Essential Oil of Cymbopogon nardus (L.) Rendle: A Strategy to Combat Fungal Infections Caused by Candida Species

Background: The incidence of fungal infections, especially those caused by Candida yeasts, has increased over the last two decades. However, the indicated therapy for fungal control has limitations. Hence, medicinal plants have emerged as an alternative in the search for new antifungal agents as they present compounds, such as essential oils, with important biological effects. Published data demonstrate important pharmacological properties of the essential oil of Cymbopogon nardus (L.) Rendle; these include anti-tumor, anti-nociceptive, and antibacterial activities, and so an investigation of this compound against pathogenic fungi is interesting. Objective: The aim of this study was to evaluate the chemical composition and biological potential of essential oil (EO) obtained from the leaves of C. nardus focusing on its antifungal profile against Candida species. Methods: The EO was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). Testing of the antifungal potential against standard and clinical strains was performed by determining the minimal inhibitory concentration (MIC), time-kill, inhibition of Candida albicans hyphae growth, and inhibition of mature biofilms. Additionally, the cytotoxicity was investigated by the IC₅₀ against HepG-2 (hepatic) and MRC-5 (fibroblast) cell lines. Results: According to the chemical analysis, the main compounds of the EO were the oxygen-containing monoterpenes: citronellal, geranial, geraniol, citronellol, and neral. The results showed important antifungal potential for all strains tested with MIC values ranging from 250 to 1000 μg/mL, except for two clinical isolates of C. tropicalis (MIC > 1000 μg/mL). The time-kill assay showed that the EO inhibited the growth of the yeast and inhibited hyphal formation of C. albicans strains at concentrations ranging from 15.8 to 1000 μg/mL. Inhibition of mature biofilms of strains of C. albicans, C. krusei and C. parapsilosis occurred at a concentration of 10× MIC. The values of the IC₅₀ for the EO were 96.6 μg/mL (HepG-2) and 33.1 μg/mL (MRC-5). Conclusion: As a major virulence mechanism is attributed to these types of infections, the EO is a promising compound to inhibit Candida species, especially considering its action against biofilm.     

Volume estimation in a Eucalyptus plantation using multi-source remote sensing and digital terrain data: a case study in Minas Gerais State,Brazil

In this study, we tested the effectiveness of stand age, multispectral optical imagery obtained from the Landsat 8 Operational Land Imager (OLI), synthetic aperture radar (SAR) data acquired by the Sentinel-1B satellite, and digital terrain attributes extracted from a digital elevation model (DEM), in estimating forest volume in 351 plots in a 1,498 ha Eucalyptus plantation in northern Minas Gerais state, Brazil. A Random Forest (RF) machine learning algorithm was used following the Principal Component Analysis (PCA) of various data combinations, including multispectr al and SAR texture variables and DEM-based geomorphometric derivatives. Using multispectral, SAR or DEM variables alone (i.e. Experiments (ii)–(iv)) did not provide accurate estimates of volume (RMSE (Root Mean Square Error) > 32.00 m³ ha^?1) compared to predictions based on age since planting of Eucalyptus stands (Experiment (i)). However, when these datasets were individually combined with stand age (i.e. Experiments (v)–(vii)), the RF models resulted in better volume estimates than those obtained when using the individual multispectral, SAR and DEM datasets (RMSE < 28.00 m³ ha^?1). Furthermore, a model that integrated the selected variables of these data with stand age (Experiment (viii)) improved volume estimation significantly (RMSE = 22.33 m³ ha^?1). The large and increasing area of Eucalyptus forest plantations in Brazil and elsewhere suggests that this new approach to volume estimation has the potential to support Eucalyptus plantation monitoring and forest management practices.     

Oxidized Cashew Gum Scaffolds for Tissue Engineering

In the last few years, several strategies have been proposed to fabricate scaffolds for tissue engineering (TE) applications; however, they are based on harsh and time‐consuming techniques. The choice for natural polymers such as cashew gum (CG) allows to circumvent the demands of biocompatibility and degradability of TE systems. In this work, CG, a polysaccharide derived from Anacardium occidentale trees, is functionalized with aldehyde groups through periodate oxidation. The resultant oxidized cashew gum (CGO) is mixed with gelatin (GE) to yield a covalently crosslinked hydrogel. CGO/GE sponges are obtained by employing a freeze‐drying methodology to the previously obtained hydrogels. The mechanical properties, swelling ability, and porosity of the GE/CGO sponges are tuned by using CGO with different degrees of oxidation. The resultant sponges can maintain high levels of water absorption and recover their initial mechanical properties after cyclic compression. Moreover, these porous and mechanically robust devices can support the adhesion and proliferation of cells, which can envision their application for the regeneration of soft tissues.     

Antioxidant potential of mate tea (Ilex paraguariensis) in type 2 diabetic mellitus and pre-diabetic individuals

The effect of long-term mate tea (Ilex paraguariensis) consumption on the oxidative stress biomarkers of type 2 diabetic mellitus and pre-diabetic individuals was investigated. A 60-day intervention pilot study where 11 T2DM and 11 pre-diabetic volunteers ingested 1 L/day of mate tea was carried out. Ferric reducing antioxidant power (FRAP), erythrocyte reduced glutathione (GSH), serum lipid hydroperoxides (LOOH) using ferrous oxidation-xylenol orange (FOX2), advanced glycation end-products (AGEs), and glycaemic and lipid profiles were assessed at baseline and after 20, 40, and 60 days of intervention. Mate tea consumption promoted a significant increase of GSH concentration and a decrease of LOOH levels in T2DM and pre-diabetic subjects. In addition, GSH concentration was inversely correlated with LOOH in T2DM and pre-diabetic individuals and with AGEs in T2DM subjects. No correlations between glycaemic and lipid profiles with oxidative stress biomarkers were found. Thus, ingestion of mate tea attenuated oxidative stress in T2DM and pre-diabetic subjects, which may prevent diabetes complications.