Three new Diels–Alder type adducts from the stem bark of Morus cathayana

Abstract

Three new Diels–Alder type adducts cathayanons C (1), D (2), and E (3), together with one known compound sanggenon C (4), were isolated from the stem bark of Morus cathayana. Their structures were fully elucidated by spectroscopic and chemical methods. Compound 2 showed good anti-oxidation activity with the inhibitory rate of malondialdehyde being 88% at a concentration of 10^− 6 mol/l.

Keywords:

• Morus cathayana
• cathayanon C
• cathayanon D
• cathayanon E
• anti-oxidation activity

Acknowledgements

This research program was supported by the National Natural Science Foundation of China (Nos 20432030 and 20572133). We thank the Departments of Instrumental Analysis and Pharmacology (Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College) for the measurements of IR, UV, NMR, ESI, and HR-ESI-MS spectra, and performing the anti-oxidation bioassay, respectively.