Cytotoxic Evaluation of (E)-1-(2',4'-difluorobiphenyl-4-yl)-3-arylprop-2-en-1-one Derivatives

M. Fathimunnisa1 and H. Manikandan2

1Department of Chemistry, AVC College (autonomous), Mannampandal - 609 305, Tamilnadu, INDIA.
2Department of Chemistry, Annamalai University, Annamalainagar - 608 002, Tamilnadu, INDIA.

(Received on: November 8, Accepted: November 17, 2017)


A series of (E)-1-(2',4'-difluorobiphenyl-4-yl)-3-arylprop-2-en-1-one derivatives were synthesized and in vitro cytotoxic activity of the compounds were evaluated against Hep-2 cell line by MTT assay. The structure activity relationship based on the type of substituent on C-3 propenones was explored.

Keywords:Cytotoxic activity; MTT assay; Hep-2 cell line; Difluorobiphenyl chalcone.


Although there is a rapid development in diagnosing and treating cancer, it remains a major threat to the patients. It is a challenge for the chemists to develop new anticancer drugs with high selectivity and absorptivity than the existing drugs. To overcome the side effects emerging from the presently available drugs, there is a need to develop better cytotoxic agents to prevent such a problem1.
Chalcones possess wide range of therapeutic and pharmacological activities due to the presence of methylene and carbonyl moieties in their structure. They present in many naturally occurring vascular plants not only in their terrestrial parts but also in roots, flakes and seeds. A large variety chalcone based derivatives were reported and identified as better anticancer agent. These compounds exhibits a wide variety of pharmacological activities which includes anticancer, antiinflammatory, immunomodulatory, antibacterial, and immunosuppressive, as well as antiprotozoan activity, including trypanocidal, leishmanicidal, and antimalarial2-8. The biphenyl moiety is also found in many natural products that exhibits a wide variety of biological activities such as anti-cancer9-12, anti-angiogenic9,11, anti-viral13 and have the ability to display enhanced fluorescence14. We recently reported the synthesis, characterization, in vitro antimicrobial activity against various microbes and in silico docking studies against cancer protein 4LRH15. From the molecular docking studies it was concluded that the synthesized difluorobiphenyl chalcones was found to be exhibit anticancer activity against the tested ligand. With the aim to evaluate the in vitro cytotoxic activity of the synthesized analogues, in the present study the cytotoxic activity was tested against Hep-2 cell line.


The cytotoxicity of the synthesized compounds were tested against Hep-2 cell lines using the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay16. The cells were seeded into a 96-well plate at a density of 1.5 × 104 cells/well and incubated at 37 oC, 5 % CO2, for 24 h to allow the cells to attach. Cells were incubated with 10 μM of synthesized compounds into designated wells. After 48 h of incubation at 37 oC, 20 μL of MTT solution (4 mg/mL) was added to each well. The plates were further incubated for 4 h at 37 oC, allowing viable cells to change the yellow-colored MTT into dark-blue formazan crystals. Consequently, without disturbing the cells the MTT medium was removed from each well, and 100 μL of DMSO was added into each well. Plates were placed on a shaking table to thoroughly mix the formazan into the solvent. Finally, the absorbance was determined at 570 nm by microplate reader (Tecan infinite M200 pro multimode reader, Austria). The MTT assays were performed four times independently, and each independent experiment was done in triplicate. The percentage of survival was calculated using the formula: % Survival = [live cell number (test)/live cell number (control)] × 100
Cytotoxicity (%) = 100 ‒ % survival


Various (E)-1-(2',4'-difluorobiphenyl-4-yl)-3-arylprop-2-en-1-ones (3a-l) were prepared with excellent yield by Claisen-Schimidt condensation of 1-(2',4'- difluorobiphenyl-4-yl)ethanone (1) with various substituted aldehydes (2a-l) under basic condition as displayed in Table 1 (Scheme 1).

Table 1 Synthesis of (E)-1-(2',4'-difluorobiphenyl-4-yl)-3-arylprop-2-en-1-ones

Compound Ar Compound Ar
3a C6H5 3g 4-BrC6H4
3b 4-CH3C6H4 3h 3-NO2C6H4
3c 4-FC6H4 3i 2-furyl
3d 3-OCH3C6H4 3j 2-thiophenyl
3e 2-OCH3C6H4 3k 2-naphthyl
3f 4-ClC6H4 3l CH=CHC6H5

The in vitro cytotoxic activity of the compounds 3a-l was evaluated against Hep-2 cell line which is derived from laryngeal carcinoma cells by MTT assay. The percentage of the cell viability was determined and cytotoxicity percentage was calculated (Table 2). The graphical representation was displayed in Fig. 1. On critically analyzing the results, all the compounds exhibit moderate to potent activities. From the cytotoxicity data it was noticed that the conjugates 3d and 3e with methoxy substitution (3-OCH3 and 2-OCH3) have higher cytotoxicity of 56.7 and 45.5 % respectively. The results were in concord with the reported literature that the electron donating groups on aryl substituted chalcones exhibit relatively higher cytotoxicity than the electron withdrawing group17. The compounds 3a, 3b, 3f, 3g and 3l with phenyl, 4-methyl, 4-chloro, 4-bromo and cinnamyl substitution displayed moderate activity with 25.5-29.1%. Moreover, the furyl (i), thiophenyl (3i) and naphthyl (3k) substituted derivatives were found to possess less activity (12.6-15.8%) while the 4-fluoro and 3-nitro derivatives were found to possess very poor cytotoxic activity (5.6-8.4%). Based on the substitution on the phenyl ring, the cytotoxic activity decreases in the order of 2-OCH3 > 3-OCH3 > H > 4-Br> cinnamyl > 4-Cl > 4-CH3 > 2-furyl > 2-thiophenyl > 2-naphthyl > 3-NO2 > 4-F. From the results it seems that the methoxy group at both ortho and meta position have significant activity against the tested cell line. However, the modifications in the chalcone analogs can explore new cytotoxic agents.

Table 2 Cytotoxicity (%) of the compounds 3a-3l

Compound 3a 3b 3c 3d 3e 3f 3g 3h 3i 3j 3k 3l
Cell viability (%) 7.9 74.5 94.4 54.4 43.3 74. 7.6 9.6 84. 85.3 87.4 79.
Cytotoxicity (%) 9. 5.5 5.6 45.5 56.7 5.8 7.4 8.4 5.8 4.7 .6 .8


In the present work, the efficiently synthesized derivatives were tested against Hep-2 cancer cell line. The 2-methoxy (3e) and 3-methoxy (3d) substituted compounds displayed high potency than the other substituted analogues. In conclusion, these findings suggest that the(E)-1-(2',4'-difluorobiphenyl-4-yl)-3-arylprop-2-en-1-ones exhibit cytotoxic activity and might be developed as an anticancer agent.


Authors thank SAIF, IIT-Madras for the support in single crystal data collection and gratefully acknowledge UGC for financial support under MRP scheme.


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