Nutraceutical Role of Polyphenols and Triterpenes Present in the Extracts of Fruits and Leaves of Olea europaea as Antioxidants, Anti-Infectives and Anticancer Agents on Healthy Growth.

There is currently a worldwide consensus and recognition of the undoubted health benefits of the so-called Mediterranean diet, with its intake being associated with a lower risk of mortality. The most important characteristics of this type of diet are based on the consumption of significant amounts of fruit, vegetables, legumes, and nuts, which provide, in addition to some active ingredients, fiber and a proportion of vegetable protein, together with extra virgin olive oil (EVOO) as the main sources of vegetable fat. Fish and meat from poultry and other small farm animals are the main sources of protein. One of the main components, as already mentioned, is EVOO, which is rich in monounsaturated fatty acids and to a lesser extent in polyunsaturated fatty acids. The intake of this type of nutrient also provides an important set of phytochemicals whose health potential is widely spread and agreed upon. These phytochemicals include significant amounts of anthocyanins, stilbenes, flavonoids, phenolic acids, and terpenes of varying complexities. Therefore, the inclusion in the diet of this type of molecules, with a proven healthy effect, provides an unquestionable preventive and/or curative activity on an important group of pathologies related to cardiovascular, infectious, and cancerous diseases, as well as those related to the metabolic syndrome. The aim of this review is therefore to shed light on the nutraceutical role of two of the main phytochemicals present in Olea europaea fruit and leaf extracts, polyphenols, and triterpenes, on healthy animal growth. Their immunomodulatory, anti-infective, antioxidant, anti-aging, and anti-carcinogenic capabilities show them to be potential nutraceuticals, providing healthy growth.

Synthesis and in vitro antiproliferative evaluation of PEGylated triterpene acids.

A set of PEGylated derivatives of oleanolic and maslinic acids has been semi-synthesised, attaching ethylene glycol, diethylene glycol, triethylene glycol or tetraethylene glycol to the C-28 carboxyl group of these natural triterpenes and some derivatives. Another set of PEGylated derivatives has been semi-synthesised by connecting the same four ethylene glycols to the hydroxyl groups of the A ring of these triterpenic acids, through a carbonate linker, by reaction with trichloromethyl chloroformate. The aqueous solubility of some of these PEGylated derivatives has been compared with that of maslinic acid. The cytotoxic effects of 28 triterpenic PEGylated derivatives in three cancer-cell lines (B16-F10, HT29, and Hep G2) have been assayed. The best results have been achieved with the HT29 cell line, and specifically with the oleanolic acid derivatives having ethylene glycol or tetraethylene glycol attached to the C-28 carboxyl group, which are approximately 27-fold more effective than their natural precursor. Eight PEGylated derivatives have been selected to compare the cytotoxicity results in the HT29 cancer-cell line with those of a non-tumour cell line of the same tissue (IEC-18), four of which were less cytotoxic in the non-tumour cell line. These compounds showed apoptotic effects on treated cells, with percentages of total apoptosis between 20% and 53%, relative to control, at 72h and IC50 concentration, and between 29% to 62%, relative to control, for the same time and IC80 concentration. We have also found that with the treatment of these compounds in HT29 cancer cells, cell-cycle arrest occurred in the G0/G1 phase. Finally, we have also studied changes in mitochondrial membrane potential during apoptosis of HT29 cancer cells, and the results suggest an activation of the extrinsic apoptotic pathway for these compounds.

Target molecules in 3T3-L1 adipocytes differentiation are regulated by maslinic acid, a natural triterpene from Olea europaea.

BACKGROUND: Metabolic syndrome is a set of pathologies among which stand out the obesity, which is related to the lipid droplet accumulation and changes to cellular morphology regulated by several molecules and transcription factors. Maslinic acid (MA) is a natural product with demonstrated pharmacological functions including anti-inflammation, anti-tumor and anti-oxidation, among others. PURPOSE: Here we report the effects of MA on the adipogenesis process in 3T3-L1 cells. METHODS: Cell viability, glucose uptake, cytoplasmic triglyceride droplets, triglycerides quantification, gene transcription factors such as peroxisome proliferator-activated receptor γ (PPARγ) and adipocyte fatty acid-binding protein (aP2) and intracellular Ca2+ levels were determined in pre-adipocytes and adipocytes of 3T3-L1 cells. RESULTS: MA increased glucose uptake. MA also decreased lipid droplets and triglyceride levels, which is in concordance with the down-regulation of PPARγ and aP2. Finally, MA increased the intracellular Ca2+ concentration, which could also be involved in the demonstrated antiadipogenic effect of this triterpene. CONCLUSION: MA has been demonstrated as potential antiadipogenic compound in 3T3-L1 cells.

Maslinic Acid, a Triterpene from Olive, Affects the Antioxidant and Mitochondrial Status of B16F10 Melanoma Cells Grown under Stressful Conditions.

