首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
The phytoalexin production potential of three American Vitis species and that of three cultivars of Vitis vinifera were evaluated in response to UV-C irradiation. Time course changes in resveratrol, piceid, epsilon-viniferin, and pterostilbene contents were studied within 3 days after a short UV-C irradiation. Results show that the two major stilbenes accumulated as a response to UV-C elicitation are resveratrol and epsilon-viniferin, a resveratrol dehydrodimer, the concentration of both compounds usually reaching quantities >100 microgram/g of fresh weight. In contrast, piceid and pterostilbene were constantly produced in low quantities. Owing to the results obtained, the role of stilbene phytoalexins in the resistance of grapevines to diseases is discussed.  相似文献   

2.
Postharvest treatment of seedless white table grapes (var. 'Superior') with different gas ozone concentrations (3.88 and 1.67 g/h) for 1, 3, and 5 h induced an increase in stilbenoid biosynthesis [trans-resveratrol, piceatannol, and viniferinas (resveratrol dehydrodimers and dehydrotrimers)] during storage at 22 degrees C and 95% relative humidity. The maximal resveratrol concentration was reached after 2 days of storage, and this amount was similar to that induced by optimized UV-C treatments (1 min, 510 W, 40 cm). Although similar resveratrol concentrations accumulated in grapes after both UV-C and O3 treatments (maximum ozone production and time), the ozone treatment was more efficient in inducing viniferins accumulation in grape berries. A sequence in the biosynthesis of stilbenoids was observed, starting with the resveratrol monomer, continuing with the resveratrol dehydrodimers epsilon-viniferin and delta-viniferin, and ending with four different resveratrol dehydrotrimers. These trimers were different from alpha-viniferin, a trimer previously reported to be induced in grapes after biotic and abiotic stresses. Two alpha-viniferin isomers were also detected in the ozone-treated grapes, although at very low concentrations that prevented their quantification.  相似文献   

3.
A method using HPLC analysis has been used to compare the level of resveratrol and its derivatives, piceid, pterostilbene and epsilon-viniferin, in grapevine berries of three Vitis vinifera varieties. The concentration of these compounds has been evaluated in healthy and Botrytis cinerea infected grape clusters, both in natural vineyard conditions and in response to UV elicitation.  相似文献   

4.
Resveratrol (trans-3,5,4'-trihydroxystilbene) is a plant phytoalexin which has positive effects on human health. Stilbene synthase (STS) is a key enzyme involved in resveratrol biosynthesis. To construct a vector for STS expression in lettuce plant, a cDNA-encoding STS of Parthenocissus henryana was fused to the Cauliflower mosaic virus (CaMV) 35S promoter, and the bar gene was used as a selective marker gene. To increase the expression of STS, the expression cassette was flanked by MARs. In transgenic lettuce plants, an additional compound was identified as resveratrol by HPLC and ESI-MS. Quantitative analysis showed that the average content of resveratrol reached 56.40 +/- 5.52 microg/g leaf fresh weight, which was comparable to the amount in grape skin. Anticancer assay in HeLa cells revealed that apoptosis was induced by 200 microM of resveratrol extracted from transgenic lettuce.  相似文献   

5.
In the skin of cv. Napoleon table grapes, the anthocyanins malvidin 3-glucoside (and its acetyl and p-coumaroyl derivatives), cyanidin 3-glucoside, peonidin 3-glucoside, cyanidin 3-glucoside, petunidin 3-glucoside, and delphinidin 3-glucoside were identified by HPLC-DAD-MS. In addition, quercetin 3-glucoside and 3-glucuronide, caffeoyltartaric, piceid, and resveratrol were also detected. The content of most phenolics remained quite constant during postharvest refrigerated storage (10 days at 0 degrees C) while the resveratrol derivatives increased 2-fold. Postharvest treatments of grapes with UVC and UVB light induced a large increase in resveratrol derivatives (3- and 2-fold, respectively). This means that a serving of mature Napoleon grapes (200 g) provides approximately 1 mg of resveratrol, which is in the range of the amount supplied by a glass of red wine. This can be increased to 2 or 3 mg of resveratrol per serving in grapes that have been irradiated with UVB or UVC, respectively. These results show that refrigerated storage and UV irradiation of table grapes can be beneficial in terms of increasing the content of potentially health-promoting phenolics.  相似文献   

