Chemistry of glandular trichomes in Hymenoxys and related genera

• Published in: Biochemical systematics and ecology 1994-03, Vol.22 (2), p.171-195
• Main Authors: Spring, Otmar, Zitterell-Haid, Barbara, Bierner, Mark W., Mabry, Tom J.
• Format: Article
• Language: English
• Subjects: Amblyolepis; Asteraceae; Biological and medical sciences; chemical constituents of plants; chemotaxonomy; Dugaldia; Fundamental and applied biological sciences. Psychology; Gaillardiinae; gaillardinae; glandular trichomes; Heliantheae; Hymenoxys; inositol derivatives; Macdougalia; monoterpenes; monoterpenoids; myo-inositol; Plant cytology, morphology, systematics, chorology and evolution; Plateilema; Plummera; sesquiterpene lactones; sesquiterpenoid lactones; Spermatophyta; Systematics (diagnosis, chromosome numbers); Tetraneuris; trichomes
• ISSN: 0305-1978; 1873-2925
• DOI: 10.1016/0305-1978(94)90007-8

All currently recognized taxa from the genera Amblyolepis (one species), Dugaldia (three species), Hymenoxys (22 taxa in 21 species), Macdougalia (one species), Plateilema (one species), Plummera (two species) and Tetraneuris (15 taxa in eight species) were examined for chemical constituents accumulated in capitate glandular trichomes. Fifty-nine high pressure liquid chromatography (HPLC) peaks were detected, over 70% of which could be tenatatively assigned to known compounds of the sesquiterpene lactone, monoterpene and inositol types. This is the first report of sesquiterpene lactone glycosides, monoterpene glycosides and a myoinositol derivative in capitate glandular trichomes. Apart from Amblyolepis and Plateilema, which did not afford anlyzable glandular trichomes, sesquiterpene lactones of the pseudoguaianolide type were present in all species, and guaianolides were found in all but two, Hymenoxys anthemoides and H. chrysanthemoides. Compound patterns of the Hymenoxys, Plummera, Dugaldia and Macdougalia species were very similar to one another, but they differed from those of Hymenoxys texana and all taxa of Tetraneuris, which lacked modified pseudoguaianolides (secohelenanolides), but contained monoterpene glycosides. Taxonomic implications of compound patterns in the species examined includes: (1) incorporation of Dugaldia, Plummera and Macdougalia into a broader concept of Hymenoxys; and (2) recognition of Tetraneuris as a distinct genus. Hymenoxys texana requires further investigation since its morphology is typical of Hymenoxys, but its chemistry is typical of Tetraneuris.