Aqueous extracts of green yerba maté (Ilex paraguariensis) and green tea (Camellia sinensis) are good sources of phenolic antioxidants, as already described in the literature. The subject of this study were organic extracts from yerba maté, both green and roasted, and from green tea. Their phenolic profiles were characterized by direct infusion electrospray insertion mass spectrometry (ESI-MS) and their free radical scavenging activity was determined by the DPPH assay. Organic extracts containing phenolic antioxidants might be used as natural antioxidants by the food industry, replacing the synthetic phenolic additives used nowadays. Ethanolic and aqueous extracts from green yerba maté, roasted yerba maté and green tea showed excellent DPPH scavenging activity (>89%). The ether extracts from green and roasted yerba maté displayed a weak scavenging activity, different from the behavior observed for the green tea ether extract. The main phenolic compounds identified in green yerba maté water and ethanolic extracts were: caffeic acid, quinic acid, caffeoyl glucose, caffeoylquinic acid, feruloylquinic acid, dicaffeoylquinic acid and rutin. After the roasting process two new compounds were formed: caffeoylshikimic acid and dicaffeoylshikimic acid. The ethanolic extracts from yerba maté, both roasted and green, with lower content of phenolic compounds (3.80 and 2.83 mg/mL) presented high antioxidant activity and even at very low phenolic concentrations, ether extract from GT (0.07 mg/mL) inhibited DPPH over 90%.
The plasmalogens are a class of glycerophospholipids which contain a vinyl-ether and an ester bond at the sn-1 and sn-2 positions, respectively, in the glycerol backbone. They constitute 10 mol% of the total mass of phospholipids in humans, mainly as membrane structure components. Plasmalogens are important for the organization and stability of lipid raft microdomains and cholesterol-rich membrane regions involved in cellular signaling. In addition to their structural roles, a subset of ether lipids are thought to function as endogenous antioxidants and emerging studies suggest that they are involved in cell differentiation and signaling pathways. Although the clinical significance of plasmalogens is linked to peroxisomal disorders, the pathophysiological roles and their possible metabolic pathways are not fully understood since they present unique structural attributes for the different tissue types. Studies suggest that changes in plasmalogen metabolism may contribute to the development of various types of cancer. Here, we review the molecular characteristics of plasmalogens in order to significantly increase our understanding of the plasmalogen molecule and its involvement in gastrointestinal cancers as well as other types of cancers.
1 December 2010 in Journal of Molecular Catalysis B: Enzymatic
During the extraction of propolis several factors were varied in order to determine how they affected the yield and phenolic composition of the obtained extracts. Six samples of green propolis from the Southeastern region of Brazil were tested. The results indicate that the highest yield of propolis extracts obtained by maceration, which also had the greatest number of components, were those using 70% (v/v) ethanol or more as a solvent. The Soxhlet extraction procedure resulted in even higher yields. No differences were observed between extracts macerated in the presence or absence of light. An increase in yield was observed between extracts macerated for 10 and 30 days although the phenolic content did not vary significantly. The total phenolic content of all extracts varied from 6.41 to 15.24 % but no direct correlation could be found between any of the factors tested.