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Nectandra grandiflora Nees (Lauraceae) is a Brazilian native tree recognized by its durable wood and the antioxidant compounds of its leaves. Taking into account that the forest industry offers the opportunity to recover active compounds from its residues and by-products, this study identifies and underlines the potential of natural products from Nectandra grandiflora that can add value to the forest exploitation. This study shows the effect of three different extraction methods: conventional (CE), ultrasound-assisted (UAE) and microwave-assisted (MAE) on Nectandra grandiflora leaf extracts (NGLE) chemical yields, phenolic and flavonoid composition, physical characteristics as well as antioxidant and antifungal properties. Results indicate that CE achieves the highest extraction phytochemical yield (22.16%), but with similar chemical composition to that obtained by UAE and MAE. Moreover, CE also provided a superior thermal stability of NGLE. The phenolic composition of NGLE was confirmed firstly, by colorimetric assays and infrared spectra and then by chromatographic analysis, in which quercetin-3-O-rhamnoside was detected as the major compound (57.75–65.14%). Furthermore, the antioxidant capacity of the NGLE was not altered by the extraction methods, finding a high radical inhibition in all NGLE (>80% at 2 mg/mL). Regarding the antifungal activity, there was observed that NGLE possess effective bioactive compounds, which inhibit the Aspergillus niger growth. [ABSTRACT FROM AUTHOR] more...

This study is designed to evaluate the physicochemical properties and the decay resistance of leaf extracts obtained from a native Brazilian tree Ocotea lancifolia . Ethanol was used to obtain crude extract from milled leaves, which was further partitioned with ethyl acetate and butanol achieving two phenolic-rich fractions. Furthermore, wood veneers were impregnated with crude extract and its fractions (at 1 and 4%), and evaluated against two wood-destroying fungi. Firstly, Fourier transform infrared and thermogravimetric analysis confirmed chemical differences on structure, stability and purity of the evaluated extract samples. Crude extract presented lower total phenolic content (178 mg GAE/g dried sample) and lower antioxidant activity than its fractions. Moreover, the fractions showed 360–405 mg GAE/g dried sample and a high scavenging effect (IC 50 < 0.75 mg/mL). Chromatographic analysis revealed the presence of quercetin-derived monoglucosides in all samples, such as quercetin-3- O -rhamnoside (∼20–22% in crude extract and ethyl acetate fraction) and quercetin-3- O -glucoside in butanolic fraction (20.71%). Crude extract and ethyl acetate fraction at 4% were the most effective treatments to reduce the action of two wood-rot fungi (mass loss < 8%). Overall, leaf extracts from O. lancifolia can provide a renewable source of antioxidants and eco-friendly wood preservatives. [ABSTRACT FROM AUTHOR] more...