Cellular Antioxidant Activity of Olive Pomace Extracts: Impact of Gastrointestinal Digestion and Cyclodextrin Encapsulation

Abstract

Olive pomace is a valuable secondary raw material rich in polyphenols, left behind after the production of olive oil. The present study investigated the protective effect of a polyphenolic extract from olive pomace (OPE) on cell viability and antioxidant defense of cultured human HepG2 cells submitted to oxidative stress induced by tert-butylhydroperoxide (tBOOH). The investigation considered possible matrix effects, impact of gastrointestinal digestion and cyclodextrin (CD) encapsulation. Pre-treatment of cells with OPE prevented cell damage and increased intracellular glutathione but did not affect the activity of glutathione peroxidase and superoxide dismutase. OPE matrix significantly enhanced cell protective effects of major antioxidants, such as hydroxytyrosol (HTS), while cyclodextrin encapsulation enhanced activity of OPE against intracellular reactive oxygen species (ROS) accumulation. The obtained results show that OPE is more potent antioxidant in comparison to equivalent dose of main polyphenols (HTS and TS) and that increasing solubility of OPE polyphenols by CD encapsulation or digestion enhances their potential to act as intracellular antioxidants. Antioxidative protection of cells by OPE was primarily achieved through direct radical-scavenging/reducing actions rather than activation of endogenous defense systems in the cell.

Food (Matrix) Effects on Bioaccessibility and Intestinal Permeability of Major Olive Antioxidants

“…The influence of MIX and investigated food components on the viability of human epithelial colorectal adenocarcinoma cells Caco-2 was determined by using the MTT assay ( Figure 4 a) and by measuring TEER values, before and after the experiment ( Figure 4 b), as previously described. The results presented in Figure 4 show that cell viability was significantly decreased when cells were treated with the MIX and HPB, which is consistent with previously obtained data [ 48 ]. Although significantly decreased in relation to positive control (CTR+), viability of monolayers treated with MIX and HPB was above 80% (81.4 and 80.3%, respectively) and, therefore, suitable for further analysis.…”

Utilization of Olive Pomace in Green Synthesis of Selenium Nanoparticles: Physico-Chemical Characterization, Bioaccessibility and Biocompatibility

“…NPs < 10 mm are particularly toxic since they can enter the cell nucleus [ 56 ]. Additionally, functionalization of the surface of NPs with OPE could alter their interactions with cell structures and result in the synergistic effects of SeNPs and OPE polyphenols, which are known to exert anticancer effects against Caco2 and HepG2 cells [ 57 ]; namely, as reported previously, OPE contained a significant amount of hydroxytyrosol, tyrosol and oleuropein and showed strong antiradical activity [ 39 ].…”

Employment of Phenolic Compounds from Olive Vegetation Water in Broiler Chickens: Effects on Gut Microbiota and on the Shelf Life of Breast Fillets

“…Apart from the animal breed and the length of the fattening period, other factors such as the nutrients composition of the diet, the feed intake, the environmental temperature together with other stressful conditions can lead to very different results that often are difficult to compare. Not last the type of matrix with which the diet is enriched with phenols (olive-cake, olive pomace, olive leaf extract, vegetative water extract, just to name a few) due to the concentration of the active compounds and the presence of additional substances with a synergistic or protective action present in the same matrix, can significantly influence the antioxidant action both in vivo and in meat tissue after slaughter [ 47 ]. The potential health benefits from integrating antioxidant additives in fresh meat and meat products are not always proven [ 48 ].…”