Abstract
Interaction and binding of isonicotinic acid hydrazide (INH) and its two analogs; pyrazine carboxylic acid hydrazide (PCH) and 2,4-dihydroxy benzoic acid hydrazide (2,4-DHBAH) with DNA has been investigated by UV-spectroscopy and cyclic voltammetry (CV) at physiological conditions of pH and temperature. Experimental results from both techniques were in good agreement and indicated stronger binding and formation of hydrazides–DNA complexes
via intercalation. Among three hydrazides, 2,4-DHBAH showed greater interaction toward DNA at stomach pH (4.7) as evident from its comparatively greater binding constant, {
K
b
; 2.02 × 10
4 M
−1 (UV), 3.13 × 10
4 M
−1 (CV)}. The greater binding site size (
n = 3) for 2,4-DHBAH at stomach pH inferred 3:1 binding stoichiometry and possibility of electrostatic interactions or hydrogen bonding along with intercalative mode of interaction between 2,4-DHBAH and DNA. The free energies of hydrazides–DNA complexes indicated the spontaneity of their binding. 2,4-DHBAH has shown promising anti-bacterial activities while anti-oxidant and cytotoxic potentials were exhibited by all three hydrazides.
Isonicotinic acid hydrazide, pyrazine carboxylic acid hydrazide and 2,4-dihydroxy benzoic acid hydrazide showed good DNA binding ability
via intercalation. All hydrazides have anti-oxidant potential, while 2,4-DHBAH showed promising anti-bacterial activities.
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► Hydrazide INH and its analog PCH and 2,4-DHBAH interact with DNA
via intercalation. ► All compounds showed good DNA binding as investigated by UV and voltammetric studies. ► Binding constant results from both techniques were in good agreement and showed stronger binding. ►
K
b
and
n values of 2,4-DHBAH revealed its relatively stronger binding at stomach pH. ► All compounds have anti-oxidant potential; 2,4-DHBAH showed anti-bacterial activity.