(Rel)-1 beta,2 alpha-di-(2,4-dihydroxy-6-methoxybenzoyl)-3 beta,4 alpha-di-(4-methoxyphenyl)-cyclobutane and other flavonoids from the aerial parts of Goniothalamus gardneri and Goniothalamus thwaitesii

摘要

The aerial parts of Goniothalamus gardneri (Annonaceae) has yielded the known flavonoids 2'-hydroxy-4,4',6'-trimethoxychalcone (flavokawain A), 2',4'-dihydroxy-4,6'-dimethoxydihydrochalcone, 4:2',4'-trihydroxy-6'-methoxydihydrochalcone, 5,7,4'-trimethoxyflavanone (naringenin trimethyl ether) and 7-hydroxy-5,4'-dimethoxyflavanone (tsugafolin) together with three novel compounds, the dimer characterised as (rel)-1 beta ,2 alpha -di-(2,4-dihydroxy-6-methoxybenzoyl)-3 beta ,4 alpha -di-(4-methoxyphenyl)-cyclobutane, 2',4'-dihydroxy-4,6'-dimethoxychalcone and 2'-hydroxy-4,4',6'-trimethoxydihydrochalcone. The last two have previously been synthesised but appear to be new natural products. A similar study of the aerial parts of G. thwaitesii led only to the isolation of the known flavonoids myricetin 4'-O-methyl ether-3-O-alpha -L-rhamnopyranoside (mearnsitrin) and myricetin-3-O-methyl ether (annulatin), together with the triterpenes friedelinol, friedelin and betulinic acid. All compounds were identified by spectroscopic analysis and, for known compounds, by comparison with published data. (C) 2000 Elsevier Science Ltd. All rights reserved. [References: 34]