Iminosugars from Baphia mitida Lodd

Abstract

Chromatographic separation of the 50% aqueous EtOH extract of the leaves of the African medicinal tree Baphia nitida resulted in isolation of 10 iminosugars. The plant contained 2R,5R-dihydroxymethyl-3R,4R-dihydroxypyrrolidine (DMDP) as a major alkaloid. The structure of a new alkaloid was also elucidated by spectroscopic methods as the 1-O-β-d-fructofuranoside of DMDP, and this plant produced 3-O-β-d-glucopyranosyl-DMDP as well. DMDP is a potent inhibitor of β-glucosidase and β-galactosidase, whereas the other two derivatives lowered inhibition toward both of these enzymes and improved inhibitory activities toward rice α-glucosidase and rat intestinal maltase.