Bioavailability of Bioactive Molecules from Olive Leaf Extracts and its Functional Value

Abstract

Olive leaves are an important low-cost source of bioactive compounds. The present study aimed to examine the effect of in vitro digestibility of an olive leaf aqueous extract so as to prove the availability of its phenolic compounds as well as its antioxidant, antimicrobial, and anticancer activity after a simulated digestion process. The total phenolic content was significantly higher in the pure lyophilized extract. Phenolic compounds, however, decreased by 60% and 90% in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF), respectively. Regarding antioxidant activity, it was reduced by 10% and 50% after gastric and intestinal digestion, respectively; despite this fact, high antioxidant capacity was found in both SGF and SIF. Moreover, the olive leaf extract showed an unusual combined antimicrobial action at low concentration, which suggested their great potential as nutraceuticals, particularly as a source of phenolic compounds. Finally, olive leaf extracts produced a general dose-dependent cytotoxic effect against U937 cells. To sum up, these findings suggest that the olive leaf aqueous extract maintains its beneficial properties after a simulated digestion process, and therefore its regular consumption could be helpful in the management and the prevention of oxidative stress-related chronic disease, bacterial infection, or even cancer. Copyright © 2016 John Wiley & Sons, Ltd.

Evaluation of phenolics and acrylamide and their bioavailability in high hydrostatic pressure treated and fried table olives

“…This trend can be explained by the “matrix effect,” as also Lodolini et al () reported after gastrointestinal digestion of table olives, showing that the pulp complexity of the olive aids to maintain a high level of phenolic compounds after the digestion process. Other researchers tried the digestion of only simple matrices, such as extracts (Bouayed et al, ; Martín‐Vertedor et al, ), and they observed that the bioavailability trend was completely different because phenols decreased in the last part of the gastrointestinal process.…”

“…The four table olives varieties were submitted to an in vitro gastrointestinal digestion according to the procedure reported by Martín‐vertedor, Garrido, Pariente, Espino, and Delgado‐Adámez, ().…”

Application of Phenolic Compounds for Food Preservation: Food Additive and Active Packaging

“…By-products obtained in the olive oil extraction are an excellent source of phytochemicals because of their low toxicity, limited costs, broad availability. In this sense, Ramos et al [4] and Martín-Vertedor et al [5] have studied olive mill and leaves extract like natural antioxidant, respectively.…”

Agrifood By-Products as a Source of Phytochemical Compounds

“…Concretely, an agroindustry residue, olive leaf, is a great source of phytochemicals. These contain a high concentration of oleuropein, tyrosol and hydroxytyrosol, three important phenolic compounds which have bioactive properties like antioxidant capacity [54]. The European Food Safety Association (EFSA) determined officially that oleuropein present in olive leaf extract generate a better glucose tolerance in humans [55].…”