Isolation,Identification Of Chemical Components And Biological Activities Of Neolignan Glycosides From Huangjinya Green Tea

Tea,is known as the "national drinking" in China,has a very long history in Chinese civilization.Green tea,made of leaf or bud plucked from the plant Camellia sinensis,without fermentation only by fixation,drying and other processes.Compared with other teas,it retains more natural components of fresh leaves,and contains more tea polyphenols,catechins,amino acids,caffeine,vitamins and other nutrients.These natural chemical ingredients in green tea have special effects on anti-aging,anti-cancer,anti-inflammatory,which are inferior to other teas.Huangjinya,a natural tea mutant,is one special light-sensitive albino cultivar(Camellia sinensis var.sinensis cv.Huangjinya),with albino shoots under sun-light conditions.The albino shoots will turn green under weak light conditions.These albino mutants have enhanced levels of free amino acids in its leaves,improving its drinking quality.Previous researches focused on the characteristics and underlying formation mechanism of albino tea,emphasized on the analysis of changes in transcriptome and proteome,and the expression of photoreceptor genes.This paper will focus on the analysis of the chemical components of Huangjinya green tea,and further explore the biological activity of new lignans.Neolignans are an important class of phenylpropanoids from many plant families and common foods,including grains,nuts,seeds,vegetables,and drinks including tea,coffee or wine.They are derived from the shikimic acid biosynthetic pathway and exhibit a wide range of pharmacological properties such as cytotoxic and antitumor,antioxidant,anti-inflammation,antipsychotic,neuroprotective,and anti-acetylcholinesterase activity.In the present study,Huangjinya green tea was ground and extracted respectively by petroleum ether,ethyl acetate and methanol with Ultrasonic.A new 8-O-4?-type neolignan glycoside,camellignanoside A,together with 15 known compounds(2-16)were isolated and identified by MCI,Sephadex LH-20,silica,Toyopearl HW-40 F and HPLC column chromatography.Their structures were determined by analyses of their high resolution mass(HR-MS),one and two dimensional nuclear magnetic resonance(1D and 2D NMR),infrared(IR)and circular dichroism(CD)spectroscopic data as well as comparison with those in literature.Alzheimer's disease(AD)is an irreversible neurodegenerative disorder and the leading cause of dementia,usually associated with neuron loss in the central nervous system.Acetylcholinesterase inhibitors(ACh EI)are considered as one effective approach to treat AD by inhibiting the activity of ACh E.Tea polyphenols esp.hydroxycinnamoylated catechins were reported to show strong ACh E inhibition activity.As such,we also tested the ACh E inhibitory activity of 1 and 2,indicating that 2 showed stronger while 1 showed less inhibition against ACh E than the positive ACh EI huperzine A(hup A).