Identification Of The Flavonoid Compounds And Evaluation Of The Anti-oxidant Of Blue Honeysuckle (Lonicera Cearuiea L.) Leaves

Blue honeysuckle,which is known as honeyberry and haskap,is a shrub small berry,belonging to Caprifoliaceae,Lonicera.Its leaves are symmetrical and oval in shape and large in growth.Blue honeysuckle has rich germplasm resources.Planting area of Blue honeysuckle expands year by year.Blue honeysuckle becomes more and more popular due to its fruit with abundant anthocyanins.Its leaves are very valuable in terms of research and utilization which contain rich flavonoids,and its antioxidant activity is even higher than the fruit.Exploring the functional components and availability of these waste leaves would effectively improve the income of blue honeyberry grower,and strongly supplement people's needs of natural polyphenol products.In this work,the flavonoids composition in the leaves at different periods of 20 blue honeysuckle varieties at the Small Berry Germplasm Nursery in Northeast Agricultural University were analyzed using HPLC-MS,and the in vitro antioxidant activities of leaves extracts were determined to evaluate antioxidant capacity,and then take data statistical analysis.The results as fallows:(1)11 flavonoids were detected in the leaves of blue honeysuckle,they are Quercetin 3-O-sambubioside,Kaempferol 3-O-sambubioside,Quercetin 3-O-rutinoside,Kaempferol 3-O-rutinoside,Quercetin 3-O-galactoside,Kaempferol 7-O-rutinoside,Kaempferol 3-O-neohesperidoside,Isorhamnetin 7-O-rutinosede,Apigenin 7-O-rutinoside,Quercetin 3-O-rhamnoside,Diosmetin 3-O-rutinoside,Diosmetin 3-O-glucoside.(2)The number of flavonoid glycosides in leaves among different varieties of Lonicera caerulea L..11 flavonoid glycosides were detected in the variety of ‘A2',and only 5 species were detected in ‘HSY-2',and among the leaves of most cultivars,flavonoid glycosides were between 8 and 9.(3)The composition,content and variation of flavonoid glycosides in leaves of different cultivars were different,as well as the best harvest period.The appropriate harvest time for ‘Bluebrid' is early June,and the best harvest period for ‘HSY-6' and ‘A1' is late June in the three representative cultivars.(4)Based on the two methods of DPPH and FRAP,the antioxidant activities of leaves of 20 cultivars were analyzed at different growth stages and the results showed that the antioxidant capacity of leaves which collected in early June and late July was significantly stronger than that in late September.Among the varieties with high antioxidant activity were ‘brilliant',‘HSY-2',‘HSY-6' and ‘Japan-5',which can be used as a good source of natural antioxidants.The correlation analysis showed that the content of flavonoids in leaves of blue honeysuckle was positively correlated with antioxidant activity.The higher the flavonoid content in the leaves,the stronger the antioxidant activity of the leaves.