Effects Of Ellagitannins Research Articles

Hepatoprotective and antioxidant effect of ellagitannins and galloyl esters isolated from Melaleuca styphelioides on carbon tetrachloride-induced hepatotoxicity in HepG2 cells

Context In a previous study, the total extract of Melaleuca styphelioides Sm. (Myrtaceae) showed a significant hepatoprotective effect in a CCl4-induced toxicity model in mice. However, the active components responsible for the activity of the extract were not identified.Objective To determine the in vitro hepatoprotective activity of the isolated pure compounds from M. styphelioides leaves using the CCl4-challenged HepG2 cell model.Materials and methods The hepatoprotective activity of the compounds (at concentrations of 100, 50 and 25 μm), the total extract and silymarin (Sil) (100, 50 and 25 μg/ml) was determined by measuring the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) after pretreatment with the tested samples for one hour. Glutathione (GSH) and superoxide dismutase activity (SOD) were estimated to determine the mechanisms of the hepatoprotective activity.Results Some compounds showed marked hepatoprotection, including tellimagrandin I, which produced 42, 36 and 31% decrease in ALT and 47, 43 and 37% decrease in AST, at the tested concentrations, respectively, pedunculagin (32, 32 and 30% decrease for ALT and 48, 48 and 45% for AST), tellimagrandin II (38, 32 and 26% decrease for ALT and 45, 40 and 34% for AST) and pentagalloyl glucose (30, 28 and 26% decrease for ALT and 45, 38 and 36% for AST). Tellimagrandin I and II showed the highest increase in GSH (113, 105 and 81% and 110, 103 and 79%, respectively), which was comparable to Sil. Pedunculagin produced the highest increase in SOD (497, 350 and 258%).Conclusion This study highlights promising natural hepatoprotective candidates derived from M. styphelioides.

Ellagitannins--compounds from pomegranate as possible effector in steroidogenesis of rabbit ovaries.

This study has observed possible effect of ellagitannins - compounds from pomegranate on process of steroidogenesis in ovaries. The aim of the study was to investigate the possible effect of punicalagin on secretion of steroid hormones - progesterone, androstenedione, testosterone and 17beta-estradiol by ovarian fragments of rabbits in vitro. Ovarian fragments from sexually mature female New Zealand white rabbits (n=20) were incubated without (control group) or with punicalagin at various doses 1, 10 and 100 microg.ml(-1) for 24 h. Hormones were evaluated by ELISA (The Enzyme-Linked Immunosorbent Assay). Data showed that progesterone and 17beta-estradiol (but not androstenedione and testosterone) release by rabbit ovarian fragments was significantly affected by punicalagin addition at various doses. Punicalagin (at 100 microg.ml(-1)) significantly (P<0.05) increased progesterone secretion. On the other hand, the release of 17beta-estradiol was significantly (P<0.005) decreased by punicalagin addition (at 10 microg.ml(-1)). Our results suggest that punicalagin could have dose-dependent impact on secretion of steroid hormones progesterone and 17beta-estradiol by rabbit ovarian fragments and it may be effector in process of ovarian steroidogenesis.

Cytotoxic Effects of Ellagitannins Isolated from Walnuts in Human Cancer Cells

Walnuts contain many bioactive components that may slow cancer growth. A previous report showed that a diet supplemented with walnuts decreased the tumor size formed by MDA-MB-231 human cancer cells injected into nude mice. However, the mechanism of action was never determined. We characterized the effects of a methanol extract prepared from walnuts on human MDA-MB-231, MCF7, and HeLa cells. The extract was cytotoxic to all cancer cells. We identified compounds from the methanol extract that induced this cytotoxicity. The predominant compounds were Tellimagrandin I and Tellimagrandin II, members of the ellagitannin family. We also show a walnut extract decreases the intracellular pH, depolarizes the mitochondrial membrane with release of cytochrome c and phosphatidylserine flipping. The antimitogenic effects of walnut extract were associated with a twofold reduction of mitochondria respiration. These results suggest impairment of mitochondrial function and apoptosis as relevant mechanism of anticancer effects of the walnut extract.

Effect of ellagitannins, ellagic acid and volatile compounds from oak wood on the (+)-catechin, procyanidin B1 and malvidin-3-glucoside content of model wines

Background and Aims: During ageing in oak barrels, wine undergoes changes because of the release of polyphenols and other molecules from wood. The aim of this study was to evaluate the influence of some oak wood-derived volatile compounds, ellagic acid and oak wood extracts on the levels of (+)-catechin, procyanidin B1 and malvidin-3-glucoside. Methods and Results: Phenolics and the oak wood derived volatile compounds studied were quantified by HPLC and by GC, respectively. Additionally, the new compounds formed in the solutions were characterised by their spectral properties. Ellagic acid and/or oak wood extracts slowed the decline in the levels of (+)-catechin and procyanidin B1. In contrast, the decrease in malvidin-3-glucoside was more pronounced in the presence of ellagic acid and oak wood chip extracts. Furfural slowed (+)-catechin degradation, while breakdown of malvidin-3-glucoside was slightly more pronounced in the presence of guaiacol, furfural, vanillin and eugenol. (+)-Catechin, procyanidin B1 and malvidin-3-glucoside did not significantly affect the rate of the degradation of ellagitannins during the storage time studied. Finally, new HPLC peaks were detected in the solutions containing (+)-catechin and ellagic acid, as well as with malvidin-3-glucoside with ellagic acid and oak wood extract. Conclusions: Malvidin 3-glucoside and (+)-catechin and procyanidin B1 presented distinct behaviours during time in the presence of volatile and non-volatile compounds from oak wood. Significance of the Study: This work points out the importance of oak wood components in the degradation of anthocyanins and tannins, as well as the reactions that occur during the ageing of red wine. Abbreviations ANOVA analysis of variance ; B1ME, B2ME and C1MO novel products formed in solutions containing malvidin 3-glucose (M) and ellagic acid (E) or oak wood extract (O); GC gas chromatography; HPLC high performance liquid chromatography; lmax maximum absorption wavelength; NHTP 2,3,5-nonahydroxyterphenoyl