Components,Stability And Physiological Activity Of The Pigment Of Dalbergia Bariensis Heartwood

Dalbergia bariensis becomes popular after the depletion of Dalbergia odorifera,Dalbergia cochinchinensis,P.santalinus.Dalbergia bariensis is used to manufacture rosewood furniture,handicrafts and so on for a long time,small-sized wastes such as shavings and sawdust are produced,which are often burned as heating source,resulting in great waste.In this paper,pigment was extracted from the heartwood shavings of Dalbergia bariensis and the optimum extraction process was explored.The main components and contents of the pigment were identified by UV and UPLC-MS.The stability and physiological activity of the pigment were explored.The main conclusions are as follows.1.Ethanol was chosen as the extracting solvent,UV-VIS was used to scan the whole wavelength of the pigment solution.According to the position of the peak,the main components of the pigment were identified as flavonoids.470 nm was used as the wavelength to measure the absorbance of the pigment.Ultrasound-assisted method was selected to extract the pigment from 60 mesh Dalbergia bariensis powder by 100W ultrasonic at room temperature.The results of single factor and orthogonal experiments showed the influencing order of the factors was ethanol concentration,time,material-liquid ratio.The best extraction technology of the pigment was obtained as follows:ethanol solubility70%,30 min,material-liquid ratio 1:50?g/ml?,the extraction rate reached22.92%.2.UPLC-Q-EXCTIVE-MS was used to isolate and identify the components of the pigment.The results showed that there were 18 flavonoids in the pigment:orientin,puerarin,vitexin,isorhamnetin,pelargonidin,hispidulin,chrysin,glycitein,cirsimaritin,sakuranetin,naringin,genistein,malvidin,diosmetin,medicarpin,formononetin,maackiain and 6-Hydroxyflavone.The relative content of formononetin was 2.27%.The relative content of diosmetin was0.18%.3.The stability of the pigment was studied.The results showed that long-term UV irradiation and heating deepened the color of the pigment,but made no discoloration.The pigments faded slowly and remained stable after the first two or three days of natural light exposure.The pigment were strongly influenced by some metal ions and pH.K⁺,Na⁺,Ba²⁺,Ca²⁺,Mg²⁺had almost no effect on the pigment.Al³⁺had a colour enhancement on the pigment and generated a small amount of yellow complexes.Gr⁶⁺,Cu²⁺,Fe³⁺had a great damage to the pigment,which would make the pigments discolored and precipitate.The stability of pigment was good under acidic conditions,and had a certain color enhancement effect.The stability of pigment was poor under alkaline conditions,and the pigment precipitated after pH>9.4.The antioxidant activity of the pigment was studied through DPPH and ABTS methods.The results showed that the pigment had antioxidant activity which was weaker than Vc.The DPPH·scavenging rate of the pigment was87.25%at 160 mg·L^-1.The free radical scavenging rate of ABTS·reached63.73%at concentration of 1400 mg·L^-1.The antimicrobial activity of the pigment was investigated.The results showed that the minimum antimicrobial concentration of the pigment against Escherchia coli,Salmonella enteritidis and Pseudomonas aeruginosa was 4096mg·L^-1,1024mg·L^-11 for Candida albicans,512mg·L^-11 for Staphylococcus.aureus.The inhibition rate of Aspergillus niger mycelium growth was 42.17%at the concentration of 512 mg·L^-1.The composition,application and physiological activity of the pigment were determined.The results showed the main components of the pigment were flavonoids,the pigment remained stable under certain condition and had certain physiological activities.The pigment has potential as dye and has certain biological value.The study can provide reference for the utilization of the pigment and provide some theoretical basis to make the best of Dalbergia bariensis resources.