Iminosugars from Baphia nitida Lodd

An 1- O-β- d-fructofuranoside of 2 R,5 R-dihydroxymethyl-3,4-dihydroxypyrrolidine was isolated from the leaves of Baphia nitida, together with six known iminosugars and three iminosugar glucosides. 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 2 R,5 R-dihydroxymethyl-3 R,4 R-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.