Isolation and Identification of Components from Wasabi (<i>Wasabia japonica</i> Matsumura) Flowers and Investigation of Their Antioxidant and Anti-inflammatory Activities

Abstract

Wasabi (Wasabia japonica Matsumura) is a perennial plant, and its rhizome is widely used as a pungent spice. Wasabi rhizome has been reported to have various physiological activities, but the flower has not been studied in depth. The aim of the present study was to isolate compounds from wasabi flowers and clarify their antioxidant and anti-inflammatory activities. Three phenylpropanoids, one alkaloid and seven flavonoids were isolated from wasabi flowers. Among them, 2″-O-trans sinapoyl isovitexin was identified as a novel compound. Five compounds inhibited 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, with IC50 values of less than 100 µM. Luteolin isolated in this study was found to inhibit nitric oxide production in macrophage-like J774.1 cells, with an IC50 value of 24.1 ± 4.4 µM. Our results indicate that the phenolic compounds in wasabi flowers are effective ingredients for antioxidant and anti-inflammatory activities. For these reasons, wasabi flowers are expected to be used effectively as a functional food.