<b>Background and Objective:</b> <i>Celosia cristata</i> L. is an ornamental plant that has the potency to be developed as a medicinal plant. The mutation breeding of <i>C. cristata</i> targets the increase of biochemical compounds that are potential as antioxidants. This study aimed to evaluate the phenolic and flavonoid contents and antioxidant activity of the putative mutants of <i>C. cristata</i> in the M1 generation. <b>Materials and Methods:</b> The samples used in this study were flowers and seeds. Induced mutation, using ethyl methane sulphonate (EMS) was used to obtain M1 generation of putative mutants and twelve putative mutants were selected for polyphenol contents analysis composed of total phenolic (TPC), total flavonoid (TFC) and antioxidant activities analysis using two approaches, i.e., 2,2-diphenyl picrylhydrazyl (DPPH) method and ferric reducing antioxidant power (FRAP). <b>Results:</b> This study showed that total phenolics were varied from 11.73-18.06 mg GAE g<sup></sup><sup>1</sup> DW and total flavonoids were varied from 2.34-3.11 mg QE g<sup></sup><sup>1</sup> DW. Meanwhile, the antioxidant activity gain using the DPPH method ranged from 16.43-19.02 μmol TE g<sup></sup><sup>1</sup> DW and the FRAP method ranged from 40.72-59.61 μmol TE g<sup></sup><sup>1</sup> DW. The clustering analysis results formed three clusters with two clusters consisting of potential mutants with higher biochemical content and antioxidant capacities. It was found that total phenolic and flavonoids highly correlated with the antioxidant FRAP. <b>Conclusion:</b> Induced mutation using EMS can increase the diversity of biochemical characters and antioxidant activity of <i>C. cristata</i> and provide potential genetic material with higher chemical content for further development.
Keywords: C. cristata; Polyphenols; genetic material; mutation breeding; putative mutants.