Why are grape/fresh wine anthocyanins so simple and why is it that red wine color lasts so long?

Vitis vinifera red berries are characterized by anthocyanins whose chemical structures are among the simplest encountered in higher plants. On the contrary, many plants, including orchids, petunias, red cabbage, elderberries, potatoes for instance, have developed very complicated anthocyanins featuring side-chains at the available positions of the aglycone skeleton. Such pigments were shown to possess bio-physico-chemical properties not to be seen with the grape common anthocyanins. Among beverages (water, tea, beer, wine, coffee, juices, milk), red wine is the only one whose organoleptic properties improve with time and this is called ageing. The grape/fresh red wine pigments, after a few months, disappear from the wine giving birth to new pigments resulting from the wine spontaneous chemistry allowing it to remain red for many years. What are the wine pigments and why are they so stable is the purpose of this mini-review. The structural simplicity of grape anthocyanins and the long lasting colour of red wine is another French paradox; we call it French paradox II.

Analysis and biological activities of anthocyanins.

Anthocyanins are naturally occurring compounds that impart color to fruits, vegetables, and plants. They are probably the most important group of visible plant pigments besides chlorophyll. Apart from imparting color to plants, anthocyanins also have an array of health-promoting benefits, as they can protect against a variety of oxidants through a various number of mechanisms. However, anthocyanins have received less attention than other flavonoids, despite this. This article reviews their biological functions and pre-clinical studies, as well as the most recent analytical techniques concerning anthocyanin isolation and identification.

Two diacylated malvidin glycosides from Petunia hybrida flowers.

Two novel diacylated and two known anthocyanins were isolated from violet flowers of Petunia hybrida cv Festival. The new anthocyanins are malvidin 3-O-(6-O-(4-O-(4-O-(6-O-feruloyl-beta-D-glucopyranosyl)-E-p-coumaroyl)-alpha-rhamnosyl)-beta-D-glucopyranoside)-5-beta-D-glucopyranoside and malvidin 3-O-(6-O-(4-O-(4-O-(6-O-E-p-coumaroyl-beta-D-glucopyranosyl)-E-p-coumaroyl)-alpha-rhamnosyl)-beta-D-glucopyranoside)-5-beta-D-glucopyranoside. The two known pigments are the 3-caffeoylglucosyl-p-coumaroylrutinoside-5-glucosides of malvidin and petunidin.

Influence of trans-cis isomerisation of coumaric acid substituents on colour variance and stabilisation in anthocyanins.

The recently isolated pigments from Petunia integrifolia and Triteleia bridgesii present a distinct feature that sheds new light on the understanding of intramolecular copigmentation of anthocyanins. These are among the infrequent anthocyanins that naturally present a coumaric acid substituent in both cis and trans forms. As a consequence, the two isomers demonstrate substantial variations of their thermodynamic and kinetic constants and also colour properties. A possible explanation for these characteristics is presented, making use of molecular modelling and taking into account the three-dimensional structures of the pigments.

Polyphenols produced during red wine ageing.

Over the past few years, it has been accepted that a moderate red wine consumption is a factor beneficial to human health. Indeed, people of France and Italy, the two major wine-producing European countries, eat a lot of fatty foods but suffer less from fatal heart strokes than people in North-America or in the northern regions of Europe, where wine is not consumed on a regular basis. For a time, ethanol was thought to be the "good" chemical species hiding behind what is known as the "French paradox". Researchers now have turned their investigations towards a family of natural substances called "polyphenols", which are only found in plants and are abundant in grapes. It is well known that these molecules behave as radical scavengers and antioxidants, and it has been demonstrated that they can protect cholesterol in the LDL species from oxidation, a process thought to be at the origin of many fatal heart attacks. However, taken one by one, it remains difficult to demonstrate which are the best polyphenols as far as their antioxidant activities are concerned. The main obstacle in that kind of research is not the design of the chemical and biological tests themselves, but surprisingly enough, the limited access to chemically pure and structurally elucidated polyphenolic compounds. In this article, particular attention will be paid to polyphenols of red wine made from Vitis vinifera cultivars. With respect to the "French paradox", we address the following question: are wine polyphenolic compounds identical to those found in grapes (skin, pulp and seed), or are there biochemical modifications specifically taking place on the native flavonoids when a wine ages? Indeed, structural changes occur during wine conservation, and one of the most studied of those changes concerns red wine colour evolution, called "wine ageing". As a wine ages, it has been demonstrated that the initially present grape pigments slowly turn into new more stable red pigments. That phenomenon goes on for weeks, months and years. Since grape and wine polyphenols are chemically distinct, their antioxidant activities cannot be the same. So, eating grapes might well lead to beneficial effects on human health, due to the variety and sometimes large amounts of their polyphenolic content. However, epidemiological surveys have focused on wines, not on grapes....

