Antioxidant, antiproliferative, and pro-apoptotic capacities of pentacyclic triterpenes found in the skin of olives on MCF-7 human breast cancer cells and their effects on DNA damage.

This research aimed to investigate erythrodiol, uvaol, oleanolic acid, and maslinic acid scavenging capacities and their effects on cytotoxicity, cell proliferation, cell cycle, apoptosis, reactive oxygen species (ROS) level, and oxidative DNA damage on human MCF-7 breast cancer cell line. The results showed that erythrodiol, uvaol, and oleanolic acid have a significant cytotoxic effect and inhibit proliferation in a dose- and time-dependent manner. At 100 µM, erythrodiol growth inhibition occurred through apoptosis, with the observation of important ROS production and DNA damage, whereas uvaol and oleanolic acid growth inhibition involved cell cycle arrest. Moreover, although all tested triterpenes did not show free radical scavenging activity using ABTS and DPPH assays, they protected against oxidative DNA damage at the concentration 10 µM. Uvaol and oleanolic and maslinic acids, tested at 10 and 100 µM, also reduced intracellular ROS level and prevented H(2)O(2)-induced oxidative injury. Overall, the results suggest that tested triterpenes may have the potential to provide significant natural defense against human breast cancer.

Hydroxytyrosol protects against oxidative DNA damage in human breast cells.

Over recent years, several studies have related olive oil ingestion to a low incidence of several diseases, including breast cancer. Hydroxytyrosol and tyrosol are two of the major phenols present in virgin olive oils. Despite the fact that they have been linked to cancer prevention, there is no evidence that clarifies their effect in human breast tumor and non-tumor cells. In the present work, we present hydroxytyrosol and tyrosol's effects in human breast cell lines. Our results show that hydroxytyrosol acts as a more efficient free radical scavenger than tyrosol, but both fail to affect cell proliferation rates, cell cycle profile or cell apoptosis in human mammary epithelial cells (MCF10A) or breast cancer cells (MDA-MB-231 and MCF7). We found that hydroxytyrosol decreases the intracellular reactive oxygen species (ROS) level in MCF10A cells but not in MCF7 or MDA-MB-231 cells while very high amounts of tyrosol is needed to decrease the ROS level in MCF10A cells. Interestingly, hydroxytyrosol prevents oxidative DNA damage in the three breast cell lines. Therefore, our data suggest that simple phenol hydroxytyrosol could contribute to a lower incidence of breast cancer in populations that consume virgin olive oil due to its antioxidant activity and its protection against oxidative DNA damage in mammary cells.

Antioxidant and antiatherogenic activities of pentacyclic triterpenic diols and acids.

The present paper aimed to test the potential cardioprotective activity of four pentacyclic triterpenes, uvaol, erythrodiol, oleanolic acid and maslinic acid, widely distributed throughout the vegetable kingdom. For this purpose, their antioxidant and antithrombotic activities related to LDL particles have been in vitro evaluated. Results demonstrated that maslinic acid, uvaol and erythrodiol exert antiatherogenic effect while no effect was observed for oleanolic acid. Specifically, maslinic acid has shown the most potent dose-dependent antioxidant effect and did not have antithrombotic properties, whereas uvaol and erythrodiol exhibited both antioxidant and antithrombotic activities. In addition, antioxidant mechanisms of action were determined. While maslinic acid possesses dual activity acting as scavenger of free radicals and as copper chelator, uvaol is able to form a complex with copper and erythrodiol seems to behave as a retarder antioxidant. In conclusion, dietary triterpenes may exert a cardioprotective effect by different mechanisms of action related to antioxidant and antithrombotic activities.

Squalene protects against oxidative DNA damage in MCF10A human mammary epithelial cells but not in MCF7 and MDA-MB-231 human breast cancer cells.

