Rakesh Kumar Mishra

Design, synthesis, antimicrobial, anticancer evaluation, and QSAR studies of 4-(substituted benzylidene-amino)-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-ones

A series of 4-(substituted benzylidene-amino)-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-ones (1–17) was synthesized and tested in vitro for its antimicrobial and anticancer potentials. The biological screening results indicated that compounds having m-chloro substituent on benzaldehyde portion showed antimicrobial potential, whereas compounds having chloro, methoxy, and hydroxyl groups showed anticancer potential. The quantitative structure activity relationship (QSAR) studies indicated the importance of topological parameter, valence first order molecular connectivity index in describing antifungal activity. The developed QSAR models, however, were statistically insignificant with reference to anticancer activity of the synthesized compounds.

Chitosan coated alginate-xanthan gum bead enhanced pH and thermotolerance of Lactobacillus plantarum LAB12.

The vulnerability of probiotics at low pH and high temperature has limited their optimal use as nutraceuticals. This study addressed these issues by adopting a physicochemical driven approach of incorporating Lactobacillus plantarum LAB12 into chitosan (Ch) coated alginate-xanthan gum (Alg-XG) beads. Characterisation of Alg-XG-Ch, which elicited little effect on bead size and polydispersity, demonstrated good miscibility with improved bead surface smoothness and L. plantarum LAB12 entrapment when compared to Alg, Alg-Ch and Alg-XG. Sequential incubation of Alg-XG-Ch in simulated gastric juice and intestinal fluid yielded high survival rate of L. plantarum LAB12 (95%) at pH 1.8 which in turn facilitated sufficient release of probiotics (>7 log CFU/g) at pH 6.8 in both time- and pH-dependent manner. Whilst minimising viability loss at 75 and 90 °C, Alg-XG-Ch improved storage durability of L. plantarum LAB12 at 4 °C. The present results implied the possible use of L. plantarum LAB12 incorporated in Alg-XG-Ch as new functional food ingredient with health claims.

Development of novel pectin based membranes as proton conducting material

This work reports the synthesis and characterization of modified pectin based polymer electrolyte membranes crossilnked with glutaraldehyde (GA). The prepared diethanolamine modified pectin (DAP) membranes were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), methanol permeability and impedance spectroscopy. FTIR spectroscopic investigation indicates the presence of secondary amide absorption bands in the developed polymer electrolyte membranes. X-ray analysis reveals considerable improvement in the crystallinity of the electrolyte membranes after modification. The methanol permeability measurement confirms the lower methanol cross-over through the developed DAP membranes. A maximum room temperature proton conductivity of 2.536 × 10−2 was obtained for the membrane, which was designated as DAP-4. These properties make them good candidates for low cost biopolymer electrolyte membranes for fuel cell applications.

Synthesis, antimicrobial, anticancer, antiviral evaluation and QSAR studies of 4-(1-aryl-2-oxo-1,2-dihydro-indol-3-ylideneamino)-N-substituted benzene sulfonamides

Abstract A series of 4-(1-aryl-2-oxo-1,2-dihydro-indol-3-ylideneamino)-N-substituted benzenesulfonamide derivatives (1–32) was synthesized and evaluated for its in vitro antimicrobial, antiviral and cytotoxic activities. Antimicrobial results indicated that compounds (11) and (18) were found to be the most effective ones. In general, the synthesized compounds were bacteriostatic and fungistatic in their action. The cytotoxic screening results indicated that the compounds were less active than the standard drug 5-fluorouracil (5-FU). None of the compounds inhibited viral replication at subtoxic concentrations. In general, the presence of a pyrimidine ring with electron releasing groups and an ortho- and para-substituted benzoyl moiety favored antimicrobial activities. The results of QSAR studies demonstrated the importance of topological parameters, valence zero order molecular connectivity index (0 χ v ) and valence first order molecular connectivity index (1 χ v ) in describing the antimicrobial activity of synthesized compounds.

Synthesis, Antimicrobial and Anticancer Evaluation of 2-Azetidinones Clubbed with Quinazolinone

A novel series of 2-azetidinones clubbed with quinazolinone was synthesized using anthranilic acid. All the synthesized compounds were evaluated for their antimicrobial activity against two Gram positive bacterial strains (Bacillus subtilis and Staphylococcus aureus), one Gram negative bacterial strain (Escherichia coli) and two fungal strains (Candida albicans and Aspergillus niger). All the synthesized compounds were also screened for their anticancer activity against human breast cancer cell line, MCF-7. Results of antimicrobial and anticancer study indicate that compounds 12 and 5 (IC50 = 49.52 μM) are the most potent antimicrobial and anticancer agents, respectively.

