Synthesis and characterisation of novel 2,4-diphenyloxazole derivatives and evaluation of their in vitro antioxidant and anticancer activity

Background In the present study, novel 2,4-disubstitued oxazoles were synthesised, characterised and screened for their biological activities. Methods Various substituted benzoic acids were refluxed with phenylacyl bromide in presence of triethylamine, to yield the respective phenylacyl esters, which on further refluxation with acetamide gave 2,4-disubstituted oxazole. The synthesised compounds were analysed by spectral studies to confirm their structure. Then, they were studied for their in vitro antioxidant activity by DPPH and nitric oxide radical scavenging methods. In addition, the in vitro anticancer activity was determined by MTT assay using HepG2 and HeLa cell lines. Results Totally, fifteen novel 2,4-disubstituted oxazole derivatives were synthesised, characterised and screened for their biological activities. Among the compounds tested, OXD-10, having 4-nitro-3-hydroxy phenyl substitution at the second position showed 50% free radical scavenging at 461.28 μg/ml by nitric oxide radical scavenging method. Other compounds were not found to have antioxidant activity by both methods. In vitro anticancer activity was performed on two different cancerous cell lines and compounds OXD-6 and OXD-15 showed promising activity on HepG2 cell line and their IC50 value was calculated as 16.89 and 16.65 μM respectively. Whereas, compound OXD-13 exhibited significant growth inhibition on HeLa cells and the IC50 value was 56.52 μM. Conclusion The above results concluded that, the compounds containing 2-nitro phenyl and 4-acetyloxyphenyl substituents at the second position in the oxazole scaffold played an important role in determining their anticancer potential and the 4-nitro-3-hydroxy phenyl group at second position in the scaffold could impart a major role in their radical scavenging property.