In vitro: |
ChemInform, 1996, 27(33). | Calystegin N1, a Novel Nortropane Alkaloid with a Bridgehead Amino Group from Hyoscyamus niger: Structure Determination and Glycosidase Inhibitory Activities.[Reference: WebLink] | METHODS AND RESULTS:
Seven calystegins were isolated from the whole plant of Hyoscyamus niger. They are calystegins A 3, A 5, A 6, B t , B 2, B 3, and N 1. The structure of new calystegin A 6 was determined as la,2~,7a-trihydroxy-nor-tropane, and another new Calystegine N1 was elucidated to be a trihydroxy-nor-tropane alkaloid with a bridgehead NH 2 group in the place of a bridgehead OH group in calystegin B 2. Very interestingly, on storage for a half year in a refrigerator, approximately 40% of calystegin N I was nonenzymically converted into calystegin B 2.
CONCLUSIONS:
Calystegin N~ was a weaker inhibitor of glycosidases compared to calystegin B 2 but with the same inhibitory spectrum. However, calystegin N~ inhibited porcine kidney trehalase in a noncompetitive manner, whereas calystegin B 2 inhibited this enzyme in a competitive manner. |
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