Vikramjeet Judge

Synthesis, antimicrobial and antiviral evaluation of substituted imidazole derivatives

In the present study, we have synthesized 2-(substituted phenyl)-1H-imidazole (1-12) and (substituted phenyl)-[2-(substituted phenyl)-imidazol-1-yl]-methanone (13-26) analogues and screened them for their antimicrobial activity against gram positive, gram negative and fungal species. The results of antibacterial study indicated that compounds 15, 17 and 24 showed appreciable antibacterial activity and compound 26 emerged as the most potential antifungal agent. The results of SAR studies indicated that the presence of electron withdrawing groups is necessary for the antimicrobial activity of the synthesized compounds. The results of the present study indicated that compounds 15, 17 and 24 might be of interest for the identification of new antimicrobial molecules as their antibacterial activity is equivalent to the standard drug norfloxacin. Further, the antiviral screening of (substituted phenyl)-[2-(substituted phenyl)-imidazol-1-yl]-methanones (13-26) against a panel of viral strains indicated that compounds 16 and 19 can be selected as lead compounds for the development of novel antiviral agents.

Hansch analysis of substituted benzoic acid benzylidene/furan-2-yl-methylene hydrazides as antimicrobial agents.

A series of substituted hydrazide derivatives have been synthesized and screened for their in vitro antimicrobial activities against five representative microorganisms. The results of antimicrobial study indicated that the presence of electron withdrawing groups on the benzoic acid moiety improved antimicrobial activity. Further, the presence of heterocyclic ring furan does not improve the antimicrobial activity of substituted hydrazides. To understand the relationship between physicochemical parameters and antimicrobial activity of substituted hydrazide derivatives, QSAR investigation was performed by the development of one-target and multi-target models. The multi-target model was found to be effective in describing the antimicrobial activity of substituted hydrazides in comparison to the one-target models. Further, it indicated the importance of the topological parameter, valence third order molecular connectivity index ((3)chi(v)) and the electronic parameter, energy of highest occupied molecular orbital (HOMO) in describing the antimicrobial activity of substituted hydrazides.

Benzylidene/2-chlorobenzylidene hydrazides: Synthesis, antimicrobial activity, QSAR studies and antiviral evaluation

Abstract A series of benzylidene hydrazides (1–20) was synthesized and tested, in vitro, for antibacterial, antifungal and antiviral activities. The microbial screening results indicated that compounds having chloro and nitro substituents were the most active ones. The antiviral evaluation depicted that compounds 9 and 19 were active against Vesicular stomatitis virus (VSV) in HeLa cell cultures. QSAR investigations indicated that the multi-target QSAR model was effective in describing the antimicrobial (antibacterial and antifungal) activity over the one-target QSAR models. Further the mt-QSAR model indicated that the topological parameters, second order molecular connectivity index (2 χ) and third order Kiers alpha shape index (κα 3) are effective in describing the antimicrobial activity of synthesized hydrazides.

Isonicotinic acid hydrazide derivatives: synthesis, antimicrobial activity, and QSAR studies

A series of isonicotinic acid hydrazide derivatives (1–19) was synthesized and tested in vitro for antimycobacterial activity against Mycobacterium tuberculosis and antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Candida albicans, and Aspergillus niger and the results indicated that the compounds with OH, SCH3, and OCH3 groups were found to be active against the tested strains. None of the test compounds were active against a broad variety of RNA and DNA viruses at subtoxic concentrations, except 8, that showed some selective anti-reovirus-1 activity. The multi-target QSAR models were found to be effective in predicting the antimicrobial activity of the isoniazid derivatives and indicated the importance of nuclear repulsion energy (Nu.E) in explaining the antimicrobial activity of isoniazid derivatives. The developed QSAR models were validated using the external test set of synthesized derivatives.

Hansch analysis of veratric acid derivatives as antimicrobial agents.

The synthesis, characterization and antimicrobial evaluation of a new series of veratric acid derivatives are presented. Preliminary in vitro antimicrobial activity of the title compounds was assessed against a panel of microorganisms including Gram-positive and Gram-negative bacteria and fungi. Some of the veratric acid derivatives exhibited significant in vitro antimicrobial activity. QSAR investigation applied to find a correlation between different physicochemical parameters of the veratric acid derivatives and their antimicrobial activity indicated the importance of topological parameters in describing the antimicrobial activity.

