Sophopterocarpans A-B, two undescribed pterocarpan derivatives from Aspergillus sp.-fermented Sophora flavescens

Sophopterocarpans A-B (1-2), two undescribed pterocarpan derivatives with a rare spirotetrahydrofuran ring, along with two known pterocarpans were isolated from the Aspergillus sp.-fermented Sophora flavescens. Their planar structures and absolute configurations were established through comprehensive analyses of NMR, HR-ESI-MS, ECD, DP4+ (for 2), and single-crystal X-ray diffraction (XRD) (for 1). In addition, all isolated compounds were assessed for their renoprotective effects. In the MTT assay, none of the compounds showed significant cytotoxicity at a concentration of 100.0 μM. Sophopterocarpan A (1) could dose-dependently decrease intracellular ROS levels, suggesting that these compounds protect against renal injury by inhibiting inflammatory responses and oxidative stress.