Study On The Purification,Components Analysis And Biological Activity Of Anthocyanin And Volatile Oil From Dendrobium Nobile Lindl.Flower

Dendrobium nobile Lindl.,the genus of Orchidaceous,is traditional Chinese medicine.The flowers of Dendrobium nobile Lindl.are gorgeous and colorful,which have a high medicinal value.In this thesis,extraction,purification,composition analysis,stability,antioxidant activity and antimicrobial activity were systematically studied and results were as follows:On the basis of single factor experiment,optimum conditions of anthocyanin extracted from Dendrobium nobile Lindl.flower by orthogonal experiment design were: solvent:acidified ethonal concentration 70%,temperature: 60?,solid-liquid ratio: 1:100,pH: value:1.0.Optimum conditions by response surface methodology were: temperature: time: 50.31 min,60.80 ?,power: 221.86 W,respectively.Based on the pre-experiment,macroporous resins were used in separating and purifying pigments of Dendrobium nobile Lindl.flowers.The experiments were carried to determine the optimum resin and parameters which the adsorption ratio and desorption ratio were indexes.The results showed that AB-8 resin offered better adsorption and desorption capacities for anthocyanins than other resins and the optimum parameters for adsorption and desorption were as follows: for adsorption were: flow rate 2 BV/h,sample concentration 125?g/mL and for desorption were: flow rate 2 BV/h.The color value increased by 7.76 times.The components of anthocyanin in the flower of Dendrobium nobile Lindl.were identified by UV-vis,IR and high performance liquid chromatography-mass spectrometry?HPLC-MS?.The results showed that thirteen anthocyanins were identified-mainly cyanidin.The essential oil was extracted by SD and SPME and then analyzed by GC-MS.The results showed that 69 compounds were identified.Sixty-three and twenty-four compounds extracted by SPME and SD were recognized respectively,which representing 80.49% and 54.92% of the total volatile oil.The main components were limonene?25.87%?,tetrahydrocitral?11.10%?,terpinene?8.70%?,2-furancarboxaldehyde?6.51%?,hexyl formate?2.12%?,linoleic acid?36.92%?,heptane?7.69%?,tetradecanoic acid?3.51%?,methyl linoleate?2.12%?,etc.The stability properties of Dendrobium nobile Lindl.flower showed that anthocyanin was sensitive to the pH value of the solution.As pH value increased,the color of solvents changed from red to blue.The pigment was stable under the 4?,25?,Cu²⁺,Na⁺,and unstable under the pH value,ascorbic acid,sucrose solution,Fe2+ and Fe3+,etc.The antioxidant activity showed that the EC50 values of DPPH radical scavenging activity of anthocyanins,volatiles and Trolox were 159.92 ?g/mL,868.42 ?g/mL and 33.17 ?g/mL,respectively.The EC50 values of ABTS radical scavenging activity of anthocyanins,volatiles and Trolox were 524.84 ?g/mL,374.92 ?g/mL and 33.55 ?g/m L,respectively.The antimicrobial activity of anthocyanins and volatiles showed that the degree of anti-bacteria activity of anthocyanins was: Bacillus subtilis > Staphyloccocus aureus > E.coli.The anti-bacteria activity of volatile components was: E.coli > Staphyloccocus aureus > Bacillus subtilis.