Cycloartanes from the red alga Galaxaura sp.

Abstract

Six cycloartane triterpenes have been isolated from the red alga Galaxaura sp. The new structures (galaxaurols A–E) were determined to be methyl 3β-hydroxy-23-oxocycloart-24-en-29-oate (2), methyl 23(E)-3β-hydroxy-25-methoxycycloart-23-en-29-oate (3), methyl 23(E)-3β-hydroxycycloarta-23,25-dien-29-oate (4), 23(E)-25-methoxycycloart-23-en-3β,29-diol (5), and cycloart-24-en-3β,23α,29-triol (6), respectively.

Keywords:

• Galaxaura sp.
• Galaxaurol
• Cycloartane triterpenes

Acknowledgements

This work was partially supported by a grant from the Research Grant Council of Hong Kong (to C.-T. Che). We are grateful to Professor Liu Xijin for taxonomic identification of the algal specimen. Data presented in this paper were taken from the PhD thesis of W.-H. Zhang (Hong Kong University of Science and Technology, 2000).