Studies On Chemical Components And Bioactivities Of Dendrocalamus Farinosus Culm

China is rich in bamboo resources and has a long history both in cultivation and utilization.To promote the basic research and comprehensive utilization of bamboo resources, chemicalcomponents of bamboo culms were studied. The compounds from Dendrocalamus farinosusculms were isolated and identified, and the composition and relative molecular mass（Mw） ofbamboo culm polysaccharides was analyzed by high performance ion chromatography（HPIC） and high performance gel penetration chromatography （HPGPC）, alone with thestructure characterized by IR and1HNMR&1CNMR. Volatile compounds both from D.farinosus culm and leaves were collected through hydrodistillation （HD） technologies andanalyzed qualitatively with chromatography-mass spectrometry （GC/MS）, and thenantibacterial effects of two samples were compared. The chemical compositions ofDendrocalamus farinosus culm were tested, including ash content,1%NaOH extractive, hotwater extractive, benzene-alcohol extractive, pentosan, klason lignin, holocellulose andelements. The Ionic liquid-based microwave-assisted was applied to the extraction of isorientinin Dendrocalamus farinosus culm.The antibacterial activity and antioxidant activity of16bamboo culms extract were evaluated. The main results were as following:1. Extracting compounds from Dendrocalamus farinosus culm with95%ethanol coldsoak extract method. Extraction was purified by AB-8macroporous absorption resin. Then30%ethanol,60%ethanol,80%ethanol and acetine eluted respectively. The elution wereisolated by Sephadex LH-20, GX-281High Voltage HPLC Separate system and Sepacorelow-pressure HPLC Separate system.9compounds were isolated from Dendrocalamusfarinosus. On the basis of physic-chemical characters and spectroscopic analysis such as UVIR, NMR and MS,10compounds were identified as:4-hydroxybenzaldehyde（1）, tricin（2）,p-hydroxybenzoic acid （3）, β-sitosterol （4）, isoorientin （5）, isovitexin （6）, tricin-7-O-glucopyranoside （7）,2,6-Dimethoxy-1,4-benzoqunone （8）, ferulic acid（9）,p-coumaric acid（10）.2. The results showed that the water-soluble polysaccharide of Dendrocalamus farinosusculm were arabinose、galactose、glucose、xylose and mannose with the contents of21.88%,7.5%,40.57%,19.89%and0.15%respectively by HPIC. The average molecular weights（Mw） of BCP was16900Da and the polydispersity was1.33. Infrared spectrogram showedthat BCP had the characteristic absorption peak of polysaccharides.1HNMR and13CNMRindicated that its main chains were composed of β-pyranglycoside linkage. Thermal analysisshowed the degradation of BCP occurred in the second stage rapidly. The mass loss was about65%during the temperature240~340℃.3A total of40volatile compounds were extracted and separated in bamboo culm,including ester, acid, wine, aldehydes, ketone, phenol, etc., while76compounds wereseparated in bamboo leaves. Comparison analysis showed that there were10volatilecompounds both in Dendrocalamus farinosus culm&leaves, included caproaldehyde,（E）-2-Hexenal, benzaldehyde, phenylacetaldehyde, beta-Damascenone, beta-Ionol, ethyl laurate,Farnesyl acetone, ethyl palmitate, Phytol. These compounds have been applied in the field offragrance and flavor, daily-use chemical, and food preservative.The volatile compounds from Dendrocalamus farinosus culm&leaves were diluted into aseries of concentration of sample solutions:5.0mg mL-1,10.0mg mL-1,15.0mg mL-1,20.0mg mL-1,25.0mg mL-1, and the antibacterial effects of sample solutions on Bacillus subtili,Staphyloccocus aureus, Candida albicans and Escherichia coli were tested by using filterpaper method. After24hours’ culture, the volatile