Oleacein

Food Chemistry, 2012, 131(3):940-947.

A comparison of antioxidant activities of oleuropein and its dialdehydic derivative from olive oil, oleacein.[Reference: WebLink]

Phenolic compounds from virgin olive oil are known to play an antioxidant role in preventing biomolecule damage. One of the most abundant components of olive oil is an oleuropein derivative named Oleacein (dialdehydic form of decarboxymethyl elenolic acid linked to hydroxytyrosol; 3,4-DHPEA-EDA).
METHODS AND RESULTS:
The aim of the study was to establish the antioxidant activity of Oleacein for an array of reactive oxygen (superoxide anion, ; hydrogen peroxide, H2O2; hypochlorous acid, HOCl) and nitrogen species (nitric oxide, NO; peroxynitrite, ONOO−) formation, using in vitro non-cellular systems, as well as cellular screening systems (human neutrophil oxidative burst, monocytes’ nitric oxide production). We used a well-known antioxidant, oleuropein, as a reference compound.
CONCLUSIONS:
Oleacein proved to be stronger in the reduction of formyl-met-leu-phenylalanine (f-MLP) and phorbol–myristate–acetate (PMA)-induced oxidative bursts in neutrophils (IC50 = 1.8 μM, IC50 = 1.5 μM, respectively) and myeloperoxidase release (IC50 = 8.8 μM) than was oleuropein (IC50 = 2.4 μM, IC50 = 16.0 μM, IC50 = 30.7 μM, respectively). Both compounds were stronger scavengers of than H2O2. Oleuropein did not scavenge HOCl as opposed to Oleacein (IC50 = 1.5 μM). Both compounds, in a concentration range 1–10 μM, significantly decreased nitrogen species formation in cell-free systems and by lipopolysaccharide (LPS)-stimulated monocytes.

Phytomedicine, 2015, 22(14):1255-1261.

Oleacein enhances anti-inflammatory activity of human macrophages by increasing CD163 receptor expression.[Reference: WebLink]

Oleacein (dialdehydic form of decarboxymethyl elenolic acid linked to hydroxytyrosol; 3,4-DHPEA-EDA) have been proven to possess antioxidant and anti-inflammatory activity.
METHODS AND RESULTS:
In this study, we examined whether Oleacein could increase CD163 and IL-10 receptor expression as well as HO-1 intracellular secretion in human macrophages.Effect of Oleacein (10 and 20 μmol/l) or Oleacein together with complexes of haemoglobin (Hb) and haptoglobin 1-1 (Hp11) or haptoglobin 2-2 (Hp22) on expression of IL-10 and CD163 receptor was determined by Flow Cytometry. Expression of CD163mRNA was measured by real-time quantitative RT-PCR. Heme oxygenase 1 (HO-1) intracellular secretion in macrophages was investigated by enzyme-linked immunosorbent assay (ELISA).Oleacein (OC) together with complexes HbHp11 or HbHp22 stimulated the expression of CD163 (30-100-fold), IL-10 (170-300-fold) and HO-1 secretion (60-130-fold) after 5 days of coincubation. The 2-fold (24 h), 4-fold (48 h) increase of CD163 mRNA level and its final (72 h) decrease was also observed.
CONCLUSIONS:
Our results suggested that Oleacein enhances anti-inflammatory activity of complexes haemoglobin with haptoglobin 1-1 and 2-2 and could play a potential role in the prevention of inflammatory disease related to atherosclerosis.

Frontiers in Endocrinology, 19 Mar 2018, 9:116

Effects of Oleacein on High-Fat Diet-Dependent Steatosis, Weight Gain, and Insulin Resistance in Mice.[Reference: WebLink]

Many reports indicate that the protective action of nutraceuticals in the Mediterranean diet, against metabolic and cardiovascular diseases, can be attributed to the action of polyphenolic components of extra-virgin olive oil (EVOO).
METHODS AND RESULTS:
Here, we evaluated the protective effects of Oleacein, one of the most abundant secoiridoids in EVOO, on the damages/metabolic alterations caused by high-fat diet (HFD) in male C57BL/6JolaHsd mice. After 5 weeks of treatment with 20 mg/kg of Oleacein, body weight, glycemia, insulinemia, serum lipids, and histologic examination of liver tissue indicated a protective action of Oleacein against abdominal fat accumulation, weight gain, and liver steatosis, with improvement of insulin-dependent glucose and lipid metabolism. Both serum parameters and hepatic histologic examination were altered in mice fed with HFD. By contrast, in the animals that received Oleacein, plasma glucose, cholesterol and triglyceride serum levels, and liver histology were similar to controls fed with normocaloric diet. In addition, protein levels of FAS, SREBP-1, and phospho-ERK in liver were positively modulated by Oleacein, indicating an improvement in liver insulin sensitivity. In a group of obese mice, treatment with Oleacein determined a light, but still significant reduction of the increase in body weight, mainly due to lesser liver steatosis enlargement, associated with reduced levels of SREBP-1 and phospho-ERK and lower levels of total serum cholesterol; in these animals, altered plasma glucose and triglyceride serum levels were not reverted by Oleacein.
CONCLUSIONS:
These results indicate that HFD-related hepatic insulin resistance may be partially prevented by oral administration of Oleacein, suggesting a protective role of this nutraceutical against diet-dependent metabolic alterations. Additional studies are necessary to check whether Oleacein can be used as an adjuvant to improve insulin sensitivity in humans.

Food & Function, 2020, 11(8).

Oleacein inhibits STAT3, activates the apoptotic machinery and exerts anti-metastatic effects in the SH-SY5Y human neuroblastoma cells.[Reference: WebLink]

Several studies published in the last decade, suggest that the beneficial role of extra-virgin olive oil (EVOO) in human health is mostly attributable to the main secoiridoid derivatives (oleuropein, oleocanthal and Oleacein). Anti-cancer properties have also been demonstrated for certain compounds present in small quantities in the EVOO, including oleuropein and hydroxytyrosol, that have been extensively studied, while minor attention has been addressed to the most abundant secoiridoid Oleacein.
METHODS AND RESULTS:
Aim of our research was to study the molecular mechanisms underlying the anti-proliferative and the anti-metastatic capacity of Oleacein in the SH-SY5Y human neuroblastoma cell line. Our results demonstrate that Oleacein is able to reduce the proliferation of SH-SY5Y cells by blocking the cell cycle in S phase and inducing apoptotic cell death, through the increase of both Bax and p53, as well as a reduction of Bcl2 expression and STAT3 phosphorilation. Moreover, Oleacein determined a reduction of SH-SY5Y cell adhesion and migration.
CONCLUSIONS:
Overall, these findings indicate that Oleacein exerts anticancer effects against neuroblastoma cells, suggesting a promising role as candidate against this type of cancer.