Study On The Biological Activity Of Extracts From Samara Of Acer Truncatum

Acer truncatum Bunge,known as Yuanbaofeng in China,is a plant belonging to Aceraceae family.The tree is one of the main species of the red-leaf trees in the hardwood forests of China.It is rich in nervonic aicd which is essential for the development of the brain and significantly contributes to enhanc the activity of brain nerves and protected brain nerves from against.The essential oil obtained from the samara of A.truncatum using soxhlet and ultrasonic extraction methods,was analyzed by GC-MS for the first time and 50 compounds were detected.The main constituents were lipids,aldehydes,acids and terpenoids.The n-hexane,CH2Cl2,EtOAc,n-BuOH and H2O fractions were obtained by extraction of A.truncatum samara 95%EtOH extracts using organic solvents of different polarity.The contents of total polysaccharides,total phenolics,total tannin and total flavonoids of each fractions were measured by UV-Spectrophotometric method.The result showed that the contents of above ingredients were higher in n-BuOH,H2O,and EtOAc fractions.In order to evaluate the antioxidant activity,DPPH,ABTS,hydroxyl radical scavenging assays and reduction were carried out.The results showed that all soluble fractions showed somewhat oxidative activities,and n-BuOH and H2O fractons presented the most significant effects.However,n-hexane and CH2Cl2 fractions displayed the worst antioxidative property.Antibacterial activities of the 95%extract and fractions were analyzed were analyzed against Bacillus subtilis,Staphylococcus aureus,Corynebacterium glutamicum,Escherichia coli and Salmonella enteric by double dilution method.Results showed that the EtOAc and n-BuOH fractons have the best antibacterial activity.However,Cl2CH2 and n-hexane fractions didn’t show any antibacterial activity.All fractions and 95%extract presented a certain degree of thermal stability.Inhibition rate gradually increased with temperature,and antibacterial activity gradually decreased when the temperature exceeded 100℃.In this work,extractives from the n-BuOH fraction of A.truncatum samara were systematically isolated and separated by column chromatography and TLC,which led to the purification of three flavonoid glycosides:quercetin-3-O-α-L-rhamnopyranoside(Ⅰ),myricetin-3-O-α-L-rhamnopyranoside(Ⅱ)and quercetin-3-O-β-D-glucopyranoside(Ⅲ).The chemical structures of the three flavonoid glycosides were elucidated by spectroscopic and chemical analysis.All of them was identified from the samara of A.truncatum for the first time.Plackett-Burman combined with Central Composite Design response surface design was adopted to study the optimized parameters in order to increase the polyphenolic yield of of A.truncatum samara.Through complete quadratic response surface regression fitting of independent variables and the dependent variable,optimum technology was determined by intuitive analysis of 3D surface chart,and predictive analysis was used.Optimum extraction technology was as following:extraction time of 1.27 h,ethanol concentration of 55.28%and ultrasound extraction time of 19.23 min.The deviation between observed and predicted values was-0.93%.This optimized process was simple,accurate,reproducible with good predictability.