Synthesis, characterization and biological evaluation of Schiff’s bases derivatives as potent antibacterial agents

Objective: To design, synthesize and screen biologically newer Substituted Schiff bases by condensing substituted acid hydrazides with various benzaldehydes and explore their antimicrobial potential.Methods: Present study synthesis of various derivatives of Schiffs bases was carried out by: firstly converting substituted acids to acid hydrazides and then to Schiff's bases after condensation with substituted benzaldehyde. Synthesized compounds were characterised on the basis of spectral studies (like UV, IR, and NMR). All the synthesized derivatives were screened further for their antibacterial effect against Salmonella typhimurium, Shigella sonnei, Staphylococcus aureus& Bacillus cereus.Results: From this study it could be observed that schiff’s bases 2-[( aminophenylhydrazinyldene o,m,dinitrobenzoyl] aniline (H) and compound 2-[( aminophenylzinyldene) p amino benzoyl] aniline (I) showed very good zone of inhibition against almost all strains tested for.Conclusions: So further attempts could be made to extend the series and explore their antibacterial potential to achieve hopeful goal.

SYNTHESIS AND EVALUATION OF SOME SUBSTITUTED ARYL OXADIAZOLE AND MERCAPTO OXADIAZOLE DERIVATIVES FOR ANTIFUNGAL, ANTIMICROBIAL AND ANTITUBERCULAR ACTIVITIES

A number of substituted aryloxadiazoles and mercaptooxadiazoles are known for their biological importance like anti-bacterial, antifungal, anticancer and anti-inflammatory activity. The present investigation is carried out for the synthesis of certain substituted aryloxadiazole and mercaptooxadiazoles and evaluation of their biological activity. The title compounds have been synthesized by reacting isoniazid with substituted aryl aldehydes to give Schiffs bases which on treatment with aromatic acids in presence of phosphorus oxychloride gives aryl oxadiazoles. Mercaptooxadiazoles were synthesized using isoniazid and carbon disulphide. The newly synthesized compounds have been characterized by IR, 1H NMR and CHN analysis. Selected compounds are screened for antimicrobial and antitubercular activity in vitro. Few of them exhibited promising activity.

SYNTHESIS AND ANTIMICROBIAL STUDY OF SOME NEW PICRIC ACID DERIVATIVES

In the present study, a new series of picric acid derivatives including their Schiffs bases were synthesized and characterized by their physical (m.p., Rf value), analytical (CHN) and spectral (UV-Visible, IR,1 HNMR, MS) data. The synthesized compounds were screened for antimicrobial activity by paper disc diffusion method against four different strains of Gram positive (Bacillus subtilis, Staphylococcus aureus)and Gram negative bacteria (Eschericia coli, Pseudomonas aeruginosa) and against two fungal strains(Candida albicans, Aspergillus fumigates). All the compounds showed antibacterial activity at the tested dose but were considerably less as compared to the standard drug ciprofloxacin. The antifungal activity was also found to be very less when compared to the standard drug ketoconazole for all the synthesized compounds. However, among the synthesized compounds Schiffs bases of picric acid showed better activity than that of parent compounds.

Synthesis of Novel Piperonal Derivatives and Evaluation of their Anticonvulsant Activity using A Nanoparticular Formulation

Ancient Chinese medical literature and independent studies indicate that piperine possess anticonvulsant activity and demonstrates a high degree of safety. A similarity was also demonstrated with synthetic piperine derivatives as well. In this study, chalcones and Schiffs bases of piperonal with different any methyl ketones, and aromatic primary amines were synthesized using conventional and microwave-irradiation methods. Purification of these compounds was effected by recrystallization from alcohol and characterized by NMR and IR spectra. The synthesized compounds were screened for their anticonvulsant activity using a 4-aminopyridine induced model with the help of a conventional and a current nanoparticular formulation approach. A drug delivery system methodology in the form of nanoparticles for screening was adopted because it has more advantages when compared to conventional formulations in drug discovery stages. Nanoparticle formulations encapsulating selected synthesized compounds were prepared using solvent evaporation technique by taking polycaprolactone as the polymer. Few piperonal synthesized derivatives demonstrated anticonvulsant activity which was lesser than the standard phenytoin. Unfortunately, nanoparticular formulations prepared in this current study encapsulating selected synthesized compounds did not show any activity, suggesting more work is needed to demonstrate positive results.