Mashooq A. Bhat

Steroidal pyrazolines evaluated as aromatase and quinone reductase-2 inhibitors for chemoprevention of cancer

The aromatase and quinone reductase-2 inhibition of synthesized heterocyclic pyrazole derivatives fused with steroidal structure for chemoprevention of cancer is reported herein. All compounds were interestingly less toxic than the reference drug (Cyproterone(®)). The aromatase inhibitory activities of these compounds were much more potent than the lead compound resveratrol, which has an IC(50) of 80 μM. In addition, all the compounds displayed potent quinone reductase-2 inhibition. Initially the acute toxicity of the compounds was assayed via the determination of their LD(50). The aromatase and quinone reductase-2 inhibitors resulting from this study have potential value in the treatment and prevention of cancer.

Synthesis and anti-Candidal activity of N-(4-aryl/cyclohexyl)-2-(pyridine-4-yl carbonyl) hydrazinecarbothioamide.

Eighteen N-(4-aryl/cyclohexyl)-2-(pyridine-4-yl carbonyl) hydrazinecarbothioamide derivatives were synthesized, evaluated against ten clinical isolates of Candida spp. and compared with itraconazole. Introduction of p-chloro (2c), p-iodo (2q), m-chloro (2l) and o-nitro (2r) substitution at phenyl ring of thiosemicarbazide enhanced the anti-Candida activity. Compound (2c) bearing p-cholorophenyl ring was found to be the most effective against Candida albicans ATCC 66027, Candida spp. 12810 (blood) and Candida spp. 178 (HVS) with MIC value of 0.09-0.78 μg/mL, whereas itraconazole exhibits the inhibitory activity with MIC value of 0.04-1.56 μg/mL against all tested strains. There is a correlation between anti-Candidal activity and p-chloro substitution at phenyl ring of thiosemicarbazide. All synthesized compounds were investigated for their potential cytotoxicity against non cancer cell line MCF-10A. The active compounds 2c, 2r and 2a were further investigated for their cytotoxic effects on three cancer cell lines; HT1080 (skin), HepG2 (liver) and A549 (lung). The active compounds showed minimal cytotoxic activity against non cancer cell line and all three cancer cell lines. Moreover, compound 2c displaying better activity against C. albicans ATCC66027 and Candida spp. [blood] compared to reference drug (itraconazole), represents a good lead for the development of newer, potent and broad spectrum anti-Candidal agents.

Unexpected Configuration in Stereoselectively Synthesis of Some Novel (1Z)-1-(morpholin-1-yl)-N2-Arylamidrazones

The nucleophilic substitution reaction of hydrazono-N-(aryl)-propanehydrazonyl chlorides 7 with piperidine or morpholine, under the same reaction conditions, resulted in the formation of 1-(piperdin-1-yl / morpholine-1-yl)-N 2 - arylamidrazones 8a-k, respectively. The X-ray diffraction of piperidin-1-yl-N 2 -arylamidrazone (8b) confirmed its 1E- configuration in agreement with the previously reported, whereas X-ray showed the unexpected 1Z-configuration of their analogs, morpholin-1-yl-N 2 -arylamidrazone (8j). This study established the role of hydrogen bond interaction in the

Microwave-Assisted Synthesis and Antimicrobial Activity of Some Novel Isatin Schiff Bases Linked to Nicotinic Acid via Certain Amino Acid Bridge

The coupling reaction of nicotinic acid with certain L-amino acid methyl esters including valine, leucine, and phenylalanine was done by the use of acid chloride method. The products were reacted with hydrazine hydrate 99% to give the corresponding hydrazides that were reacted with indoline-2,3-dione (isatin) to get Schiff bases under the application of microwave irradiation technique. These novel compounds were characterized by means of their FT-IR, 1H NMR, and mass spectral data. Additionally, the specific optical rotation and elemental analysis were measured. The in vitro antimicrobial activity of the synthesized compounds was evaluated by agar diffusion method. The compounds showed a strong antimicrobial inhibitory activity. Most of the test compounds possessed a broad spectrum of activities having MIC values ranging from 50 µg/mL to 500 µg/mL.

