Abstract
Three glucosides, paederoside (Pa), paederosidic acid (Paa) and scandoside (Sca) were isolated as iridoid glucosides from Paederia scandens Merrill. For the examination of their biological activities, iridoid glucosides including asperuloside (As), deacetyl asperulosidic acid (Daa) and deacetyl asperuloside (Da) were also used as a reference (Fig. 1).
The inhibitory activities of Paa and Sca, which were produced by the cleavage of a lactone ring and desorption of S-methyl thiocarbonate were reduced compared with those of Pa, which has a lactone ring. Sca also displayed a promoting activity fowards the growth of lettuce seedlings. Pa showed a similar inhibitory activity to that of Asp and Da in the plant growth inhibition test and antimicroorganism activity test (Tables 1, 2 and 3).
These results suggest that the lactone ring is the essential part of the structure for the activity.
