Natural acetylenes. Part XLVII. Biosynthetic experiments with the fungus Lepista diemii(singer). Biogenesis of the C8 acetylenic cyano-acid diatretyne 2

Bioactive polyacetylenes in food plants of the Apiaceae family: Occurrence, bioactivity and analysis

“…Feeding experiments with 14 Cand 3 H-labelled precursors have confirmed this assumption and shown that they are built up from acetate and malonate units [7][8][9][10][11][15][16][17][18][19]. Polyacetylenes of the falcarinol-type are formed from oleic acid by dehydrogenation leading to the C 18 -acetylenes crepenynic acid and dehydrocrepenynic acid, which is then transformed to C 17 -acetylenes by ␤-oxidation.…”

“…In the beginning of 1980s anticancer activity was demonstrated for petrol extracts of the roots of P. ginseng [43], and since then the lipophilic portion of this plant has been intensively investigated. This had led to the isolation and identification of several cytotoxic polyacetylenes [24,[44][45][46][47], including falcarinol (1), panaxydol (17) and panaxytriol (18) (Figs. 1 and 3).…”

Acetylenes and Psoralens

“…Figures 5.1 and 5.2) makes it reasonable to assume that most acetylenes are biosynthesized with the latter acids as precursors. Many feeding experiments with 13 C-, 14 C-and 3 H-labelled precursors have confirmed this assumption and further that they are built up from acetate and malonate units (Bu'Lock and Smalley 1962;Bu'Lock and Smith 1967;Bohlmann et al 1973;Jones et al 1975;Barley et al 1988;Bohlmann 1988;Jente et al 1988;Christensen and Lam 1990). Further evidence of C 18 -acids as precursors in the biosynthesis of most acetylenes has recently been obtained through identification of a gene coding for a fatty acid acetylenase (triple bond forming enzyme), which occurs in the same plant species that produce acetylenes and can be induced by fungal infection (Cahoon et al 2003).…”

Biosynthesis of the allene (–)-marasin in Marasmius ramealis

“…In 1959 Bendz described the isolation and characterization of the antibiotic (−)-marasin (7) from the fungus Marasmius ramealis. 14 The (+)-enantiomer, accompanied by at least ten other polyacetylenes, was subsequently isolated from Aleurodiscus roseus by Jones et al, 15 and the same research group isolated the (−)-enantiomer, together with two other polyacetylenes, from Cortinellus berkeleyanus.…”

“…14 The (+)-enantiomer, accompanied by at least ten other polyacetylenes, was subsequently isolated from Aleurodiscus roseus by Jones et al, 15 and the same research group isolated the (−)-enantiomer, together with two other polyacetylenes, from Cortinellus berkeleyanus. 11 Since (−)-marasin (7) is the only major polyacetylene isolated from M. ramealis, this organism was selected for the present studies.…”