6.
Previous studies on the transport and absorption of resveratrol (3,5,4-O-trihydroxystilbene) were done using the pure compound. In this study, the absorption of resveratrol in digested peanut micellar from boiled and roasted peanuts was investigated using a human intestinal Caco-2 cell monolayer. The amount transported and rate of transport of both resveratrol glycosides and its hydrolytic product were quantified by a reverse-phase high-performance liquid chromatography method with mass spectrometric detection. Four peaks were identified in the digested peanut micellar of both boiled and roasted peanuts: two resveratrol glycosides, one resveratrol diglycoside, and possibly an acylated resveratrol glycoside. Resveratrol from roasted peanut micellar had a higher transport rate than those from the boiled peanut. This implies that resveratrol from roasted peanut is better absorbed than from boiled peanut. Also, the rate of transport and amount of resveratrol transported were higher for the hydrolytic product than the nonhydrolyzed glycosides. This has strong implications for in vivo absorption as the enzymatic activity of gut microflora could enhance the bioavailability of β-glycosides of dietary polyphenols.  相似文献   

7.
The effect of the complexation of resveratrol with hydroxypropyl-beta-cyclodextrins (HP-beta-CDs) on the antioxidant capacity of the polyphenol is studied for the first time by means of the oxygen radical absorbance capacity (ORAC) method, using fluorescein (FL) as the fluorescent probe. The method is validated through its linearity, precision, and accuracy for measuring the ORAC of resveratrol in the absence or presence of cyclodextrins (CDs). The complexation of resveratrol in CDs increased the net area under the FL decay curve (net AUC) of resveratrol up to its saturation level, at which the polyphenol showed almost double the antioxidant activity it shows in the absence of CDs. The complexation constant ( K c) between resveratrol and HP-beta-CDs was calculated by linear regression of the phase solubility diagram ( K c = 18048 M (-1)). The antioxidant activity of resveratrol was dependent on the complexed resveratrol because CDs acts as a controlled dosage reservoir that protects resveratrol against rapid oxidation by free radicals. In this way, its antioxidant activity is prolonged and only reaches its maximum when all the resveratrol is complexed.  相似文献   

8.
This study investigated the occurrence of resveratrol in Fragaria x ananassa Duchesne and the effect of preharvest conditions on resveratrol content. Both cis- and trans-resveratrol were detected in strawberry achenes (seeds) and pulp (receptacle tissue). Resveratrol was found to be higher in achenes than in fruit pulp. The levels of resveratrol were affected by genotype variations, fruit maturation, cultural practices, and environmental conditions. High growing temperature (25 and 30 degrees C) or enriched CO 2 in the atmosphere significantly enhanced resveratrol content of strawberries. Advancing maturation also increased resveratrol content. The mature pulp and achenes contained higher amounts of resveratrol than the immature fruit. Adding compost as a soil supplement or preharvest application of methyl jasmonate (MJ) also significantly enhanced the level of resveratrol in strawberry fruit. Among the plants grown in hill plasticulture, fruits of 'Ovation (B28)', 'Mohawwk', 'Earliglow', and 'B35' had higher amounts of resveratrol than fruits of other genotypes. 'Ovation' contained the highest amount of resveratrol among strawberries grown in matted row, whereas 'Latestar' contained the least. Ten of 14 tested genotypes (all except 'Allstar', 'Delmarvel', 'Northeaster', and 'MEUS 8') had higher amounts of resveratrol when grown in hill plasticulture compared to matted row.  相似文献   

9.
Electron spin resonance (ESR) spectroscopy and near-infrared (NIR) fluorescence spectroscopy were performed to observe singlet oxygen quenching by resveratrol. Resveratrol greatly decreased the 2,2,6,6-Tetramethyl-4-piperidone-N-oxyl radical signal as determined by ESR spectroscopy. Resveratrol also efficiently decreased luminescence emission at 1268 nm as studied with a NIR spectrofluorometer, showing positive evidence of singlet oxygen quenching by resveratrol. The total singlet oxygen quenching rate constant (kr+kq) of resveratrol in methanol was determined to be 2.55×10(7) M(-1) s(-1). The singlet oxygen chemical quenching rate constant (kr) of resveratrol was calculated by measuring its reaction rate with singlet oxygen relative to that of α-terpinene in the same solution under light illumination. The kr value of resveratrol was 1.15×10(6) M(-1) s(-1). The percent partition of chemical quenching over total singlet oxygen quenching (kr×100)/(kr+kq) for resveratrol was 5.11%. The results showed that resveratrol quenches singlet oxygen almost exclusively through the mechanism of physical quenching. Resveratrol showed a protective activity similar to that of BHA on the methylene blue sensitized photooxidation of α-terpinene. This unambiguously explains the mechanism of how resveratrol protects tissues and cells in biological systems or important nutrients in food systems against their photosensitized oxidations.  相似文献   

