Structure-Based Virtual Screening of Sterols and Triterpenoids Isolated from Ganoderma (Agaricomycetes) Medicinal Mushrooms Shows Differences in Their Affinity for Human Glucocorticoid and Mineralocorticoid Receptors.

Abstract

An extensive database of sterols and triterpenoids isolated from Ganoderma mushrooms was evaluated by in silico structure-based virtual screening to determine their respective ligand affinities for the glucocorticoid or mineralocorticoid receptor (GCR or MNR). The main ligands for GCR in our database were ergosta-7,22-dien-3-one (compound 1) and ganodermaside B (compound 2), while the best ligands for MNR were 2β,3α,9α-trihydroxyergosta-7,22-diene (compound 8) and 5α-ergosta-7,22-dien-3β-ol (compound 3). The binding free energy (BFE) values calculated for such metabolites were similar to those of the natural ligands for each receptor (i.e., dexamethasone for GCR and aldosterone for MNR). Moreover, the differences between mean BFE values calculated for both receptors suggest that ergosta-7,22-dien-3-one (compound 1), ganodermaside B (compound 2), fungisterol (compound 5), ganoderic acid Ma (compound 9), and cerevisterol (compound 10) might be used as specific ligands for GCR, with a significantly lower affinity for MNR. Finally, it is worth noting that even though this work is exclusively theoretical, the reported bioactivities (either pro- or anti-inflammatory) for those metabolites that were previously studied are consistent with our findings, suggesting that the well-known immunomodulatory effect of Ganoderma triterpenoids and sterols might be attributed, at least partially, to their ability to act as specific GCR ligands.