RESUMEN
Two new cyclic lipopeptides, acuminatums E (1) and F (2), together with four known cyclic lipopeptides, acuminatums A-D (3-6) were isolated from the corn culture of endophytic Fusarium lateritium HU0053. Their structures were elucidated by spectroscopic and advanced Marfey's amino acid analysis. All compounds were found to exhibit antifungal activities against Penicillium digitatum. Acuminatum F (2), a new cyclic lipopeptide containing an unusual 3, 4-dihydroxy-phenylalanine unit exhibited the strongest antifungal activities with inhibition zone of 6.5 mm at the dose of 6.25 µg. Therefore, acuminatum F might be a potential environmental-friendly preservative for citrus fruits.
Asunto(s)
Antifúngicos , Fusarium , Antifúngicos/química , Fusarium/química , Lipopéptidos/farmacología , Lipopéptidos/química , Lipopéptidos/metabolismo , Péptidos Cíclicos/farmacología , Péptidos Cíclicos/químicaRESUMEN
Three new phlorizin derivatives, 6"-O-vanilloylphlorizin (1), 6"-O-(4-hydroxybenzoyl)phlorizin (2), 6"-O-feruloylphlorizin (3), along with four known dihydrochalcones, phlorizin (4), 3-hydroxyphlorizin, trilobatin, and 6"-O-acetylphlorizin were isolated from the leaves of Lithocarpus litseifolius. Their structures were established by analysis of extensive spectroscopic data. The new compounds were shown to be non-cytotoxic when tested against A549, HeLa, HepG2, and MCF-7 cell lines.
Asunto(s)
Chalconas , Fagaceae , Chalconas/farmacología , Estructura Molecular , Hojas de la PlantaRESUMEN
The absolute configurations of four resorcylic acid lactones (RALs), paecilomycins J-M (1-3 and 5), were assigned by Time-Dependent Density-Functional Theory (TDDFT) calculations of their electronic circular dichroism (CD) spectra. The previously reported structure 4 for paecilomycin M was found to be incorrect and should be changed to structure 5. Analysis of structure-spectrum relationship for this group of RALs suggested that V'-shape conformations give type I CD spectra (two negative Cotton effects around 300 and 260 nm, a positive Cotton effect around 220 nm) while V-shape conformations yield type II spectra (signs of three Cotton effects were opposite to those in type I).