Key Bioactive Substances And Their Antioxidant Activities In Cyclocarya Paliurus Leaves Collected From Natural Populations

Cyclocarya paliurus is a multiple-function tree species with timber,ornamental and medicinal utilization.However,recently the most utilization of C.paliurus the in the market is to collect its leaves to make nutraceutical tea with health benefits.This paper investigated the contents of total flavonoids,total triterpenoids,total polyphenols,rude polysaccharides and their antioxidant activities of the leaves of C.paliurus collected from 34 natural populations by water extraction,and analyzed the correlation between the contents and antioxidant activities.The objective of the present study is to select the superior provenance s or natural populations of C.paliurus for medicinal purposes base on their contents of key bioactive substances and their antioxidant activities.The main conclusions are as follows:(1)The contents of the flavonoids,triterpenoids,polyphenols and polysaccharides exhibited significant variation in extracts of leaves of C.paliurus collected from different natural populations.The total flavonoids content in the leaves ranged from 2.85 mg/g-10.45 mg/g,while the contents of total triterpenoids,the total polyphenols and the rude polysaccharides ranged from2.62 mg/g-14.33 mg/g,4.96 mg/g-26.44 mg/g and 55.07 mg/g-103.96 mg/g,respectively.The cluster dendrogram indicated that the 34 natural populations were classified into 4 distinct groups for total flavonoids,5 distinct groups for total triterpenoids,4 distinct groups for total polyphenols and 4 distinct groups for rude polysaccharides respectively based on their contents in the leaves.The comprehensive analysis of the populations with high content of key bioactive substances among populations is Anhui Jixi(AHJX),Guizhou Shijie(GZSQ),Hubei Hefeng(HBHF)and Hubei Wufeng(HBWF).There were also significant variations in the contents of the key bioactive substances in extracts of the individual plants within the natural population(Sichuan Muchuan,Jiangxi Xiushui,Hunan Yongshun).The best individials with high content of key bioactive substances are No.26 and No.29 within Sichuan Muchuan population,No.2 within Hunan Yongshun population,and No.8 within Jiangxi Xiushui.(2)The antioxidant activities exhibited significant variation in extracts of leaves of C.paliurus collected from different natural populations.Among them,the best population with the highest DPPH free radical scavenging ability is Gui Zhou Shi Q ian(GZSQ),with an IC50 value of0.88 mg/ml.The population with best ABTS~+free radical ability is also Gui Zhou Shi Q ian(GZSQ),with an IC50 value of 1.16 mg/ml,and the strongest total reducing population is Sichuan Muchuan(SCMC),with the absorbance valueof 0.78 at a concentration of 2.4 mg/ml.The comprehensive analysis showed that the populations with strong antioxidant activities among populations are Guizhou Shi Q ian(GZSQ),Hubei Hefeng(HBHF)and Hubei Wufeng(HBWF).There were also significant variations in the antioxidant activities in extracts of the individual plants within the natural populations(Sichuan Muchuan,Jiangxi Xiushui,Hunan Yongshun).The superior individials with strong antioxidant activities are No.4 and No.29 within Sichuan Muchuan population,No.2 within Hunan Yongshun population,and No.7 and No.8within Jiangxi Xiushui.(3)Correlation analysis showed that there was a significant positive correlation between total flavonoids,total triterpenoids,total polyphenols and rude polysaccharides,and these key bioactive substances were also significantly and positively correlated with DPPH free radical scavenging activity,ABTS~+free radical scavenging activity and total reducing power.Combined with the difference of key bioactive substances contents and antioxidant activities in natural populations and individual plants,that selected the superior provenances or natural populations of C.paliurus for medicinal purposes are Anhui Jixi(AHJX),Guizhou Shi Q ian(GZSQ),Hubei He Feng(HBHF)and Hubei Wufeng(HBWF),the superior individual plants are Sichuan Muchuan No.4、No.26、No.29,Hunan Yongshun No.2,Jiangxi Xiushui No.7 and No.8.