Development and validation of UHPLC-MS/MS assay for rapid determination of a carvone Schiff base of isoniazid (CSB-INH) in rat plasma: application to pharmacokinetic study

In this study, a fast UHPLC-MS/MS method was developed and validated for the determination of a novel potent carvone Schiff base of isoniazid (CSB-INH) in rat plasma using carbamazepine as an internal standard (IS). After a single-step protein precipitation by acetonitrile, CSB-INH and IS were separated on an Acquity BEH(TM) C18 column (50 × 2.1 mm, 1.7 µm) under an isocratic mobile phase, consisting of acetonitrile: 10 mM ammonium acetate (95:5, v/v), at a flow rate of 0.3 mL/min. Quantification was performed on a triple quadrupole tandem mass spectrometer in multiple reactions monitoring mode by using positive electrospray ionization source. The precursor to product ion transitions were set at m/z 270.08 → 79.93 for CSB-INH and m/z 237.00 → 178.97 for IS. The proposed method was validated in compliance with US Food and Drug Administration and European Medicines Agency guidelines for bioanalytical method validation. The method was found to be linear in the range of 0.35-2500 ng/mL (r(2)  ≥ 0.997) with a lower limit of quantification of 0.35 ng/mL. The intra- and inter-day precision values were ≤12.0% whereas accuracy values ranged from 92.3 to 108.7%. In addition, other validation results were within the acceptance criteria and the method was successfully applied in a pharmacokinetic study of CSB-INH in rats.

Targeting Cancer Stem Cells with Novel 4-(4-Substituted phenyl)-5-(3,4,5-trimethoxy/3,4-dimethoxy)-benzoyl-3,4-dihydropyrimidine-2(1H)-one/thiones.

Novel 4-(4-substituted phenyl)-5-(3,4,5-trimethoxy/3,4-dimethoxy)-benzoyl-3,4-dihydropyrimidine-2(1H)-one/thione derivatives (DHP 1–9) were designed, synthesized, characterized and evaluated for antitumor activity against cancer stem cells. The compounds were synthesized in one pot. Enaminones E1 and E2 were reacted with substituted benzaldehydes and urea/thiourea in the presence of glacial acetic acid. The synthesized compounds were characterized by spectral analysis. The compounds were screened in vitro against colon cancer cell line (LOVO) colon cancer stem cells. Most of the compounds were found to be active against side population cancer stem cells with an inhibition of >50% at a 10 μM concentration. Compounds DHP-1, DHP-7 and DHP-9 were found to be inactive. Compound DHP-5 exhibited an in vitro anti-proliferative effect and arrested cancer cells at the Gap 2 phase (G2) checkpoint and demonstrated an inhibitory effect on tumor growth for a LOVO xenograft in a nude mouse experiment.

Preclinical pharmacokinetics, tissue distribution and excretion studies of a novel anti-candidal agent-thiosemicarbazide derivative of isoniazid (TSC-INH) by validated UPLC-MS/MS assay.

A simple and sensitive UPLC-MS/MS assay was developed and validated for rapid determination of thiosemicarbazide derivative of isoniazid (TSC-INH), a potent anti-candidal agent in rat plasma, tissues, urine and feces. All biological samples were prepared by protein precipitation method using celecoxib as an internal standard (IS). Chromatographic separation was achieved on Acquity BEH™ C18 (50×2.1 mm, 1.7 μm) column using gradient mobile phase of acetonitrile and water (containing 0.1% formic acid) at flow rate of 0.3 mL/min. The MRM transitions were monitored at m/z 305.00→135.89 for TSC-INH and m/z 380.08→316.03 for IS in ESI negative mode. All validation parameter results were within the acceptable range described in guideline for bioanalytical method validation. The pharmacokinetic study showed that the compound TSC-INH was orally active with 66% absolute bioavailability in rats. It was rapidly absorbed with peak plasma concentration of 1985.92 ng/mL achieved within 1 h after single oral dose (10 mg/kg) administration. TSC-INH exhibited rapid distribution across the body with highest levels in liver and lungs. Penetration in brain tissues suggests that TSC-INH crossed the blood brain barrier. Only 5.23% of the orally administered drug was excreted as unconverted form in urine and feces implying that TSC-INH was metabolized extensively before excretion. With the preliminary knowledge of in vivo pharmacokinetics and disposition properties, this study will be beneficial for further development of compound TSC-INH in future studies.

