Abstract Dicksonia sellowiana (Dicksoniaceae) is a tree fern characteristic of the mixed ombrophilous forests of southern Brazil in the Atlantic Forest. Due to its extensive use in the past for making garden pots, this species is at risk of extinction. The objective of this study was to evaluate the phytochemical composition of D. sellowiana leaves and their structures and correlate it with their antioxidant potential. Measurements of moisture content, extraction yield, preliminary phytochemical analysis, chemometric analysis by 1H NMR PCA, UPLC-PDA-MS analysis, total polyphenol content, and antioxidant activity were conducted on the leaves and their structures. The phytochemical composition confirmed the presence of polyphenols, including tannins and flavonoids (derived from kaempferol), with higher concentrations in the pinna and lower in the rachis. The pinnule exhibits high diversity and concentration of phytochemical compounds, which justify its antioxidant activity due to the presence of polyphenols. In conclusion, this study highlights that the pinnae and leaves of D. sellowiana exhibit a similar and more diverse phytochemical composition compared to the other evaluated structures, showing higher concentrations of polyphenols and antioxidant activity. The results reinforce the preservation of the endangered species and its potential as a resource for pharmacological and nutritional phytochemical compounds.

Resumo Dicksonia sellowiana (Dicksoniaceae) é uma samambaia arborescente, característica das florestas ombrófilas mistas do Brasil meridional na Floresta Atlântica. Por ter sido muito utilizada no passado na confecção de vasos para jardinagem, essa espécie está em risco de extinção. Neste estudo se objetivou avaliar a composição fitoquímica das folhas de D. sellowiana e suas estruturas, e correlacionar com o seu potencial antioxidante. Foi realizado os teores de umidade, rendimento de extração, análise fitoquímica preliminar, análise quimiomética por PCA de 1H NMR, UPLC-PDA-MS analysis, teores de polifenóis totais e atividade antioxidante da folha e suas estruturas. A composição fitoquímica confirmou a presença de polifenóis, entre eles taninos e flavonoides (derivados de kaempferol), com maior concentração na pínula e menor na raque. A pínula apresenta alta diversidade e concentração de compostos fitoquímicos, o que justifica sua atividade antioxidante devido aos polifenóis. Em conclusão, este estudo evidencia que as pínulas e as folhas de D. sellowiana apresentam uma composição fitoquímica semelhante e mais diversificada das demais estruturas avaliadas, se destacando na concentração de polifenóis e atividade antioxidante. Os resultados reforçam a preservação da espécie ameaçada e seu potencial como recurso para compostos fitoquímicos farmacológicos e nutricionais.

Abstract The Brazilian native species Cestrum intermedium, known as mata-boi, induces hepatotoxicity and death when ingested by cattle. While most studies on this species focus on toxicological features, our study is the first to describe the anatomy and in vitro biological activities of Cestrum intermedium. We investigated adult leaves and stems by histochemistry, described their anatomy, performed physical-chemical analysis, determined in vitro antioxidant and antimicrobial activities, and identified secondary metabolites. A few noteworthy anatomical features were the anomocytic stomata on the abaxial surface and the absence of trichomes, in addition to the circular shaped petiole with two projections on the adaxial surface. Histochemical analysis showed chemical markers such as alkaloids, usually reported as toxic, and terpenoids. Potassium nitrate (ATR-FTIR) and lupeol palmitate (NMR) were detected on the crude stem extract. Thermogravimetric and physical-chemical analysis provided fingerprint parameters for the species. Minimal Inhibitory Concentration (MIC) assay revealed that Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans were weakly inhibited by extract samples. Chloroform and ethyl acetate fractions presented high phenolic content, which resulted in in vitro antioxidant activity. These novel features expand the knowledge about this species, considering that previous studies mainly focused on its toxicity. Our study also provided characteristics that may help in avoiding misidentification between Cestrum members, especially when taxonomic keys cannot be employed, as in the absence of flowers and fruits.

Abstract Our study aimed to evaluate the chemical composition of the essential oil from the leaves of Eugenia pyriformis Cambess., belonging to the Myrtaceae family and native to the Brazilian Atlantic forest. The volatile compounds in the essential oil were extracted by hydrodistillation and analyzed using GC-MS; 36 compounds accounted for 78.80% of the total oil content. The major compounds were β-caryophyllene, bicyclogermacrene, globulol, and (δ-cadinene. We evaluated their antimicrobial potential of the essential oil and toxicity to Artemia salina. The antimicrobial activity of the essential oil was evaluated against 12 microorganisms using the broth microdilution method. Our results showed moderate inhibition of Staphylococcus aureus and methicillin-resistant S. aureus (MIC, 250 and 125 μg.mL-1, respectively) and toxicity to A. salina (LC50, 125.64 μg.mL-1). Our results establish the biological activity of the essential oil obtained from E. pyriformis.