Gredson Keiff Souza

This study reports the first phytochemical and anticancer investigation of the Brazilian orchid Epidendrum cristatum. Classical chromatography led to the isolation of the steroids sitosterol (1) and stigmasterol (2), the phenolic compound vanillin (3), and the flavone tricin (4). Additionally, the compounds moupinamide (5), corchoionoside (6), phytosphingosine (7), syringaresinol (8), and 4-(2,6,6-trimethyl-4-oxo-2-cyclohexen-1-yl)-2-butanyl β-D-glucopyranoside (9) were putatively identified using ultra-high-performance liquid chromatography coupled with high-resolution tandem time-of-flight mass spectrometry (UHPLC-QToF-HR-MS/MS) analyses. Cytotoxicity assays were conducted against HeLa (human colon cancer cells modified by HPV) and VERO (non-cancerous green monkey kidney cells) cell lines. The crude extract of the plant (CE), the acid chloroform fraction (CAF), and the basic chloroform fraction (CBF) were tested. These fractions exhibited activity against HeLa cells, with cytotoxic concentrations (CC50) of 1.88, 5.69, and 5.04 µg mL-1, respectively, and showed activity against non-cancerous VERO cells, with CC50 values of 1.33, 0.75, and 1.46 µg mL-1, respectively. Finally, the chemophenetic and ecological relevance of the isolated and putatively identified compounds from E. cristatum was discussed based on the available literature.

The drugs delivery system in the treatment of diseases has advantages such as reduced toxicity, increased availability of the drug, etc. Therefore, studies of the supramolecular interactions between local anesthetics (LAs) butamben (BTB) or ropivacaine (RVC) complexed with 2-hydroxypropyl-β-cyclodextrin (HP-βCD) and carried in Stealth liposomal (SL) are performed. ¹H-NMR nuclear magnetic resonance (DOSY and STD) were used as the main tools. The displacements observed in the ¹H-NMR presented the complexion between LAs and HP-βCD. The diffusion coefficients of free BTB and RVC were 7.70 × 10⁻¹⁰ m² s⁻¹ and 4.07 × 10⁻¹⁰ m² s⁻¹, and in the complex with HP-βCD were 1.90 × 10⁻¹⁰ m² s⁻¹ and 3.64 × 10⁻¹⁰ m² s⁻¹, respectively, which indicate a strong interaction between the BTB molecule and HP-βCD (98.3% molar fraction and Ka = 72.279 L/mol). With STD-NMR, the encapsulation of the BTB/HP-βCD and RVC/HP-βCD in SL vesicles was proven. Beyond the saturation transfer to the LAs, there is the magnetization transfer to the hydrogens of HP-βCD. BTB and RVC have already been studied in normal liposome systems; however, little is known of their behavior in SL.

A biofilm is represented by a community of microorganisms capable of adhering to a surface and producing substances that envelop the cells, forming an extracellular matrix. The extracellular matrix is responsible for protecting microorganisms against environmental stress, hosts the immune system and confers resistance to antimicrobials. Fusarium keratoplasticum is a common species of FSSC (Fusarium solani species complex) associated with human infections, being the most prevalent species related to biofilm formation in hospital water systems and internal pipelines. With this in mind, this study aimed to characterise the biofilm formed by the fungus F. keratoplasticum and to evaluate the effects of farnesol, a fungal quorum sensing (QS) molecule, on the preformed biofilm and also during its formation at different times (adhesion and 24, 48 and 72 h). F. keratoplasticum is able to adhere to an abiotic surface and form a dense biofilm in 72 h, with increased total biomass and matrix modulation with the presence of extracellular DNA, RNA, polysaccharides and proteins. Farnesol exhibited important anti-biofilm activity, causing the destruction of hyphae and the extracellular matrix in preformed biofilm and preventing the adhesion of conidia, filamentation and the formation of biofilm. Few studies have characterised the formation of biofilm by filamentous fungi. Our findings suggest that farnesol acts efficiently on F. keratoplasticum biofilm since this molecule is capable of breaking the extracellular matrix, thereby disarranging the biofilm.

This study investigated the effects of variations in oil contents and fatty‐acid composition, density, viscosity, acid values, saponification values, specific oxidative stability, and antioxidant concentration of Acrocomia totai kernel oil during fruit maturation. Fatty acids were quantified using ¹H nuclear magnetic resonance (NMR) spectroscopy, gas chromatograph‐flame‐ionization detector (GC‐FID), and Fourier transform Raman (FT‐Raman) spectroscopy analyses. The results showed that all physicochemical characteristics and oil composition changed during the ripening stage. The CG‐FID analysis showed a reduction in the unsaturated fatty‐acid content (from 78.8% to 22.1%), with a proportional increase in the saturated fatty‐acid contents (from 21.6% to 77.9%). The difference in the fatty‐acid composition was confirmed by analysis of the ¹H NMR and FT‐Raman spectra. The degree of unsaturation was calculated to determine the oxidative stability of oil. These results suggest that the fruit's maturation contributes to the specific oxidative stability. The antioxidant concentration revealed higher contents of carotenoids in the ripe fruit (0.16 mg of carotenoid per 100 g_KERNEL) when compared to the unripe fruit (0.05 mg of carotenoid per 100 g_KERNEL). In the total phenolics analysis, there was no change in concentration over ripening time. These results show that kernel oil has physicochemical properties comparable with high‐quality commercial vegetable oils, suggesting that it is a promising alternative to conventional vegetable oils.

The phytochemical study of Laelia marginata (Lindl.) L. O. Williams (Orchidaceae) led to the isolation of a new natural product named crispoic acid (1), together with six other known compounds (2–7). The new natural product was identified as a dimer of eucomic acid and was structurally characterised based upon 1D and 2D NMR and HRMS data. Biological assays with plant crude extract, fractions and isolated compounds were performed against two human cancer cell lines (Hela and Siha), and the tropical parasites Trypanosoma cruzi and Leishmania (Leishmania) amazonensis. The phenantrenoid 9,10-dihydro-4-methoxyphenanthren-2,7-diol 2 was active against Hela and Siha cells (CC₅₀ 5.86 ± 0.19 and 20.78 ± 2.72 μg/mL, respectively). Sub-lethal concentrations of the flavone rhamnazin 4 were not able to rescue the viability of the Vero cells infected by Zika virus.