New Ferrocene Compounds as Selective Cyclooxygenase (COX-2) Inhibitors: Design, Synthesis, Cytotoxicity and Enzyme-inhibitory Activity
Authors: Farzaneh Shabnam , Zeinalzadeh Elnaz , Daraei Bahram , Shahhosseini Soraya , Zarghi Afshin 
Published: October 2017

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.