compounds from culm had a stronginhibition effect to B. subtili at high concentration （25.0mg mL-1）. The volatile compoundsfrom leaves had strong inhibition effect to B. subtili, S. aureus and E. coli. The volatilecompounds from leaves had better inhibition effect than that from culms, due to the content ofwine, aldehydes, phenol, acid. 4. The chemical compositions of Dendrocalamus farinosus culm were tested. Resultsshow that the chemical components of Dendrocalamus farinosus are determined as ash content1.24%,1%NaOH extractive30.71%, hot water extractive1.58%, cold water extractive9.16%,benzene-alcohol extractive3.27%, pentosan19.44%, klason lignin22.18%, holocellulose72.7%. The contents of18kinds of inorganic elements was investigated by inductively coupledplasma-mass spectrometry （ICP/MS）, combinning with mircowave sample digestion, whichwere Ca（587.13mg·kg-1）, Mg（448.75mg·kg-1）,Al（76.51mg·kg-1）, Fe（66.38mg·kg-1）,N（a51.4mg·kg-1）, Zn（16.47mg·kg-1）, Mn（15.52mg·kg-1）, C（r5.26mg·kg-1）, N（i3.54mg·kg-1）,M（o3.03mg·kg-1）, C（u2.48mg·kg-1）, P（b2.46mg·kg-1）, C（d30.39mg·kg-1）, S（e0.35mg·kg-1）,Ag（0.26mg·kg-1）,As（0.23mg·kg-1）, Co（0.09mg·kg-1）, Hg（0.07mg·kg-1） respectively.Ca, Mg, Al, Fe, Na are relative abundant in the bamboo culm among the elements above.5. Ionic liquid-based microwave-assisted extraction coupled with high performance liquidchromatography was first applied to isolate and determinate isorientin in Dendrocalamusfarinosus culm. Response surface experimental design was used to explore for the bestextraction conditions of isorientin: The amount of culm0.5g, in the1.5mol/L1-Butyl-3-methylimidazolium tetrafluoroborate （[bmim][BF4]） system, the extractiontemperature60.2℃, extraction time12.36min, and liquid-to-solid ratio of16.74:1（mL/g）.Under the condition, the extraction yield was1.693mg/g. Furthermore, the comparison of theproposed ILMAE approach with the conventional method was also studied to demostrate themethod feasibility. It is worth mentioning that the proposed approach could dramaticallyimprove both the extraction efficiency of the menthol and the total extraction time.6. The antimicrobial activity of the extracts from4genuses,16species bamboo culmsagainst X.oryzae pv.oryzae, S.arueus, R.solanacearum, E.coli, Botrytis cinerea, Valsa maliMiyabe et Yamada, M.grisea and C.gloeosporioides were evaluated.Filter paper in each extract to add a dose of0.02g. The results indicated that P.maculatusmaculatus showed the most obvious antibacterial activeites to X.oryzae pv.oryzae. Thediameter of antibacterial ring after24h was18.33mm. P. china f.hisauchii showed the most obvious antibacterial activeites to S.arueus, with the diameter of antibacterial ringwas19.33mm. Bambusa rigida Keng and P. iridescens extract showed most obviousantibacterial activeites to R.solanacearum and E.coli. The diameter of antibacterial ring wereboth exceed18mm. At the concentration of0.04g/mL, P.heteroclada showed most obviousantifungal activities to Valsa mali Miyabe et Yamada, the inhibition rates after48h was above56.84%. P.nigra var.henonis showed most obvious antifungal activities to Valsa mali Miyabeet Yamada, with the inhibition rates was80.94%. P.heteroclada and P.nigra var.henonisshowed most obvious antifungal activities to M.grisea and C.gloeosporioides, the inhibitionrates were both above40%.The antioxidant capacities of bamboo culms extracts were investigated using DPPH test.In the DPPH assays, the antioxidant activities were evident in all the extracts, and theP.heterocycla cv.Pubesceus extract indicated the most effective scavenging effect on theDPPH·. Its scavenging effect of DPPH·（IC50=136.5mg/L）.was even better than that of BHT.