Pharmacological evaluation of ONNO donor quadridentate Schiff bases

Abstract

Four ONNO donor Schiff bases 2-(( E )-(2-(( E )-2-hydroxybenzylideneamino)ethylimino) methyl)phenol (H 2 L 1 ), 2-(( E )-(2-(( E )-2-hydroxybenzylideneamino)propylimino)methyl) phenol (H 2 L 2 ), 2-(( E )-1-(2-(( E )-1-(2-hydroxyphenyl) ethylideneamino)ethylimino)ethyl) phenol (H 2 L 3 ) and 2-(( E )-1-(2-(( E )-1-(2-hydroxyphenyl)ethylideneamino)propylimino) ethyl)phenol (H 2 L 4 ) were synthesized by the reactions of ethylene/propylene diamines with 2-hydroxy benzaldehyde/2-hydroxy acetophenone. The new compounds were characterized by FT-IR and NMR ( 1 H and 13 C) spectroscopic techniques accompanied by elemental, GC/MS and single crystal X-ray diffraction analyses. These compounds were screened for various biological studies i.e. brine shrimp cytotoxic, antitumor and antibacterial activities The compound H 2 L 3 showed highest cytotoxic and antitumor activities with lowest LD 50 (14.27) and IC 50 values (18.90). All the compounds were highly active in protecting DNA against hydroxyl free radicals. Antibacterial studies had shown that these were inactive against Gram positive bacteria ( Staphylococcus aureus and Micrococcus luteus) while active against Gram negative bacteria ( Enterobacter aerogenes , Bordetella bronchiseptica and Salmonella typhi) showing variable antibacterial activity.