---

In this study, the antioxidant activity and protective effects of Purslane Seed Water-Methanolic Extract (PSWME) in stabilizing SoyBean Oil (SBO) were tested. DPPH radical scavenging activity of PSWME at different concentrations varied significantly (P< 0.05), ranging from 15.41% to 79.06%. Total phenolic content in PSWME was 121.09 mg Gallic Acid Equivalent (GAE) kg^-1 dw. The protective effects of PSWME at the level of 100 mg L^-1 in stabilizing SBO were tested and compared to BHT in a concentration of 100 mg L^-1 by measuring Peroxide Value (PV) and ThioBarbituric Acid (TBA) during accelerated storage (at 60°C). The results showed that PSWME, similar to BHT, reduced the formation of primary and secondary oxidation products in SBO. Therefore, the use of this extract as a natural antioxidant is recommended to prevent the oxidation of vegetable oils.