Muhammad Iqbal Choudhary

University of Karachi · H.E.J. Research Institute of Chemistry

Since more than 100 years Staphylococcus aureus has been identified as one of the main causes of infectious diseases. S. aureus causes diverse range of diseases, from devastating septicemia and endocarditis to chronic bone infections and even minor skin infections. A single bacterial cell contains repertoire of proteins that are very important for...

Inhibition of dipeptidyl peptidase-IV (DPP-IV) has been identified as a promising approach for the treatment of type 2 diabetes mellitus (T2DM). Therefore, development of DPP-IV inhibitors with new chemical scaffold is of utmost importance to medicinal chemistry. In the present study, we identified benzophenone thio- and semicarbazone scaffolds as...

Diabetes is one of the most prevalent diseases worldwide. Vildagliptin is a drug which overcomes the existing problems of anti-diabetic drugs. However, the short half-life (2–3 h) of vildagliptin remains an important concern. Recently there is growing interest in using metal nanoparticles for sustained drug delivery. In the present study, we aimed...

Breast cancer is one the most aggressive cancer worldwide, especially Pakistan due to limited therapeutic options. This study was conducted to repurpose the use of selective serotonin reuptake inhibitors (SSRIs), in the treatment of breast cancers, and merit to pursue drug re-positioning in oncology. Anti-proliferative activity of SSRIs, such as fl...

Melanoma, the most dangerous skin cancer, originates from the melanocytes and has a high tendency to invade neighboring tissues, and metastasize. Both antioxidant and pro-oxidant appear to be involved in modulating melanocyte transformation, melanoma progression and invasion. Consequently, potent antioxidants and pro-oxidant may prevent cell transf...

The microbial transformation of anabolic androgenic steroid mestanolone (1) with Macrophomina phaseolina and Cunninghamella blakesleeana has afforded seven metabolites. The structures of these metabolites were characterized as 17β-hydroxy-17α-methyl-5α-androsta-1-ene-3,11-dione (2), 14α,17β-dihydroxy-17α-methyl-5α-androstan-3,11-dione (3), 17β-hydr...

Exodeoxyribonuclease VII (ExoVII) is an enzyme that catalyzes the bidirectional exonucleolytic cleavage of single stranded DNA. ExoVII comprises of two subunits i.e. large XseA and small XseB [1]. It is one of the key players of DNA repair and recombination processes occur in bacteria. Despite having central role in DNA repair and recombination, th...

Crude extracts (70% ethanolic) and fractions (hexane, dichloromethane, butanol, aqueous) of brans of four Sri Lankan traditional red rice varieties (Oryza sativa L.), namely, Sudu Heeneti, Goda Heeneti, Masuran and Dik Wee were studied for a range of anti-inflammatory activities. The investigated activities included oxidative burst inhibitory activ...

Background: Multidrug resistance (MDR) is a major challenge in the treatment of infectious diseases. The MDR in urinary tract infection causing bacteria, such as Escherichia coli, has made treatment of UTI very difficult. Objective: The aims of the current study were to synthesize a library of harmaline derivatives, and to evaluate their activit...

Background The present research was carried out to investigate pharmacological properties of Buxus papillosa C.K. Schneid. (Buxaceae). Methods Buxus papillosa extracts of leaves (BpL), stem (BpS), roots (BpR) and BpL fractions: hexane (BpL-H), aqueous (BpL-A) also plant constituent, cyclomicrobuxine effect were studied in jejunum, atria, aorta and...

A series of benzoxazinones 1-28 were synthesized via reaction of anthranilic acid with various substituted benzoyl chlorides in the presence of triethylamine in chloroform. Compounds 1-18 showed a good inhibition of α-chymotrypsin with IC50 ± SEM values between 6.5 to 341.1 μM. Preliminary structure-activity relationships studies indicated that the...