Synthesis, antimicrobial and antiviral activity of substituted benzimidazoles

In the present study we have synthesized (4-nitrophenyl)-[2-(substituted phenyl)-benzoimidazol-1-yl]-methanones, (2-bromophenyl)-[2-(substituted phenyl)-benzoimidazol-1-yl]-methanone analogues (1–14) and evaluated them for their antimicrobial and antiviral potential. The results of antimicrobial screening indicated that none of the synthesized compounds were effective against the tested bacterial strains. Compounds 3, 11, 13 and compounds 5, 11, 12 were found to be active against Aspergillus niger and Candida albicans respectively, and may be further developed as antifungal agents. Furthermore, evaluation against a panel of different viruses pointed out the selective activity of compounds 5 and 6 against vaccinia virus and Coxsackie virus B4.

Synthesis, antimycobacterial, antiviral, antimicrobial activities, and QSAR studies of isonicotinic acid-1-(substituted phenyl)-ethylidene/cycloheptylidene hydrazides

A series of isonicotinic acid-1-(substituted phenyl)-ethylidene/cycloheptylidene hydrazide derivatives (1–12) was tested for their, in vitro antimycobacterial activity against Mycobacterium tuberculosis, and compound 2 was found to be more active than isoniazid. The antiviral screening results indicated that none of the tested compounds was active against a broad variety of DNA and RNA viruses at subtoxic concentrations, except compounds 8 and 10 that proved to be active against DNA viruses at concentrations close to their cytostatic potential. The synthesized compounds were also screened for their antimicrobial potential against S. aureus, B. subtilis, E. coli, C. albicans and A. niger, and the results indicated that compounds having Br, OCH3 and Cl groups were highly active. The multi-target QSAR models indicated the importance of lipophilic (log P) and topological parameters (3χv) in describing the antimicrobial activity.

Isoniazid: the magic molecule

The resurgence of tuberculosis and emergence of multidrug resistant isolates has focused attention on the need for an improved understanding of molecular aspects of the disease, and for elucidation of the factors responsible for drug action and resistance. Isoniazid is the frontline drug employed in the treatment of tuberculosis. Recent research has probed the mechanism of action of isoniazid (INH), a key drug in the chemotherapy of tuberculosis and also the anti-mycobacterial potential of derivatives of isoniazid has been evaluated. We have made an attempt to compile an account of various derivatives of isoniazid reported for their diverse biological activities like anti-mycobacterial, -bacterial, -fungal and -viral activities.

Antimicrobial evaluation of 4-methylsulfanyl benzylidene/3-hydroxy benzylidene hydrazides and QSAR studies

A series of 4-methylsulfanyl benzylidene/3-hydroxy benzylidene hydrazides (1–20) was synthesized and tested for in vitro antimicrobial activity against S. aureus, B. subtilis, E. coli, C. albicans and A. niger. The results of antimicrobial studies indicated that 3-phenylacrylic acid-(3-hydroxybenzylidene)-hydrazide, 16, was the most effective as it showed both bactericidal and fungicidal properties and other compounds possessed bacteriostatic/fungistatic activity. The multi-target QSAR model demonstrated that the topological parameter, Balaban topological index (J) is effective in describing the antimicrobial activity of synthesized substituted hydrazides.

2,4-Disubstituted thiazoles as multitargated bioactive molecules

Thiazoles are important heterocyclics exhibiting boundaryless biological activities, such as antibacterial, antifungal, anti-inflammatory, antitumor, antitubercular, antidiabetic, antiviral, and antioxidant. Substituents on a particular position of the thiazole ring affect the biological outcomes to a great extent. Therefore, researchers have synthesized compounds containing the thiazole ring with variable substituents as target structures, and evaluated their biological activities. The present review describes the biological importance of recently developed 2,4-disubstituted thiazole derivatives. Moreover, we have thrown light on various targets of 2,4-disubstituted thiazoles through which they induce biological effects, which will be helpful to those who are working on the design and structure–activity relationship of bioactive molecules.