10.
Resveratrol is a naturally occurring phytoalexin, present in grapes and other food products, with important antioxidant properties. Although still under debate, it is generally assumed that resveratrol has protective effects against heart diseases and probably tumor development. Lipoxygenase is a dioxygenase with peroxidase activity involved in the synthesis of mediators in inflammatory, atherosclerotic, and carcinogenic processes. Lipoxygenase activity is also involved in the generation of flavors and aromas in foods from animal or vegetal sources. The results presented here show that resveratrol was a potent inhibitor of the dioxygenase activity of lipoxygenase, with an IC(50) = 13 microM. Simultaneously, resveratrol was oxidized by the peroxidase activity of lipoxygenase with a V(max) = 0.28 microM min(-1) and a k(M) = 16.6 microM. Furthermore, oxidized resveratrol was as efficient a lipoxygenase inhibitor as in its reduced form. From the data obtained it can be concluded that both resveratrol and its oxidized form can act as inhibitors of the dioxygenase activity of lipoxygenase. In contrast, the hydroperoxidase activity of lipoxygenase was not inhibited by resveratrol. These results suggest that resveratrol may be used as an antioxidant food additive and as a pharmacological agent to prevent the generation of eicosanoids involved in pathological processes.  相似文献   

11.
In this work the oxidative degradation of resveratrol catalyzed by lipoxygenase-1 (LOX-1) has been studied. The process has been characterized by spectroscopic and polarographic measurements. The oxidation of resveratrol was dependent on the concentration of resveratrol and the enzyme. When resveratrol was incubated in the presence of lipoxygenase at pH 9.0, the reaction displayed a k(M) value of 18.6 x 10(-)(6) M and a catalytic efficiency (k(cat)/k(M)) of 4.3 x 10(4) s(-)(1) M(-)(1). These values are close to those shown by the enzyme when linoleic acid is used as the substrate. The effect of lipoxygenase inhibitors on the lipoxygenase-catalyzed resveratrol oxidation was also evaluated. The rate of resveratrol oxidation was markedly decreased by the presence of NDGA in the incubation mixture. From HPLC measurements, it can be deduced that resveratrol is oxidatively decomposed to a complex mixture of products similar to those obtained when the molecule is oxidized by hydrogen peroxide.  相似文献   

12.
The present study investigated the mechanism of the synergistic antioxidant activity of alpha-tocopherol with resveratrol (3,5,4'-trihydroxy-trans-stilbene, 3,5,4'-THS) and its synthetic analogues, that is, 3,4-dihydroxy-trans-stilbene (3,4-DHS), 4,4'-dihydroxy-trans-stilbene (4,4'-DHS), 4-hydroxy-trans-stilbene (4-HS), and 3,5-dihydroxy-trans-stilbene (3,5-DHS). The reaction kinetics of alpha-tocopheroxyl radical with resveratrol and its analogues were studied in sodium dodecyl sulfate (SDS) and cetyl trimethylammonium bromide (CTAB) micelles using the stopped-flow electron paramagnetic resonance (EPR) technique. It was found that resveratrol and its analogues could regenerate alpha-tocopherol with rate constants (k(REG)) in the order of 3,4-DHS > 4,4'-DHS > resveratrol > or = 4-HS > or = 3,5-DHS in SDS and CTAB micelles. It was found that the analogues bearing o-dihydroxyl groups (3,4-DHS) and p-dihydroxyl groups (4,4'-HS) exhibited remarkably higher alpha-tocopherol-regenerating activity than those bearing no such groups (resveratrol, 4-HS, and 3,5-DHS). In addition, the alpha-tocopherol-regenerating activity of resveratrol and its analogues was correlated with their electrochemical behaviors, suggesting that electron transfer might play a critical role during the regeneration reaction.  相似文献   

