Meirols A-C: Bioactive Catecholic Compounds from the Marine-Derived Fungus Meira sp. 1210CH-42

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.