Grape Leaf Extract Research Articles

Development of antivaricose gel technology

A technological scheme for producing an antivaricose gel containing a combination of grape leaf extract and heparin has been developed based on results of an investigation of the properties of the active ingredients and excipients. The scheme can be included into technical documentation for manufacturing the proposed gel.

Red grape leaf extract improves endurance capacity by facilitating fatty acid utilization in skeletal muscle in mice

Improving endurance capacity leads to increased athletic performance and active lifestyles. The aim of this study was to investigate the effect of the intake of red grape leaf extract (RGLE), used as a traditional herbal medicine in the Mediterranean area, on endurance capacity in mice. Male BALB/c mice were divided into three experimental groups with similar swimming times and body weights; control group, 0.2% (w/w) and 0.5% RGLE group. Swimming times were measured for evaluation of endurance capacity once a week during the 10-week experimental period. Blood and tissues were collected from anesthetized mice immediately after 30 min of swimming exercise, and analyzed blood component and fatty acid oxidation enzyme activity, and gene expression in soleus muscle and mesenteric adipose tissue. Endurance capacity was improved by RGLE in a dose-related manner, and was significantly longer in the 0.5% RGLE group than in the control group at week 10. Plasma lactate levels after exercise in the 0.5% RGLE group were significantly lower than that in the control group. RGLE induced the upregulation of hormone-sensitive lipase mRNA in mesenteric adipose tissue, increased the plasma free fatty acid concentration after exercise, and enhanced fatty acid oxidation enzyme activity in the soleus muscle. Furthermore, peroxisome proliferator-activated receptor-gamma coactivator 1α (Pgc1α) and its downstream target genes were also significantly upregulated in the soleus muscle in the 0.5% RGLE group. Intake of RGLE upregulated Pgc1α expression and facilitated fatty acid oxidation in skeletal muscle, and these effects contributed, in part, to improve endurance capacity.

Relaxatory effect of Vitis vinifera leaf extract on rat isolated trachea

In previous studies, we have shown the relaxatory effect of grape leaf (Vitis vinifera) extract on isolated ileum, uterus and aorta. In rat aorta it was revealed that the NO and endothelium are involved in the relaxation induced by grape leaf extract. The aim of present study was to investigate the effect of the Vitis vinifera leaf hydroalcoholic extract (VLHE) on rat trachea precontracted by Ach and KCl. Extract was prepared by maceration method using 70% alcohol for 72 hours and then, the solvent was evaporated. Male Sprague Dawley rats were anaesthetized by ketamine hydrochloride (50 mg/kg i.p.), the trachea (5-6 cartilage rings) were isolated and suspended in an organ bath containing Kreb’s solution (37?C, pH 7.4) bubbled with oxygen. Following 60 min period equilibrium, tissue was contracted by either Ach (55 µM) or KCl (60 mM) under 1.5 g initial tension and tissue responses were recorded isometrically. After reaching to plateau, different concentrations of VLHE (0.5, 1, 2, 4 and 8 mg/ml) applied to the organ bath in a non-cumulative manner. Results are presented in mean±SEM of g contraction force. Trachea precontracted by Ach or KCl were relaxed by VLHE significantly (P

Effect of grape (Vitis vinifera L.) leaf extract on alcohol induced oxidative stress in rats

Alcoholic liver disease is a major medical complication of drinking alcohol. Oxidative stress plays an important role in the development of alcohol liver disease. The present study was carried to evaluate the effect of grape leaf extract (GLEt) on antioxidant and lipid peroxidation states in liver and kidney alcohol induced toxicity. In vitro studies with DPPH∗ and ABTS∗+ (cation radical) showed that GLEt possesses antioxidant activity. In vivo administration of ethanol (7.9g/kg bw/day) for 45 days resulted an activity of liver marker enzymes (AST, ALT, ALP and GGT), lipid peroxidation markers (TBARS, lipid hydroperoxides) in liver and kidney with significantly lower activity of SOD, CAT, GPx, GST and non-enzymatic antioxidants (vitamin E, vitamin C and GSH) in liver and kidney as compared with control rats. Administration of ethanol along with GLEt significantly decreased the activities of liver markers enzyme in serum towards near normal level. GLEt at a dose of 100mg/kg was highly effective than 25 and 50mg/kg body weight. In addition GLEt also significantly reduced the levels of lipid peroxidation and addition, significantly restored the enzymic and non-enzymatic antioxidants level in liver and kidney of alcohol administration rats. This observation was supplemented by histopathological examination in liver and kidney. Our data suggest that GLEt exerts its protective effect by decreased the lipid peroxidation and improving antioxidants status, thus proving itself as an effective antioxidant in alcohol induced oxidative damage in rats.

