Isolation, absolute configuration and immunosuppressant activities of pyrrole and furanone derivatives from the edible mushroom Grifola frondosa

Chemical investigation on methanol extract of the fruiting bodies of Grifola frondosa led to the isolation of seven pyrrole alkaloids and two furanone metabolites, including two undescribed ones (compounds 1 and 3). The structures were established by spectroscopic data analysis and quantum chemical calculations. The absolute configuration of 2 was established for the first time on the basis of its optical rotation and electronic circular dichroism aided with quantum calculations. Compound 1 showed the suppressive activity against the cell proliferation of LPS-induced B lymphocytes with IC₅₀ value of 30.53 μM and Con A-induced T lymphocytes with IC₅₀ value of 46.79 μM, respectively.