2-Hydroxyflavanones from Leptospermum polygalifolium subsp. polygalifoliumEquilibrating sets of hemiacetal isomers
摘要:
2,5-Dihydroxy-6-methyl-7-methoxyflavanone and its isomer 2,5-dihydroxy-8-methyl-7-methoxyflavanone have been identified as the principal components in the ethanol extract of L. polygal folium subsp. polygalifolium. The former compound has been separated from the latter for the first time by crystallisation. Other flavonoids identified include an equilibrating mixture of novel 2,3,5-trihydroxyflavanones; the first discovery of this type of compound from a natural source. This study has also confirmed the presence of the triketones, flavesone and leptospermone, along with the closely related isoleptospermone as anti-microbial components. (C) 2003 Elsevier Ltd. All rights reserved.