Masood Ahmad Rizvi

Nuclear blebbing of biologically active organoselenium compound towards human cervical cancer cell (HeLa): in vitro DNA/HSA binding, cleavage and cell imaging studies.

New pharmacophore organoselenium compound (1) was designed, synthesized and characterized by various spectroscopic methods (IR, ESI-MS, (1)H, (13)C and (77)Se NMR) and further confirmed by X-ray crystallography. Compound 1 consists of two 3,5-bis(trifluoromethyl)phenyl units which are connected to the selenium atom via the organometallic C-Se bond. In vitro DNA binding studies of 1 was investigated by absorption and emission titration methods which revealed that 1 recognizes the minor groove of DNA in accordance with molecular docking studies with the DNA duplex. Gel electrophoretic assay demonstrates the ability of 1 to cleave pBR322 DNA through hydrolytic process which was further validated by T4 religation assay. To understand the drug-protein interaction of which ultimate molecular target was DNA, the affinity of 1 towards HSA was also investigated by the spectroscopic and molecular modeling techniques which showed hydrophobic interaction in the subdomain IIA of HSA. Furthermore, the intracellular localization of 1 was evidenced by cell imaging studies using HeLa cells.

Highly efficient dehydrogenative cross-coupling of aldehydes with amines and alcohols

A common protocol for the synthesis of amides, esters and α-ketoesters via cross dehydrogenative coupling of aldehydes and amines/alcohols has been developed. The method is applicable to a wide variety of alcohols and amines as well as aliphatic and aromatic aldehydes. Also, the use of acetaldehyde for acetylation and ethyl glyoxalate to access 2-oxo-amino esters is presented for the first time.

An investigation of in vitro cytotoxicity and apoptotic potential of aromatic diselenides.

A target synthesis of a library of symmetric aromatic diselenides was attempted with the aim of generating anticancer lead compounds. Out of thirteen screened molecules (1-13) against a panel of human cancer cell lines, compound 8 exhibited highest cell growth inhibition in Human leukemia HL-60 cells with IC50 value of 8 μM. Compound 8 had a good pro-apoptotic potential as evidenced from several apoptotic protocols like DNA cell cycle analysis and monitoring of apoptotic bodies formation using phase contrast and nuclear microscopy with Hoechst 33,258. Also, 8 significantly inhibits S phase of the cell cycle and eventually trigger apoptosis in HL-60 cells through mitochondrial dependent pathway substantiated by the loss of mitochondrial potential. A theoretical investigation of DNA binding ability of 8 showed that it selectively bind to minor groove of DNA, where it is stabilized by hydrogen bonding and hydrophobic interactions.

A general metal-free approach for the stereoselective synthesis of C-glycals from unactivated alkynes

Summary A novel metal-free strategy for a rapid and α-selctive C-alkynylation of glycals was developed. The reaction utilizes TMSOTf as a promoter to generate in situ trimethylsilylacetylene for C-alkynylation. Thanks to this methodology, we can access C-glycosides in a single step from a variety of acetylenes , i.e., arylacetylenes and most importantly aliphatic alkynes.

Acetaldehyde in asymmetric organocatalytic transformations

The role of acetaldehyde as a nucleophile in various asymmetric C–C bond forming transformations is presented, with consideration given not only to the optimization of reaction parameters relevant to product formation, polymerization, by-products, purification, chirality and instability of the final products, but also to the application of the final products in the synthesis of bioactive molecules. This review is organized according to the use of acetaldehyde in different organocatalytic reactions covering the most recent reports. In the last section indirect sources of acetaldehyde are discussed from the perspective of difficult handling and its requirement of slow addition as well as being freshly distilled in some of the transformations, which is one of the most critical issues in the late exploitation of acetaldehyde as a nucleophile in synthetic chemistry.

Complexation modulated redox behavior of transition metal systems (review)

Ligand effect is a favorable factor in modulation of redox potential of transition metal ion oxidation-reduction systems. Coordination promoted redox action of transition metals can be an efficient approach to design of new redox systems with specific applications. The current review is devoted to the complexation effect of selected ligands on the redox potential of iron, cobalt and copper redox couples and application of such systems in analytical estimations. Indirect estimation of non redox systems by a non redox reaction over a platinum electrode has been referred to as a pseudo indicator action. Application of coordination modulated redox potentials in the natural attenuation of toxic environmental contaminants is also presented.

Anti-inflammatory terpenoids from Boswellia ovalifoliolata

Ten compounds, including three new compounds (1–3, one sesquiterpenoid and two triterpenoids), were isolated and characterized from the ethanolic extract of oleo-gum-resin from Boswellia ovalifoliolata. It is noteworthy that, for the first time, compound 4 has been reported from any of Boswellia species, and 5–9 from B. ovalifoliolata. These isolated compounds were screened for TNF-α inhibition and the results showed that 2 and 5 significantly inhibited the expression of TNF-α at 1 μM, whereas inhibition by rolipram (a standard TNF-α inhibitor) occurred at 100 μM. Furthermore, 2 and 5 were found to considerably reduce levels of interleukin (IL-6 and IL-8) and nitric oxide (NO) production, which suggests they have anti-inflammatory potential and possible therapeutic uses.

