Synthesis and biological activity of alkylthio and arylthio Derivatives of tert-butylquinone

Abstract

Biological activity of 2-tert-butyl-1,4-benzoquinone (TBQ) and its deri­vatives, 2-tert-butyl-5-(2-propylthio)-1,4-benzoquinone, 2-tert-butyl-5- -(propyl­thio)-1,4-benzoquinone, 2-tert-butyl-5,6-(ethylenedithio)-1,4-benzo­quinone, 2-tert-butyl-5-(phenylthio)-1,4-benzoquinone and 2-tert-butyl-6-(phe­nylthio)-1,4-benzo­quinone, were tested for their antioxidant, antibacterial, toxic, cytotoxic and geno­toxic potential. Using the DPPH test, all derivatives showed good antioxidant act­ivity, better than ascorbic acid, and the 2-tert- -butyl-5-(propylthio)-1,4-benzo­quin­one derivative showed the strongest effect. Better antibacterial potential was obs­erved against Gram-positive bacteria in the broth microdilution method in which the 2-tert-butyl-5-(phenylthio)-1,4- -benzoquinone derivative showed the strongest activity (MIC = 15.6 µM). The results of toxicity tests, using the Brine shrimp test, indicated that the deri­vatives lose their toxic potential compared to TBQ, except for 2-tert-butyl-6-(phenylthio)-1,4-benzoquinone, which showed a 3 times stronger effect. Cyto­tox­icity was assessed by the MTT assay in 24 and 72 h treatments in MRC-5, HS 294T and A549 cell lines in threefold decreasing gradient (11, 33 and 100 μM). Modifications potentiate the cytotoxic effect, and the strongest effect was observed with the 2-tert-butyl-5,6-(ethylendithio)-1,4-benzoquinone derivative. In addition, the genotoxic potential was examined in the MRC-5 cell line using the comet assay. All tested derivatives of TBQ showed a genotoxic effect at all applied subtoxic concentrations. In general, the chemical modifications of TBQ enhanced its biological activity.