Pyrrole alkaloids and ergosterols from Grifola frondosa exert anti-α-glucosidase and anti-proliferative activities

•Bioactive anti-α-glucosidase and anti-proliferative fraction of Grifola frondosa were determined.•20 compounds, including one new compound were isolated from the bioactive fraction GF-3.•Pyrrole alkaloids were found in G. frondosa for the first time.•Pyrrole alkaloids showed potent inhibition against α-glucosidase, ergosterols displayed inhibition against tumor cells.•G. frondosa may be beneficial to diabetic or tumor patients. Previously, polysaccharides with hypoglycemic effects from G. frondosa were reported by us. To explore compounds against α-glucosidase and human tumor cells, three extractive fractions (GF-1–GF-3) were prepared from G. frondosa ethanol extraction (GF) by chromatographic column. Rather than GF-1 and GF-2, the fraction GF-3 demonstrated inhibitory actions against α-glucosidase and proliferation of human tumor cells dominantly. To identify the bioactive compounds in GF-3, one new compound named pyrrolefronine together with 19 known ones, which included seven pyrrole alkaloids, nine ergosterols and three others, were isolated and characterized from GF-3. Significantly, pyrrole alkaloids were found in G. frondosa for the first time, showing potent inhibition against α-glucosidase. Obtained ergosterols displayed inhibition against proliferation of tumor cells. This study provides a basis for further development and utilization of G. frondosa as natural nutraceuticals and functional food ingredients.