13.
Peanut roots as a source of resveratrol   总被引：12，自引：0，他引：12  
A potent antioxidant, resveratrol (3,4',5-trihydroxystilbene), was extracted using 80% methanol from peanut roots (Arachis hypogaea L.), isolated with a solid-phase extraction column, purified by a semipreparative HPLC, and identified with 1H NMR and MS. The highest and lowest resveratrol contents in the peanut roots of 2000 fall and 2001 spring crops were 1.330 and 0.130 mg/g and 0.063 and 0.015 mg/g, respectively. When the dehydrated peanut root powders of spring and fall crops were combined and cooked with pork-fat patties (1%, w/w) and the separated oils were stored at 60 degrees C for conjugated diene hydroperoxide (CDHP) determination, CDHP contents of the control oils increased after 3 days of storage, whereas the contents in the peanut root-treated oils of spring and fall crops did not increase after 9 and 15 days of storage, respectively. It is of merit to find that peanut roots, usually left in the field as agricultural waste, contain resveratrol and bear potent antioxidative activity.  相似文献   

14.
Extractable amounts of resveratrol in berry skins and seeds were studied in 120 grape (Vitis) germplasm cultivars during two consecutive years to determine the distribution of resveratrol among the main grape genotypes. Interspecific rootstock cultivars had much higher extractable amounts of resveratrol in skin and seed than all other grape genotypes studied in both years. Extremely high extractable amounts of resveratrol in berry skins [>100 microg g(-1) of skin fresh weight (FW)] and seeds (>20 microg g(-1) of seed FW) were observed on two rootstock cultivars obtained from hybrids of V. monticula x V. riparia. Extractable amounts of resveratrol in berries of rootstock cultivars that are the descendants of V. riparia were also very high. The cultivated European type (V. vinifera) cultivars and their hybrids with V. labrusca had relatively low levels of extractable resveratrol in berry skin and seed, and the extractable amounts of resveratrol in berry skin and seeds were, with a few exceptions, <2 microg g(-1) of skin or seed FW. Extractable amounts of resveratrol in berry skin and seeds were closely related with fruit traits or purpose of uses and climate. Significantly higher extractable amounts of resveratrol in berry skin were found in seeded cultivars than in seedless ones, in both berry skin and seeds in winemaking grapes than in table grapes, and in red grapes than in green ones. Moreover, rainfall during fruit development resulted in higher extractable amounts of resveratrol in berry skin, whereas resveratrol synthesis and accumulation in grape seeds were not related to climate change.  相似文献   

15.
为探究水分胁迫对葡萄果实白藜芦醇合成的影响,本研究以赤霞珠为试验材料,对其进行不同程度水分胁迫处理,测定葡萄果实白藜芦醇含量及白藜芦醇生物合成相关基因表达量。结果表明,葡萄果实进入转色期,PAL、4CL、STS基因随白藜芦醇合成而大量表达;不同水分胁迫处理均能增加葡萄果实白藜芦醇含量,同时提高白藜芦醇合成相关基因的表达量,不同水分胁迫处理间存在差异;水分胁迫对果实转色前期和后期PAL、STS基因表达的促进作用最为显著,但水分胁迫显著降低了CHS基因的表达量。相关性分析表明,白藜芦醇含量与PAL、STS基因的表达量呈显著正相关,表明水分胁迫主要通过诱导PAL、STS基因表达来增加果实白藜芦醇含量。本研究结果为进一步阐明葡萄白藜芦醇合成调控机制奠定了理论基础。  相似文献   

16.
Oxidative stress can result in insulin resistance, a primary cause of type-2 diabetes. Methylglyoxal (MG), a highly reactive dicarbonyl metabolite generated during glucose metabolism, has also been confirmed to cause pancreatic injury and induce inflammation, thereby resulting in insulin resistance. Recently, resveratrol has been reported to exert antioxidant properties, protecting cells from the generation of reactive oxygen species (ROS). The aim of this study was to evaluate resveratrol activation of nuclear factor erythroid 2-related factor 2 (Nrf2) to attenuate MG-induced insulin resistance in Hep G2 cells. Therefore, the molecular signaling events affecting resveratrol-mediated heme oxygenase-1 (HO-1) and glyoxalase expression levels were further investigated in this study. Our findings indicated that resveratrol activated the extracellular signal-regulated kinase (ERK) pathway but not the p38 or c-Jun N-terminal kinase (JNK) pathways, subsequently leading to Nrf2 nuclear translocation and elevation of HO-1 and glyoxalase expression levels. Moreover, resveratrol significantly elevated glucose uptake and protected against MG-induced insulin resistance in Hep G2 cells. In contrast, depletion of Nrf2 by small interfering RNA (si-RNA) resulted in the abrogation of HO-1 and glyoxalase expression in the MG-treated resveratrol group in Hep G2 cells. Administration of an appropriate chemopreventive agent, such as resveratrol, may be an alternative strategy for protecting against MG-induced diabetes.  相似文献   

