Studies On The Changes Of Resveratrol And Piceid During The Growth And Post-harvest UV Treatment Of Grape

Resveratrol (trans-3, 4', 5-trihydoystilbene), as a phytoalexin, exists in berry peelof most grapes cultivars and its synthesis was stimulated by the UV ray, fungal infectionand mechanical injury. Recently, more and more researches proved that resveratrol hadmany beneficial effects on human health, such as reducing the risk of coronary heartdisease, inhibiting platelets aggregation and low-density lipoproteins oxidation. The relationships between the changes of resveratrol, piceid and relevant enzymaticactivities during the development of grape were studied, taking the fruits of Merlot, BacolNoir, Yan73, Carbernet Gernisch Rkatsiteli grapes as experimental material. The effect ofUV treatment on the changes of resveratrol and piceid and relevant enzymatic activities inpost-harvest grape was discourvered. The main results gained in this study were asfollows: 1. The testing methods of resveratrol and piceid in grape were determined by meansof high performance liquid chromatography(HPLC). The isocratic elution condition Iwas suitable to trans-resveratrol test, and both isocratic elution condition II and gradientelution condition were fit methods for trans-resveratrol test, cis-resveratrol and its piceid.The testing method of cis-resveratrol, trans-resveratrol and piceid was determined too. 2. The optimum extraction condition of resveratrol in grape with a high recovery wasdetermined by orthogonal design, i.e. sample was extracted with 60% methanol for 6 h,purified through a solid-phase extraction column, then dissolved in the solution of 50%methanol. 3. The trends of resveratrol and piceid chages in different grape cultivars weredifferent during the development of fruit. The chages of resveratrol and its piceid contentin Carbernet Gernischet was a curve of double peaks. The content of resveratrol inRkatsiteli slowly decreased, whereas its piceid gradually increased during thedevelopment of fruit. 4. It was frist time that the relationships among resveratrol and its piceid andphenylalanineammonia-lyase(PAL), and β-glucosidase, had been studied during thegrowth and development of grape. The PAL activity in Rkatsiteli was lower, anddecreased gradually as the fruit grew, which in Carbernet Gernischet increased andappeared an obvious peak in the chromatogram. There was a positive correlation betweenPAL activity and the formation of resveratrol. The β-glucosidase activity in CarbernetGernischet and Rkatsiteli was at high level in the early stage of the fruit development andthen decreased rapidly. It was postulated that this kind of chage of β-glucosidase probablyattributed to the enzymatic hydrolysis of piceid indican into resveratrol. The Peroxidase(POD) activity hadn't been tested during the fruit development of grape. 5. The enzymatic activities of PAL and POD could be stimulated by UV radiation ingrape. In the treatment of Carbernet Gernischet by UV radiation for 200 s and thenstoring for 48 h at 30℃, the maximum concentrations of resveratrol could be increase upto seven times of that in the contrast. But β-glucosidase activity and piceid had not beenchecked in grape after the treatment of UV radiation.