| The comprehensive utilization of plant resources has become the focus of research, it is very important to develop and utilize the effective components from plants. Many plant essential oils are composed of the special chemical compositions, displaying the strong biological activities, and become the important source of highly effective low poisonous natural perfume, the antioxidant and the fungicide. There are many kinds of bamboo species in our country that have broad area and the high economic value. The essential oil from bamboo leaves has the green leaf fragrance, the same as melon, fruit and the tea fragrance, which is a good natural perfume. The essential oils from bamboo leaves including the many kinds of active components may be made into the perfume, the cosmetics, the natural antioxidant and the natural fungicide through a series of technical processing.The purpose of this paper is to describe chemical components of essential oils from bamboo leaves, and summarize the composition law of chemical components of essential oils from bamboo leaves, and reveal the antioxidant activity, antibacterial activity and their action mechanism of essential oils, so as to provide reference for the future application of essential oils in the field of daily chemical industry. This study used Acidosasa gigantea, Bambusa chungii, Bambusa multiplex (Lour.)Raeuschel, Bambusa multiplex cv.Silvertripe, Bambusa textilis, Bambusa ventricosa, Bambusa vittata, Brachystachyum densiflorum, Cephalostachyum pergracile, Chimonobambusa quadrangularis, Chimonocalamus delicatus, Dendrocalamopsis oldhami, Dendrocalamus hamiltonii, Dendrocalamus latiflorus, Dendrocalamus amoenus, Dendrocalamus yunnanicus, Indocalamus latifolius, Indocalamus tessellatus, Phyllostachys acuta, Phyllostachys aurea, Phyllostachys spectabilis, Phyllostachys dulcis, Phyllostachys glauca, Phyllostachys heteroclada, Phyllostachys mannii, Phyllostachys nidularia, Phyllostachys pubescens, Phyllostachys vivax, Pleioblastus yixingensis and Pseudosasa convexa as the research object. The essential oils from bamboo leaves were extracted by steam distillation, the chemical components of the essential oil were separated and structurally identified by gas chromatography/mass spectrometry, the relative contents of these components by the peak-area normalization method adopted in gas chromatography; Infrared features of essential oils from bamboo leaves were described by infrared spectrum technology; The antioxidant activities of essential oils were evaluated using the DPPH assays, and antibacterial activities of essential oils were experimented by filter paper method. Through the research some conclusions were as follows:1. For the fidelity of chemical components of essential oils from bamboo leaves, the essential oils from the bamboo leaves were obtained by steam distillation, and water soluble components were also extracted. The results indicated that the conditons of steam distillation were: the distillation time was 6h, theratio of material was 1:8, analytically pure hexane and absolute ether were used as extraction solvents. The equipment of steam distillation method is suitable for extracting essential oils from bamboo leaves. The yield distribution of essential oils was 0.252% to 0.921% (dry weight basis). The yield range of essential oils from bamboo leaves was 0.2% to 0.4%, including P. pubescens, P. acuta, P. glauca, P. heteroclada, B. multiplex cv.Silvertripe, B.ventricosa, P. spectabilis, P. nidularia, P. yixingensis, C. delicatus, P. vivax and P. convexa; The bamboo species whose essential oil yield was between 0.4% and 0.6%, including B. densiflorum, B. textilis, P. dulcis, P. mannii, C. pergracile, I. tessellatus, B. multiplex (Lour.)Raeuschel, B. chungii, D. amoenus, D. hamiltonii and C. quadrangularis, sum to 11 kinds; The yield range of essential oils was between 0.6% and 0.8%, including D. yunnanicus, D. latiflorus, P. aurea, D. oldhami and A. gigantea; The yields of essential oils from I. latifolius and B. vittata were more than 0.8%.2. The chemical components in the essential oils from bamboo leaves were analyzed by GC-MS. The oxygenated compounds composed of alcohols, hydrocarbon, phenols, ketones, aldehydes and acids are main fraction in essential oils. The alcohols hold about 24.703% to 78.524% of the total essential oils from bamboo leaves. After the GC-MS analysis, the essential oils from different bamboo leaves are basically identical with the main chemical components; The difference among the essential oils mainly display in some different compound types, as well as different amount of the same compound. The main components of essential oils from bamboo leaves were (z)-3-hexen-1-ol, phytol, 3,7,11-trimethyl-1,6,10-dodecatrien-3-ol, 2-octanol, isophytol, 2-methoxy-4-vinylphenol, 6,10,14-trimethyl-2-pentadecanone,β-ionone,α-ionone, farnesyl acetone, megastigmatrienone, (e)-6,10-dimethyl-5,9-undecadien-2-one, 2-hexenal, nonanal, benzeneacetaldehyde, 5,6,7,7a-tetrahydro-4,4,7a-trimethyl-2(4H) benzofuranone, 1,2-benzenedicarboxylic acid butyl octyl ester, 1-heneicosyl formate, 2-dimethylamino-4-methyl-pent-4-enenitrile, n-hexadecanoic acid, octadecanoic