Flavonoid characters contributing to the taxonomic revision of the Hebe parviflora complex

Comparative flavonoid chemistry is a key element of a multidisciplinary study aimed at a revision of the genus Hebe, New Zealand's largest genus of flowering plants. One aspect of this study has been an investigation of the Hebe parviflora complex. A recent botanical paper on this topic marshalls generalised flavonoid data and morphological characters to support the recognition of two species in this complex, Hebe stenophylla and Hebe parviflora, which are clearly distinguishable from each other and from the related Hebe traversii and Hebe strictissima. A detailed study of the flavonoid chemistry and the distributional data used to support these conclusions are presented here. Six new compounds have been isolated in this study, including 6-hydroxyapigenin-7-O-beta-[2-O-beta -xyloxyloside] and-7-O-beta-[2-O-beta -xyloglucoside], 6-hydroxyluteolin-7-O-beta-[2-O-beta -xyloxyloside] and, luteolin-, 6-hydroxyluteolin- and 4'-O-methylluteolin-7-O-beta-[6-O-beta -xyloglucoside]. Other flavonoids include apigenin and luteolin 7- and 4'- mono-, di- and possibly tri-O-glycosides, 8-hydroxyluteolin 7- and 8-O-glucosides, and kaempferol and quercetin 3-O-mono- and di-glycosides. New structure assignments are supported with detailed (1)H and (13)C NMR data, including HMQC and HMBC measurements. (C) 2001 Elsevier Science Ltd. All rights reserved.