Synthesis and in vitro antioxidant activity study of some new piperazinyl flavone compounds

Flavones as a Privileged Scaffold in Drug Discovery: Current Developments

BACKGROUND

Flavones are one of the main subclasses of flavonoids with diverse pharmacological properties. They have been reported to possess antimalarial, antimicrobial, anti-tuberculosis, anti-allergic, antioxidant, anti-inflammatory activities, among others.

OBJECTIVE

The present review summarizes the recent information on the pharmacological properties of naturally occurring and synthetic flavones.

METHODS

Scientific publications referring to natural and synthetic flavones in relation to their biological activities were hand-searched in databases such as SciFinder, PubMed (National Library of Medicine), Science Direct, Wiley, ACS, SciELO, Springer, among others.

RESULTS

As per the literature, seventy-five natural flavones were predicted as active compounds with reference to their IC50 (<20 µg/mL) in in vitro studies. Also, synthetic flavones were found active against several diseases.

CONCLUSION

As per the literature, flavones are important sources for the potential treatment of multifactorial diseases. However, efforts toward the development of flavone-based therapeutic agents are still needed. The appearance of new catalysts and chemical transformations is expected to provide avenues for the synthesis of unexplored flavones, leading to the discovery of flavones with new properties and biological activities.

Synthesis and in vitro antioxidant activity of new pyrimidin/benzothiazol-substituted piperazinyl flavones

Aim: Synthesis of novel 2(2-hydroxyphenyl) pyrimidine/benzothiazole piperazinyl-substituted flavones end evaluate their antioxidant activity. Results: Six novel 2-(2-hydroxyphenyl) pyrimidine/benzothiazole-substituted flavones were synthesized, their structures were confirmed by elementary and spectral analyses. The compounds were evaluated for their in vitro antioxidant potency by employing various antioxidant assays. Conclusion: All tested compounds acted as scavengers of free radicals like hydroxyl (15–45%), 2,2-diphenyl-1-picrylhydrazyl• (17–48%) at 1.25 and 0.5 mM concentrations respectively. The total antioxidant status activity values of the compounds ranged from 234.1 to 464.1 μm trolox equivalent/g, the total antioxidant capacity – from 24.9 to 52.7 μm trolox equivalent per gram. Compounds incorporating the benzothiazole group on the piperazine ring were more effective antioxidants than those with the 2-(2-hydroxyphenyl) pyrimidine group.