QUANTIFICAÇÃO POR CLAE DE NAFTOQUINONAS DO EXTRATO DAS RAÍZES DE Cordia leucocephala Moric.

Três naftoquinona, (11S, 13S, 16R)-cordiaquinona J ((+)-cordiaquinona J), 6-[10-(12,12-dimetil-13α-hidroxi-16-metil-ciclohexil]-1,4-naftalenodiona (cordiaquinona L) e 5-metil-6-[10-(12,12-dimetil-13β-hidroxi-16ciclohexil)-metil-1,4-naftalenodiona (cordiaquinona M) foram isoladas do extrato etanólico das raízes de Cordia leucocephala Moric. Estas naftoquinonas, exceto a cordiaquinona M foram quantificadas por CLAE no extrato bruto das raízes de C. leucocephala. Os padrões da (+)-cordiaquinona J e cordiaquinona M foram identificados no cromatograma pelos respecttivos tempo de retenção e espectro-UV. A quantificação das duas naftoquinonas apresentou teores de 310 μg de (+)-cordiaquinona J e 180 μg de cordiaquinona M, em 100 mg de raízes dessa espécie vegetal

Chemical Composition and Antifungal In Vitro and In Silico, Antioxidant, and Anticholinesterase Activities of Extracts and Constituents of Ouratea fieldingiana (DC.) Baill

Ouratea fieldingiana (Gardner) Engl is popularly used for wound healing. This study describes the main chemical compounds present in extracts of O. fieldingiana and evaluates their biological potential by investigating antifungal, antioxidant, and anticholinesterase activities. The action mechanism of main antifungal compound was investigated by molecular docking using the enzyme sterol 14-α demethylase, CYP51, required for ergosterol biosynthesis. The seeds and leaves were extracted with ethanol in a Soxhlet apparatus and by maceration, respectively. Both extracts were subjected to silica gel column chromatography for isolation of main constituents, followed by purification in sephadex. The structures of compounds were established by 1H and 13C-NMR spectroscopy and identified by comparison with literature data as amentoflavone and kaempferol 3-O-rutinoside, respectively. The antioxidant activities of the extracts were determined by the DPPH and ABTS free radical inhibition methods. In general, the extracts with the highest antioxidant activity corresponded to those with higher content of phenolic compounds and flavonoids. The ethanol extracts and two isolated compounds presented relevant antifungal activity against several Candida strains. The in silico findings revealed that the compound amentoflavone coupled with the CYP450 protein due to the low energy stabilization (-9.39 kcal/mol), indicating a possible mechanism of action by inhibition of the ergosterol biosynthesis of Candida fungi

Atlantic forest woody carbon stock estimation for different successional stages using Sentinel-2 data

The Atlantic Forest is one of the most threatened biodiversity hotspots and environmental impacts has made its landscape fragmented and heterogeneous. The heterogeneity of the fragments is a challenge for the characterization and quantification of forest resources, such as the stock of biomass and carbon. Methodologies based on remote sensing have been used, to improve these estimates without compromising execution costs. The objective was to estimate, with high spatial resolution passive remote sensing, the aboveground carbon stock in fragments of different successional stages of the Atlantic Forest. Forests were classified into initial, intermediate, and advanced successional stages. In each stratum, 10 plots (20x50 m) were established, and the carbon stock was calculated by adjusted Schumacher and Hall model. The reflectances of the blue, green, red, and near-infrared bands and vegetation indices (VIs) were obtained in the dry and rainy seasons, from MSI/Sentinel-2 images, with a resolution of 10 m. Artificial Neural Networks (ANN), with different combinations of variables, were trained and validated with simulated reflectance values. Carbon was estimated by ANN with the best performance in training and validation. The average carbon stock in the initial, intermediate, and advanced strata was 24.99, 35.79 and 82.28 Mg ha−1, respectively, with a general average of 47.68 Mg ha−1. The carbon estimates were better with the ANN trained with the reflectances of the rainy season. The addition of VIs did not improve ANN performance. The simulated spectral data were consistent and adequate to validate the selected ANN. The total carbon stock, modeled was 41,962.15 Mg, ranging from 6.68 to 108.29 Mg ha−1, with an average of 48.70 Mg ha−1. The carbon stock in the advanced stratum is more than three times that observed in the initial stratum, and they were efficiently estimated using high-resolution multispectral data, obtained in the rainy season, as inputs