Macathiohydantoin L, a Novel Thiohydantoin Bearing a Thioxohexahydroimidazo [1,5-a] Pyridine Moiety from Maca (Lepidium meyenii Walp.)
Ranran Zhang, Junhong Liu, Hui Yan, Xing‐Rong Peng, Ling Zhang, Ming‐Hua Qiu
Abstract
Five new thiohydantoin derivatives (1–5) were isolated from the rhizomes of Lepidium meyenii Walp. NMR (1H and 13C NMR, 1H−1H COSY, HSQC, and HMBC), HRESIMS, and ECD were employed for the structure elucidation of new compounds. Significantly, the structure of compound 1 was the first example of thiohydantoins with thioxohexahydroimidazo [1,5-a] pyridine moiety. Additionally, compounds 2 and 3 possess rare disulfide bonds. Except for compound 4, all isolates were assessed for neuroprotective activities in corticosterone (CORT)-stimulated PC12 cell damage. Among them, compound (−)-3 exhibited moderate neuroprotective activity (cell viability: 68.63%, 20 μM) compared to the positive control desipramine (DIM) (cell viability: 88.49%, 10 μM).