the synthesized compounds were characterized by IR, EI-MS, 1H-NMR, 13C-NMR and CHN analysis data. All of the synthesized compounds showed higher urease inhibitory activity than the standard thiourea. The compound 5 F: exhibited very excellent enzyme inhibitory activity with IC50 value of 0.0171±0.0070 µM relative to standard thiourea having IC50 value of 4.7455±0.0546 µM. Molecular docking studies suggested that ligands have good binding energy values and bind within the active region of taget protein. Chemo-informatics properties were evaluated by computational approaches and it was found that synthesized compounds mostly obeyed the Lipinski' rule.
2-Furoic piperazide derivatives as promising drug candidates of type 2 diabetes and Alzheimer's diseases: In vitro and in silico studies

Abbasi MA, Hassan M, Ur-Rehman A, Siddiqui SZ, Hussain G, Shah SAA, et al.

Comput Biol Chem, 2018 Dec;77:72-86.
PMID: 30245349 DOI: 10.1016/j.compbiolchem.2018.09.007

The heterocyclic compounds have been extensively reported for their bioactivity potential. The current research work reports the synthesis of some new multi-functional derivatives of 2-furoic piperazide (1; 1-(2-furoyl)piperazine). The synthesis was initiated by reacting the starting compound 1 with 3,5-dichloro-2-hydroxybenzenesulfonyl chloride (2) in a basic, polar and protic medium to obtain the parent sulfonamide 3 which was then treated with different electrophiles, 4a-g, in a polar and aprotic medium to acquire the designed molecules, 5a-g. These convergent derivatives were evaluated for their inhibitory potential against α-glucosidase, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Acarbose was used as a reference standard for α-glucosidase inhibition while eserine for AChE and BChE inhibition. Some of the synthesized compounds were identified as promising inhibitors of these three enzymes and their bioactivity potentials were also supported by molecular docking study. The most active compounds among the synthetic analogues might be helpful in drug discovery and development for the treatment of type 2 diabetes and Alzhiemer's diseases.
Isolation and characterization of novel antibacterial compound from an untapped plant, Stereospermum fimbriatum

Izyani Awang AF, Ahmed QU, Shah SAA, Jaffri JM, Ghafoor K, Uddin ABMH, et al.

Nat Prod Res, 2020 Mar;34(5):629-637.
PMID: 30470132 DOI: 10.1080/14786419.2018.1494170

Stereospermum fimbriatum or locally known as "Chicha" is traditionally used for itchy skin, earache, stomachache and postpartum treatments. This study was designed to evaluate the antimicrobial potential of S. fimbriatum's stem bark against 11 pathogens and isolate its bioactive compound. Successive soxhlet extraction was conducted using n-hexane, dichloromethane (DCM) and methanol. Disc diffusion, minimum inhibitory and bactericidal concentration (MIC & MBC) assays were done to examine the antimicrobial activity. Bioassay-guided isolation was conducted on S. fimbriatum's extract. The DCM extract of stem bark (DS) was the most potent extract followed by n-hexane extract of the stem bark (NS). A novel compound was isolated and coded as C1 which demonstrated potent antibacterial effects with the MIC values as low as 3.13 µg/mL to 6.25 µg/mL, against S. epidermidis, MRSA and S. aureus. Thus, S. fimbriatum could be a potential source of antimicrobial agents for the treatment of skin infections, specifically, MRSA.
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.
BSA Binding, molecular docking and in vitro biological screening of some new 1, 2, 4-triazole heterocycles bearing azinane nucleus

Iqbal J, Rehman A, Abbasi MA, Siddiqui SZ, Khalid H, Laulloo SJ, et al.

