The major vacuolar flavonoid of a greenhouse-grown plant of Becium grandiflorum has been identified as the 8-O-glucoside of isothymusin (5,8,4'-trihydroxy-6,7-dimethoxyflavone), while the major external flavonoids in the diethyl ether surface wash of the same plant are found to be isothymusin and cirsimaritin (5,4'-dihydroxy-7,8-dimethoxyflavone). Although isothymusin is already known as a conversion product of thymusin (5,6,4'-trihydroxy-6,7-dimethoxyflavone) formed by means of the Wessely-Moser rearrangement, this is the first report of isothymusin as a plant constituent, both as aglycone and glycoside. The biogenetic and chemotaxonomic implications of the occurrence of these flavonoids in B. grandiflorum are briefly discussed.
chemotaxonomy, flavonoid glycosides, Lamiaceae, Becium grandiflorum, external flavonoids, isothymusin 8-O-glucoside, isothymusin, cirsimaritin
NCBI PubMed ID: 9542170Publication DOI: 10.1016/s0031-9422(97)00626-2Journal NLM ID: 0151434Publisher: Elsevier
Institutions: Dipartimento di Chimica delle Sostanze Naturali, Università degli Studi di Napoli ‘Federico II’, Napoli, Italy
Methods: 13C NMR, 1H NMR, acid hydrolysis, HPLC, UV, extraction, ROESY, TOCSY, PC, COSY, HSQC
Found