Correlation Among Color Values,functional Components And Antioxidant Activities In Loquat(Eriobotrya Japonica) Leaves

Loquat(Eriobotrya japonica)is a kind of subtropical evergreen tree,its leaves can be used as the raw materials of traditional Chinese medicine because of pharmacological activities.There are different kinds of Loquat varieties,and can be picked all year round,the leaf function is affected by many factors.In this study,loquat leaves in Ankang area of were collected with different cultivars,different leaf positions and different periods.While 3antioxidant activities,3 color parameters and 12 functional component contents of leaves were determined.The effects of cultivar,leaf position and period on the utilization value of loquat leaf were analyzed by variance analysis and principal component analysis.At the same time,the functional evaluation and variety identification of loquat leaf were explored by discriminant analysis,correlation analysis and regression analysis based on the color parameters of loquat leaf.The main results are as follows:(1)Leaf position,variety and harvest period had certain effects on the quality fraction of functional components and antioxidant activity of loquat leaf.The mass fraction of new chlorogenic acid and chlorogenic acid showed a rapid decreasing trend with the increase of leaf position in the leaves of 6 cultivars in December,while the mass fraction of corosolic acid showed an obvious increasing trend.In the same period,the content of 8 functional components and 3 antioxidant activities of‘Dawuxing’loquat leaf were significantly higher than other cultivars.The contents of rutin chlorogenic acid and isoquercetin in 4 varieties of loquat leaves which collected in March was significantly higher than that in December,June and September.(2)Functional indexes of loquat leaf in 4 periods,4 cultivars and 5 leaf positions were comprehensively analyzed.The comprehensive evaluation of‘Dawuxing’loquat leaf was the highest.The higher the leaf order value,the better the comprehensive evaluation.The comprehensive evaluation of loquat leaves harvested in March was the best.(3)The color parameters of loquat leaves showed a trend of change with the increase of leaf order.The color parameters of loquat leaves at different leaf positions of each cultivar were correlated with the content of functional components and antioxidant activity.The quadratic,cubic and composite curves have good fitting effect on items with correlation coefficient higher than 0.7 of each variety.Eleven regression equations with R~2 between0.575 and 0.718 were established,and the regression equation was significant.(4)The color parameters of loquat leaves of 6 cultivars were different in the same period.Three discriminant functions was established based on the color parameters of 9th leaves,and this group of functions can explain 100%variance changes and can be used to identify 6 varieties.These results provided a theoretical reference for the standard collection of loquat leaves and the efficient rational utilization of functional components and antioxidant activities in loquat leaves.