Five new terpenoids from the rhizomes of Isodon adenantha

Abstract

Five new terpenoids including 2 labdane diterpenoids (1 and 2), 2 ent-kaurane diterpenoids (3 and 4), and a new oleanane triterpenoid (5), along with 13 known compounds (6–18), were isolated from the ethyl acetate fraction of 70% acetone extract of the rhizomes of Isodonadenantha. Their structures were elucidated based on the analyses of spectroscopic data and comparison of their physicochemical properties. The structure of 1 was further confirmed by single-crystal X-ray diffraction. Cytotoxicity and antibacterial activities of the samples were measured by MTT method and the filter paper disk agar diffusion method. But none of them showed significant activities.

Keywords::

• Isodonadenantha
• chemical constituents
• terpenoids
• cytotoxicity
• antibacterial activity

Acknowledgments

This research was financially supported by the National Natural Science Foundations of China (No. 81060259), as well as the program of ‘Reserve Talents of the Young Academy and Technology Leaders in Yunnan Province’ (No. 2008PY005). The authors thank Prof. Haofu Dai from Hainan Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences for bioassay of cytotoxic activities.