RESUMO
Three new catecholic compounds, named meirols A-C (2-4), and one known analog, argovin (1), were isolated from the marine-derived fungus Meira sp. 1210CH-42. Their structures were determined by extensive analysis of 1D, 2D NMR, and HR-ESIMS spectroscopic data. Their absolute configurations were elucidated based on ECD calculations. All the compounds exhibited strong antioxidant capabilities with EC50 values ranging from 6.01 to 7.47 µM (ascorbic acid, EC50 = 7.81 µM), as demonstrated by DPPH radical scavenging activity assays. In the α-glucosidase inhibition assay, 1 and 2 showed potent in vitro inhibitory activity with IC50 values of 184.50 and 199.70 µM, respectively (acarbose, IC50 = 301.93 µM). Although none of the isolated compounds exhibited cytotoxicity against one normal and six solid cancer cell lines, 1 exhibited moderate cytotoxicity against the NALM6 and RPMI-8402 blood cancer cell lines with GI50 values of 9.48 and 21.00 µM, respectively. Compound 2 also demonstrated weak cytotoxicity against the NALM6 blood cancer cell line with a GI50 value of 29.40 µM.
Assuntos
Basidiomycota , Neoplasias Hematológicas , Humanos , Fungos/química , Antioxidantes/farmacologia , Antioxidantes/química , Espectroscopia de Ressonância Magnética/métodos , Estrutura MolecularRESUMO
The fungal genus Meira was first reported in 2003 and has mostly been found on land. This is the first report of second metabolites from the marine-derived yeast-like fungus Meira sp. One new thiolactone (1), along with one revised thiolactone (2), two new Δ8,9-steroids (4, 5), and one known Δ8,9-steroid (3), were isolated from the Meira sp. 1210CH-42. Their structures were elucidated based on the comprehensive spectroscopic data analysis of 1D, 2D NMR, HR-ESIMS, ECD calculations, and the pyridine-induced deshielding effect. The structure of 5 was confirmed by oxidation of 4 to semisynthetic 5. In the α-glucosidase inhibition assay, compounds 2-4 showed potent in vitro inhibitory activity with IC50 values of 148.4, 279.7, and 86.0 µM, respectively. Compounds 2-4 exhibited superior activity as compared to acarbose (IC50 = 418.9 µM).