Phytochemical composition, antioxidant capacity and ACE-inhibitory activity of China-grown radish seeds

The seeds of nine China-grown radish cultivars were analyzed for their phytochemical composition, antioxidant properties and ACE-inhibitory activity. Radish seeds contained 36.87–43.06% (w/w) oils, whereas 64.55–69.26% of the fatty acids were monounsaturated and 20.33–25.11% were polyunsaturated. The levels of δ- tocopherol (552.24–670.31 μg/g seed oils) and lutein (4.82–8.95 μg/g seed oils) differed in cultivars. The nine cultivars were varied in total phenolics, flavonoids, and free phenolic acids, but not in proanthocyanidins. Seed extracts of Hybrid #63, Tou Xin Hong, and Hybrid #72 showed stronger DPPH radical scavenging capacity, ORAC, and FRAP than others (p<0.05). The Yanzhi #2 extracts exhibited a strong ACE-inhibitory activity, which was positively correlated with vanillic acid contents (r = 0.890, p = 0.001). It provides evidence on developing value-added utilization of radish seeds or seed fractions such as oil and flour as nutraceuticals or functional food ingredients.