Abstract
Foliar flavonoids of Crossostephium chinense in Japan and Taiwan were isolated and further characterized. Eighteen flavonoid aglycones, luteolin, apigenin, hispidulin, chrysoeriol, 5,7,4′-trihydroxy-6,3′,5′-trimethoxyflavone, jaceosidin, cilsimaritin, quercetin 3-methyl ether, axillarin, chrysosplenol-D, cirsiliol, apometzgerin, 5,7,3′-trihydroxy-6,4′,5′-trimethoxyflavone, luteolin 3′,4′-dimethyl ether, cirsilineol, eupatilin, nepetin and 5,7,3′,4′-tetrahydroxy-6,5′-dimethoxyflavone, were identified by UV, 1H and 13C NMR spectroscopic, LC-MS and HPLC comparisons with authentic samples. The compounds existed on the leaf surface. Four flavonoid glycosides, quercetin 3,7-di-O-glucoside, quercetin 3-O-rutinoside, luteolin 7-O-glucoside and apigenin 7-O-rutinoside, were also isolated as the intracellular flavonoids. It was shown by HPLC survey that variation of the species’ flavonoids occurs among the collection sites.