Analysis of plant secondary metabolites from specialized organs, tissue and cells
In Chapter 3, HPLC-SPE-NMR was successfully applied to elucidate structures of secondary metabolites from different plant materials. Twelve C-methylated chalcones and flavonoids were identified from Myrica gale seeds. Eleven and ten phenylphenalenone-type compounds were identified from aerial parts and roots of Wachendorfia thyrsiflora plant, respectively, and four others from both parts. Twelve of them are new compounds. Among the 25 phenylphenalenone-type compounds from W. thyrsiflora, the phenylphenalenones occurred exclusively in roots, oxa-phenylphenalenones were found in both aerial part and roots, and most aza-phenylphenalenones were detected in aerial parts. Eight phenylphenalenones including a new one and a corresponding dimer were elucidated from W. thyrsiflora seeds. Seventeen phenylphenalenones, oxa-phenylphenalenones and aza-phenylphenalenones, including five new ones, and three flavonoids were identified from Xiphidium caeruleum flowers. In Chapter 4, eleven glucosinolates and eighteen phenolics including seven new lignans were characterized from rapeseed (Brassica napus) cultivar “Emerald”. Further study on the organ-specific distribution of these compounds in rapeseed was conducted. As a result, glucosinolates and sinapine were proven to be accumulated evenly in rapeseed embryo, while a cyclic spermidine conjugate was exclusively found in hypocotyl and/or radicle, and the major amount of flavonoids was detected in cotyledons of rapeseed embryo. Chapter 5 was dedicated to explore spatio-temporal formation and accumulation of the predominant lignan, secoisolariciresinol diglucoside (SDG), in flaxseed (Linum usitatissimum). SDG was detectable in developing flaxseed around six days after flowering, and its biosynthesis ceased before the seeds browned and desiccated. SDG accumulates predominantly in parenchymatous cells in mature flaxseed coat. This finding is different from previous reports of SDG accumulation in sclerified cells of the seeds coat.