Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

We report the isolation and structural determination of fourteen iminosugars, containing five pyrrolizidines and five indolizidines, from Castanospermum australe. The structure of a new alkaloid was elucidated by spectroscopic methods as 6,8-diepi-castanospermine (13). Our side-by-side comparison between bicyclic and corresponding monocyclic iminosugars revealed that inhibition potency and spectrum against each enzyme are clearly changed by their core structures. Castanospermine (10) and 1-deoxynojirimycin (DNJ) have a common d-gluco configuration, and they showed the expected similar inhibition potency and spectrum. In sharp contrast, 6-epi-castanospermine (12) and 1-deoxymannojirimycin (manno-DNJ) both have the d-manno configuration but the α-mannosidase inhibition of 6-epi-castanospermine (12) was much better than that of manno-DNJ. 6,8-Diepi-castanospermine (13) could be regarded as a bicyclic derivative of talo-DNJ, but it showed a complete loss of α-galactosidase A inhibition. This behavior against α-galactosidase A is similar to that observed for 1-epi-australine (6) and altro-DMDP.

Original publication

DOI

10.1016/j.phytochem.2014.12.011

Type

Journal article

Journal

Phytochemistry

Publication Date

03/2015

Volume

111

Pages

124 - 131

Keywords

Australine, Castanospermine, Castanospermum australe, Glycosidase inhibitor, Iminosugar, Structure–activity relationship, 1-Deoxynojirimycin, Alkaloids, Castanospermum, Enzyme Inhibitors, Glucosamine, Glycoside Hydrolases, Hypoglycemic Agents, Imino Sugars, Indolizines, Piperidines, Stereoisomerism, Structure-Activity Relationship