Content Analysis Of Functional Components In Mulberry Leaves From Different Areas And Study On The Biological Activity Of Mulberry Leaves In Vitro

Mulberry leaf is a traditional Chinese medicine which is rich in phenols and alkaloids active compoments.There are many reports regarding the use of mulberry leaves for antioxidation activity,hypoglycemic activity,anti-inflammatory,anti-tumor,weight loss and beauty care and other medical and health functions.It has been applied in food,medicine and healthy product fields and has a wide application prospect.In this paper,a new HPLC-ESI-MS method was bulid to determine the phenols and alkaloids.The optimized method could identify 5 phenols at the same time.Additionally,the total phenolic and total flavonoid contents,antioxidant and glycosidase inhibitory activities were tested to comprehensively evaluate the quality of the mulberry leaves.The principal component analysis was used to determine the internal relations between different parameters in order to screen out the producing areas suitable for health products and pharmaceutical industry.The rresults of the study are as follows:1.The mass spectrometry behavior of 5 phenols and DNJ and fagomine under the ESI ion source were analyzed and the mass spectral conditions were optimized.Then a new HPLC-ESI-MS method was established which could separate 5 kind of phenols within 45 min simultaneously.The method for separating DNJ and fagomine was achieved by using an amino column,and a new HILIC-MS/MS method was established,which could avoid the uncertainty and tedious procedure of derivatization and shorten the time of separation.DNJ and fagomine could be separated.The stability and feasibility of the methods were vertified.2.The active components of the mulberry leaves collected in autumn from 8 main sericulture regions were qualitatively and quantitatively analyzed by the new method.Additionally,the content of total phenol and total flavonoids were measured,and the effects of different producing areas on the content of active components and total flavonoids of total phenols were also explored.The results showed that 7 components of fagomine,DNJ,chlorogenic acid,isoquercetin,rutin,quercetin and kaempferol were separated in the extract of mulberry leaves,of which the contents of kaempferol and quercetin were too low to be quantified.The content of chlorogenic acid relatively high which could reach 10.050 + 0.143 mg/g,the contents of most of the samples were distributed in 2-8 mg/g.The contents of DNJ,fagomine and phenols were significantly effected by regions.The contents of DNJ and fagomine in samples from Guangdong were relatively high and the content of fagomine in samples from Fuling were the highest.Therefore,these two areas can be used as the main production areas of DNJ and fagomine in autumn.The contents of phenols in samples from Guangdong,Guangxi,Chongqing and Anhui were relatively higher,so were the contents of total phenol and total flavonoids.Therefore,these 4 regions can be recognized as the dominant producing areas of phenols and flavonoids.3.The antioxidant antivity and α-glucosidase inhibition activity of samples from different collecting areas were evaluated.In order to compare the antioxidant activities of different samples,DPPH assay,ABTS assay,FRAP assay were used to analysis.The results showed that mulberry leaf had good antioxidant activity and glycosidase inhibition activity,but there were differences among samples from different collecting areas.The results of three different assays of Guangdong,Guangxi,Chongqing and Anhui were higher than those of other collecting areas,so Guangdong,Guangxi,Chongqing and Anhui were suitable for planting mulberry leaves used in antioxidant application.The glycosidase inhibition ability of Jiangxi was the highest,followed by Guangdong and Guangxi.It was presumed that there were other active components in the extract of mulberry leaves also had the ability to inhibit glycosidase or there was synergistic effect among different components in the inhibition ability of glycosidase.In a word,the content of DNJ and fagomine could not represent of the glycosidase inhibition ability of samples.4.Principal component analysis was carried out depend on previous data.The results showed that PC 1 represented the data related to antioxidant activity and PC 2 represented the content of DNJ.It can be found that the contents of chlorogenic acid,isoquercitrin,rutin,and total phenolic flavonoid content were mainly related to the antioxidant activity.However,the α-glycosidase inhibitory capacity was not highly correlated with DNJ content and fagomine content,indicating that the α-glycosidase inhibitory ability of mulberry leaves was not determined solely by these two component.The α-glycosidase inhibitory capacity might be related to other active ingredients and the interrelated interactions among active ingredients in mulberry leaves.