The procedures for the extraction and the successive hydrolysis of the oleuropein for the synthesis of its aglycon and the hydroxytyrosol, resolve the problems tied to the quantitative yield of the products and to the use of highly-toxic and expensive catalysts.; Furthermore, the innovative and inventive contribution is given by the peracylation of the oleuropein and its products of synthesis, aglycon and hydroxytyrosol, that supply a new class of molecule, biologically active as anti-oxidants and anti-inflammatory ones.
(2006) Pomegranate as a cosmeceutical source: pomegranate fractions promote proliferation and procollagen synthesis and inhibit matrix metalloproteinase-1 production in human skin cells.
In this study, samples of Erkence olives were collected from the northeast and southwest orientation of trees cultivated in both orchards A and B. No effect on the oleuropein composition due to tree orientation was found (). obtained a higher phenolic concentration in olive oils extracted from fruit located at higher layers of the olive trees than lower layers, and reported that olive oils from sunny areas had a higher concentration of these substances than those from shady areas. A trend was observed for the rest of the phenolic compounds analyzed in Erkence olives (), although it was not statistically significant. It must be noted that the synthesis of phenolic compounds is influenced by solar radiation, the longer the hours of exposure to solar radiation of fruit and leaves, the higher the concentration of certain phenolic compounds will be found in these materials (; ).
Erkence olives change their color during ripening in a similar way to many other olive varieties. The surface color turns to yellow, purple and finally black as a consequence of anthocyanin synthesis that also continues inside the pulp. In contrast, Hurma olives change their color directly from green-yellow to brown or dark brown not only on their surface but also in their pulp. An explanation for these color changes in Hurma olives remains unsolved. Erkence olives with a maturation index of 3-4 had a significant content in anthocyanins (). This maturation index means olives with purple or black surface color and white color inside the pulp so that it was predictable to find anthocyanins in these olives, mainly cyanidin-3- rutinoside and cyanidin-3-glucoside (). Surprisingly, free anthocyanins were not detected in Hurma olives which were classified with a maturation index of 7. In addition, the color parameters (*, *, *, λ520) of olive extracts from Erkence and Hurma olives revealed that those from Erkence had a purple/red color whereas those of Hurma had a slightly yellow color (). Anthocyanins are found free in raw olives and can be oxidized and polymerized during processing (). The results presented in indicate the absence of these substances either free or polymerized in Hurma olives so that their dark brown color could be formed from the oxidation of -diphenols, particularly oleuropein. The oxidation of the latter substance gives rise to non-bitter substances (), and it has been proposed as the explanation for the de-bittering of black dry-salted and dried green olives (; ).
Human follicle dermal papilla cells (DPCs) were purchased from PromoCell (PromoCell, Heidelberg, Germany) and maintained in follicle DPC growth medium containing supplement mix (PromoCell) at 37°C in 5% CO2. When the cells reached 80% confluence, they were subcultured in 4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid-buffered saline solution, trypsin/ethylenediaminetetraacetic acid (EDTA) solution, and neutralizing solution (PromoCell). To investigate whether oleuropein regulation of LEF1, CycD-1, IGF-1, HGF, VEGF, and KGF occurs indirectly through newly synthesized transcription factors, the effect of the protein synthesis inhibitor, cycloheximide (CHX; Sigma-Aldrich, MO, USA) was determined. Trypsinized DPCs were allowed to attach overnight and then treated (60 min) with cycloheximide (10 μg/ml) and thereafter switched to medium with or without oleuropein (20 μM) in the presence of cycloheximide (10 μg/ml) for 24 h. Control cells were treated similarly except that no cyclohexmide was included at any time.
We described here oleuroepin-induced stimulation of the Wnt/β-catenin signaling pathway both in vitro and in vivo and the upregulation of IGF-1, KGF, HGF, VEGF gene expression in mouse skin tissues. To check whether the effects of oleuroepin were due to a direct action on β-catenin accumulation and gene transcription or mediated through increased expression of oleuroepin-dependent auxiliary proteins, we analyzed the effect of oleuropein in the presence of the protein synthesis inhibitor, CHX (). Our results showed that the accumulation of β-catenin by oleuropein, as determined by immunocytochemistry, was blocked by cycloheximide (). The expressions of Wnt target genes, such as LEF1 and Cyc-D1, and several growth factors, including IGF-1, HGF, VEGF, and KGF, were upregulated by oleuropein within 24 h, but the effect of oleuropein was indirect since induction on these genes was abolished by CHX ().