The advent of second dimension was a major step in the development of modern NMR spectroscopy. Interpretation of spectral data and obtaining useful information about the inter- and intra-molecular interactions in complex molecules was greatly helped through the advent of two-dimensional (2D)-NMR spectroscopy. The concept of dimensionality is discus...

Key recent developments in NMR hardware such as bench-top and earth-field NMR spectrometers, high-field NMR magnets, cryogenically cooled probes, dynamic nuclear polarization (DNP), and low-temperature sample cooled magic angle spinning (MAS) solid-state probes as well as dual receivers for parallel detection of several nuclei have changed the way...

This chapter discusses the nuclear overhauser effect or nOe in short. The nOe is one of the most powerful and widely exploited methods for structure determination, nOe difference (NOED) or the two-dimensional experiment (NOESY) is used extensively for stereo-chemical assignments. In nOe, the main concern is with longitudinal relaxation, which is th...

Spin-echo and polarization transfer techniques have a central importance in NMR spectroscopy. Spin-echo formation, an essential component of various NMR pulse sequences, provides precision and flexibility in the handling of magnetization vectors. Various types of spin-echo pulse sequences are used to facilitate multiplicity assignment and to overco...

Multidimensional NMR spectroscopy has substantially broadened the scope and applications of NMR techniques. Three-dimensional (3D) NMR in various combinations provides much needed information about homo- and heteronuclear correlations, both through bond and through space, that is particularly useful in unravelling complex structures. Concatenated o...

This chapter describes how NMR signals are created. The fundamentals of pulse Fourier transform NMR spectroscopy are explained using vector models. The effect of application of pulses on various nuclei can be predicted, making NMR spectroscopy an exciting science. The decay of magnetization vectors after excitation toward thermal equilibrium is car...

We have presented in this poster recently undertaken a series of studies aimed to synthesize and evaluate the biological activities of new pyrimidine nucleotide analogues. These bases were found to posses remarkable antioxidant activities against free radicals in vitro. The objective of the study was to identify potential pyrimidine based anti-canc...

Two new malonamide derivatives were synthesized via the Michael addition of N¹,N³-di(pyridin-2-yl)malonamide to α,β-unsaturated ketones using a 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) catalyst at room temperature. All reactions efficiently furnished the desired malonamide derivatives, which differed only in their substitution on one phenyl group,...

Two new prenylated flavonoids, thunbergiols A (1) and B (2), along with three known compounds, chrysin (3), quercetin (4) and berberine (5) were obtained from the methanolic extract of roots of Berberis thunbergii DC. MS, NMR and other spectroscopic techniques were employed for their structural characterisation.

Twenty-five benzophenone semicarbazones and thiosemicarbazones 3–27 were synthesized starting from benzophenones via hydrazones treated with different aryl isocyanates and isothiocyantes under reflux. All synthetic derivatives were evaluated for their urease inhibitory potential. Good to moderate inhibition trend against urease was observed with th...

Thymidine phosphorylase (TP) catalyzes the cleavage of thymidine into thymine and 2-deoxy-α-D-ribose-1-phosphate. Elevated activity of TP prevents apoptosis, and induces angiogenesis which ultimately leads to tumor growth and metastasis. Critical role of TP in cancer progression makes it a valid target in anti-cancer research. Discovery of small mo...

Honey is often adulterated because of its high economic value and increasing consumption. Among the most common adulterants, brown rice syrup (B.R.S.) is relatively difficult to detect. We present here a simple and fast quantitative ¹H-NMR method to identify adulteration of honey by brown rice syrup using the concentration conversion factor. The pr...

Background Diabetes mellitus is a metabolic disorder of epidemic proportion, projected to become the major cause of morbidity and mortality in the world in future. Despite extensive research in understanding this disease at molecular level, and the discovery of new drugs, diabetes and its complications remain largely untreated. Many of the late dia...

Acute leukemia is a critical neoplasm of white blood cells. In order to differentiate between the metabolic alterations associated with two subtypes of acute leukemia, acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML), we investigated the serum of ALL and AML patients and compared with two controls (healthy and aplastic anemia) us...

