The Study On Flower Colors And Anthocyanins Of Tree Peony

Tree peony is well-known in China, be named as"Wan Hua Yi Pin"and enjoy the honor of"The King of Flowers". Flower color is one of the most important ornamental characters of tree peony . Anthocyanidins is material basis of forming flower colors of tree peony and have potential practical values bacause of many physiological activeties. The flower colors, anthocyanins, the relationship between them of Zhongyuan tree peony cultivar-groups were studied.The optimum conditions of the purification of anthocyanins from tree poney flowers were determined by the method of macroporous adsorbtion resins and the antioxidant activity of extract and anthocyanins from tree peony flower were assayed. The results were as follows:1.The flower colors of 94 cultivars of Zhongyuan tree peony were measured by a NF333 spectrophotometer based on the International Commission on Illumination(CIE) color system. CIE color system L*, a* and b* were cluster analysed by CLUSTER process using Ward square sum of deviations. The results indicated that Zhongyuan tree peony was classified into nine color series ,such as , white(20), green(1), pale red and blue(8), pale red(13), pale blue(12), red(14), purple(11), reddish purple(7) and reddish black(8). And it showed the features of the values of L*, a* and b* of different color tree peony. The relationship between L* and a*, and L* and C* were showed obviously negative correlation of white, light pink, pale red, red and pale blue, purple , reddish purple tree peony ( the correlation coefficient between L* and a* were 0.9703 and 0.6067, L* and C* were 0.8519 and 0.714). Most flower color tree peony( except red and reddish black) had notebility positive correlation between L* and b* (R2 0.8653).2. The total content and varieties of anthocyanins and the relative abundance of anthocyanin monomers in the petals of 48 cultivars of Zhongyuan tree peony were analysed by HPLC-DAD-ESI-MS. Five anthocyanins extracted from Zhongyuan tree peony were respectively cyanidin-3,5-di-O-glucoside(Cy3G5G), cyanidin-3-O-glucoside(Cy3G5G), peonidin-3,5-di-O-glucoside(Pn3G5G), peonidin-3-O- glucoside(Pn3G) and pelargonidin-3,5-di-O-glucoside(Pg3G5G), except for pelargonidin-3-O-glucoside(Pg3G). The variation range of total content of anthocyanins in 48 cultivars tree peony was 0~289.5mg/100g. The diversity of relative abundance of anthocyanin monomers in different color tree peony was obvious, and the major anthocyanins in pale red and red cultivars were Pg3G5G (respectively, 88.09 and 79.06%), belongs to PgPn and in pale blue, purple, reddish purple and reddish black cultivars Pn3G5G was major (respectively, 88.35,82.19 and 75.65,72.74%), belongs to PnCy. The relative abundance of cyanidin was bigger in reddish purple and reddish black cultivars. The relationship between flower colors and anthocyanins of tree peony was analysed, which indicated that the bright value(L*) and total anthocyanins(TA) had obviously negative correlation, and no correletion in PnCy type between a* and TA, or b* and TA but in PnPg tree peony between a* and TA displayed positive correlation, and no relation between b* and TA.3. The static adsorption characters of a variety of macroporous adsorption resins were studied, a resin fitted to purify peony anthocyanins was selected and the process parameters of Fixed-bed adsorption and desorption were determined. The results indicated that the adsorptive capacity and the rate of desorption of 3 resins D-101, D-401 and D-1300 were higher than others. The adsorption kinetics behavior was accord with the secondary adsorption rate equation and the adsorption isotherm curves could be described by Langmuir equation of the three macroporous resins. D-1300 was chosen to purify peony anthocyanin because at the same conditions the saturated adsorption amount was higher than other 2 resins. The breakthrough curve experiment data of D-1300 on anthocyanin was fitted by the Bohart-Adams equation, and the fitted formula can calculate breakthrough time of anthocyanins in given conditions. The optimum conditions of dynamic adsorption by D-1300 were as follows: the sample concentration, 0.141mg·mL-1; flow velocity, 2BV·h-1; eluent solvent, 60% ethanol; eluent velocity, 2BV·h-1. The purity of anthocyanins was increased from 0.31% to 20.05% at the conditions mentioned above.4. Anthocyanins from 48 cultivars of tree penoy flowers were extracted with methanol. Antioxidant activities were determined by the ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH·) methods. The results showed all clutivar extracts exhibited different DDPH·scavenging capacity and the reducing power, however, varying within a wide range, respectively 8.45~33.46,19.73~74.86 mg Vc/100g Petal fresh weight. Reducing power was highly correlated with DDPH·scavenging capacity (R2=0.9396). Antioxidant activities of partial puried 'Luo Yang Hong'anthocyanin (LYHA) were further evaluated. It is found that DDPH·scavenging capacity of LYHA (IC50=96.28μg·mL-1) was higher than rutin and significantly lower than ascorbic acid, while its reduing power was much greater than rutin and equal to ascorbic acid. Also, LYHA at 0.1~500μg·mL-1 inhibited oxidative damage of Bovine Serum Albumin(BSA) induced by hydroxy radical in a concentration-dependent manner. However, rutin and ascorbic acid showed prooxidant activity towards BSA at high concentrations.