Comparative Studies On Distributions And Antioxidant Activities Of Three Different Forms Of Phenolic Compounds In Lonicera Japonica And L.macranthoides

Lonicera japonica Thunb.and L.macranthoides Hand.-Mazz.belong to the family Caprifoliaceae,which are widely distributed in most areas of China and have a long history of medicinal use in Chinese traditional medicines.In the Chinese Pharmacopoeia,dried flower buds of L.japonica is also called’Jinyinhua’,while that of L.macranthoides is one of the four kinds of ’Shanyinhua’,but both have the effects of clearing heat-toxin and heat dissipation.Different classifications have spawned different demands in the medicine market,so the price of Jinyinhua is high and that of Shanyinhua is low.In this study,the free,esterified and insoluble-bound phenolics of L.japonica and L.macranthoides were qualitatively and quantitatively determined combined with common antioxidant activity assays(DPPH,ABTS and ORAC)and supercoiled DNA oxidative damage protection to systematically elucidate and compare the phenolics and antioxidant activities of the flowers,stems and leaves of the two.The main results are as follows:In the qualitative and quantitative tests of phenolics,the free phenolic fractions in the three organs of the two plants had the highest total phenols and total flavonoids contents.In L.japonica,the total phenols and total flavonoids contents of flowers was higher than those of leaves and stems,while those in leaves of L.macranthoides was the highest.10 major phenolics including chlorogenic acid(3-CQA)and its five derivatives(4-CQA,5-CQA,3,4-diCQA,3,5-diCQA and 4,5-diCQA),three flavonoids(luteoloside,lonicerin,and isoquercitrin)and caffeic acid were qualitatively and quantitatively determined by high performance liquid chromatography(HPLC)and ultra performance liquid chromatography-mass spectrometry(UPLC-DAD-QTOF-MS/MS),wherein the chlorogenic acids was only present in free phenolic fractions.In addition,total phenols and total flavonoids contens as well as 10 quantitative phenolics contents of L.macranthoides were superior to L.japonica in multiple organs and fractions.In the determinations of antioxidant capacity,DPPH and ABTS free radical scavenging abilities and oxidative free radical absorption capacity(ORAC)of free phenolic fractions were significantly higher than those of esterified and insoluble-bound phenolic fractions.The effects of each fraction on the protection of supercoiled DNA damage showed a dose-dependent effect,and the protection of free phenolic fractions was better.From the interspecific level,the phenolic fractions of L.macranthoides showed better performance than L.japonica in three kinds of antioxidant capacity assays and DNA damage protection determination.In conclusion,L.macranthoides has great potential in the field of natural antioxidants and should be paid more attention in the pharmaceutical market.