4-Thiazolidinone derivatives: synthesis, antimicrobial, anticancer evaluation and QSAR studies

A series of 4-thiazolidinone derivatives (1–18) was synthesized and tested in vitro for its antimicrobial and anticancer potential. Synthesized compounds were found to be 5 more potent antimicrobial agents than anticancer agents. Anticancer screening results indicated that compound 13 (IC50 = 15.18 μM) was the most active anticancer agent and was more potent than the standard drug, carboplatin (IC50 > 100 μM). Antimicrobial activity results indicated that 14 was the most active antimicrobial agent (pMICec = 2.14 μM) and may serve as an important lead for the discovery of novel antimicrobial agents. The QSAR studies indicated that the antibacterial and antifungal activities of the synthesized derivatives against different microbial strains were governed by lipophilic parameter, log P, topological parameter, κα3 and electronic parameters cos E and Nu. E.

Synthesis, Antimicrobial, Anticancer Evaluation of 2-(aryl)-4- Thiazolidinone Derivatives and their QSAR Studies

A new class of 4-thiazolidinones clubbed with quinozolinone nucleus has been synthesized. The title compounds were screened for their in vitro antimicrobial and anticancer potentials. Results of antimicrobial and anticancer study revealed that compounds 7 (pMICam = 1.69 μM/ml) and 2 (IC50 = 12.83 μM) were found to be the most potent antimicrobial and anticancer agents respectively. QSAR studies indicated that antimicrobial activity of synthesized 4-thiazolidinone derivatives was governed by the electronic parameters, dipole moment (μ), energy of highest occupied molecular orbital (HOMO), lipophilic parameter, log P and topological parameter, valence third order molecular connectivity index ((3)χ(v)).

Synthesis, characterization and material properties of novel poly vinyl acetate grafted pectin

Graft copolymerization of vinyl acetate (VAc) on pectin was performed using a redox initiator ceric ammonium nitrate (CAN). The grafting conditions were optimized by studying the effect of monomer, vinyl acetate (VAc) and initiator (CAN) concentrations as well as temperature and time. These variables appreciably affected the percentage of grafting and grafting efficiency of the grafted pectin (GP). GP was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Thermal properties of GP were evaluated by differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). DSC result showed a slight elevation in glass transition temperature (Tg) of the GP in comparison to pectin. XRD study revealed an increase in crystallinity of the pectin after grafting with VAc. This indicates that the chemical structure and morphology of pectin changes after modification. TGA exhibits an increase in thermal stability of the grafted copolymer as compared to the reference pectin.

Synthesis, antimicrobial, anticancer evaluation and QSAR studies of thiazolidin-4-ones clubbed with quinazolinone.

A series of 3-(5-(arylidene)-2-(aryl)-4-oxothiazolidin-3-yl)-2-phenylquinazolin-4(3H)-one derivatives (1-18) was synthesized in appreciable yield and characterized by physicochemical and spectral means. The synthesized compounds were evaluated for their in vitro antimicrobial and anticancer potentials. Antimicrobial properties of the title compounds were investigated against Gram positive and Gram negative bacterial as well fungal strains. 3-(5-(3- Methoxybenzylidene)-2-(4-(dimethylamino)phenyl)-4-oxothiazolidin-3-yl)-2-phenyl quinazolin-4(3H)-one (16, pMICam = 1.71 µM/ml) was found to be the most active antimicrobial agent. The anticancer evaluation of synthesized compounds against human colon (HCT116) cancer cell line indicated that 3-(5-(4-bromobenzylidene)-2-(3-chlorophenyl)-4- oxothiazolidin-3-yl)-2-phenylquinazolin-4(3H)-one (7, IC50 = 5.27 µM) was the most active anticancer agent and was more potent than standard drug, 5-fluorouracil (IC50 = 6.00 µM). QSAR models developed for antimicrobial activity of synthesized compounds indicated that antimicrobial activity of synthesized 4-thiazolidinone derivatives was governed by the topological parameters, valence first and second order molecular connectivity indices ((1)Χ(v) and (2)Χ(v)) and the electronic parameters, total energy (Te) and cosmic energy (Cos E).