Spasmolytic Effect of Vitis Vinifera Leaf Hydroalcoholic Extract on Rat's Isolated Vas Deferens

Introduction: Many reports have shown that the grape (Vitis vinifera) seed extract induces antioxidant, hypotensive hypolipidemic, and vasodilatory effects. We have recently shown the relaxatory effect of grape leaf extract on rat's aorta, ileum, uterus and frog's heart rate and contractility. The objective of this study was to investigate the spasmolytic effect of Vitis Vinifera Leaf Hydroalcoholic extract (VLHE) on rat's isolated vas deferens. Materials & Methods: Vas deferens of male adult rat (Sprague Dawley) was removed, placed in an organ bath containing Tyrode’s solution (30oC, pH 7.4) and the bath bubbled with air. Then its contractions under 1 g initial tension, were recorded isometrically. The vas deferens was contracted either by KCl (80 mM) or adrenaline (2 μg/ml). Results: The results demonstrated that the VLHE at 1, 2, 4 and 8 mg/ml reduced the vas deferens contractions evoked by KCl (80 mM) significantly (P<0.0001) and dose-dependently. VLHE (1, 2 and 4 mg/ml) also reduced the adrenaline-induced vas deferens contractions (P<0.0001). In calcium free Tyrod’s solution, KCl-induced contractions were occurred only after adding normal calcium (1.77 mM) to the organ bath solution. VLHE (3mg/ml) reduced the calcium-induced contraction by KCl too. The VLHE-induced vas deferens relaxation was unaffected by the β- adrenoceptor antagonist (propranolol, 3 μM for 5 min). Nitric oxide synthase inhibitor (L-NAME, 300 μM for 10 min) was unable to modify either KCl-induced contraction or the vas deferens relaxation induced by the extract. Conclusion: These results suggested that the spasmolytic effect of Vitis vinifera leaf hydroalcoholic extract on rat's vas deferens occurred through the blockage of voltage dependent calcium channels (VDCC). Also, neither NO nor β-adrenoceptors were involved in this inhibitory effect of the extract.

VASORELAXATORY EFFECT OF VITIS VINIFERA EXTRACT ON RAT AORTA

Reports have shown the antioxidant, hypotensive, hypolipidemic and vasodilatory effects of grape (Vitis vinifera L.) seed extract. We have recently shown the relaxatory effect of grape leaf extract on rat uterus and reduction of frog heart rate and contractility. The aim of the present study was to investigate the relaxant effect of Vitis vinifera leaf hydroalcoholic extract (VLHE) on rat thoracic aorta contractions induced by phenylephrine and KCl and the role of aorta endothelium on this action. Rat aorta was removed and placed in an organ bath containing Krebs-Henseleit solution and aorta contractions were recorded isometrically. The results demonstrate that VLHE (0.125-2 mg/ml) reduces the endothelial intact aorta reconstructed by phenylephrine (1 μM) dose-dependently (P<0.0001). Extract induced the same response in endothelial denuded aorta, but in a much lesser extent. The IC 50 for both groups were 0.45±0.08 and 1.73±0.23 mg/ml, respectively. However, the contractile responses of these groups were similar. VLHE (0.125-2 mg/ml) reduced the contractions induced by KCl (80 mM) dose-dependently (P<0.0001). The relaxatory effect of VHLE on KCl–induced contractions was less than those evoked by Phenylephrine. Vasorelaxatory effect of VHLE on intact aorta was attenuated by nitric oxide synthase inhibitor (L-NAME, 100 μM) and gaunyl cyclase inhibitor (methylene blue, 10 μM) significantly, but was unaffected by atropine (1 μM). The results suggest that the greatest vasorelaxant effect of VHLE on rat aorta is endotheliumdependent and nitric oxide (NO) and cGMP are mostly responsible but cholinergic receptors are not involved.

