DISTRIBUTION AND IDENTITY OF PHYTOECDYSTEROIDS IN GOMPHRENA SPP. (AMARANTHACEAE)

Bioassay/RIA-based screening of seeds of seven species of the genus Go mphrena revealed the presence of phytoecdysteroids in five of them, bu t not in G. globosa and G. hybrida. The accumulation of phytoecdystero ids was highest in G. affinis (ca. 8.6 mg ecdysone equivalent/g seed, using the DBL-1 antiserum). The four other ecdysteroid-positive specie s (G. canescens, G. cunninghamii, G. dispersa and G. haageana) contain ed moderate levels of phytoecdysteroids (1-2 mg ecdysone eq./g). 20-Hy droxyecdysone was the predominant ecdysteroid present in each of these seed extracts, accounting for > 90% of the total ecdysteroids. Severa l of the minor ecdysteroids have been tentatively identified. Among di fferent parts (seeds, roots, stems, leaves and flowers) of G. dispersa and G. haageana, seeds contained the highest, and roots the lowest, l evels of phytoecdysteroids. RP-INP-HPLC separation coupled with monito ring by UV, RIA and bioassay revealed that 20-hydroxyecdysone generall y constituted ca. 95% of the total ecdysteroid content, but in a few o f the extracts the levels and identities of other ecdysteroids varied significantly. (C) 1998 Elsevier Science Ltd. All rights reserved.