Structural transformation of anticancer drug exemestane (1) with fungi Cunninghamella blakesleeana (ATCC 8688A), Curvularia lunata (ATCC 12017), Aspergillus niger (ATCC 10549), and Gibberella fujikuroi (ATCC 10704) yielded eleven metabolites 2-12, in which 2 and 8 were identified as new. Their structures were characterized as 6-methylene-5α-androst...

In this study, 45 bisindolylmethanes having sulfonamide moiety had been synthesized through 3 steps. In vitro assay for inhibition of carbonic anhydrase showed that some of the compounds having sulfonamide moiety are capable of inhibiting carbonic anhydrase II. Bisindoles having halogens at fifth position showed better inhibitory activity as compar...

One pot synthesis of two novel hitherto unreported thiophenes was achieved by a facile and selective synthetic method. The crystal structures of the synthesized compounds were determined using an X-ray single crystal technique. The synthesized thiophenes were evaluated for their anti-cancer and antimicrobial activities. Molecular docking studies of...

A phytochemical investigation on the chloroform extract of Caesalpinia pulcherrima roots led to the isolation of ten known furanocassane diterpenoids, vouacapen-5α-ol (1), 8,9,11,14-didehydrovouacapen-5α-ol (2), 6β-cinnamoyl-7β-hydroxyvouacapen-5α-ol (3), pulcherrin A (4), pulcherrin B (5), pulcherrin J (6), pulcherrimin A (7), pulcherrimin B (8),...

The volatile composition of the leaf, stem-bark, and nut of Artocarpus camansi (Moraceae) were studied. Essential oils were obtained by hydrodistillation in a modified Clevenger-type apparatus and analyzed by GC-MS. A total of 32, 11, and 26 compounds were identified, representing 99.09%, 99.45%, and 99.89% of the leaf, stem-bark, and nut oils, res...

Biotransformation is the structural modification of compounds using enzymes as the catalysts and it plays a key role in the synthesis of pharmaceutically important compounds. 10β,17β-Dihydroxy-17α-methylestr-4-en-3-one dihydrate, C 19 H 28 O 3 ·2H 2 O, was obtained from the fungal biotransformation of methyloestrenolone. The structure was refined u...

Microbial transformation of the anti-inflammatory steroid medrysone (1) was carried out for the first time with the filamentous fungi Cunninghamella blakesleeana (ATCC 8688a), Neurospora crassa (ATCC 18419), and Rhizopus stolonifer (TSY 0471). The objective was to evaluate the anti-inflammatory potential of the substrate (1) and its metabolites. Th...

The MS and NMR spectra of compound 6. (PDF)

The MS and NMR spectra of compound 2. (PDF)

The MS and NMR spectra of compound 3. (PDF)

The MS and NMR spectra of compound 1. (PDF)

The MS and NMR spectra of compound 4. (PDF)

The MS and NMR spectra of compound 5. (PDF)

The MS and NMR spectra of compound 7. (PDF)

The MS and NMR spectra of compound 8. (PDF)

The antiproliferative effect of the fatty acid components of Clerodendrum volubile leaves as well as its antioxidant effect on MCF-7 and MDA-MB-231 human breast cancer cell lines were investigated. Fatty acids extracted from C. volubile leaf oil were subjected to gas chromatography mass spectrometry (GCMS) analysis. The cells were cultured and trea...

Oxidation of the cassane diterpenoids 6β-cinnamoyl-7α-hydroxyvouacapen-5α-ol (1) and pulcherrimin A (2), which were isolated from the roots of Caesalpinia pulcherrima, yielded four new derivatives 3–6. The structures of the new compounds were confirmed on the basis of 1D and 2D NMR spectroscopy as well as mass spectrometry. The derivatives were tes...