Pak J Pharm Sci, 2020 Jan;33(1):149-160.
PMID: 32122843

A series of new compounds (5a-q), derived from 5-(1-(4-nitrophenylsulfonyl) piperidin-4-yl)-4-phenyl-4H-1,2,4-triazole-3-thiol (3) were proficiently synthesized to evaluate their biological activities. 1-(4-Nitrophenylsulfonyl) piperidine-4-carbohydrazide (2) was refluxed with phenylisothiocyanate to yield an adduct which was cyclized to compound 3 by reflux reaction with 10 % potassium hydroxide. The targeted compounds 5a-q, were synthesized by stirring alkyl/aralkyl halides (4a-q) and compound 3 in a polar aprotic solvent. 1H-NMR, 13C-NMR, EI-MS and IR spectral techniques were employed to confirm the structures of all the synthesized compounds. The compounds were biologically evaluated for BSA binding studies followed by anti-bacterial, anti-inflammatory and acetylcholinesterase (AChE) activities. The active sites responsible for the best AChE inhibition were identified through molecular docking studies. Compound 5e bearing 4-chlorobenzyl moiety found most active antibacterial and anti-inflammatory agent among the synthesized compounds. The whole library of synthesized compounds except compounds 5d and 5f was found highly active for AChE inhibition and recommended for in vivo studies so that their therapeutic applications may come in utilization.
Synthesis and structure-activity relationship of elastase inhibiting novel ethylated thiazole-triazole acetamide hybrids: Mechanistic insights through kinetics and computational contemplations

Butt ARS, Abbasi MA, Aziz-Ur-Rehman, Siddiqui SZ, Hassan M, Raza H, et al.

Bioorg Chem, 2019 05;86:197-209.
PMID: 30711702 DOI: 10.1016/j.bioorg.2019.01.040

Keeping in mind the pharmacological importance of 2-aminothiazole and 1,2,4-triazole heterocyclic moieties, a series of novel ethylated bi-heterocyclic acetamide hybrids, 9a-p, was synthesized in a multi-step protocol. The structures of newly synthesized compounds were characterized by 1H NMR, 13C NMR, IR and EI-MS spectral studies. The inhibitory effects of these bi-heterocyclic acetamides (9a-n) were evaluated against elastase and all these molecules were identified as potent inhibitors relative to the standard used. The Kinetics mechanism was analyzed by Lineweaver-Burk plots which revealed that, 9h, inhibited elastase competitively by forming an enzyme-inhibitor complex. The inhibition constants Ki calculated from Dixon plots for this compound was 0.9 µM. The computational study was articulate with the experimental results and these ligands unveiled good binding energy values (kcal/mol). So, these molecules can be considered as promising medicinal scaffolds for the treatment of skin melanoma, wrinkle formation, uneven pigmentation, and solar elastosis.
N-([1,1'-biaryl]-4-yl)-1-naphthamide-based scaffolds synthesis, their cheminformatics analyses, and screening as bacterial biofilm inhibitor

Ejaz S, Zubair M, Rasool N, Ahmed F, Bilal M, Ahmad G, et al.

J Basic Microbiol, 2021 Nov 01.
PMID: 34724237 DOI: 10.1002/jobm.202100288

Naphthamides have pharmacological potential as they express strong activities against microorganisms. The commercially available naphthoyl chloride and 4-bromoaniline were condensed in dry dichloromethane (DCM) in the presence of Et3 N to form N-(4-bromophenyl)-1-naphthamide (86%) (3). Using a Pd(0) catalyzed Suzuki-Miyaura Cross-Coupling reaction of (3) and various boronic acids, a series of N-([1,1'-biaryl]-4-yl)-1-naphthamide derivatives (4a-h) were synthesized in moderate to good yields. The synthesized derivatives were evaluated for cytotoxicity haemolytic assay and biofilm inhibition activity through in silico and in vitro studies. Molecular docking, ADME (absorption, distribution, metabolism, and excretion), toxicity risk, and other cheminformatics predict synthesized molecules as biologically active moieties, further validated through in vitro studies in which compounds (4c) and (4f) showed significant haemolytic activity whereas (4e) exhibited an efficient biofilm inhibition activity against Gram-negative bacteria Escherichia coli and Gram-positive bacteria Bacillus subtilis. When forming biofilms, bacteria become resistant to various antimicrobial treatments. Currently, research is focused on the development of agents that inhibit biofilm formation, thus the present work is valuable for preventing future drug resistance.
Fulltext Evaluation of pharmaceutically compounded oral caffeine on the impact of medication adherence and risk of readmission among preterm neonates: A single-center quasi-experimental study

Ambreen G, Kumar M, Ali A, Shah SAA, Saleem SM, Tahir A, et al.

