In the present study, five 4-aminophenol derivatives (4-chloro-2-(((4-hydroxyphenyl)imino)methyl)phenol(S-1), 4-((4-(dimethylamino)benzylidene)amino)phenol(S-2), 4-((3-nitrobenzylidene)amino)phenol(S-3), 4-((thiophen-2-ylmethylene)amino)phenol(S-4) and 4-(((E)-3-phenylallylidene)amino)phenol(S-5)) were synthesized and characterized by FT-IR, ¹H-NMR, ¹³C-NMR and elemental analyses. The synthesized compounds were tested for their antimicrobial (Gram-positive and Gram-negative bacteria and Saccharomyces cervesea fungus) and antidiabetic (α-amylase and α-glucosidase inhibitory) activities. All the compounds showed broad-spectrum activities against the Staphylococcus aureus (ATCC 6538), Micrococcus luteus (ATCC 4698), Staphylococcus epidermidis (ATCC 12228), Bacillus subtilis sub. sp spizizenii (ATCC 6633), Bordetella bronchiseptica (ATCC 4617) and Saccharomyces cerevisiae (ATCC 9763) strains. The newly synthesized compounds showed a significant inhibition of amylase (93.2%) and glucosidase (73.7%) in a concentration-dependent manner. Interaction studies of Human DNA with the synthesized Schiff bases were also performed. The spectral bands of S-1, S-2, S-3 and S-5 all showed hyperchromism, whereas the spectral band of S-4 showed a hypochromic effect. Moreover, the spectral bands of the S-2, S-3 and S-4 compounds were also found to exhibit a bathochromic shift (red shift). The present studies delineate broad-spectrum antimicrobial and antidiabetic activities of the synthesized compounds. Additionally, DNA interaction studies highlight the potential of synthetic compounds as anticancer agents. The DNA interaction studies, as well as the antidiabetic activities articulated by the molecular docking methods, showed the promising aspects of synthetic compounds.

The drug–DNA interaction study has significant role in pharmacology and helps to determine drug action mechanisms. Interaction of Salmon sperm DNA (D1626) immobilized on glassy carbon electrode (GCE) with metronidazole (MTZ) was investigated by employing constant current Potentiometry, UV‑Visible and FT-IR spectroscopic techniques. The decline in the peak area and current typically of guanine base with an increase in MTZ concentration was employed as analytical signal to investigate MTZ interaction with DNA. Acetate buffer solutions were used with pH values ranging from 4.0 to 8.0. The linear segment increased from 3 × 10^–4 to 1.5 × 10⁻³ M. It was observed that 8.05 × 10⁻⁶ M concentration of metronidazole (MTZ) (three minutes accumulation time) can be detected by use of this methodology. Reduction in oxidation potential for immobilized DNA (0.89 to 0.86 V) was noted after three minutes time of interaction. 5.5 × 10³ M^–1 binding constant (K) value was observed for MTZ drug. Hypochromic and hypsochromic shifts in the maximum adsorption bands of MTZ were observed in UV-Visible studies. The IR spectrum of MTZ–DNA complex comparison of DNA revealed spectral changes in several prominent DNA vibrations in terms of intensity compared to that of shift that reflected the weak (electrostatic) mode of interaction of MTZ with DNA. The present project aims to appraise and deliver some basic information of the employed technique to outline its application in order to estimate the pharmaceutically active compounds in their biological fluids and dosage forms.