Investigating the spectrum of biological activity of ring-substituted salicylanilides and carbamoylphenylcarbamates

Abstract

In this study, a series of twelve ring-substituted salicylanilides and carbamoylphenylcarbamates were prepared and characterized. The compounds were analyzed using RP-HPLC to determine lipophilicity. They were tested for their activity related to the inhibition of photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Moreover, their site of action in the photosynthetic apparatus was determined. Primary in vitro screening of the synthesized compounds was also performed against mycobacterial, bacterial and fungal strains. Several compounds showed biological activity comparable with or higher than the standards 3-(3,4-dichlorophenyl)-1,1-dimethylurea, isoniazid, penicillin G, ciprofloxacin or fluconazole. The most active compounds showed minimal anti-proliferative activity against human cells in culture, indicating they would have low cytotoxicity. For all compounds, the relationships between lipophilicity and the chemical structure are discussed.

Scheme 1

Synthesis of the studied compounds.

Figure 1

Comparison of the log P data calculated using the two programs with the experimentally found log k values. The compounds are arranged in the ascending manner according to the experimental log k values.

Figure 2

EPR spectra of control chloroplasts (A) and chloroplasts treated with 0.05 M of compound 3 (B). Full lines were recorded in darkness. Dotted lines were recorded under irradiation (~400 μE/m²s PAR) directly in the resonance cavity with a 250 W halogen lamp from 0.5 m distance through a 5 cm water filter.