Antifungal Methylphenone Derivatives and 5-Methylcoumarins from Mutisia friesiana

Abstract

In addition to the known mutisicoumarin A, the aerial parts of the shrub Mutisia friesiana afforded five new methylphenones, two new 5-methylcoumarins and a new related chromone. Their structures were elucidated by spectroscopic methods. 13C NMR data for mutisicoumarin A are reported for the first time. Mutisiphenones A and B and mutisicoumarin A showed antifungal activity against the phytopathogenic fungus Cladosporium cucumerinum.

5-Methylcoumaranones from Mutisia friesiana and Their Bioactivity

“…1 H and 13 C NMR data of 4 (Table ) were nearly identical to those of compounds 1 − 3 with the exception of resonances corresponding to the monooxygenated farnesyl group attached to C-3. On the other hand, the NMR data resembled those of the sesquiterpene unit of mutisiphenone B, isolated previously by us from M. friesiana . The presence of duplicated signals for certain carbons and for H-6‘, H-10‘, and Me-12‘ protons (Table ) indicated that compound 4 was a mixture of diastereomers (epimers at C-3 or C-8‘).…”

“…On the other hand, the NMR data resembled those of the sesquiterpene unit of mutisiphenone B, isolated previously by us from M. friesiana. 7 The presence of duplicated signals for certain carbons and for H-6′, H-10′, and Me-12′ protons (Table 2) indicated that compound 4 was a mixture of diastereomers (epimers at C-3 or C-8′). The isolation of 5-methylcoumaranones A-D (1-4) together with structurally related 5-methylcoumarins and 5-methylphenones 7 containing mono-and sesquiterpene residues enabled us to suggest a biosynthetic relationship between these three groups of compounds in the shrub M. friesiana (Figure 1).…”

“…Bioassay-guided fractionation of the aqueous extract of M. friesiana afforded caffeic acid derivatives and flavonoids as the main active compounds showing radical-scavenging activity . Recently, we have reported the isolation and structural elucidation of new antifungal diastereomeric furanones, 5-methylphenones, 5-methylcoumarins, and a related chromone …”

Structure Elucidation of Prenyl- and Geranyl-Substituted Coumarins in Gerbera piloselloides by NMR Spectroscopy, Electronic Circular Dichroism Calculations, and Single Crystal X-ray Crystallography

“…Based on information from the two biochromatograms shown in Figures 1 and 2, material correlated with bioactivity as well as material suggested by LC-PDA-HRMS to be prenyl-or geranyl coumarin derivatives were isolated by preparative-scale HPLC followed by analytical-scale HPLC as detailed in the Materials and Methods section. This led to isolation of the new compounds 2, 5, 6, 8, 10, 11, 14, 15, 17-19, and 23-25 as well as identification of the known compounds marmesin (1) [28], 7-demethylsuberosin (3) [29], apigravin (4) [30], bothrioclinin (7) [31], (+)-2-[(2R)-6-acetyl-2,3-dihydro-5-hydroxybenzofuran-2-yl]-prop-2-enyl 15-methylbutanoate (8) [29], 3,5-bis-(isopent-2-en-1-yl)-4-hydroxyacetophenone (9) [32], 6-acetyl-2,2-dimethyl-8-(3-methylbut-2-en-1-yl)-2H-chromene (12) [33], and mutisicoumarin B (16) [34] by comparison of their 1 H NMR data with data from the literature. Retention times, HRESIMS, and 1 H NMR data for 1, 3, 4, 7-9, and 12 are given in Table S1 .…”

“…Compound 2 is a new compound for which the name gerbeloid 1 is proposed. [33], and mutisicoumarin B (16) [34] by comparison of their 1 H NMR data with data from the literature. Retention times, HRESIMS, and 1 H NMR data for 1, 3, 4, 7-9, and 12 are given in Table S1, Supplementary Material.…”