BRINE SHRIMP TOXICITY: CERTAIN COMPONENTS OF STAPELIA, CORYPHANTA, LUPINUS, AND QUINOA

A method utilizing brine shrimp, Artemia salina (Leach), is proposed as a simple, rapid, and inexpensive bioassay for screening and fractionation monitoring of physiologically active plant extracts. Activities of a broad range of compounds are manifested as toxicity to the shrimp. The procedure was investigated as a general bioassay tool during the fractionation and isolation of components of the title plants. Candicine (N,N,N-trimethyltyramine) (LC(,50) 923 (mu)g/ml) was isolated and choline, tyramine, and N-methyltyramine were detected in Stapelia gigantea N. E. Br. (Asclepiadaceae). Two new naturally occurring quaternary amines, O-methylcandicine (LC(,50) 425 (mu)g/ml and (+)-coryphanthine (N,N,N-trimethyl-(beta)-methoxyphenethylamine ) (LC(,50) 354 (mu)g/ml) were isolated from the Mexican cactus, Coryphantha greenwoodii H. Bravo. Optically active coryphanthine was synthesized from resolved (beta)-hydroxyphenethylamine through N,N-dimethyl-(beta)-chlorophenethylamine. (-)-(alpha)-Isosparteine (LC(,50) 0.9 (mu)g/ml was identified as the previously isolated by uncharacterized major alkaloid component of the toxic Lupinus argenteus var. stenophyllus (Rydb.) Davis (Fabaceae). A bitter tetraoside (LC(,50) 260 (mu)g/ml) of hederagenin (olean-12-ene-3,23-dihydroxy-28-oic acid) was isolated and characterized from quinoa, Chenopodium quinoa Willd. (Chenopodiaceae), a valuable South American food crop. Screening for quaternary alkaloids by thin-layer chromatography and by laser desorption tandem mass spectrometry resulted in the detection of known candicine, but no new compounds except for those in C. greenwoodii, in several cactus species