17.
In recent years an effort has been made to isolate and identify biologically active compounds that are included in the Mediterranean diet. The existence of naturally occurring acetylated phenolics, as well as studies with synthetic ones, provide evidence that acetyl groups could be correlated with their biological activity. Platelet activating factor (PAF) is implicated in atherosclerosis, whereas its inhibitors seem to play a protective role against cardiovascular disease. The aim of this study was to examine the biological activity of resveratrol and tyrosol and their acetylated derivatives as inhibitors of PAF-induced washed rabbit platelet aggregation. Acetylation of resveratrol and tyrosol was performed, and separation was achieved by HPLC. Acetylated derivatives were identified by negative mass spectrometry. The data showed that tyrosol and its monoacetylated derivatives act as PAF inhibitors, whereas diacetylated derivatives induce platelet aggregation. Resveratrol and its mono- and triacetylated derivatives exert similar inhibitory activity, whereas the diacetylated ones are more potent inhibitors. In conclusion, acetylated phenolics exert the same or even higher antithrombotic activity compared to the biological activity of the initial one.  相似文献   

18.
The roots of two varieties of Polygonum cuspidatum (Hu Zhang and Mexican Bamboo) were analyzed for resveratrol and analogues. The roots of each variety were dried and ground into a powder. The powdered roots were then extracted with methanol and ethyl acetate. The ethyl acetate fraction of the Mexican Bamboo was then subjected to fractionation and purification using silica gel column chromatography and semipreparative HPLC. In addition to resveratrol (3,5,4'-trihydroxystilbene), three stilbene glucosides were identified by (1)H NMR, (13)C NMR, and MS. The stilbene glucosides were shown to be a piceatannol glucoside (3,5,3', 4'-tetrahydroxystilbene 4'-O-beta-D-glucopyranoside), resveratroloside (3,5,4'-trihydroxystilbene 4'-O-beta-D-glucopyranoside), and piceid (3,5,4'-trihydroxystilbene 3-O-beta-D-glucopyranoside). The levels of the piceatannol glucoside and piceid were twice as high in the Mexican Bamboo as compared to the Hu Zhang.  相似文献   

19.
Piceid is widely used in food, cosmetics, and pharmaceuticals because of its therapeutic benefits. However, the use of piceid as a drug is limited because of its low solubility. To increase solubility, we synthesized piceid glucosides using maltosyltransferase from Caldicellulosiruptor bescii . The MTase gene was cloned and expressed in Escherichia coli . The enzyme had a unique transfer specificity to the transfer of maltosyl units. Four piceid transglycosylation products were present and identified by thin-layer chromatography and recycling preparative high-performance liquid chromatography. The major product was purified by C(18) and gel filtration chromatography, and its molecular structure was determined using nuclear magnetic resonance spectroscopy to be α-d-maltosyl-(1→4)-piceid. The solubility of maltosyl piceid was 8.54 × 10(3) and 1.86 × 10(3) times those of natural resveratrol and piceid, respectively, suggesting that the transglycosylation greatly increased the water solubility. This suggests that dietary intake of this compound can enhance the bioavailability of resveratrol in the human body.  相似文献   

20.
Pterostilbene, a natural methoxylated analogue of resveratrol, was evaluated for antioxidative potential. The peroxyl-radical scavenging activity of pterostilbene was the same as that of resveratrol, having total reactive antioxidant potentials of 237 +/- 58 and 253 +/- 53 microM, respectively. Both compounds were found to be more effective than Trolox as free radical scavengers. Using a plant system, pterostilbene also was shown to be as effective as resveratrol in inhibiting electrolyte leakage caused by herbicide-induced oxidative damage, and both compounds had the same activity as alpha-tocopherol. Pterostilbene showed moderate inhibition (IC50 = 19.8 microM) of cyclooxygenase (COX)-1, and was weakly active (IC50 = 83.9 microM) against COX-2, whereas resveratrol strongly inhibited both isoforms of the enzyme with IC50 values of approximately 1 microM. Using a mouse mammary organ culture model, carcinogen-induced preneoplastic lesions were, similarly to resveratrol, significantly inhibited by pterostilbene (ED50 = 4.8 microM), suggesting antioxidant activity plays an important role in this process.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号