New Ferrocene Compounds as Selective Cyclooxygenase (COX-2) Inhibitors: Design, Synthesis, Cytotoxicity and Enzyme-inhibitory Activity

BACKGROUND

Due to the astonishing properties of ferrocene and its derivatives, it has a broad application in diverse areas. Numerous ferrocene derivatives demonstrated anti-proliferative activity. Also COX-2, as a key isoenzyme for production of prostaglandins, is frequently overexpressed in various cancers. It is now recognized that COX-2 over expression promotes tumorigenic functions which can be suppressed by COX-2 inhibitors, a phenomenon useful for the preventing of tumor progression. The combination of COX-2 inhibitors with other anti-cancer or cancer prevention drugs may reduce their side effects in future cancer prevention and treatment.

OBJECTIVE

Owing to high anticancer potential of ferrocene derivatives and considerable COX-2 inhibitory and cytotoxicity effects of our previously synthesized chalcones, we decided to incorporate the ferrocenyl moiety into appropriate COX-2 inhibitor chalcone based scaffold, to evaluate COX-2 inhibitory activity as well as anticancer activities.

METHODS

Chalcones were synthesized via clasien-schmidt condensation of methylsulfonyl aldehyde and acetyl ferrocene. Further different amines with solvent free and ultra sound condition were reacted with chalcones to have different 1-ferrocenyl-3-amino carbonyl compounds. Docking study was carried out with Auto Dock vina software. All the newly-synthesized compounds were evaluated for their cyclooxygenase-2 (COX-2) inhibitory activity using chemiluminescent enzyme assays as well as cytotoxicity activity against MCF-7 and T47D and fibroblast cell lines by MTT assay.

RESULTS

In vitro COX-1/COX-2 inhibition studies demonstrated that all compounds were selective inhibitors of the COX-2 isozyme with IC50 values in the highly potent 0.05-0.12 µM range, and COX-2 selectivity indexes (SI) in the 148.3-313.7 range. These results indicated that either potency or selectivity of COX-2 inhibitory activity was affected by the nature and size of the substituents on C-3 of propane-1-one. Also anti-proliferative and toxicity activities of synthesized compounds against breast cancer cell lines MCF-7 and T47D and fibroblast cell lines showed that the synthesized compounds had mild to moderate cytotoxicity against MCT7 and T47D breast cancer cell lines at 10 µM concentration. In vitro COX-1/COX-2 inhibition studies and anticancer activity against MCF-7, identified 1-ferrocenyl-3-(4-methylsulfonylphenyl) propen-1-one as a potent compound (IC50 COX-2 = 0.05 µM, MCF-7: % inhibition (at concentration of 10 µM) = 32.7%), and also 1-ferrocenyl-3- (propan-1-amine)-3-(4-methylsulfonylphenyl) propan-1-one showed the most selectivity on COX-2 inhibition (selectivity index= 313.7).

CONCLUSION

A novel group of ferrocene compounds, possessing a methyl sulfonyl COX-2 pharmacophore were synthesized to investigate the effect of different substituents on selectivity and potency of COX-2 inhibitory activity and their cytotoxicity effects. This study indicates that 1-ferrocenyl-3-amino carbonyl compounds having ferrocene motif and methyl sulfonyl COX-2 pharmacophore is a suitable scaffold to design COX-2 inhibitors and anti-cancer agents.

Thymol and carvacrol strongly inhibit biofilm formation and growth of carbapenemase-producing Gram negative bacilli

Discovery of novel drugs with new mechanisms of action and without cross-reaction with current therapeutic agents is crucial in the management of infections caused by multi-drug resistant (MDR) bacteria. The aim of the present study was to investigate effects of carvacrol and thymol on biofilm formation and antimicrobial activity against different carbapenemase-producing Gram negative bacilli. The antimicrobial and antibiofilm effect of thymol and carvacrol was investigated against strains harboring different genes related to carbapenemase resistance. Antimicrobial resistance was examined by an agar dilution method and antibiofilm effect was evaluated by microtiter plate assay and staining by crystal violet. Thymol and carvacrol had antibacterial effects ranging from 200-1600 μg/mL and 62-250 μg/mL respectively, and antibiofilm effect from 125-500 and 400-1600 μg/mL respectively. Seoul imipenemase- (SIM) producing isolates had the highest sensitivity, and NDM (New Delhi metallo-beta-lactamase) producing isolates had the lowest sensitivity to these components. Findings of the present study indicated a potential role of carvacrol and thymol in controlling carbapenemase-producing gram negative bacterial infections. These findings helped to develop herbal drugs for replacing antibiotics. In addition, their antibiofilm effects showed that carvacrol and thymol inhibit biofilm formation of carbapenemase-producing strains.