No abstract

Oleuropein is one of the most abundant phenolic compounds present in olive leaves, and many studies have shown that this compound has important biological properties (anti-inflammatory, anti-atherogenic, anticancer, antimicrobial and antiviral) and that is why it has been gaining prominence in research. Oleuropein can be extracted from different sources using standard and unconventional methods, and can be recovered and purified (mainly by chromatographic techniques), for later use in several areas. The literature presents information about oleuropein alone in scientific research with different objectives, however, it was observed by the authors that studies that compile the existing information on these secoiridoides are very scarce and, therefore, this review was developed with the aim of providing current information to the scientific community, about the different techniques of extraction and purification of oleuropein, as well as the opportunities for applications and uses of this compound.

It is important to determine the chemical composition of fruits in order to establish their potential health benefits for human nutrition and thus stimulate their cultivation and consumption. Therefore, the objective of this study was to determine the physical and chemical parameters, vitamin C content, phenolic compounds, flavonoids and carotenoids, fatty acid profile and antioxidant activity of fruits from different regions of Brazil. We observed that the different regions and fruits studied presented very distinct characteristics. For example, the cupuaçu pit is rich in unsaturated fatty acids, while the genipap and java plum presented high flavonoid content and the butia had a high concentration of carotenoids. Guava was the fruit with the highest antioxidant activity through the ABTS radical, while the yellow mombim presented the best response when the activity was determined by FRAP.

Research has indicated the antifungal activity of ethanol extracts from propolis (EEP) on fungi of the genera Phakopsora, Colletotrichum, and Cercospora. Here, chemical compositions and antioxidant activity of three EEP (propolis from Scaptotrigona polysticta stingless bee and two types produced by Apis mellifera-red and brown) were evaluated and their action against Aspergillus flavus was investigated. Ash, dry extract, total phenolic and total flavonoid contents were determined. Phenolic composition was evaluated by high performance liquid chromatography, with using the following reference substances: gallic acid, caffeic acid, ρ-coumaric acid, ferulic acid, quercetin, kaempferol, and apigenin. Tests on mycelial growth, sporulation, and germination of spores were performed to assess the biological activity of the EEP on A. flavus. All EEP showed low dry extract content (<11%) with adequate amounts of ash (<5%). The red EEP (Apis mellifera) showed the highest contents of total phenolic and total flavonoid (5.38 and 2.77 g 100 g-1), while the highest recorded antioxidant activity was exhibited by brown EEP (92.9%). The EEP of S. polysticta presented higher levels of ρ-coumaric acid (10.99 mg g-1), while red and brown extracts from A. mellifera stood out with the highest levels of quercetin (27.26 mg g-1) and gallic acid (5.88 mg g-1), respectively. No extract was effective in inhibiting mycelial growth and sporulation of A. flavus, but red EEP inhibited spore germination. On the basis of these results, it is suggested that the inhibitory effect of red EEP on spore germination may be associated with increased levels of flavonoids found in it as compared with the other extracts investigated here.

Ilex paraguariensis is a perennial plant used in the production of mate tea, “chimarrão” and “tererê,” cosmetics, and other food products. Its leaves are harvested every 12 or 18 months. Approximately 2 to 5 tons of residue are generated per hectare during the harvest. The bioactive composition of this residue has not been characterized to date. Therefore, this paper presents for the first time, the simultaneous characterization of the bioactive compounds of the leaves, thin branches, and thick branches (residue) from I. paraguariensis grown under two cultivation systems: “full sun” and “shaded.” The identification and quantification of the compounds was performed using high‐performance liquid chromatography coupled to electrospray ionisation and quadrupole time‐of‐flight mass spectrometer (HPLC‐ESI‐QTOF‐MS). Consequently, 35 compounds were identified. The average dry weight of phenolic compounds in the residue was 4.1 g/100 g, whereas that in the bark of the residue was 12.9 g/100 g, which was similar to the content found in leaves. The same compounds were identified in the two cultivation systems but with a difference in their contents. While the “full sun” cultivation had a higher content of phenolic acids, the “shaded” cultivation had a higher content of flavonoids and saponins. It was found that the I. paraguariensis residue, particularly the bark, is rich in bioactive compounds, such as quinic, 3‐caffeoylquinic, 5‐cafefoylquinic, 3,5‐dicaffeoylquinic, and 4,5‐dicaffeoylquinic acids as well as rutin, and their contents vary according to the cultivation system. Therefore, this residue is an underutilized natural resource with a potential for industrial applications. Practical Application Yerba mate producers will be able to choose the best cultivation system (“full sun” or “shaded”) to increase the content of bioactive compounds. New products may be developed with yerba mate residue due to its high concentration of compounds that are beneficial to the human health. New destinations may be applied to yerba mate residue from the harvest pruning, adding commercial value to this unexplored natural resource.