2-Pyrazol-1-yl-thiazole derivatives as novel highly potent antibacterials.

The present report describes our efforts to identify new structural classes of compounds having promising antibacterial activity using previously published double-reporter system pDualrep2. This semi-automated high-throughput screening (HTS) platform has been applied to perform a large-scale screen of a diverse small-molecule compound library. We have selected a set of more than 125,000 molecules and evaluated them for their antibacterial activity. On the basis of HTS results, eight compounds containing 2-pyrazol-1-yl-thiazole scaffold exhibited moderate-to-high activity against ΔTolC Escherichia coli. Minimum inhibitory concentration (MIC) values for these molecules were in the range of 0.037-8 µg ml-1. The most active compound 8 demonstrated high antibacterial potency (MIC = 0.037 µg ml-1), that significantly exceed that measured for erythromycin (MIC = 2.5 µg ml-1) and was comparable with the activity of levofloxacin (MIC = 0.016 µg ml-1). Unfortunately, this compound showed only moderate selectivity toward HEK293 eukaryotic cell line. On the contrary, compound 7 was less potent (MIC = 0.8 µg ml-1) but displayed only slight cytotoxicity. Thus, 2-pyrazol-1-yl-thiazoles can be considered as a valuable starting point for subsequent optimization and morphing.

Trans-, cis-, and dihydro-resveratrol: a comparative study.

BACKGROUND: Recent studies showed that moderate consumption of red or white wines increased the chances of breast cancer, while similar consumption of red wines, rich in trans-resveratrol (trans-R), decreased the rate of prostate cancer. This prompted us to explore the role of various forms of R in cancer proliferation. RESULTS: Trans-R was found to be the most potent antiproliferative agent. Cis-R demonstrated somewhat less potency compared to trans-R. Unlike cis-R and trans-R, dihydro-R exhibits moderate proliferative effect on androgen-independent prostate cancer cell lines PC-3 and DU-145 at picomolar concentrations. At higher concentrations, dihydro-R caused proliferation inhibition, similar to cis-R and trans-R. The proliferative effect of dihydro-R at low concentrations can be reversed by trans-R which acts as a partial antagonist in the presence of dihydro-R. Mixtures of dihydro-R and trans-R demonstrated complex non-monotonic cross-modulation activity patterns. CONCLUSIONS: Dihydro-R exhibits proliferative effects in androgen-independent prostate cancer cells at picomolar and nanomolar concentrations. While the exact mechanism of these effects requires further evaluation, our preliminary results point to hormone receptor modulation activity. We also observed strong cross modulation between trans-R and dihydro-R at sub-picomolar concentrations. The role of dihydro-R in cancer proliferation related to moderate consumption of red wine remains an open question because dihydro-R has a very complex activity pattern in the presence of trans-R.

Dihydro-resveratrol--a potent dietary polyphenol.

Dihydro-resveratrol (dihydro-R), a prominent polyphenol component of red wine, has a profound proliferative effect on hormone-sensitive tumor cell lines such as breast cancer cell line MCF7. We found a significant increase in MCF7 tumor cells growth rates in the presence of picomolar concentrations of this compound. The proliferative effect of dihydro-R was not observed in cell lines that do not express hormone receptors (MDA-MB-231, BT-474, and К-562).