Investigation of two o-hydroxy Schiff bases in terms of prototropy and radical scavenging activity

Background & Introduction : Antioxidants are known to prevent oxidative stress-induced damage to the biomolecules and thus, delay the onset of cancers and many age-related diseases. Therefore, the development of novel and potent antioxidants is justified. Method: During this study, we synthesized symmetrical bis-Schiff bases of carbohydrazide 1-27, and evaluated their in vitro antioxidative activity and cytotoxic activity. Results: Among synthesized compounds, six compounds 20 (IC50 = 12.89 ± 0.02 µM), 16 (IC50 = 14.32 ± 0.43 µM), 17 (IC50 = 18.52 ± 0.83 µM), 19 (IC50 = 22.84 ± 0.62 µM), 24 (IC50 = 35.1 ± 0.82 µM) and 15 (IC50 = 40.03 ± 1.06 µM) showed an excellent 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, better than the standard butylatedhydroxyanisole (BHA) (IC50 = 44.6 ± 0.6 µM). Likewise, two compounds 16 (IC50 = 4.3 ± 1.3 µM) and 20 (IC50 = 6.6 ± 1.6 µM) showed oxidative burst scavenging activity better than the standard drug ibuprofen (IC50 = 11.2 ± 1.9 µM). Some synthesized compounds showed good to moderate toxicity against prostate cancer (PC-3) cell lines. Conclusion: This study has identified potent antioxidants and good cytotoxic agents with the potential to further investigate.

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Microwave-assisted Green Synthesis of β-Diketone Hydrazone Derivatives and Evaluation of their Antioxidant and Antibacterial Activities

Current Microwave Chemistry ◽

10.2174/2213335607999200917145217 ◽

2020 ◽

Vol 7 (3) ◽

pp. 222-229

Author(s):

Syed Tajudeen Syed Ameen ◽

Anbalagan Vilvanathan ◽

Syed Zameer Ahmed Khader ◽

Gayathri Mahalingam

Keyword(s):

Schiff Bases ◽

Radical Scavenging Activity ◽

Research Work ◽

Radical Scavenging ◽

Reaction Times ◽

Spectroscopic Techniques ◽

Scavenging Activity ◽

Standard Drug ◽

Antioxidant Power ◽

Microwave Assisted

Background: A series of β-diketone hydrazones have been synthesized via condensation of isoniazid with series of β-diketone. The structures of the Schiff bases are established by elemental and spectroscopic techniques. The prepared compounds were screened for antibacterial and antioxidant potential by DPPH free-radical scavenging activity and Ferric reducing antioxidant power (FRAP) assays. Methods: β-diketone hydrazine derivatives were synthesized by simple condensation between various β-diketones and isoniazid. The titled compounds were synthesized following both conventional and microwave irradiation methods. The in vitro antibacterial activity of synthesized derivatives was evaluated against gram-positive (B. subtilis, S. aureus and S. pyogenes) and gram-negative (E. coli, and K. pneumonia) bacterial strains and expressed in terms of zone of inhibition and also screened for antioxidant activity. Results: The yield of products was appreciably increased in shorter reaction times with the aid of microwave-assisted synthesis. Therefore, it follows the green chemistry approach by making the above reactions eco-friendly. The synthesized compounds were characterized using FT-IR, 1H NMR, 13C NMR, and elemental analysis techniques. The spectroscopic techniques showed the formation of β-diketone hydrazone compounds. Theoretical data show good agreement with the experimental results. Some of the compounds displayed significant antibacterial and antioxidant potentials when compared to the standard drug. Conclusion: In the present research work, we report the synthesis of some novel β-diketone hydrazone derivatives. A high yield of compounds was noted under microwave-assisted reaction in shorter reaction times. The results revealed that the synthesized Schiff bases showed good radical scavenging activity.

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