Al Skaltsounis

Olive oil and its main phenolic micronutrient (oleuropein) prevent inflammation-induced bone loss in the ovariectomised rat

The present study was designed to evaluate the effect of olive oil and its main polyphenol (oleuropein) in ovariectomised rats with or without inflammation. Rats (6 months old) were ovariectomised or sham-operated as control. Ovariectomised rats were separated into three groups receiving different diets for 3 months: a control diet with 25 g peanut oil and 25 g rapeseed oil/kg (OVX), the control diet with 50 g olive oil/kg or the control diet with 0.15 g oleuropein/kg. The sham-operated group was given the same control diet as OVX. Inflammation was induced 3 weeks before the end of the experiment by subcutaneous injections of talc (magnesium silicate) in one-half of each group. The success of ovariectomy was verified at necropsy by the atrophy of uterine horns. Inflammation, oleuropein or olive oil intakes did not have any uterotrophic activity, as they had had no effect on uterus weight. The plasma concentration of alpha-1-acid glycoprotein (an indicator of inflammation) was increased in OVX rats with inflammation. With regard to bone variables, osteopenia in OVX was exacerbated by inflammation, as shown by a decrease in metaphyseal and total femoral mineral density. Both oleuropein and olive oil prevented this bone loss in OVX rats with inflammation. At necropsy, oleuropein and olive oil consumption had had no effect on plasma osteocalcin concentrations (marker of bone formation) or on urinary deoxypyridinoline excretion (marker of bone resorption). In conclusion, oleuropein and olive-oil feeding can prevent inflammation-induced osteopenia in OVX rats.

Identification of the factors responsible for the in vitro pro-oxidant and cytotoxic activities of the olive polyphenols oleuropein and hydroxytyrosol.

The olive polyphenols oleuropein and hydroxytyrosol were reported recently to produce extracellular hydrogen peroxide (H2O2) under standard culture conditions. The precise factors responsible for this production and the conditions promoting or retarding it are critical for the interpretation of the in vitro results. In this study, a systematic evaluation of the components of the most commonly used culture media revealed that sodium bicarbonate is the defining cause for the production of H2O2 by these polyphenols. The produced H2O2 caused extensive oxidative DNA damage and significant decrease in cell viability of cancer (MDA-MB-231) and normal (MCF-10A, STO) cells alike. Sodium pyruvate and the antioxidant N-acetyl cysteine (NAC) totally reversed these effects. Therefore, we conclusively identified the culture conditions that promote H2O2 production by these polyphenols, producing artifacts that may be misinterpreted as a specific anticancer activity. Our findings raise considerable questions regarding the use of culture media with sodium bicarbonate or sodium pyruvate as components, for the in vitro study of these and possibly other plant polyphenols.

Grape pomace extract exerts antioxidant effects through an increase in GCS levels and GST activity in muscle and endothelial cells

In a previous study, we demonstrated that a grape pomace extract (GPE) exerted antioxidant activity in endothelial (EA.hy926) and muscle (C2C12) cells through an increase in glutathione (GSH) levels. In the present study, in order to elucidate the mechanisms responsible for the antioxidant activity of GPE, its effects on the expression of critical antioxidant enzymes, such as catalase (CAT), superoxide dismutase (SOD)1, heme oxygenase 1 (HO-1) and gamma-glutamylcysteine synthetase (GCS) were assessed in EA.hy926 and C2C12 cells. Moreover, the effects of GPE on CAT, SOD and glutathione S-transferase (GST) enzymatic activity were evaluated. For this purpose, the C2C12 and EA.hy926 cells were treated with GPE at low and non-cytotoxic concentrations (2.5 and 10 µg/ml for the C2C12 cells; 0.068 and 0.250 µg/ml for the EA.hy926 cells) for 3, 6, 12, 18 and 24 h. Following incubation, enzymatic expression and activity were assessed. The results revealed that treatment with GPE significantly increased GCS levels and GST activity in both the C2C12 and EA.hy926 cells. However, GPE significantly decreased CAT levels and activity, but only in the muscle cells, while it had no effect on CAT levels and activity in the endothelial cells. Moreover, treatment with GPE had no effect on HO-1 and SOD expression and activity in both cell lines. Therefore, the present results provide further evidence of the crucial role of GSH systems in the antioxidant effects exerted by GPE. Thus, GPE may prove to be effective for use as a food supplement for the treatment of oxidative stress-induced pathological conditions of the cardiovascular and skeletal muscle systems, particularly those associated with low GSH levels.

Herbal Substance, Acteoside, Alleviates Intestinal Mucositis in Mice

This study investigated the role of acteoside in the amelioration of mucositis. C57BL/6 mice were gavaged daily with acteoside 600u2009μg for 5u2009d prior to induction of mucositis and throughout the experimental period. Mucositis was induced by methotrexate (MTX; 12.5u2009mg/kg; s.c.). Mice were culled on d 5 and d 11 after MTX. The duodenum, jejunum, and ileum were collected for myeloperoxidase (MPO) activity, metallothionein (MT) levels, and histology. Acteoside reduced histological severity scores by 75, 78, and 88% in the duodenum, jejunum, and ileum, respectively, compared to MTX-controls on d 5. Acteoside reduced crypt depth by 49, 51, and 33% and increased villus height by 19, 38, and 10% in the duodenum, jejunum, and ileum, respectively, compared to MTX-controls on d 5. Acteoside decreased MT by 50% compared to MTX-control mice on d 5. Acteoside decreased MPO by 60% and 30% in the duodenum and jejunum, respectively, compared to MTX-controls on d 5. Acteoside alleviated MTX-induced small intestinal mucositis possibly by preventing inflammation.