New aspects of anthocyanin complexation. Intramolecular copigmentation as a means for colour loss?

Two series of structurally related anthocyanins, extracted from the blue flowers of Evolvulus pilosus cv. Blue Daze and from the blue-purple flowers of Eichhornia crassipes, exhibit remarkable colour stabilities in aqueous solution at mildly acidic pH values. All the pigments possess the same chromophore (delphinidin), but a different pattern of glycosylation and acylation. Moreover, one of the pigments has an apigenin 7-glucoside molecule (a flavone) attached to the glycosidic chain by two ester bonds with malonic acid, instead of an aromatic acid and is the only known anthocyanin with such a structure. All the molecules studied, except one which has only a 3-gentiobioside (a disaccharide) as substituent, denote an effect of reduction in the hydration constant when compared with the parent delphinidin 3-glucoside or 3,5-diglucoside molecules, which supports the existence of intramolecular hydrophobic interactions between the chromophoric skeleton and the acyl or flavonoid groups. The role played by the sugar units on the hydrophobicity/hydrophilicity of the pigments is also discussed.

The effect of liver denervation on hepatic hemodynamics during hypovolemic shock in swine.

This study tested the hypothesis that the denervated liver is more susceptible to hypovolemic shock than the normal liver. Fourteen swine, seven nondenervated and seven after liver denervation, were studied during hypovolemic shock to 50% of baseline blood pressure. Hepatic artery and portal vein flows were measured using transonic flow probes, and cardiac output and central venous pressure were measured using Swan-Ganz catheters. Hepatic artery flow fell equivalently in the two groups, from 132 +/- 71 to 94 +/- 17 ml/min in the nondenervated group compared with 149 +/- 56 to 91 +/- 55 ml/min in the denervated group. In contrast, portal flow in the denervated group (276 +/- 71 to 119 +/- 53 ml/min) fell significantly (p less than 0.001) more than in the nondenervated group (289 +/- 135 to 194 +/- 70 ml/min). The 58% reduction from baseline in portal flow in the denervated group compared with the 30% reduction in the nondenervated group suggests that the normal compensatory mechanism to maintain portal flow during hypovolemic shock is neurally mediated. It can be hypothesized that sensory afferent fibers might initiate a feedback to splanchnic vasodilatation in response to reduced portal flow. This study supports the hypothesis that the denervated liver is more susceptible to hypovolemic shock.

An in vivo examination of rat brain during sepsis with 31P-NMR spectroscopy.

Neurological symptoms including lethargy, obtundation, and confusion are early and common findings in patients with sepsis. The etiology of the mental status changes that occur during severe infection is not known. We investigated the effects of sepsis on the levels of high-energy phosphates to determine whether decreased energy metabolism was a factor in the depressed neurological state. The time course of changes in brain pH and brain high-energy phosphate metabolites during an Escherichia coli infusion was determined from sequential phosphorus-31 nuclear magnetic resonance (31P-NMR) spectra of ketamine-xylazine-anesthetized rats. A second group of rats received 0.9% saline infusion and served as a control group. Despite severe obtundation and near loss of righting reflex, the rats in the septic group had no significant differences in the brain pH, the ratio of phosphocreatine (PCr) to beta-adenosine 5'-triphosphate (beta-ATP), or in the ratio of PCr to Pi. The only significant decrease in brain high-energy phosphates or pH occurred terminally in the septic rat group and corresponded with a rapidly falling arterial blood pressure. We conclude that the severe neurological depression that is characteristic of sepsis is not due to decreased levels of brain high-energy phosphates or brain acidosis.

