The Determination Of Composition And Construction Of Chemical Fingerprints In Buckwheat

Buckwheat (Fagopyrum esculentum and Fagopyrum tataricum) is a dicotyledons of the polygonaceae family, including two main cultivated species:Fagopyrum esculentum and Fagopyrum tar tar icum).Buckwheat (Fagopyrum tataricum) is a minor grain crop in China. Buckwheat is widely distributed in the regions of northeast, north, northwest and southwest. In the middle Yellow River regions, concentrated areas of northern buckwheat is in the Middle Inner Mongolia. In the Upper Yangtze River, buckwheat is mainly growing in high altitude areas. Commmon buckwheat distributed in the low-lying areas of middle Yangtze River. Common buckwheat and buckwheat both have high nutritional value, not only protein, fat, vitamins,trace elements and others, but also flavonoids, fatty acids, steroids, cyclitol and other bioactive substances. The main purpose of this research was to investigate theβ-sitosterol,HPLC fingerprint and antioxidant activity of buckwheat.1,This research was to set up an exact method to determingβ-sitosterol in buckwheat by HPLC (High Performance Liquid Chromatography). By the method, we testedβ-sitosterol contents of 34 different varieties of buckwheat in Sichuan, Yunnan and other districts. The results of HPLC showed that:The P-sitosterol content of tartary buckwheat in 34 cultivars was within the range of 4.1～65.3 mg/100g,β-sitosterol content in various buckwheat varieties were quite different. Theβ-sitosterol content of tartary buckwheat in different parts was compared, the highest is bran(116 mg/100 g), the lowest is center flour.2,Established a fingerprints of buckwheat by HPLC.The substances extracted with methanlo was studied, which were in the 34 different varieties of buckwheat from Sichuan, Guizhou and other districts. Taking acetonitrile-0.3% phosphoric acid as mobile phase in a gradient program,fingerprint was established. The results demonstrated that various species of common buckwheat performed 12 peaks and different varieties of buckwheat exhibited 10 peaks.Common buckwheat and buckwheat fingerprints can be separated apparently. The 10 peaks of the buckwheat are characteristic peaks, and represented the main features of methanol extract of buckwheat, which can be used to identify the origins of buckwheat and provide references for quality controlling. It also showed the various buckwheat varieties exhibited the similar characteristic peaks and the differences were main in the peak area.3,Antioxidant activity of 40 buckwheat varieties were tested in vitro. Determined the DPPH radical elimination rate, flavonoids, and fingerprints of 40 tested products.The data of DPPH antioxidant activity system and two different components were dealed with correlation analysis and linear regression. It showed that taking IC50 antioxidant capacity as an indicator, the IC50 value of buckwheat ranged from 6.7 to 14.1 and the IC50 value of common buckwheat ranged from 23.7 to 59.5.The results that the IC50 value of buckwheat is lower than common buckwheat, indicated that the antioxidant capacity of buckwheat stronger than common buckwheat (p<0.01). Flavonoid in buckwheat ranged from 0.3345 mg/ml to 0.714 mg/ml and it in common buckwheat ranged from 0.0056 mg/ml to 0.0103 mg/ml, which indicated that flavonoid in buckwheat was more than common buckwheat. The IC50 value as abscissa, and the content of flavonoid as ordinate, tested the correlation between IC50 and flavonoid.The final result was R2=0.7672; The antioxidant as dependent variable Y, the eight common peak area of buckwheat fingerprint as independent variable X, multiple linear regression equation was acquired using stepwise regression analysisY=9.97534491+0.000019467871103X1-0.00009931806499X3+0.00007380263883X4-0.00 0005816347270X5+0.00006563684762X6+0.000003346261718X7-0.00015529781630X8, (R=0.74072, P=0.0099<0.01), were significantly different, the partial correlation of X1, X3, X4, X5, X6, X7, X8 were 0.41130,-0.53245,0.40065,-0.44428,0.46648,0.29449,-0.56531, 2#peak (unknowns) contributed slightly to the antioxidant activity of buckwheat,The effect of 5#peak (rutin) for the DPPH radical scavenging was significant.3#peak (unknowns) and 8#peak (kaempferol) can be regarded as standards for quality controling of buckwheat varieties.