PLoS One, 2022;17(11):e0275655.
PMID: 36350877 DOI: 10.1371/journal.pone.0275655

BACKGROUND: Caffeine is available in an ampoule, used via parenteral and enteral routes in preterm neonates to treat apnea of prematurity (AOP) in neonates of gestational age ≥ 35-40 weeks. A longer duration of therapy has a higher risk of medication non-adherence due to higher costs and inappropriate dosage forms. Pharmaceutically compounded oral caffeine (PCC) could be an appropriate alternate dosage form. The researchers aimed to determine the impact of PCC on medication-related factors influencing medication adherence (MA) and the frequency of hospital readmission with apnea (HRA) in preterm neonates.
METHODS: We conducted a single-center quasi-experimental study for this quality improvement project using PCC among the preterm neonates admitted in a tertiary care level-III NICU at the Aga Khan University Hospital Karachi, Pakistan, received caffeine therapy, and survived at discharge. The researchers compared pre-PCC data (April-December 2017) with post-PCC data (April-Dec 2018) each for nine months, with three months intervals (January-March 2018) of PCC formulation and implementation phase. The study was conducted according to the SQUIRE2.0 guidelines. The Data were collated on factors influencing MA, including the cost of therapy, medication refill rates, and parental complaints as primary outcome measures. The Risk factors of HRA were included as secondary outcomes.
RESULTS: After PCC implementation cost of therapy was reduced significantly from Rs. 97000.0 (729.0 USD) to Rs. 24500.0 (185.0 USD) (p<0.001), significantly higher (p<0.001) number of patients completed remaining refills (77.6% pre-phase vs 97.5% post-phase). The number of parental complaints about cost, ampoule usage, medication drawing issue, wastage, inappropriate dosage form, and longer duration of therapy reduced significantly in post-phase. HRA reduced from 25% to 6.6% (p<0.001). Post-implementation of PCC (RR 0.14; 95% CI: 0.07-0.27) was a significant independent risk factor for reducing HRA using a multivariate analysis model. Longer duration of caffeine therapy after discharge (RR 1.05; 95% CI: 1.04-1.04), those who were born in multiple births (RR 1.15; 95% CI: 1.15-1.15), and those who had higher number of siblings were other significant independent risk factors for HRA.
CONCLUSIONS: PCC dispensation in the appropriate dosage form at discharge effectively reduced cost, non-adherence to therapy, and risk of hospital readmissions. This neonatal clinical and compounding pharmacist-led model can be replicated in other resource-limiting setting.
Semicarbazones, thiosemicarbazone, thiazole and oxazole analogues as monoamine oxidase inhibitors: Synthesis, characterization, biological evaluation, molecular docking, and kinetic studies

Qazi SU, Naz A, Hameed A, Osra FA, Jalil S, Iqbal J, et al.

Bioorg Chem, 2021 10;115:105209.
PMID: 34364054 DOI: 10.1016/j.bioorg.2021.105209

