Volatiles and Nonvolatiles in Flourensia campestris GRISEB. (Asteraceae), How Much Do Capitate Glandular Trichomes Matter?

SILVA MARIANA P.; CANTERO JUAN J.; LÓPEZ DANIELA; TOURN G. MÓNICA; PIAZZA LEONARDO A.; LÓPEZ RIVILLI MARISA J.; SCOPEL ANA L.

Chemistry and Biodiversity

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2018 vol. 15 p. 1 - 15

1612-1872

The distribution and ultrastructure of capitate glandular trichomes (GTs) in Flourensia species (Asteraceae) havebeen recently elucidated, but their metabolic activity and potential biological function remain unexplored. Selectivenonvolatile metabolites from isolated GTs were strikingly similar to those found on leaf surfaces. The phytotoxicallelochemical sesquiterpene (?)-hamanasic acid A ((?)-HAA) was the major constituent (ca. 40%) in GTs. AlthoughGTs are quaternary ammonium compounds (QACs)-accumulating species, glycine betaine was not found in GTs; itwas only present in the leaf mesophyll. Two (?)-HAA accompanying surface secreted products: compounds4-hydroxyacetophenone (piceol; 1) and 2-hydroxy-5-methoxyacetophenone (2), which were isolated and fullycharacterized (GC/MS, NMR), were present in the volatiles found in GTs. The essential oils of fresh leaves revealedca. 33% monoterpenes, 26% hydrocarbon- and 30% oxygenated sesquiterpenes, most of them related to cadineneand bisabolene derivatives. Present results suggest a main role of GTs in determining the volatile and nonvolatilecomposition of F. campestris leaves. Based on the known activities of the compounds identified, it can be suggestedthat GTs in F. campestris would play key ecological functions in plant-pathogen and plant-plant interactions. Inaddition, the strikingly high contribution of compounds derived from cadinene and bisabolene pathways, highlightsthe potential of this species as a source of high-valued bioproducts.