86.Gentiana urnula Harry Sm.の花由来の新規抗酸化成分(口頭発表)

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Objectives: Gentiana urnula Harry Sm. is a small perennial plant distributed in the high mountain regions (3700-5700m altitude) in western China and Himalaya, and its flower has been used traditionally as "Gang-gah Chung" in Tibetan medicine systems. Our extensive screenings of alpine plants in the regions have shown the flower of G. urnula contains strong antioxidants. Regarding the chemical ingredients, however, little information is currently available except for the presence of some iridoid compounds. This study, therefore, focused on the exploration of main antioxidants contained in the flower. Methods: Methanol extract from the dried flowers of G. urnula was used as a starting material for purification. The crude extract dispersed in water was extracted with ethyl acetate and subsequently with n-butanol. The n-butanol fraction was further purified by mid-pressure LC (Yamazen) and HPLC (Shiseido) using C18 reverse phase columns. DPPH radical scavenging assay was used for the evaluation of antioxidant activity. Three antioxidant compounds were purified and subjected for structural analyses (NMR and HR-MS). Results: Two compounds were identified as known iridoid glycosides (Gentiournoside A and Gentiournoside E). The other one, which exhibited the highest antioxidant activity, was a novel iridoid with MW 782. The content of the novel iridoid in the dried flower was calculated to be approximately 0.7w/w% from its recovery rate.
2010-10-01