Banca de DEFESA: ALAN FELIX DE MEDEIROS

Chemical Characterization and Bioactivity of Froelichia humboldtiana

ervanço; photosensitization; toxic plants; veterinary toxicology.

Photosensitization associated with the ingestion of toxic plants represents a significant
sanitary and economic problem for livestock farming, with Froelichia humboldtiana,
popularly known as "ervanço," frequently associated with outbreaks of primary
photosensitization. Considering that the chemical composition of F. humboldtiana is not yet
fully understood, this study aimed to identify its secondary metabolites, with emphasis on the
detection, concentration, and isolation of compounds with the potential to cause primary
photosensitization, as well as to evaluate their bioactivity through a lethality bioassay against
Artemia salina. The plant was harvested, botanically identified, separated into parts, subjected
to drying, grinding, and extraction of secondary metabolites. Ethanol extraction yields varied
among different parts of the plant. The crude extracts obtained from the different parts of F.
humboldtiana were fractionated by liquid-liquid partitioning, and preliminary phytochemical
screening revealed the presence of coumarins, anthrones, and anthraquinones in all parts of
the plant. Additionally, lethality tests against Artemia salina indicated greater bioactivity in
the ethyl acetate fraction of the inflorescence. Column chromatography allowed the
concentration of metabolites of interest, with their concentration being predominantly
observed in the hexane fraction of the analyzed plant parts. Under the methodological
conditions employed, Gas Chromatography coupled with Mass Spectrometry did not identify
coumarins in the evaluated fraction. It is concluded that F. humboldtiana presents a chemical
profile with photodynamic compounds, homogeneously distributed in the evaluated plant
organs. The results reinforce the hypothesis of the involvement of these metabolites in
primary photosensitization in ruminants and equines.