A series of semicarbazone, thiosemicarbazone, thiazole, and oxazole derivatives were designed, synthesized, and examined for monoamine oxidase inhibition using two isoforms, i.e., MAO-A and MAO-B. Among all the analogues, 3c and 3j possessed substantial activity against MAO-A with IC50 values of 5.619 ± 1.04 µM and 0.5781 ± 0.1674 µM, respectively. Whereas 3d and 3j were active against monoamine oxidase B with the IC50 values of 9.952 ± 1.831 µM and 3.5 ± 0.7 µM, respectively. Other derivatives active against MAO-B were 3c and 3g with the IC50 values of 17.67 ± 5.6 µM and 37.18 ± 2.485 µM. Moreover, molecular docking studies were achieved for the most potent compound (3j) contrary to human MAO-A and MAO-B. Kinetic studies were also performed for the most potent analogue to evaluate its mode of interaction with MAO-A and MAO-B.
Synthesis, enzyme inhibition and molecular docking studies of 1-Arylsulfonyl-4-phenylpiperazine derivatives

Abbasi MA, Anwar A, Rehman A, Siddiqui SZ, Rubab K, Shah SAA, et al.

Pak J Pharm Sci, 2017 Sep;30(5):1715-1724.
PMID: 29084694

Heterocyclic molecules have been frequently investigated to possess various biological activities during the last few decades. The present work elaborates the synthesis and enzymatic inhibition potentials of a series of sulfonamides. A series of 1-arylsulfonyl-4-Phenylpiperazine (3a-n) geared up by the reaction of 1-phenylpiperazine (1) and different (un)substituted alkyl/arylsulfonyl chlorides (2a-n), under defined pH control using water as a reaction medium. The synthesized molecules were characterized by 1H-NMR, 13C-NMR, IR and EI-MS spectral data. The enzyme inhibition study was carried on α-glucosidase, lipoxygenase (LOX), acetyl cholinesterase (AChE) and butyryl cholinesterase (BChE) enzymes supported by docking simulation studies and the IC50 values rendered a few of the synthesized molecules as moderate inhibitors of these enzymes where, the compound 3e exhibited comparatively better potency against α-glucosidase enzyme. The synthesized compounds showed weak or no inhibition against LOX, AChE and BChE enzymes.
Synthesis and in vitro study of benzofuran hydrazone derivatives as novel alpha-amylase inhibitor

Taha M, Shah SAA, Imran S, Afifi M, Chigurupati S, Selvaraj M, et al.

Bioorg Chem, 2017 12;75:78-85.
PMID: 28918064 DOI: 10.1016/j.bioorg.2017.09.002

The α-amylase acts as attractive target to treat type-2 diabetes mellitus. Therefore in discovering a small molecule as α-amylase inhibitor, we have synthesized benzofuran carbohydrazide analogs (1-25), characterized through different spectroscopic techniques such as 1HNMR and EI-MS. All screened analog shows good α-amylase inhibitory potentials with IC50 value ranging between 1.078±0.19 and 2.926±0.05µM when compared with acarbose having IC50=0.62±0.22µM. Only nine analogs among the series such as analogs 3, 5, 7, 8, 10, 12, 21, 23 and 24 exhibit good inhibitory potential with IC50 values 1.644±0.128, 1.078±0.19, 1.245±0.25, 1.843±0.19, 1.350±0.24, 1.629±0.015, 1.353±0.232, 1.359±0.119 and 1.488±0.07µM when compare with standard drug acarbose. All other analogs showed good to moderate α-amylase inhibitory potentials. The SAR study was conducted on the basis of substituent difference at the phenyl ring. The binding interaction between analogs and active site of enzyme was confirmed by docking studies.
Synthesis, molecular docking study and in vitro thymidine phosphorylase inhibitory potential of oxadiazole derivatives

Ullah H, Rahim F, Taha M, Uddin I, Wadood A, Shah SAA, et al.

