Chemistry and Biology of the GenusFlourensia(Asteraceae)

Toxicity Evaluation of a Polyphenolic Extract from Flourensia cernua DC through Artemia Lethality Assay, Hemolytic Activity, and Acute Oral Test

Flourensia cernua DC, commonly known as hojasen or tarbush, is a medicinal plant used in arid regions due to its therapeutic properties, especially in the treatment of gastrointestinal disorders. This study aimed to assess the toxicity of a polyphenolic extract obtained from F. cernua. This research involved both in vitro (hemolytic and brine shrimp assay) and in vivo tests (acute oral toxicity) to determine the safety profile of this extract. The extract was obtained through a novel ultrasound-microwave extraction and purified by ion-exchange chromatography. Analysis of the polyphenolic extract revealed a rich composition of flavonoids and hydroxycinnamic acids, mainly apigenin glycosides. In toxicity tests, the polyphenols did not exhibit toxicity towards Artemia salina at a concentration of 1 mg/ml. Furthermore, incubation at 500 μg/ml for 4 hours showed a slight toxic effect on erythrocytes. In the acute oral toxicity test in mice, doses of 300 mg/kg and 2000 mg/kg did not result in animal mortality, indicating that the LD50 exceeds 2000 mg/kg. However, the higher dose induced signs of toxicity, including lethargy, drowsiness, piloerection, and a significant decrease in weight during the initial two days postadministration of the polyphenolic extract. In addition, histological analysis suggested potential kidney damage at the 2000 mg/kg dose. According to OECD guidelines, while the extract can be classified as category 5 (low acute toxicity) due to the absence of mortality at 2000 mg/kg, the observed signs of toxicity should be considered in the overall risk assessment. These findings highlight the potential of F. cernua in pharmaceutical and nutraceutical applications due to its high polyphenolic content. However, further investigations are necessary to explore the specific effects of the compounds present in the extract. In addition, continuous evaluation of its long-term toxicity is essential to fully understand the extract's safety profile and efficacy.

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

The distribution and ultrastructure of capitate glandular trichomes (GTs) in Flourensia species (Asteraceae) have been recently elucidated, but their metabolic activity and potential biological function remain unexplored. Selective nonvolatile metabolites from isolated GTs were strikingly similar to those found on leaf surfaces. The phytotoxic allelochemical sesquiterpene (-)-hamanasic acid A ((-)-HAA) was the major constituent (ca. 40%) in GTs. Although GTs are quaternary ammonium compounds (QACs)-accumulating species, glycine betaine was not found in GTs; it was only present in the leaf mesophyll. Two (-)-HAA accompanying surface secreted products: compounds 4-hydroxyacetophenone (piceol; 1) and 2-hydroxy-5-methoxyacetophenone (2), which were isolated and fully characterized (GC/MS, NMR), were present in the volatiles found in GTs. The essential oils of fresh leaves revealed ca. 33% monoterpenes, 26% hydrocarbon- and 30% oxygenated sesquiterpenes, most of them related to cadinene and bisabolene derivatives. Present results suggest a main role of GTs in determining the volatile and nonvolatile composition of F. campestris leaves. Based on the known activities of the compounds identified, it can be suggested that GTs in F. campestris would play key ecological functions in plant-pathogen and plant-plant interactions. In addition, the strikingly high contribution of compounds derived from cadinene and bisabolene pathways, highlights the potential of this species as a source of high-valued bioproducts.

Constituents of Flourensia blakeana (Asteraceae)

Chemical study of the aerial parts of Flourensia blakeana Dillon allowed the isolation and identification of two novel compounds, 3, 5, 5'-trihydroxy-7, 3'-dimethoxyflavanone (1), and 2α-angeloyloxycostic acid (2) together with several known compounds. The structures were elucidated using spectroscopic data from 1D, 2D NMR and HRDEIMS experiments.