RESUMO
Two new sesquiterpene derivatives (1 and 2), ramarin A (1) and ramarin B (2), together with three known compounds (3-5) were isolated from the fruiting bodies of Ramaria formosa. The structures of the two sesquiterpenes were established by extensive spectroscopic studies and chemical evidence. The inhibitory activity of the isolated compounds (1-5) against human neutrophil elastase (HNE) was evaluated in vitro. All compounds tested inhibited HNE by 35-30% at the highest concentration used (100 µM), whereas the positive control, epigallocatechin gallate (EGCG), exhibited 60% inhibition at 100 µM.
Assuntos
Basidiomycota/química , Elastase de Leucócito/antagonistas & inibidores , Inibidores de Proteases/química , Sesquiterpenos/química , Basidiomycota/metabolismo , Carpóforos/química , Carpóforos/metabolismo , Humanos , Elastase de Leucócito/metabolismo , Espectroscopia de Ressonância Magnética , Conformação Molecular , Inibidores de Proteases/isolamento & purificação , Ligação Proteica , Sesquiterpenos/metabolismoRESUMO
Two new labdane diterpenes (1 and 2) were isolated from the fruiting bodies of Ramaria formosa. The structures of these compounds were established by extensive spectroscopic studies and chemical evidence. The inhibitory activity of compounds 1 and 2 against human neutrophil elastase (HNE) was evaluated in vitro. Compounds 1 and 2 inhibited HNE activity moderately. The IC50 values for compounds 1 and 2 were 36.4 ± 1.2 and 40.8 ± 1.5 µM, respectively; the IC50 value for the positive control, EGCG, was 12.5 ± 0.8 µM. In addition, the mechanism by which 2 inhibited HNE was a mixed-type noncompetitive inhibition, with a Ki of 41.5 ± 1.8 µM.
Assuntos
Basidiomycota/química , Diterpenos/farmacologia , Carpóforos/química , Elastase de Leucócito/antagonistas & inibidores , Inibidores de Proteases/farmacologia , Diterpenos/química , Diterpenos/isolamento & purificação , Humanos , Inibidores de Proteases/química , Inibidores de Proteases/isolamento & purificaçãoRESUMO
The crude methanol extract of the dried aerial parts of Siegesbeckia glabrescens (Compositae) showed antibacterial activity against the foodborne pathogen Staphylococcus aureus. Bioactivity-guided separation led to the isolation of 3-(dodecanoyloxy)-2-(isobutyryloxy)-4-methylpentanoic acid from nature for the first time. The structure was determined by spectroscopic data analysis (UV, MS, and NMR). The minimal inhibitory concentration (MIC) of 3-(dodecanoyloxy)-2-(isobutyryloxy)-4-methylpentanoic acid against S. aureus was found to be 3.12 μg/mL. In addition, in a further antimicrobial activity assay against Gram-positive (B. subtilis, E. faecalis, P. acnes, S. epidermidis, S. schleiferi subsp. coagulans, S. agalactiae and S. pyrogens), and Gram-negative bacteria (E. coli and P. aeruginosa), and yeast strains (C. alibicans and F. neoformans), the antimicrobial activity of the compound was found to be specific for Gram-positive bacteria. The MIC values of the compound for Gram-positive bacteria ranged from 3.12 to 25 mg/mL. Furthermore, it was found that the 2-(isobutyryloxy)-4-methylpentanoic acid substituent may operate as a key factor in the antibacterial activity of the compound, together with the laurate group.
