Valorization of wild olives (Olea europaea var. sylvestris) as potential source of functional ingredients

Tese de mestrado. Biologia (Biologia Humana e Ambiente). Universidade de Lisboa, Faculdade de Ciências, 2013 ; The olives and olive oil are known to have many health-promoting effects, having been associated to a decrease in the risk of some diseases, due the presence of polyphenols, which have several bioactivities, mainly antioxidant capacity. The wild olives tree, zambujeiro, which belongs to the Mediterranean forest, survives harsh environmental changes. It is expected that, similarly to the common olive tree, its fruits will have a composition that reflects that adaptation capacity. In this work, extracts of wild and cultivar olive seeds and stones were characterized, regarding their phenolic content. Seed extracts were prepared using solvent mixtures and analyzed for the total phenols concentration (TPC) and by HPLCDAD/ MSMS. Methanol proved to be the best solvent for the extraction of these compounds. The phytochemical composition of the seed extracts yielded high TPC, mainly seicoiridoids. Extracts of zambujeiro olive stones were prepared using three different methodologies (MeOH at reflux, refined olive oil, and conventional solvents). Extraction by methanol at reflux yielded a richer composition, when compared to the other two procedures, and was the only method that showed lignan compounds, such as Ac-Pr and OH-Pr. All the extracts showed a high TPC. Antioxidant activity assays using the seed extracts showed a good scavenging activity against the peroxyl radical, whereas the stone extracts displayed a higher scavenging activity against hydroxyl radicals, while also preventing their formation. The extracts obtained from the seeds revealed an antiproliferative effect in colon cancer cell line HT29, unlike to the extracts from cultivars’ varieties. This assay was made in parallel by a co-laboratory. In case this method is integrated as a compound recovery system from wild olives, it would require an initial 2-3 hour extraction with sc-CO2,. The delipidated matix must then be extracted with PLE+25:65:10 ...