Taxonomic distribution of phytoecdysteroids in seeds of members of the Chenopodiaceae

Extracts of seeds of ca. 200 species in the Family Chenopodiaceae have been assessed for the presence of insect steroid hormone agonists and antagonists by means of a bioassay based on the ecdysteroid-induced responses of the Drosophila melanogaster B-II cell line and ecdysteroid-specific radioimmunoassay (using the DBL-1 antiserum). Phytoecdysteroids (ecdysteroid agonists) were found in ca. 35% of the species, but no antagonistic extracts were detected. Some samples, especially in the genus Bassia sect. Kochia where phytoecdysteroid levels are low, were cytotoxic to D, melanogaster B-II cells when assessed as a neat extract. Phytoecdysteroid levels varied considerably with highest levels detected in seeds of Halimione portulacoides (3.6 mg ecdysone equivalents g(-1)), Atriplex isatidea (3.7 mg ecdysone equivalents g(-1)) and Rhagodia candolleana. (8.9 mg ecdysone equivalents g(-1)). The presence/absence of phytoecdysteroids has been related to a taxonomic classification of the Family. Phytoecdysteroids are almost absent from the sub-family Salsoloideae. Within the sub-family Chenopodioideae, ecdysteroids have been detected in all tribes except the Salicornieae and possibly the Camphorosmeae, but are most commonly present in the Atripliceae and Chenopodieae, Within the genus Chenopodium, all tested species of the sub-genus Ambrosia are ecdysteroid-negative, while most of those of the sub-genus Chenopodium are ecdysteroid-positive. Within the genus Atriplex, the situation is not so clear-cut, but most ecdysteroid-positive species occur within the Sections Semibaccata, Dialysex and Deserticola. Thus, the distribution of ecdysteroid-containing species within the Chenopodiaceae is not random, but it is rather related to the position of the species within a modern classification of the Family. (C) 1998 Elsevier Science Ltd. Ail rights reserved.