Structures and allelopathic effects ofNuphar alkaloids: Nupharolutine and 6,6′-dihydroxythiobinupharidine

Abstract

Two of the majorNuphar alkaloids, nupharolutine and 6,6′-dihydroxythiobinupharidine, were isolated from the aquatic perennial herbNuphar lutea (L.) Sibth. & Sm., yellow water lily. In a lettuce seedling bioassay of the two pure compounds, the former was inactive and the latter was highly inhibitory of radicle elongation at concentrations greater than 2 ppm. Structures and stereochemistry of the two compounds were confirmed by DEPT,¹H-¹H COSY,¹H-¹³C COSY, and¹H-¹H NOESY experiments.