Effect of the form of the sesame-based diet on the absorption of lignans.

The effect of different forms of sesame-based diets on the concentration of plasma lignans was assayed by estimating the levels of certain lignans (sesame lignans and enterolignans) in the plasma of experimental animals. In a series of experiments, male Wistar rats were fed either a raw sesame-enriched diet or a tahini-enriched diet. The plasma concentration of the lignans (sesame lignans and enterolignans) was determined at various time intervals over a 24 h period after a single administration. Enterodiol and enterolactone concentration in the tahini-treated group was significantly higher than in the raw sesame-treated group. In another series of experiments, male Wistar rats were fed, for 15 d, diets enriched in raw dehulled sesame, sesame perisperm, sesame oil, tahini and a polyphenolic extract derived from the seed perisperm. Enterodiol and enterolactone plasma concentration was high in the case of the sesame perisperm in spite of its low concentration in the assessed sesame lignans. Overall, the levels of the sesame lignans and enterolignans present in plasma seem to be influenced not only by the amount of lignan intake but also by other factors such as the form of the sesame-based diet.

Antinociceptive and anti-inflammatory activities of standardized extract of polymethoxyflavones from Ageratum conyzoides

ETHNOPHARMACOLOGICAL RELEVANCEnAgeratum conyzoides L. is a plant widely used in traditional medicine in tropical and subtropical regions of the world due to its anti-inflammatory, antinociceptive and antibacterial properties.nnnAIM OF THE STUDYnTo characterize the standardized extract of polymethoxyflavones (SEPAc) from the plant and evaluate its antinociceptive and anti-inflammatory effects.nnnMATERIALS AND METHODSnThe SEPAc purified from the ethanol extract of the plant leaves was characterized by high resolution mass spectrometry and the methoxyflavones were quantified by a validated UPLC-PDA method. The antinociceptive and anti-inflammatory activities of the SEPAc were evaluated after oral administration on the acute nocifensive behavior of mice induced by formalin, prostaglandin E2 (PGE2) and proinflammatory cytokines (interleukin-1beta (IL-1β)) and tumor necrosis factor-alpha (TNF-α) in mice.nnnRESULTSnQualitative analyses revealed the presence of seven methoxyflavones in the SEPAc, also a simple UPLC-PDA method was developed and validated for the quantification of 5,6,7,3,4,5-hexametoxyflavone; nobiletin; 5-methoxynobiletin and eupalestin, major compounds in the extract. The SEPAc exhibited antinociceptive and anti-inflammatory activities in both formalin phases, with significant inhibition of the paw edema formation and significant reduction of the nocifensive response induced by an intraplantar injection of PGE2 and intrathecal injection of interleukin-1β.nnnCONCLUSIONSnThe SEPAc exhibited significant antinociceptive and anti-inflammatory effects. These results provided scientific suggestion of its potential as a source of new medicines to treat inflammatory diseases, such rheumatoid arthritis.

Rare bisindole alkaloids from the Amazonian tree Raputia simulans.

The stem bark of Raputia simulans (Rutaceae) has been reported to contain simple and dimeric indole alkaloids. Further phytochemical investigation of R. simulans stem bark resulted in the isolation of three new alkaloids. These compounds represent a relatively new category of dimeric indole alkaloids with a cyclohexene moiety in their core. Their structure elucidations were based on NMR and HR‐MS techniques, while structural aspects concerning their relative configuration were investigated using molecular mechanics calculations and NOESY experiments.

Metabolomic studies on Isatis tinctoria - Comparison of different origins, harvesting dates, and the effect of repeated harvesting

Isatis tinctoria (Brassicaceae) is an ancient dye and medicinal plant with potent anti-inflammatory and anti-allergic properties [1]. We investigated metabolic differences by NMR spectroscopy of plants grown under identical conditions on experimental plots at the Agricultural Field Station of Thuringia in Dornburg, Germany. Comparisons were carried out for plants of different geographic origins, different harvesting dates, and between single and repeatedly harvested plants. For the study, plants of six origins were compared, and they were harvested at six time points. In addition, the effect of repeated harvesting was investigated. Leaf samples were shock-frozen with liquid N2 immediately after harvest, freeze-dried, and cryomilled prior to extraction. Extracts were prepared by pressurized liquid extraction (PLE) with 70% aqueous methanol. The spectra were analyzed by multivariate data analysis. The score plots produced by principal component analysis (PCA) revealed differences in the metabolic profile between the harvesting dates. The loading plots showed that the spectral region of carbohydrate resonances was responsible for these differences. In contrast, no major differences were seen in the metabolites of different origins. Partial least square discriminant analysis (PLS-DA) revealed no effect of repeated harvesting on the metabolic profiles. Reference: [1] Hamburger M., Phytochemistry Reviews, 1, 333 – 344 (2002)

Evaluation of natural products as potential agrochemical agents with insecticide, fungicide and herbicide activities

The International Congress on Natural Products Research, New York City, 28 July - 1 August 2012