Targeted nano-delivery of novel omega-3 conjugate against hepatocellular carcinoma: Regulating COX-2/bcl-2 expression in an animal model

The present approach enumerates the effectiveness of tuftsin tagged nano-liposome for the cytosolic transport of 2,6-di-isopropylphenol-linolenic acid conjugate against liver cancer in mice. Initially, the conjugate in its free form was examined for anticancer potential on HepG2 liver cancer cells. Induction of apoptosis and suppression of migration and adhesion of HepG2 cells confirmed the effectiveness of conjugate as an anticancer agent. After this, role of the conjugate entrapped in a nano-carrier was evaluated in animal model. The nano-formulation comprising of conjugate bearing tuftsin tagged liposome was firsly characterized and then its therapeutic effect was determined. The nano-formulation had 100-130nm size nanoparticles and showed sustained release of the conjugate in the surrounding milieu. The nano-formulation distinctly reduced the expression of COX-2, an important molecule that is vastly expressed in hepatocellular carcinoma. The utilization of in-house engineered nano-formulation was also successful in significantly up-regulating Bax and down-regulating bcl-2 gene expression eventually helping in better survival of treated mice. Histopathological analysis also revealed positive recovery of the general architecture and the violent death of cancer cells by apoptosis at tumor specific site. The site specific delivery of conjugate entrapped in tuftsin tagged liposomes was highly safe as well as efficaceous. Nano-formulation based approach showed a visible chemotherapeutic effect on liver cancer progression in experimental mice thereby making it a potential candidate for treatment of liver cancer in clinical settings.

Microwave-Assisted Synthesis and Characterization of Certain Oximes, Hydrazones, and Olefins Derived from β-Keto Sulfones

A new series of β-keto sulfone derivatives containing oximes 4a–e, hydrazones 5a, b, and chalcones 7a–d were prepared using microwave irradiation (MWI) by the reaction of β-keto sulfones 3 with hydroxyl amine, hydrazines, and aromatic aldehydes, respectively. The comparative study between microwave irradiation and conventional syntheses showed that MWI is effective in the synthesis of the title compounds through shortening of the reaction time and improvements in their yields. The structures of the synthesized compounds were established under the basis of their spectral data and X-ray single crystal analysis of compound 5a. The crystal of 5a belongs to triclinic space group P-1, with A, A, A, °, °, °, A3, Mg m−3, mm−1, , , and for 2690 observed reflections with .

(Z)-7-[2-(4-Bromo­phen­yl)hydrazin-1-yl­idene]-6-methyl-3-(pyridin-4-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thia­diazine

In the asymmetric unit of the title compound, C16H12BrN7S, there are two crystallographically independent molecules with similar conformations. Both molecules are slightly twisted; the central 1,2,4-triazolo[3,4-b]-1,3,4-thiadiazine ring system makes dihedral angles of 9.65 (15) and 13.29 (15)° with the pyridine and benzene rings, respectively, in one molecule, whereas the corresponding values in the other molecule are 9.30 (15) and 4.84 (15)°. A weak intramolecular C—H⋯N interaction with an S(6) ring motif is observed in each molecule. In the crystal, the independent molecules are each linked through N—H⋯N hydrogen bonds and weak C—H⋯N interactions into ribbons along the c axis. The ribbons are further linked together by weak C—H⋯N, C—H⋯π and π–π [centroid–centroid distances = 3.572 (2)–3.884 (2) Å] interactions.