Until now, very little has been known about the antioxidant capacity of squalene and its effect on human breast tumourigenesis. In the present work, we investigated squalene's scavenging properties and its effect on cell proliferation, cell cycle profile, apoptosis, reactive oxygen species (ROS) level and oxidative DNA damage, using human breast cell lines. Our results showed that squalene neither possesses scavenging activity nor significantly alters cell proliferation rates, the cell cycle profile or cell apoptosis in human mammary epithelial cells (MCF10A), minimally invasive (MDA-MB-231) breast cancer cells, and highly invasive (MCF7) breast cancer cells. However, we found that squalene did exert the following effects on MCF10A epithelial cells in a dose-dependent manner: (a) it decreased intracellular ROS level, (b) it prevented H(2)O(2)-induced oxidative injury, and (c) it protected against oxidative DNA damage. Interestingly, squalene did not exert these effects on MCF7 and MDA-MB-231 cancer cells. Therefore, our data suggest that squalene, found in high amounts in virgin olive oils, could be partially responsible for the lower incidence of breast cancer in populations that consume the Mediterranean diet due to its protective activity against oxidative DNA damage in normal mammary cells.

Fruit quality and olive leaf and stone addition affect Picual virgin olive oil triterpenic content.

The present research aimed to evaluate whether Picual virgin olive oil triterpenic compounds are affected by the addition of variable quantities of stones and leaves before processing or by fruit resting on the ground during 3 months. Results showed that stone addition did not influence triterpenic dialcohol content (uvaol and erythrodiol), whereas triterpenic acids (oleanolic and maslinic) increased significantly when 20 and 30% stones were added. Leaves added at 2% increased significantly oleanolic acid, maslinic acid, and erythrodiol content by 83, 41, and 36%, respectively. During fruit resting on the ground, olive oils showed no differences in uvaol content, a slight increase in erythrodiol, and a gradual increase in both oleanolic and maslinic acids, obtaining at the end of the experiment contents nearly 10- and 3-fold higher than control oils. These results confirm that olive oil triterpenic composition is modified by the factors analyzed.

Triterpenic content and chemometric analysis of virgin olive oils from forty olive cultivars.

Forty olive cultivars (Olea europaea, L.) from the World Olive Germoplasm Bank Collection of Cordoba (Spain) were studied for their oil triterpenic dialcohol (uvaol and erythrodiol) and acid (oleanolic, ursolic, maslinic) composition. Dialcohol content ranged from 8.15 to 85.05 mg/kg, erythrodiol being the most predominant (from 5.89 to 73.78 mg/kg), whereas uvaol content was found at lower levels (from 1.50 to 19.35 mg/kg). Triterpenic acid concentration oscillated between 8.90 to 112.36 mg/kg. Among them, ursolic acid was found at trace levels, while the mean values of oleanolic and maslinic acids ranged from 3.39 to 78.83 mg/kg and 3.93 to 49.81 mg/kg, respectively. The variability observed for both triterpenic dialcohols and acid content was emphasized by principal component and cluster analyses. Both analyses were able to discriminate between oil samples, especially by erythrodiol, oleanolic acid, and maslinic acids. Regarding these results, we conclude that the virgin olive oil triterpenic fraction can be considered as a useful tool to characterize monovarietal virgin olive oil.

How heating affects extra virgin olive oil quality indexes and chemical composition.

Two monovarietal extra virgin olive oils from Arbequina and Picual cultivars were subjected to heating at 180 degrees C for 36 h. Oxidation progress was monitored by measuring oil quality changes (peroxide value and conjugated dienes and trienes), fatty acid composition, and minor compound content. Tocopherols and polyphenols were the most affected by the thermal treatment and showed the highest degradation rate although their behavior was different for each cultivar. Alpha-tocopherol loss was more important in Arbequina oil whereas, total phenol content loss was greater in Picual oil. The later showed an important decrease in hydroxytyrosol (3,4-DHPEA) and its secoiridoid derivatives (3,4-DHPEA-EDA and 3,4-DHPEA-EA), while lignans decrease was lesser. For Arbequina oil these compounds remained stable, and a lowering tendency was observed for tyrosol (p-HPEA) and its derivatives (p-HPEA-EDA and p-HPEA-EA). In general, flavone content showed a decrease during heating, being higher for Arbequina oil. On the other hand, oleic acid, sterols, squalene, and triterpenic alcohols (erythrodiol and uvaol) and acids (oleanolic and maslinic) were quite constant, exhibiting a high stability against oxidation. From these results, we can conclude that despite the heating conditions, VOO maintained most of its minor compounds and, therefore, most of its nutritional properties.