Considering the therapeutic potential of Varronia curassavica Jacq. essential oil and the great value in the pharmaceutical market, this study aims to evaluate the influence of plant age on the chemical composition and biological activities of V. curassavica Jacq. essential oil. The plant age is a parameter that can influence the chemical composition of the essential oil, as well as its pharmacological potential. For this purpose, essential oils from aerial parts of V. curassavica produced at different ages (4, 10, 14 and 18 months-age) were used. According to chromatograms obtained by GC-MS, the essential oils were mainly composed of α-pinene, trans-caryophyllene, α-santalene, alloaromadendrene and α-humulene. The chemical composition of V. curassavica essential oils varied qualitatively and quantitatively with the aging of the plants, and the essential oils from plants at 18 month-age appeared to be the most distinct from the others. The tested essential oil samples showed inhibitory activity against Candida albicans (MIC = 1000 µg/mL) but did not show antibacterial activity against the tested bacteria. The cytotoxic activity levels against the murine macrophages varied among the oils extracted from the plants at different ages; the IC₅₀ values of the essential oils increased with age (171.90 µg/mL at 18 month-age). More studies should be carried out to assess whether age also affects the therapeutic effects of essential oils, resulting in the manufacture of plant-derived formulations that balance production costs, toxicity and therapeutic effects.

The potential emergence of zoonotic diseases has raised significant concerns, particularly in light of the recent pandemic, emphasizing the urgent need for scientific preparedness. The bioprospection and characterization of new molecules are strategically relevant to the research and development of innovative drugs for viral and bacterial treatment and disease management. Amphibian species possess a diverse array of compounds, including antimicrobial peptides. This study identified the first bioactive peptide from Salamandra salamandra in a transcriptome analysis. The synthetic peptide sequence, which belongs to the defensin family, was characterized through MALDI TOF/TOF mass spectrometry. Molecular docking assays hypothesized the interaction between the identified peptide and the active binding site of the spike WT RBD/hACE2 complex. Although additional studies are required, the preliminary evaluation of the antiviral potential of synthetic SS-I was conducted through an in vitro cell-based SARS-CoV-2 infection assay. Additionally, the cytotoxic and hemolytic effects of the synthesized peptide were assessed. These preliminary findings highlighted the potential of SS-I as a chemical scaffold for drug development against COVID-19, hindering viral infection. The peptide demonstrated hemolytic activity while not exhibiting cytotoxicity at the antiviral concentration.