Bioorg Chem, 2018 08;78:58-67.
PMID: 29533215 DOI: 10.1016/j.bioorg.2018.02.020

We have synthesized oxadiazole derivatives (1-16), characterized by 1H NMR, 13C NMR and HREI-MS and screened for thymidine phosphorylase inhibitory potential. All derivatives display varied degree of thymidine phosphorylase inhibition in the range of 1.10 ± 0.05 to 49.60 ± 1.30 μM when compared with the standard inhibitor 7-Deazaxanthine having an IC50 value 38.68 ± 1.12 μM. Structure activity relationships (SAR) has been established for all compounds to explore the role of substitution and nature of functional group attached to the phenyl ring which applies imperious effect on thymidine phosphorylase activity. Molecular docking study was performed to understand the binding interaction of the most active derivatives with enzyme active site.
Synthesis, Kinetics and Computational Explorations of 4-Phenylpiperazine Bearing N-(Aryl)-3-substituted-benzamides as Auspicious Tyrosinase Inhibitors

Zeb A, Abbasi MA, Aziz-Ur-Rehman, Siddiqui SZ, Hassan M, Javed Q, et al.

Chem Biodivers, 2024 Apr;21(4):e202400133.
PMID: 38363553 DOI: 10.1002/cbdv.202400133

In the aimed research study, a new series of N-(aryl)-3-[(4-phenyl-1-piperazinyl)methyl]benzamides was synthesized, which was envisaged as tyrosinase inhibitor. The structures of these newly designed molecules were verified by IR, 1H-NMR, 13C-NMR, EI-MS and CHN analysis data. These molecules were screened against tyrosinase and their inhibitory activity explored that these 3-substituted-benzamides exhibit good to excellent potential, comparative to the standard. The Kinetics mechanism was investigated through Lineweaver-Burk plots which depicted that molecules inhibited this enzyme in a competitive mode. Moreover, molecular docking was also performed to determine the binding interaction of all synthesized molecules (ligands) with the active site of tyrosinase enzyme and the results showed that most of the ligands exhibited efficient binding energy values. Therefore, it is anticipated that these molecules might serve as auspicious therapeutic scaffolds for treatment of the tyrosinase associated skin disorders.
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.
Fulltext Synthesis and Molecular Docking Studies of Novel Biheterocyclic Propanamides as Antidiabetic Agents Having Mild Cytotoxicity

Abbasi MA, Rubab K, Aziz-Ur-Rehman, Siddiqui SZ, Hassan M, Raza H, et al.

ACS Omega, 2023 Jun 27;8(25):22899-22911.
PMID: 37396264 DOI: 10.1021/acsomega.3c01882

The aim of this work was to bring forth some new hybrid molecules having pharmacologically potent indole and 1,3,4-oxadiazole heterocyclic moieties unified with a propanamide entity. The synthetic methodology was initiated by esterification of 2-(1H-indol-3-yl)acetic acid (1) in a catalytic amount of sulfuric acid and ethanol in excess, to form ethyl 2-(1H-indol-3-yl)acetate (2), which was converted to 2-(1H-indol-3-yl)acetohydrazide (3) and further transformed to 5-(1H-indole-3-yl-methyl)-1,3,4-oxadiazole-2-thiol (4). 3-Bromopropanoyl chloride (5) was reacted with various amines (6a-s) in aqueous alkaline medium to generate a series of electrophiles, 3-bromo-N-(substituted)propanamides (7a-s), and these were further reacted with nucleophile 4 in DMF and NaH base to yield the targeted N-(substituted)-3-{(5-(1H-indol-3-ylmethyl)-1,3,4-oxadiazol-2-yl)sulfanyl}propanamides (8a-s). The chemical structures of these biheterocyclic propanamides were confirmed by IR, 1H NMR, 13C NMR, and EI-MS spectral techniques. These compounds were evaluated for their enzyme inhibitory potentials against the α-glucosidase enzyme, where the compound 8l showed promising enzyme inhibitory potential with an IC50 value less than that of the standard acarbose. Molecular docking results of these molecules were coherent with the results of their enzyme inhibitory potentials. Cytotoxicity was assessed by the percentage of hemolytic activity method, and these compounds generally exhibited very low values as compared to the reference standard, Triton-X. Hence, some of these biheterocyclic propanamides might be considered as salient therapeutic agents in further stages of antidiabetic drug development.
Fulltext Convergent synthesis, kinetics insight and allosteric computational ascriptions of thiazole-(5-aryl)oxadiazole hybrids embraced with propanamides as alkaline phosphatase inhibitors

Butt ARS, Abbasi MA, Aziz-Ur-Rehman, Siddiqui SZ, Muhammad S, Raza H, et al.

