Macathiohydantoin L, a Novel Thiohydantoin Bearing a Thioxohexahydroimidazo [1,5-a] Pyridine Moiety from Maca (Lepidium meyenii Walp.)

• Published in: Molecules (Basel, Switzerland) Vol. 26; no. 16; p. 4934
• Main Authors: Zhang, Ranran, Liu, Junhong, Yan, Hui, Peng, Xingrong, Zhang, Ling, Qiu, Minghua
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 14.08.2021; MDPI
• Subjects: Chemical bonds; Chromatography; Lepidium meyenii; neuroprotective activities; thiohydantoins; thioxohexahydroimidazo [1,5-a] pyridine
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules26164934

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).