Prenylated Flavanones from Monates engleri: On-line Structure Elucidation by LC/UV/NMR

Eliane Garo, Jean Luc Welfender, Kurt Hostettmann, Wolf Hiller, Sándor Antus, Steven Mavi

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The CH2Cl2 extract of Monotes engleri GILG. (Dipterocarpaceae) showed antifungal activity against the yeast Candida albicans in our bioautographic TLC assays. After a first fractionation of the crude extract, the bioactivity was located in one of the fractions. To perform an efficient targeted isolation of the active compounds, LC/UV/MS and LC/UV/NMR analyses of the crude extract and the active fraction were performed. LC/UV, LC/MS, and LC/NMR data (ID and 2D) allowed the identification of 1 as (2S)-2,3-dihydro-5,7-dihydroxy-2-{3-hydroxy-4-[(3-methylbut-2-enyl)oxy]phenyl}- 4H-1-benzopyran-4-one, a new prenylated flavanone, named monotesone A. Subsequent isolation of 1 has permitted the determination of its absolute configuration on the basis of CD measurements. Three other prenylated flavanones 2-4 were isolated from the same extract. Compound 3 was identified as 2-(3,5-dihydroxyphenyl)-2,3-dihydro-5,7-dihydroxy-6,8-bis(3-methylbut-2-enyl)- 4H-1-benzopyran-4-one, another new natural product, named monotesone B. The structures of 2 and 4 were established as selinone and lonchocarpol A, respectively. The antifungal activity against Candida albicans was determined for all compounds.

Original languageEnglish
Pages (from-to)754-763
Number of pages10
JournalHelvetica Chimica Acta
Issue number4
Publication statusPublished - Dec 1 1998

ASJC Scopus subject areas

  • Catalysis
  • Biochemistry
  • Drug Discovery
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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    Garo, E., Welfender, J. L., Hostettmann, K., Hiller, W., Antus, S., & Mavi, S. (1998). Prenylated Flavanones from Monates engleri: On-line Structure Elucidation by LC/UV/NMR. Helvetica Chimica Acta, 81(4), 754-763.