Antimicrobial Terpenoids and Polyketides from the Algicolous Fungus Byssochlamys spectabilis RR-dl-2-13

Abstract

Four new carotane sesquiterpenoids, byssocarotins A−D (1−4), two new nor-sesquiterpenoids, byssofarnesin (5) and byssosesquicarin (6), and three new polyketides, byssoketides A and B (7 and 8) and (8R)-paecilocin A (9a), were obtained from a macroalga-associated strain (RR-dl-2-13) of the fungus Byssochlamys spectabilis. These isolates were identified by a combination of spectroscopic methods, including mass spectroscopy, nuclear magnetic resonance, electronic circular dichroism, and X-ray diffraction. Compounds 1−4 greatly contribute to the diversity of rarely occurring 2,15-epoxycarotane sesquiterpenoids, while 5 and 6 are degradation products of farnesane and sesquicarane precursors, respectively. Compound 7 is a structurally unique furan fatty acid derivative that possesses an aldehyde group and a large conjugated unit, and 8 features a hemiketal group. During antimicrobial assays, 8 showed antagonism against the phytopathogenic fungi Glomerella cingulata, Fusarium oxysporum f. sp. cucumerium, and F. oxysporum f. sp. cubense and the marine-derived bacteria Vibrio parahaemolyticus and V. harveyi with MIC values of 13 to 50 μg/mL.

Marine natural products

“…177 183 Destruxin hexadepsipeptides 483 and 484 were isolated from a culture of Beauveria felina 184 and Byssochlamys spectabilis was the source of terpenoids 485-490 and polyketides 491-493, the last a known synthetic but new NP. 185 A precursor-directed biosynthetic approach to culturing of a Chrysosporium species led to isolation of a range of metabolites. Supplementation with a range of precursors yielded neochrysosporazines A-L 494-505, chrysosporazines R 506 and S 507, neochrysosporazines M-Q 508-512 and the known terrestrial but new MNP, hancockiamide C 513.…”

Lipids and Terpenoids from the Deep-Sea Fungus Trichoderma lixii R22 and Their Antagonism against Two Wheat Pathogens

“…The other was bonded to a hydroxylated methine group based on the HMBC correlations from H-4 to C-2 and C-3 and then elongated to C-8 based on the COSY correlations from OH-4 through to HO-7 and the HMBC correlations from OH-7 to C-6, C-7, and C-8. The remaining NMR signals corresponded to a methoxy group [23], which was attached to C-8 on the basis of their HMBC correlation. To satisfy the molecular formula, an ether linkage was situated between C-5 and C-8.…”

“…Similar to previous procedures [10,[15][16][17]23], Autopol VI polarimeters were applied to determine optical rotations. The Chirascan CD spectrometer was applied to measure UV and ECD data.…”