New Phenalenone-type Phytoalexins fromMusa acuminata(Colla AAA) Grand Nain

Abstract

Four new phenalenone-type phytoalexins (2 -5) have been isolated from rhizomes of Musa acumituzta (AAA) infected with the fungus Fusurium oxysporum. The structures of the new phytoalexins were elucidated using spectroscopic evidence, chemical correlation, synthesis, and X-ray diffraction analysis. The major compound 2, has been previously described as a natural product, named anigorufone, but never as a phytoalexin. The chemical shift for all of the hydrogen and carbon atoms in the substances were unanibiguously established by mono-and bidimensional, homo-and heteronuclear NMR experiments ('HNMR, ''CNMR, COSY, HMQC and HMBC). In preliminary in virro assays, all of the four new phytoalexins have shown inhibitory activity on the growth of the germinative tube of Fusurium oxysporum f. sp. cubense race 4.

Fungus-Elicited Metabolites from Plants as an Enriched Source for New Leishmanicidal Agents: Antifungal Phenyl-Phenalenone Phytoalexins from the Banana Plant ( Musa acuminata ) Target Mitochondria of Leishmania donovani Promastigotes

“…has frequently profited by some natural antifungal drugs, such as amphotericin B, azole derivatives, paramomycin, saponins, and naphthoquinones (3,10,11,30), since similar pharmacological targets are present in these two groups of organisms. In fact, recent successful approaches to search for new leishmanicidal drugs profit from To test this strategy in phytoalexins, we assayed the leishmanicidal activity of two natural products, anigorufone and REF20 (25), and three related phenyl-phenalenone structures. These phytoalexins are synthesized under fungal challenge and showed antibiotic activity against the eliciting fungus, albeit their mechanism of action is completely unknown at present (25).…”

“…In fact, recent successful approaches to search for new leishmanicidal drugs profit from To test this strategy in phytoalexins, we assayed the leishmanicidal activity of two natural products, anigorufone and REF20 (25), and three related phenyl-phenalenone structures. These phytoalexins are synthesized under fungal challenge and showed antibiotic activity against the eliciting fungus, albeit their mechanism of action is completely unknown at present (25). The whole set of drugs caused the inhibition of both promastigote and amastigote proliferation with similar efficacy; moreover, the inhibition of amastigote proliferation was even better for EP5 and EP6.…”

“…Their inhibition of SDH and FRD activities pinpoints these enzymes as their more likely targets. Two of them were originally isolated from the banana plant (M. acuminata) elicited with the fungus F. oxysporum (25). Thus, a new approach to define leishmanicidal agents will profit from this higher probability of finding new leishmanicidal compounds in plants previously challenged with fungi.…”

“…As expected from this functional classification, the structural diversity for both groups is extremely large, and structures such as flavanones, isoflavones, aurones, stilbenes, or phenalenones are gathered under the common name of phytoalexins (13,16,18,25). A survey of the literature addressing the microbicidal activity of phytoalexins on human pathogens revealed an unexpectedly scarce number of works; these reports mainly focused on in vitro assays for bactericidal and fungicidal activities (7) and, to our knowledge, none of these studies examined the use of phytoalexins as antiprotozoal agents.…”

“…Its synthesis is triggered by infection with the fungus Fusarium oxysporum, a saprophytic pathogenic fungus that causes Panama's disease in the banana plant (25). We tested anigorufone and reference 20 (REF20), another phytoalexin from the same origin, and reference 5 (REF5), a methoxy derivative of anigorufone, together with epoxide 5 (EP5) and epoxide 6 (EP6), two precursors of their chemical synthesis, on L. donovani promastigotes and L. infantum axenic amastigotes.…”