RSC Adv, 2023 May 02;13(20):13798-13808.
PMID: 37197574 DOI: 10.1039/d3ra01348k

Considering the varied pharmacological prominence of thiazole and oxadiazole heterocyclic moieties, a unique series of bi-heterocyclic hybrids, 8a-h, was synthesized in a convergent manner. The structures of newly synthesized compounds were characterized by 1H-NMR, 13C-NMR, and IR spectral studies. The structure-activity relationship of these compounds was predicted by examining their inhibitory effects against alkaline phosphatase, whereby all these molecules exhibited superb inhibitory potentials relative to the standard used. The kinetics mechanism was determined by Lineweaver-Burk plots which revealed that 8g inhibited the studied enzyme non-competitively by forming an enzyme-inhibitor complex. The inhibition constant Ki calculated from Dixon plots for this compound was 0.42 μM. The allosteric computational study was coherent with the experimental records and these ligands exhibited good binding energy values (kcal mol-1). The hemolytic analysis revealed their mild cytotoxicity towards red blood cell membranes and hence, these molecules have potential to be nontoxic medicinal scaffolds for the treatment of alkaline phosphate-associated ailments.
Fulltext Synergistic Antibacterial Screening of Cymbopogon citratus and Azadirachta indica: Phytochemical Profiling and Antioxidant and Hemolytic Activities

Hussain S, Javed W, Tajammal A, Khalid M, Rasool N, Riaz M, et al.

ACS Omega, 2023 May 16;8(19):16600-16611.
PMID: 37214690 DOI: 10.1021/acsomega.2c06785

Current studies were performed to investigate the phytochemistry, synergistic antibacterial, antioxidant, and hemolytic activities of ethanolic and aqueous extracts of Azadirachta indica (EA and WA) and Cymbopogon citratus (EC and WC) leaves. Fourier transform infrared data verified the existence of alcoholic, carboxylic, aldehydic, phenyl, and bromo moieties in plant leaves. The ethanolic extracts (EA and EC) were significantly richer in phenolics and flavonoids as compared to the aqueous extracts (WA and WC). The ethanolic extract of C. citratus (EC) contained higher concentrations of caffeic acid (1.432 mg/g), synapic acid (6.743 mg/g), and benzoic acid (7.431 mg/g) as compared to all other extracts, whereas chlorogenic acid (0.311 mg/g) was present only in the aqueous extract of A. indica (WA). Food preservative properties of C. citratus can be due to the presence of benzoic acid (7.431 mg/g). -Gas chromatography-mass spectrometry analysis demonstrated the presence of 36 and 23 compounds in A. indica and C. citratus leaves, respectively. Inductively coupled plasma analysis was used to determine the concentration of 26 metals (Al, As, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, Si, Sn, Sr, V, Zn, Zr, Ti); the metal concentrations were higher in aqueous extracts as compared to the ethanolic extracts. The extracts were generally richer in calcium (3000-7858 ppm), potassium (13662-53,750 ppm), and sodium (3181-8445 ppm) and hence can be used in food supplements as a source of these metals. Antioxidant potential (DDPH method) of C. citratus ethanolic extract was the highest (74.50 ± 0.66%), whereas it was the lowest (32.22 ± 0.28%) for the aqueous extract of A. indica. Synergistic inhibition of bacteria (Staphylococcus aureus and Escherichia coli) was observed when the aqueous extracts of both the plants were mixed together in certain ratios (v/v). The highest antibacterial potential was exhibited by the pure extract of C. citratus, which was even higher than that of the standard drug (ciprofloxacin). The plant extracts and their mixtures were more active against S. aureus as compared to E. coli. No toxic hemolytic effects were observed for the investigated extracts indicating their safe medicinal uses for human beings.

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