Crystal structure, computational studies, and stereoselectivity in the synthesis of 2-aryl-thiazolidine-4-carboxylic acids via in situ imine intermediate

ABSTRACT This article presents the synthesis of (2R/2S,4R)-2-aryl-thiazolidine-4-carboxylic acids via nucleophilic addition of L-Cysteine on aromatic aldehydes involving a yield and time-effective room temperature reaction in an aqueous DMSO medium in the presence of NaHCO3 as a base. The synthesized diastereomers were spectroscopically characterized and quantified for diastereomeric excess by liquid chromatography-mass spectrometry analysis. The impact of the type and position of substituent in aromatic aldehydes on reaction time, % yield, 1H NMR shift at newly formed chiral center [C(2)-H], and diastereomeric excess (de%) have been investigated. A plausible mechanism for stereoselectivity via an in situ imine intermediate is proposed using real-time IR monitoring of the synthetic reaction based on the significant signals at 1597, 1593 cm−1 for imine (C=N) stretching. The imine mechanism for stereoselectivity was further supported by NMR studies of azomethine 13C NMR signals at 159, 160 δ ppm and by the single crystal structure of hitherto unknown (2S,4R)-3-(tert-butoxycarbonyl)-2-(2-hydroxyphenyl)thiazolidine-4-carboxylic acid (3a) obtained as a major diastereomer in the synthesis of the butyloxy carbonyl (BOC) derivative of (2R/2S,4R)-2-(2-hydroxyphenyl)thiazolidine-4-carboxylic acid. The significant ortho-OH effect of phenolic hydroxyl group leading to strong hydrogen bondings plays a vital role in the formation of 2S,4R BOC derivative stereoselectively. The frontier molecular orbitals, possible electronic excitations, IR band characterizations, and reactivity parameters of newly reported compound (3a) have been predicted using quantum chemical descriptors from density functional theory. The theoretical exploration of experimental spectra using time-dependent DFT indicated a (π–π*) transition between HOMO and LUMO in the ultraviolet region.

Anti-arthritogenic effect of Saponin-1 by alteration of Th1/Th2 cytokine paradigm in arthritic mice.

OBJECTIVE & DESIGN Investigation was carried out on Saponin 1 (SAP-1), a novel molecule isolated from Parthenium hysterophorus, on proinflammatory (Th1) & anti-inflammatory (Th2) cytokines in blood of arthritic balb/c mice. METHODS Adjuvant induced developing inflammatory arthritis was induced in mice which were treated with SAP-1 in graded oral doses. The molecular markers were determined using Flow Cytometry which uses sensitivity of amplified fluorescence detection to measure soluble analytes in particle based immune assay. The T-helper (Th1) deviated cells produce detectable level of Tumor necrosis factor (TNF-alpha), interleukin-2 (IL-2) & interferon-gamma (IFN-gamma), while the Th2 deviated cells produce significant amount of interleukin-4 (IL-4) and interleukin-5 (IL-5). RESULTS SAP-1 at graded oral doses inhibited expression of IFN-gamma & TNF-alpha in serum & correspondingly increased expression of IL-4 significantly. SAP-1 also inhibited IL-17 and CD4(+)CD25(+) cell population showing to have suppressive effect on Th-17 pathway as well as T-regulatory cells. It also suppressed the increased levels of pro-inflammatory mediators like IL-1β and NO. Inhibitors of Cox-2 and MCP-1 provide effective improvements in signs and symptoms of Rheumatoid Arthritis. SAP-1 decreased the elevated concentration of both COX-2 and MCP-1 in arthritic animals. CONCLUSIONS SAP-1 diminishes Th1 immunity activation, a primary cause of arthritis, in favour of Th2 dominance, which reduces arthritic condition in mice displaying immune-modulatory potential.

Antiproliferative potential of a novel parthenin analog P16 as evident by apoptosis accompanied by down-regulation of PI3K/AKT and ERK pathways in human acute lymphoblastic leukemia MOLT-4 cells

Leukemia is one of the deadliest types of cancer. Lack of effective treatment strategies has resulted in an extensive quest for new therapeutic molecules against it. This study explores the molecular mechanism of anticancer activity of P16, a semisynthetic analog of parthenin, against the human acute lymphoblastic leukemia MOLT-4 cells. P16 displayed antiproliferative activity in different cancer cell lines; however, MOLT-4 cells showed highest sensitivity for P16 with IC50 value of 0.6μM. Further studies revealed that P16 induced cell death by apoptosis. It caused mitochondrial stress, which was mediated by the translocation of Bax from cytosol to mitochondria and release of cytochrome c into the cytosol and consequent activation of caspase-9. However, P16 was also able to activate caspase-8, thus involving both extrinsic and intrinsic pathways of apoptosis. Further, activation of caspase-3 led to cleavage of its target proteins PARP-1 and ICAD, which resulted in apoptotic DNA damage. P16 induced apoptosis was accompanied by the down-regulation of important leukemic cell survival proteins like pAKT (S473), pAKT (T308), pP70S6K, pCRAF, and pERK1/2. However, inhibition of caspases by Z-VAD-FMK reversed the down-regulatory effect of P16 on pAKT (S473) and pP70S6K, as evident by the cell viability assay and flow cytometric analysis but this inhibition did not completely reverse the antiproliferative effect of P16, thereby indicating the role of additional factors apart from caspases in P16 induced apoptosis in MOLT-4 cells. Owing to its antiproliferative potential against leukemia cells, P16 can further be explored as an effective therapeutics against leukemia.