Morusalisins A-F, six new Diels-Alder type adducts, as potential PTP1B inhibitors from cell cultures of Morus alba

Six new Diels-Alder type adducts, morusalisins A-F (1-6), were isolated from Morus alba cell cultures. The structures of 1-6 were determined by extensive spectroscopic data analysis, including HRESIMS, NMR, and ECD experiments. Furthermore, compounds 1-6 exhibited potent protein tyrosine phosphatase 1B (PTP1B) inhibitory activity with IC50 values ranging from 1.14 to 2.24 mu M, making them promising as bioactive compounds for antidiabetic drug discovery.