Water vapor pressure calculation.

Accurate calculation of water vapor pressure for systems saturated with water vapor can be performed using the Goff-Gratch equation. A form of the equation that can be adapted for computer programming and for use in electronic databases is provided.

Splenic sequestration and ineffective erythropoiesis in hemoglobin E-beta-thalassemia disease.

A 13-year-old Thai female with hemoglobin E-beta-thalassemia was evaluated for anemia and splenomegaly. Globin chain synthesis in a whole cell system revealed an absence of betaA chains and excessive alpha chains. The alpha/betaE + gamma ratio was 1.26 in bone marrow and 1.90 in peripheral blood. The average gamma/betaE ratio in bone marrow and peripheral blood was 0.36 compared to peripheral blood concentrations of 49% hemoglobin E and 51% hemoglobin F. Homologous red cell 51Cr half-life increased from 22.7 days to 32.8 days after splenectomy. Total circulating hemoglobin increased from 112.9 to 149.7 g. Endogenous carbon monoxide productive (Vco) as a measure of total heme catabolism decreased from 2.00 to 1.54 mumol/hr/kg. Ineffective erythropoiesis was manifested by an increased Vco/Vheme-c ratio of 7.52.

RBC transfusions in paroxysmal nocturnal hemoglobinuria.

Frozen-thawed, deglycerolized RBCs can be substituted for saline-washed RBCs for transfusion of patients with paroxysmal nocturnal hemoglobinuria (PNH). The effect of transfusion is to decrease bone marrow production of RBCS, which results in a decreased percentage of complement-sensitive erythrocytes. In the presence of small numbers of complement-sensitive erythrocytes, major vascular surgery can be performed without hemolytic problems. This study suggests that the percentage of complement-sensitive RBCs, as well as the complement sensitivity of these cells, influence the severity of hemolysis in persons with PNH.

Endogenous production of carbon monoxide as measured simultaneously in blood and gas phase.

Endogenous carbon monoxide (CO) production rates and total body haemoglobin content were determined simultaneously in blood and gas phase in 15 individuals. At 24% oxygen (O2) concentration in the closed rebreathing system, a correlation was obtained which revealed that a 1 mumole rise in CO in the gas phase of the system was the result of 48.94 +/- 5.3 (SE) mumoles of CO rise in the body. Three individuals had heat-damaged red cells reinjected intravenously to determine if the recovery rate of the subsequently produced CO was proportionate in both the gas phase and blood phase. Changes in blood CO concentration were not consistently detected by gas phase analysis. Prediction of CO production rates utilizing gas phase data alone did not reflect accurately CO production rates determined from blood carboxyhaemoglobin rises.

Effect of blood in the gut on measurements of endogenous carbon monoxide production.

Changes induced in measurements of endogenous carbon monoxide (CO) production by blood in the lumen of the gut were studied in five normal volunteers. The study was undertaken because exogenous heme is absorbed by intestinal mucosal cells where the porphyrin ring is split with the release of CO that could contribute to blood CO levels and lead to a fallacious diagnosis of hemolytic disease. Volunteers who consumed 200 ml of their own blood doubled their endogenous production of CO (0.69 versus 0.34 mumoles/kg/hr). This suggested that at least 3% of the ingested heme was degraded and recovered as CO within 2 1/2 hr. Measurements of serum bilirubin also showed a significant increase after ingestion of blood. These data indicate that blood in the gastrointestinal tract can interfere with quantification of heme and bilirubin turnover from measurements of either endogenous CO production or bilirubin and suggest that this might occur with the ingestion of meat.