Two fungal cultures Aspergillus niger, and Cunninghamella blakesleeana were used for the biotransformation of methenolone enanthate (1). Biotransformation with A. niger led to the synthesis of three new (2-4), and three known (5-7) metabolites, while fermentation with C. blakesleeana yielded metabolite 6. Substrate 1 and the resulting metabolites w...

This presentation is a comprehensive overview about breast cancers, its statistics, risk factors, molecular basis of breast Cancer, aromatase enzyme expression, aromatase enzyme specificity, aromatase enzyme function, aromatase enzyme role in breast cancer breast cancer therapy, and related clinical trials

Abstract Benzamide sulfonamide and its derivatives were identified as potent inhibitors of carbonic anhydrase-II (bovine carbonic anhydrase-II (bCA-II) and human recombinant carbonic anhydrase-II (hCA-II)) with IC50 values 0.06–0.28 μM and 0.09–0.58 μM, respectively. Different kinetics parameter, such as V max, K m , and K i , were determined. Mole...

A series of new malonamide derivatives were synthesized by Michael addition reaction of N1,N3-di(pyridin-2-yl)malonamide into α,β-unsaturated ketones mediated by DBU in DCM at ambient temperature. The inhibitory potential of these compounds in vitro, against α-glucosidase enzyme was evaluated. Result showed that most of malonamide derivatives were...

Tyramine derivatives 3-27 were synthesized by using conventional and environmental friendly ultrasonic techniques. These derivatives were then evaluated for the first time for their α-glucosidase (Sources: Saccharomyces cerevisiae and mammalian rat-intestinal acetone powder) inhibitory activity by using in vitro mechanism-based biochemical assays....

Enzyme urease plays an important role in several pathologies, such as urolithiasis, urinary catheter encrustation, hepatic encephalopathy, peptic ulcers, and gastric cancers. Its inhibition, therefore, has a major therapeutic significance. For this purpose, nine natural flavonoids 1-9 were evaluated for their urease inhibitory activity. Five of the...

This report describes the evaluation of the biological activities of 13 gold-NHC complexes. These complexes were evaluated in vitro for their antioxidant properties, α-glucosidase, thymidine phosphorylase, β-glucuronidase and xanthine oxidase enzyme inhibition activities. Among the tested complexes, those bearing chloride ligands were found to be p...

Inhibition of α-glucosidase enzyme activity is a reliable approach towards controlling post-prandial hyperglycemia associated risk factors. During the current study, a series of dihydropyrano[2,3-c] pyrazoles (1-35) were synthesized and evaluated for their α-glucosidase inhibitory activity. Compounds 1, 4, 22, 30, and 33 were found to be the potent...

A new adduct of abietane-type diterpene, salvialeriicone (1), was isolated from Salvia leriifolia Benth., along with a new chemical entity nor-abietane diterpene, 2-isopropyl-8,8-dimethyl-7,8-dihydrophenanthrene-1,4,5(6H)-trione (2). Their structures were determined using mass spectrometry, and 1D- and 2D-NMR spectroscopy.

2,7-dimethoxyxanthone (1) along with a well known compound β-sitosterol-3-O-β-Dglucopyranoside (2) were isolated from the methonalic extract of the fruits of Terminalia arjuna. Their structures were elucidated by spectroscopic (NMR and mass) analysis.

A series of barbiturates derivatives synthesized and screened for different set of bioassays are described. The molecular structures of compounds 5a , 5d, and 5f were solved by single-crystal X-ray diffraction techniques. The results of bioassay show that compounds 4a , 4b , 4c , 4d , 4e , 4f , and 4g are potent antioxidants in comparison to the te...

This study was proposed to investigate the in-vitro antifungal, antibacterial, insecticidal, cytotoxic and phytotoxic potential of ethanolic extract of twigs of Taxus wallichiana Zucc. Traditionally, this plant is used in folk medicines in Pakistan, for the treatment of various microbial infections. The crude sub fractions of ethanolic extracts of...