Guaiane Sesquiterpenes from Biscogniauxia nummularia Featuring Potent Antigerminative Activity

Abstract

Xylaranone, a previously unreported guaiane sesquiterpene along with the known terpenoid xylaranol B and the two mellein derivatives 3,5-dimethyl-8-methoxy-3,4-dihydroisocoumarin and 3,5-dimethyl-8-hydroxy-3,4-dihydroisocoumarin were isolated from Biscogniauxia nummularia. Pogostol was also isolated from this fungus, and in light of our spectroscopic data, its structure was revised and corrected. This fungus, which was isolated as an endophyte from the plum yew Cephalotaxus harringtonia, is also suspected of being a pathogen. Interestingly, we report here the potent antigerminative activity of xylaranone and xylaranol B against seeds of Raphanus sativus at concentrations comparable to glyphosate, a commonly used herbicide. This effect suggests a role for these metabolites in the latent fungal pathogenesis of B. nummularia.

Biscogniauxone, a New Isopyrrolonaphthoquinone Compound from the Fungus Biscogniauxia mediterranea Isolated from Deep-Sea Sediments

“…The new guaiane sesquiterpene xylaranone and the known terpenoid xylaranol B (together with mellein derivatives) were isolated from Biscogniauxia nummularia . They revealed antigerminative activity against seeds of Raphanus sativus [18]. …”

Novel platensimycin derivatives with herbicidal activity

“…[1,3]cyclopropa [1,2] benzen-6-yl}-propanamide (11) 95). [1,3]cyclopropa [1,2]benzen-6-yl}-propanamide (12) [1,3]cyclopropa [1,2]benzen-6-yl}-propanamide (13) (ppm): 0.92 (t, 3H, J = 9 Hz, NCH 2 CH 2 CH 3 ); 1.09 (s, 3H, H14); 1.16 (d, 3H, J = 6 Hz, H3 ′ ); 1.21 (s, 3H, H15); 1.51 (sext, 2H, J = 6 Hz, NCH 2 CH 2 ); 1.58-1.88 (m, 5H, H4, H4 ′ , H5, H5 ′ , H6); 2.51-2.63 (m, 1H, H2 ′ ); 3.21-3.33 (quint., 2H, NCH 2 ); 3.67 (d, 1H, J = 9 Hz, H7); 5.78 (t, 1H, J = 6 Hz, NH); 5.91 (d, 1H, J = 6 Hz, H2); 7.83 (d, 1H, J = 6 Hz, H1). 13 C NMR (75 MHz, CDCl 3 ) (ppm): 7.9 (C15); 11.6 (NCH 2 CH 2 CH 3 ); 13.5 (C13); 17.7 (C14); 23.0 (NCH 2 CH 2 ); 23.1 (C5); 31.6 (C4); 40.4 (NCH 2 ); 41.5 (C3a); 42.1 (C2 ′ ); 45.3 (C6); 47.1 (C3b); 52.2 (C8); 68.7 (C7); 129.6 (C2); 163.0 (C1); 176.9 (C1 ′ ); 209.0 (C3).…”

“…13 C NMR (75 MHz, CDCl 3 ) (ppm): 7.9 (C15); 11.6 (NCH 2 CH 2 CH 3 ); 13.5 (C13); 17.7 (C14); 23.0 (NCH 2 CH 2 ); 23.1 (C5); 31.6 (C4); 40.4 (NCH 2 ); 41.5 (C3a); 42.1 (C2 ′ ); 45.3 (C6); 47.1 (C3b); 52.2 (C8); 68.7 (C7); 129.6 (C2); 163.0 (C1); 176.9 (C1 ′ ); 209.0 (C3). (2S)-N-Butyl-2-{(3aR,3bS,6S,7S)-7-hydroxy-3a,3b-dimethyl-3-oxo-3a,3b,4,5,6,7-hexahydro-3H-cyclopenta [1,3]cyclopropa [1,2]benzen-6-yl}-propanamide (14). Appearance: white solid.…”

“…Bioactive secondary metabolites are natural products that have not been efficiently explored for discovery of new pesticides. Natural products provide inspiration for the development of new products, and sesquiterpene lactones should be cited for their wide biological activity as anti‐inflammatory, antigerminative, phytotoxic and anticancer agents . Sesquiterpenes are biosynthesised mainly by plants of the family Asteraceae but are also isolated from the fungus Biscogniauxia nummularia , representing a new promising class of biological agent.…”

“…Dehydrocostuslactone (1), costunolide (2) and -santonin (3) are examples of natural sesquiterpene lactones, and -methylene--santonin (4), lumisantonin (5), -methylene-lumisantonin (6), O-acetylisophotosantonin (7), -methylene-O-acetylisophotosantonin (8) and photosantonic acid (9) are only a few examples of synthetic derivatives that exhibit some kind of biological activity ( Fig. 1).…”