82(P07) トベラ種子の新規赤色カロテノイドtobiraxanthinの構造研究(ポスター発表の部)

概要

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In the corse of the carotenoids studies, a series of red carotenoids, named tobiraxanthins A1, A2, A3, B, C and D were isolated from the seeds of Pittosporum tobira. Thetobiraxanthins were found to be consisted with a carotenoid and fatty acid(s) moieties by the analyses of MS and ^1H-NMR data. The molecular formular of tobiraxanthin A1 was assigned to be C_<68>H_<108>O_8 by HRFABMS. The fatty acid moieties of A1 were characterized to be dimyristyl acids on the basis of the characteristic fragmentions observed in FABMS; [M-C_<14>H_<27>O_2 ]^+ and [M-2(C_<14>H_<27>O)_2]^+-The structure of the carotenoid moiety was determined by ^1H decoupling, ^1H-^1H NOE, ^<13>C-^1H COSY and LSPD experiments in NMR spectroscopy (Fig. 2). Thus, tobiraxanthin A1 was determined to be 3,3'-dihydroxy-5,6,5',6'-diseco-β,β-carotene-5,6,5',6'-tetraone dimyristate (Fig. 1). The structures of A2, A3, B, C and D were determined in a similar manner as shown in Fig. 1. Chemical conversion of tobiraxanthin B to the red carotenoid 1^2 by treatment with base was also examined, since tobiraxanthins show a remarkable lability toward base.
天然有機化合物討論会の論文
1997-07-20