Maslinic acid (MA) is a natural compound whose structure corresponds to a pentacyclic triterpene. It is abundant in the cuticular lipid layer of olives. MA has many biological and therapeutic properties related to health, including antitumor, anti-inflammatory, antimicrobial, antiparasitic, antihypertensive, and antioxidant activities. However, no studies have been performed to understand the molecular mechanism induced by this compound in melanoma cancer. The objective of this study was to examine the effect of MA in melanoma (B16F10) cells grown in the presence or absence of fetal bovine serum (FBS). We performed cell proliferation measurements, and the reactive oxygen species (ROS) measurements using dihydrorhodamine 123 (DHR 123) and activities of catalase, glucose 6-phosphate dehydrogenase, glutathione S-transferase, and superoxide dismutase. These changes were corroborated by expression assays. FBS absence reduced cell viability decreasing IC50 values of MA. The DHR 123 data showed an increase in the ROS level in the absence of FBS. Furthermore, MA had an antioxidant effect at lower assayed levels measured as DHR and antioxidant defense. However, at higher dosages MA induced cellular damage by apoptosis as seen in the results obtained.

Semi-synthesis of acylated triterpenes from olive-oil industry wastes for the development of anticancer and anti-HIV agents.

A broad set of potential bioactive conjugate compounds has been semi-synthesized through solution- and solid-phase organic procedures, coupling two natural pentacyclic triterpene acids, oleanolic (OA) and maslinic acids (MA), at the hydroxyl groups of the A-ring of the triterpene skeleton, with 10 different acyl groups. These acyl OA and MA derivatives have been tested for their anti-proliferative (against the b16f10 murine melanoma cancer cells) and antiviral (as inhibitors of the HIV-1-protease) effects. Several derivatives have shown high levels of early and total apoptosis (up to 90%). Most of the compounds that exhibited anti-proliferative effects also generated ROS, probably involving the activation of an intrinsic apoptotic route. The only four compounds that did not cause the release of ROS could be related to the participation of a probable extrinsic activation of the apoptosis mechanism. A great number of these acyl OA and MA derivatives have proved to be potent inhibitors of the HIV-1-protease, the most active inhibitors having IC50 values between 0.31 and 15.6 µM, these values being between 4 and 186 times lower than their non-acylated precursors. The potent activities exhibited in the apoptosis-activation processes and in the inhibition of the HIV-1-protease by some OA and MA acylated derivatives imply that these compounds could be used as new, safe, and effective anticancer and/or antiviral drugs.

Maslinic acid-enriched diet decreases intestinal tumorigenesis in Apc(Min/+) mice through transcriptomic and metabolomic reprogramming.

Chemoprevention is a pragmatic approach to reduce the risk of colorectal cancer, one of the leading causes of cancer-related death in western countries. In this regard, maslinic acid (MA), a pentacyclic triterpene extracted from wax-like coatings of olives, is known to inhibit proliferation and induce apoptosis in colon cancer cell lines without affecting normal intestinal cells. The present study evaluated the chemopreventive efficacy and associated mechanisms of maslinic acid treatment on spontaneous intestinal tumorigenesis in Apc(Min/+) mice. Twenty-two mice were randomized into 2 groups: control group and MA group, fed with a maslinic acid-supplemented diet for six weeks. MA treatment reduced total intestinal polyp formation by 45% (P<0.01). Putative molecular mechanisms associated with suppressing intestinal polyposis in Apc(Min/+) mice were investigated by comparing microarray expression profiles of MA-treated and control mice and by analyzing the serum metabolic profile using NMR techniques. The different expression phenotype induced by MA suggested that it exerts its chemopreventive action mainly by inhibiting cell-survival signaling and inflammation. These changes eventually induce G1-phase cell cycle arrest and apoptosis. Moreover, the metabolic changes induced by MA treatment were associated with a protective profile against intestinal tumorigenesis. These results show the efficacy and underlying mechanisms of MA against intestinal tumor development in the Apc(Min/+) mice model, suggesting its chemopreventive potential against colorectal cancer.

Maslinic acid, a natural triterpene from Olea europaea L., induces apoptosis in HT29 human colon-cancer cells via the mitochondrial apoptotic pathway.

We have investigated the mechanisms of maslinic acid with regard to its inhibitory effects on the growth of HT29 colon-cancer cells. High concentrations of maslinic acid are present in the protective wax-like coating of olives. Our results show that treatment with maslinic acid results in a significant inhibition of cell proliferation in a dose-dependent manner and causes apoptotic death in colon-cancer cells. We found that it inhibits considerably the expression of Bcl-2 whilst increasing that of Bax; it also stimulates the release of mitochondrial cytochrome-c and activates caspase-9 and caspase-3. All these results point clearly to the activation of the mitochondrial apoptotic pathway in response to the treatment of HT29 colon-cancer cells with maslinic acid. Our results suggest that maslinic acid has the potential to provide significant natural defence against colon-cancer.