Phytoecdysteroids in seeds and plants of Rhagodia baccata (Labill.) moq. (Chenopodiaceae)

Seeds of Rhagodia baccata afforded, in addition to 20-hydroxy ecdysone and polypodine B, a novel phytoecdysteroid, (20R)22-deoxy-20,21-dihydroxyecdyso ne, the structure of which was elucidated unequivocally by UV, LSIMS and NM R techniques. This compound possessed agonistic activity in the Drosophila melanogaster Bn cell bioassay, with an ED50 value of 2.0 x 10(-7)M (ED50 va lue for 20 hydroxyecdysone = 7.5 x 10(-9)M). The distribution of ecdysteroi ds in plants of R, baccata has been determined. Highest levels are associat ed with the youngest aerial tissues and with the roots. Ecdysteroid profile s are qualitatively very similar throughout the plant, with 20-hydroxyecdys one and polypodine B predominating in all plant parts tested. Arch. Insect Biochem, Physiol, 41:18-23, 1999, (C) 1999 Wiley-Liss, Inc.