Antioxidant stilbenoids, such as resveratrol, arachidin-1, and arachidin-3, have demonstrated beneficial effects on human health. Although resveratrol is commercially available, arachidin-1 and arachidin-3 are not, resulting in an opportunity to explore purification methods and to confirm biological activity. Recently, Arachis hypogaea hairy root cultures (produced via Agrobacterium rhizogenes-mediated transformation) were reported to secrete stilbenoids into liquid growth media upon elicitation in quantities sufficient for commercial production. The purpose of this study was to purify substantial quantities of resveratrol, arachidin-1, and arachidin-3 from A. hypogaea hairy root cultures using centrifugal partition chromatography (CPC), determine the antioxidant activity of these compounds using the thiobarbituric acid reactive substances (TBARS) assay, and determine the cytotoxicity of the compounds using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In a single run of CPC, resveratrol, arachidin-1, and arachidin-3 were separated to a purity of 97.1%, 97.0%, and 91.8%, respectively. Lipid oxidation was inhibited by a 27 and 7 μM dose for reference standards of resveratrol and arachidin-1, respectively, while oxidation was not inhibited up to a 27 μM dose for reference standard of arachidin-3. Oxidation was inhibited at a 14, 7, and 14 μM doses for CPC-purified resveratrol, arachidin-1, and arachidin-3, respectively. Arachidin-1 and arachidin-3 demonstrated cytotoxicity at 27 and 55 μM in RAW 264.7 and HeLa cell lines, respectively; while resveratrol exhibited no cytotoxicity to either cell line. These results demonstrate the integration of a production and purification system for the manufacturing of A. hypogaea-derived stilbenoids.