The main characteristic of antioxidants is the capacity to scavenge free radicals produced during cell metabolism, and thus they prevent oxidative stress, which may reduce the risk of many diseases. In this study, we evaluate the antioxidant properties of selected four compounds Quercetin (Q), Epigallocatechin-3-Gallate, (EGCG), Indole-3-Carbinol (I3C) and Sulforaphane (SF) by DPPH assay. The view is to establish the distinction between direct and indirect antioxidants, which would be the form of the basis for subsequent cellular antioxidant assays in our further studies. For sample assay: 20 μL of antioxidant solutions of Q, EGCG, I3C, and SF was added to 180 of 2,2- Diphenyl-1-Picrylhydrazyl (DPPH) solution. For blank solution, DMSO was used. Leaving the plate for 15 min in a dark place and measure the absorbance at 540 nm. The results demonstrated that Q and EGCG possess direct antioxidant properties, which can be used in further cellular studies. I3C and SFN did not appear to possess any direct antioxidant behaviours during DPPH radical scavenging.