Evaluation of antioxidant activities of synthesized iminochalcones

The effectiveness of chalcones is related to the flavonoids properties and their imino derivatives possess promising antibacterial and antifungal activities [1a-b, 2]. This stimulated our interest to couple chalcones with various hydrazines and hydroxylamine hydrochloride to check their antioxidant activities. So, nine variably substituted chalcones (Ch1–9) have been synthesized by Claisen-Schmidt condensation reaction and then converted to their respective three series of iminochalcones (Na₁-Nc₁₁) [3].

We investigated the potential of all of these compounds as antioxidant and studied the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging effect of these molecules to ascertain their potential in reducing the level of activated oxygen species. Cytotoxic activity of these compounds was also evaluated on HaCaT, nontumorigenic human keratinocyte cell line. The change in absorbance produced by reduced DPPH was observed to be comparable to the standard quercetine for eight out of twenty six tested compounds. Interestingly for the most effective ones (IC₂₅<500µM), no cytotoxicity on HaCaT cells was observed (IC₅₀>500µM). These preliminary findings suggest that the compounds from each series may provide lead compounds which might be further explored for the design of lead antioxidant drug candidates.

Acknowledgements: This work was supported by a HEC grant (Pakistan) and presentation by the French Foreign Office (Agrocampus, Rennes)

References: 1. a) Ahmad, S. et al. (2006) Eur. J. Pharmacol. 538: 188–194. b) Hsu, Y.L. et al. (2006) Food Chem. Tox. 44: 704–713.

2. Prescott, B. (1975) Int. J. Clin. Pharmacol. Biopharm. 11: 332–5.

3. Rasheed, L. et al. (2007) Asian. J. Chem, 19: 5057–5067.