Antibacterial Activity of Plants Used in Cooking for Aroma and Taste

Thirty-three plants used in cooking for aroma and taste were examined for antibacterial activity against pathogens causing foodborne infections. Vibrio parahaemolyticus and Staphylococcus aureus were sensitive to many kinds of plant extracts, whereas Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella Enteritidis populations decreased in only six, one, and three plant extracts, respectively. The polyphenol content in the plants was significantly different between the antibacterial plants and nonantibacterial plants, indicating that the polyphenols were related to the antibacterial action of these plants. Antibacterial activity of various concentrations of leaf extracts from Japanese persimmon, white cedar, and grape were investigated. Japanese persimmon and white cedar leaf extracts at low concentrations affected L. monocytogenes and V. parahaemolyticus rapidly. With grape leaf extract at low concentrations, the population of L. monocytogenes decreased similarly to Japanese persimmon and white cedar leaves. This study demonstrates that many plants used in cooking for aroma and taste contain polyphenols and exhibit antibacterial activity against foodborne pathogens.

Improvements in Sample Preparation and Polymerase Chain Reaction Techniques for Detection ofXylella fastidiosain Grapevine Tissue

The sensitivity of detecting of <i>Xylella fastidiosa</i> in ground grape tissue via standard polymerase chain reaction (PCR) procedures is often limited by inhibitory plant compounds. Aliquots of standardized bacterial suspensions in healthy grapevine extracts were used to create a 10-fold dilution series for testing the effect of immunocapture (IC) and nested primers (N) on PCR sensitivity. DNA from <i>X. fastidiosa</i> suspended in grape leaf extract was not amplified by non-IC-PCR using standard and nested methods. The use of dynabeads for the immunomagnetic separation of target bacteria cells in plant extract was shown to reduce the inhibitory effect dramatically and increase sensitivity 10,000-fold over non-IC-PCR methods. The IC procedure with standard PCR primers achieved a sensitivity of 10,000 cells/mL of grape leaf extract. N-PCR primers were also used in combination with the IC procedure and increased sensitivity an additional 1,000-fold over standard PCR primers. The combined IC-N-PCR procedure achieved a maximum sensitivity of 2 cfu/mL of bacteria concentration in grape leaf extract. This method also gave reliable results when samples were taken from <i>X. fastidiosa</i>-infected grapevine plants. A new method was also applied for specific amplification of genomic fragments of the bacteria with nucleic acid deposition on small pieces of charged nylon membrane by spotting crude infected grapevine sap (spot-PCR) in combination with the nested primers. Spot-nested (Sp-N)-PCR was able to achieve the same level of sensitivity as IC-N-PCR with known dilutions of <i>X. fastidiosa</i> in buffer. Sp-N-PCR was able to detect positive and negative controls, but its reliability in sensitivity tests suggests that it needs further study.

Common cosmetic hydrophilic ingredients as penetration modifiers of flavonoids

Nowadays, flavonoids are present in many cosmetic formulations, mainly in the form of plant extracts. The main reason of still increasing popularity of these substances is their beneficial biochemical activity. The main factor affecting activity of flavonoids in the skin is their skin penetration ability. The studies have evidenced that flavonoids from grape leaf extract as well as flavonoids like quercetin, rutin and catechin can migrate through the model lipophilic membrane from aqueous solution. The influence of common hydrophilic cosmetic additives on the permeation profile of flavonoids has been checked. The partition coefficients of examined flavonoids in the octanol-water extraction system were determined. Correlations between permeation coefficients and log P of particular flavonoids were plotted. To determine the mechanism of influence of hydrophilic substances on the permeation profile of flavonoids, the solubility of these compounds was investigated. Studies suggest that the presence of hydrophilic additives causes the increase in the flavonoid solubility that decreases the activity of flavonoids in the vehicle. In such a situation, the driving force for the penetration is reduced and the decrease of permeation coefficient can be observed.

Inhibition of Tomato Pectinesterase by Tannic Acid

THERE have been several reports of the effect of phenolic compounds on pectinesterase activity. Pollard et al.1 found apple and pear phenolics to be inhibitory to pectinesterase, and Ramaswamy and Lamb2 found that the activity of the enzyme was partially inhibited by tea polyphenols. Kew and Veldhuis3 found that citrus pectinesterase was inhibited by grape leaf extract. Porter and Schwartz4 consider the active principle of the extract to be a tannin, and Williams5 has reported this to be an extremely efficient inhibitor of pectic enzymes (macerating enzymes and polygalacturonase).