Forest Research Centre

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Publications

Exploring the Bioactive Properties of Hydroethanolic Cork Extracts of Quercus cerris and Quercus suber

Publication . Sen, Umut; Almeida, Daiana; Silveira, Tayse F. F. da; Pires, Tânia C.S.P.; Añibarro-Ortega, Mikel; Mandim, Filipa; Barros, Lillian; Ferreira, Isabel C.F.R.; Pereira, Helena; Fernandes, Ângela

The bioactive properties of underutilized corks such as Quercus cerris cork and planted Quercus suber cork in the Eastern Mediterranean are not well-known but are crucial in developing lignocellulosic biorefineries. To assess their biological potential, hydroethanolic cork extracts of Quercus cerris and Quercus suber were analyzed for phenolic composition, antioxidant, antiproliferative, antimicrobial activities, and hepatoxicity, as well as NO-production inhibition. Here, we show that a mild hydroethanolic extraction of Q. cerris and Q. suber corks yielded 3% phenolic extracts. The phenolic composition was similar in both cork extracts, with phenolic acids and ellagitannins as the primary compounds. The bioactivity of hydroethanolic cork extracts from Q. cerris surpassed that of Q. suber and showed effectiveness against all cancer cell lines tested. This first comprehensive study on the bioactivities of different corks involves detailed characterizations of phenolic compounds of cork extracts using UPLC-DAD-ESI/MSn, evaluations of the antioxidant properties with TBARS and OxHLIA methods, evaluation of antiproliferative activity against gastric (AGS), lung (NCI-H460), colon (CaCo2), and breast cancer (MCF7) cell lines, as well as evaluations of hepatotoxicity and NO-production inhibition. The findings from this study will help bolster the potential of using underutilized cork-rich barks as a valuable resource in bark-based biorefineries.

2024Journal article

Open access

Mediterranean woody agroecosystems in a warming and drier climate: the importance of knowledge-based management

Publication . Pinheiro, Carla; David, Teresa S.; Baptista, Paula; Guerra-Guimarães, Leonor

The Mediterranean region is often described as a climate change hotspot. Not surprisingly, climate change impact on Medieterranean Agroecosystems sustainability, biodiversity, and productivity has been receiving a lot of interest from the research community. It is reported that the frequency, intensity and duration of droughts, as well as hotter droughts, are interfering with ecosystems’ structure, composition, and functions. To minimize some of the risks of the ongoing climate change, and maintain the economic viability of the agroecosystems, management strategies and practices need to be changed/adapted at the local and regional levels. This is of fundamental importance for the design of future human societies and their relationships with other species.

2022Journal article

Open access

Pine Nutshells and Their Biochars as Sources of Chemicals, Fuels, Activated Carbons, and Electrode Materials

Publication . Şen, Ali Umut; Rodrigues, João F.G.; Almeida, Daiana; Fernandes, Ângela; Gonçalves, Margarida; Martins, Marta; Santos, Diogo M.F.; Pereira, Helena

Pine nutshells (PNSs) are lignocellulosic waste materials with limited use in domestic heating. However, a biorefinery approach may be applied to fractionate PNSs and produce chemicals, materials, and improved solid fuels. In this study, we fractionated PNSs and produced antioxidant extracts, lignins, polysaccharides, chars, and activated carbons and analyzed their potential applications. Pyrolytic kinetic modeling as an alternative method to chemical fractionation was also tested. The results showed that the PNS contains low amounts of extracts with weak thiobarbituric acid reactive substances (TBARS) antioxidant properties, while its lignin content is remarkable (50.5%). Pyrolytic kinetic modeling was comparable to wet chemical analysis for estimating lignin yield. Moderate-temperature pyrolysis of the PNS resulted in a 23% char yield. The PNS chars showed improved fuel characteristics, retained 36% water, and leached 151 mg/L potassium into the water. The steam activation of PNS biochars at 750 ◦C resulted in oxygen-enriched activated carbons with specific surface areas up to 467 m2/g. The overall results indicate promising biochar applications of the PNS for soil amendment and supercapacitor uses.

2024Journal article

Open access

Bioactivities of Waste Cork and Phloem Fractions of Quercus cerris Bark

Publication . Şen, Ali Umut; Almeida, Daiana; Silveira, Tayse F. F. da; Pires, Tânia C.S.P.; Añibarro-Ortega, Mikel; Mandim, Filipa; Barros, Lillian; Ferreira, Isabel C.F.R.; Pereira, Helena; Fernandes, Ângela

Recently, more and more researchers have begun to consider using waste bark fractions to produce value-added biochemicals and materials, as well as for energy production. Extraction is often the first operation in biomass biorefineries. Here we obtained hydroethanolic extracts from waste cork and phloem fractions of Quercus cerris bark and analyzed them to determine their antioxidant, antimicrobial, and nitric oxide (NO) production inhibition properties and their hepatotoxicity. The antioxidant properties were investigated by ex vivo TBARSs as well as OxHLIA antioxidant assays, the antibacterial properties against Gram-positive and Gram-negative bacteria isolated from food and clinical sources, and antifungal properties against Aspergillus brasiliensis and A. fumigatus. The NO production inhibition activity was assessed in a lipopolysaccharide (LPS)-stimulated murine macrophage (RAW 264.7) cell line, and antiproliferative activities were determined against five different cell lines, including lung (NCI-H460), gastric (AGS), breast (MCF7), and colon (CaCo2) tumor cell lines, as well as a non-tumor cell line (PLP2). The hydroethanolic maceration of waste cork and phloem yielded 4.4% and 2.4% extracts, respectively. Gallic acid glucosides, phenolic acids, and ellagic acid were identified in both extracts. The waste cork and phloem extracts showed antioxidant, antimicrobial, antifungal, and antiproliferative properties but also showed hepatotoxicity in the case of waste cork. Both bark fractions varied in terms of their bioactivity, with waste cork extracts showing, in general, higher bioactivity than phloem extracts.

2024Journal article

Open access