Metal complexes driven from Schiff bases and semicarbazones for biomedical and allied applications: a review

Schiff Bases are versatile organic compounds which are widely used and synthesized by condensation reaction of different amino compound with aldehydes or ketones known as imine. Schiff base ligands are considered as privileged ligands as they are simply synthesized by condensation. They show broad range of application in medicine, pharmacy, coordination chemistry, biological activities, industries, food packages, dyes, and polymer and also used as an O₂ detector. Semicarbazone is an imine derivative which is derived from condensation of semicarbazide and suitable aldehyde and ketone. Imine ligand-containing transition metal complexes such as copper, zinc, and cadmium have shown to be excellent precursors for synthesis of metal or metal chalcogenide nanoparticles. In recent years, the researchers have attracted enormous attention toward Schiff Bases, semicarbazones, thiosemicarbazones, and their metal complexes owing to numerous applications in pharmacology such as Antiviral, Antifungal, antimicrobial, antimalarial, antituberculosis, Anticancer, anti-HIV, catalytic application in oxidation of organic compounds, and nanotechnology. In this review, we summarize the synthesis, structural, biological, and catalytic application of Schiff Bases as well as their metal complexes.

2,6-DAPBPTSC, 2,6-diacetylpyridine bis-4-phenyl-3-thiosemicarbazone; 35-DTBP, 3,5-di-tert-butylphenol; 3CLpro, 3C-like protease; ATNR, Amine terminated liquid natural rubber; ATT, 2-acetylthiophene thiosemicarbazone; BBPT, Biacetyl bis(4-phenyl-3-thiosemicarbazone); BBTSC, Benzyloxybenzaldehyde thiosemicarbazone; BCG, Bacillus calmette-guérine; BDT, Benzyldithiosemicarbazone; BGPT, Bipyridyl glyoxal bis(4-phenyl-3-thiosemicarbazone); BMTS, Biacetyl monothiosemicarbazone; Biological/biomedical activities; Bipy, 2,2-bipyridine; CT DNA, Calf thymus deoxyribonucleic acid; DAPY, 2,3-diamino-pyridine; DTBP, 2,6-di-tert-butylphenol; DTBQ, 2,6-di-tert-butyl-4,4′-benzoquinone; EAC, Enrichlish Ascitices Cells; HEK-293, Human Embryonic Kidney cells; HL-60, Human leukemia-60 cell line; HeLa, immortal cell lines; HepG2, Hepatic cellular carcinoma cells (Human liver cancer cell line); IgG, Immunoglobin G; K B HCT-8, Human colon cancer cell line; M-IBDET, N-methylisatin-β-4′,4′-diethylthiosemicarbazone; MCF-7, Michigan Cancer Foundation-7; MCF7 cells, Michigan Cancer Foundation-7 (breast cancer cell line); MHV, Mouse hepatitis virus; MLV, Moloney leukemia virus; MSOPD, N,N-bis(3-methylsalicylidene)-ortho-phenylenediamine; Metal complexes; NQSC, Naphthoquinone semicarbazone; NQTS, ortho-Naphthoquinone thiosemicarbazone; OLED, Organic light emitting diode; PAS, p-amino salicylic acid; PPTS, Picolinealdehyde-4-phenyl-3-thiosemicarbazone; Phen, 1,10-phenanthroline; SARS CoV, Severe Acute Respiratory Syndrome coronavirus; SARS, Severe acute respiratory syndrome; SB-HAG, Schiff bases of hydroxyamino guanidines; SK-MEL-30, Human Melanoma Cell Line; SK-OV-3 cells, Ovarian cancer cell line; SSB-HAG, salicylaldehyde Schiff bases of HAG; Schiff base; Semicarbazone; TCIDw, Tissue culture Infective Dose; TTBDQ, 3,5,3′,5′-tetra-tert-butyl-4,4′-diphenoquinone; VSV, vesicular stomatitis virus; scCO2, Super-critical carbon dioxide.