17 research outputs found
Synthesis and Physicochemical Studies of Mixed Ligand Complexes of Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) with Acetophenone Semicarbazone and Acetone Semicarbazone
Synthesis and Characterization of Mixed Ligand Complexes of Transition Metals with Schiff's Bases
Oral ingestion of silver nanoparticles induces genomic instability and DNA damage in multiple tissues
Synthesis, Characterization and Nanochemistry of Novel Antibacterial Copper (II) Semicarbazone Complexes
Unexpected transformation of ethyl 1-(4-chlorophenyl)-2-methyl-4-oxo-1,4,5,6-tetrahydropyridine-3-carboxylate and antibacterial activity of the products
A review on techniques employed for encapsulation of the bioactive components of Punicagranatum
Gamma-tocotrienol and hydroxy-chavicol synergistically inhibits growth and induces apoptosis of human glioma cells
Hydroalcoholic extracts from the bark of Quercus suber L. (Cork): optimization of extraction conditions, chemical composition and antioxidant potential
Cork is the bark of the tree Quercus suber L. which ï¬ nds use in diverse applications. However, a signiï¬ cant percentage is still rejected and burned for energy production, despite containing valuable molecules for materials processing and with important biological activities. Herein, the optimization of the extraction process to obtain these molecules, using mild solvents and conditions, is described within a bioreï¬ nery perspective. The extracts were obtained by direct contact solvent extractions with water, ethanol and its mixtures for different time and temperatures, and evaluated for chemical composition, total phenolic content (TPC) and antioxidant properties [by DPPH radical scavenging, ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays]. The results showed that the extraction process is accelerated and higher yields are achieved with the increase in temperature without chemical degradation or compromising the antioxidant capacity. For all solvents, at reï¬ ux temperature, more than 90% of the extractable material is obtained within 6 h (80% within 1 h). The highest TPC and antioxidant capacity are observed for the extracts obtained with mixtures of water and ethanol of similar volumes. The antioxidant capacity measured by DPPH, FRAP and TEAC assays was found to be proportional to the extract TPC, while ORAC is favored for higher percentages of ethanol on the extracting solvent. The main constituents of these extracts are the ellagitannins, vescalagin, castalagin and b-O-ethylvescalagin, along with other phenolic acids (mainly ellagic and gallic acids) and various ï¬ avonols. The extracts stability was monitored up to 1 year of storage with neither reduction in the antioxidant capacity nor chemical degradation. These results show that extracts with strong antioxidant potential and high content of bioactive molecules can be obtained from the processing of waste streams. Cork is a sustainable forest product and the development of new ï¬ elds of application contributes toward a zero waste cycle for a complete material bioreï¬ nery.The authors are grateful to Amorim Cork Composites for providing the cork powder
and for the financing provided by the COMPETE/QREN/EU funding program through project
BioActiveCork (QREN FCOMP-01-0202-FEDER-005455). Ivo M. Aroso and João P. Fernandes
Fig. 6 Comparison between fresh and 1 year stored extracts for a TPC and b DPPH scavenging capacity
Wood Sci Technol123 acknowledge the financial support from FCT through grants SFRH/BD/42273/2007 and SFRH/BD/73162/2010, respectively. Funding was also granted from the European Union’s Seventh Framework
Programme (FP7/2007–2013) under Grant Agreement No. REGPOT-CT2012-316331-POLARIS and
from Project ‘‘Novel smart and biomimetic materials for innovative regenerative medicine approaches
(Ref.: RL1 - ABMR - NORTE-01-0124-FEDER-000016)’’ co-financed by North Portugal Regional
Operational Programme (ON.2 – O Novo Norte), under the National Strategic Reference Framework
(NSRF), through the European Regional Development Fund (ERDF). Conflict of Interest: The authors
declare that they have no conflict of interest.info:eu-repo/semantics/publishedVersio