Gallic acid and its derivatives have a large number of applications in various fields of science. In nature, these compounds are widely distributed in plants and fruits, and thus they are being used as food stuffs, preservatives, etc. directly or indirectly by human community. They have also been implicated as anticarcinogenic, antimicrobial, antimutagenic, antiangiogenic and anti-inflammatory agents besides their use in treating critical diseases like depression, cancer, microbial infections, lipid-related diseases, etc. Herein, an attempt has been made to summarize the important uses of gallic acid derivatives which have extensively been disclosed particularly in various patents. This review would certainly create a great interest of the scientific community toward the developments and uses of gallic acid based compounds in the future.

Gallic acid and its derivatives not only exhibit excellent antioxidant, anticarcinogenic, antimutagenic, antimicrobial properties but also provide protection to the cells against oxidative stress. Gallic acid (3, 4, 5-trihydroxybenzoic acid), a low molecular triphenolic compound emerged as an efficient apoptosis inducing agent. The antimicrobial and other biological properties of gallic acid and its derivatives seemed to be linked with the hydrolysis of ester linkage between gallic acid and polyols like tannins hydrolyzed after ripening of many edible fruits. Gallic acid serves a natural defense mechanism against microbial infections and modulation of immune responses. The current review updates us with the diverse roles played by gallic acid, its antioxidant potential, action mechanism and more importantly the diverse array of applications in therapeutic and pharmaceutical areas.

The control of antimicrobial resistance (AMR) seems to have come to a dead end. The major consequences of the use and abuse of antibacterial drugs are the development of resistant strains due to genetic mutability of both pathogenic and nonpathogenic microorganisms. We, herein, report the synthesis, characterization and biological activities of coumarin-thiazole-pyrazole (CTP) molecular hybrids with an effort to explore and overcome the increasing antimicrobial resistance. The compounds were characterized by analyzing their IR, Mass, ¹H and¹³C NMR spectral data and elemental analysis. The in vitro antimicrobial activity of the synthesized compounds was investigated against various pathogenic strains; the results obtained were further explained with the help of DFT and molecular orbital calculations. Compound 1b and 1f displayed good antimicrobial activity and synergistic effects when used with kanamycin and amphotericin B. Furthermore, in vitro cytotoxicity of compounds 1b and 1f were studied against HeLa cells (cervical cancer cell) and Hek-293 cells. The results of molecular docking study were used to better rationalize the action and prediction of the binding modes of these compounds.

The biological and medicinal properties of 5-aminopyrazoles have prompted enormous research aimed at developing synthetic routes to these heterocyles. This review focuses on the biological properties associated with this system. Various synthetic methods developed up to 2010 for these compounds are described, particularly those that involve the reactions of β-ketonitriles, malononitrile, alkylidenemalononitriles and their derivatives with hydrazines, as well as some novel miscellaneous methods.