acid, 2,3-dihydro-benzofuran, heptadecyl oxirane, hexatriacontane and tetracosane.After a comprehensive analysis of chemical components in the essential oils from 30 species of bamboo leaves, the results showed that 17 kinds common components in essential oils from bamboo leaves were determined to (z)-3-hexen-1-ol, 2-hexenal, p-xylene, benzeneacetaldehyde, (e)-1-(2,6,6-trimethyl-1,3-cyclohexadien-1-yl)-2-buten-1-one,α-ionone, (e)-6,10-dimethyl-5,9-undecadien-2-one,4-(2,2,6-trimethyl-7-oxabicyclo[4.1.0]hept-1-yl)-3-buten-2-one, 5,6,7,7a-tetrahydro-4,4,7a-trimethyl-2(4H) benzofuranone, pentadecane, hexadecane, octadecane, 1,2-benzenedicarboxylic acid bis(2-methylpropyl) ester, 6,10,14-trimethyl-2- pentadecanone, farnesyl acetone, 1-(1,2-propadienyl)-cyclohexanol and 1-octadecene.To reveal the characteristic components of 17 kinds common components in essential oils, principal component analysis was used to analyze the GC-MS data of the components in these samples. The characteristic components of the essential oils were determined to (z)-3-hexen-1-ol, 6,10,14-trimethyl-2-pentadecanone, benzeneacetaldehyde, farnesyl acetone, (e)-6,10-dimethyl-5,9-undecadien-2-one, 2-hexenal andα-ionone. The content range of (z)-3-hexen-1-ol was 7.326%～69.364% in essential oils, and the content of (z)-3-hexen-1-ol in essential oil of P. glauca leaves was about 9.5 times more than that of B. densiflorum leaves. The content range of 2-hexenal was 0.671%～3.967%, and P. pubescens leaves had the most content of 2-hexenal. The contents range of 6,10,14-trimethyl-2-pentadecanone, benzeneacetaldehyde, farnesyl acetone, (e)-6,10-dimethyl-5,9-undecadien-2-one andα-ionone were respectively 0.983%～9.567%, 0.525%～4.131%, 0.110%～2.943%, 0.152%～2.575%, 0.281%～2.008%. These characteristic components with the leaf fragrance and the fruit fragrance have the important reference value for revealing characteristics of aroma constituents of essential oils from bamboo leaves.3. The essential oils from 30 kind of bamboo leaves were scanned respectively by FT-IR. Based on infrared signature of chemical components of essential oils from bamboo leaves, the infrared spectrum of essential oil from bamboo leaves was divided into 5 sections: section one(3400～3200cm-1), section two (3000～2800cm-1), section three (2200～1900cm-1), section four(1800～1350cm-1), section five(1300～800cm-1). There were the characteristic adsorption at～3360cm-1,～2950 cm-1,～2918cm-1,～2850cm-1,～1700 cm-1,～1060cm-1, which could charaterize the alcohols, phenols, hydrocarbon and carbonyl compounds of essential oils from bamboo leaves. The IR spectral which range from 2100～1850cm-1 and the 1160～400cm-1 could charaterize the difference of chemical constituents of essential oils. As the research shown, the FT-IR technique could be applied in component analysis of essential oils from bamboo leaves, and objectively reflect the global feature of essential oils. 4. By studying on absorption spectrum of DPPH solution and DPPH reaction system, the conclusion was drawn as follows, the wavelength for the determination of DPPH reaction system by spectrophotometric method was chosen to be 517nm, DPPH reaction system was 2.0mL of 51.54mg·L-1 DPPH + 0.5mL of the sample solution with the reaction time of DPPH reaction system of 40 min. IC50 value and AE value were used as the indexs to evaluate scavening capacity of essential oils from bamboo leaves. According to the median inhibition concentration( IC50 value) , the smaller the IC50 value of the essential oils have the stronger ability of scavenging DPPH free radicals. The IC50 value range of the essential oils from bamboo leaves was 2～4 mg·mL-1, including B. vittata, P. pubescens, D. latiflorus, B. multiplex (Lour.)Raeuschel, B. multiplex cv.Silvertripe, P. spectabilis; The IC50 value range of the essential oils was 4～6 mg·mL-1, including P. acuta, P. aurea, D. oldhami, P. convexa, P. heteroclada, A. gigantea, D. yunnanicus, P. vivax; The IC50 value range of the essential oils was 6～8 mg·mL-1, including D. hamiltonii, B. textilis, P. dulcis, B.ventricosa, P. mannii, P. nidularia, I. latifolius, P. yixingensis, D. amoenus, P. glauca; The IC50 value range of the essential oils was 8～10 mg·mL-1, including C. delicatus and C. pergracile; The IC50 values of B. chungii, C. quadrangularis, B. densiflorum and I. tessellatus were more than 10 mg·mL-1. The more the abilitiy of free radical elimination value(AE value), also the stronger ability of scavenging free radicals. The AE value of essential oils from B. vittata leaves was 0.370 mL·mg-1, which was 6.379 times more than that of I. tessellatus. The AE values of essential oils from P. pubescens, D. latiflorus, B. multiplex (Lour.)Raeuschel, B. multiplex cv.Silvertripe and P. spectabilis leaves were 0.349 mL·mg-1,0.303 mL·mg-1,0.291 mL·mg-1,0.277 mL·mg-1and 0.255 mL·mg-1, respectively. They all showed strong antioxidant activities.The antioxidant activities of B. vittata and P. pubescens leaves were close to that of TBHQ. The antioxidant activities of 1g essential oil from B. vittata and P. pubescens leaves were comparable with that of 0.309g,0.291g TBHQ, respectively. The antioxidant activity of 1g TBHQ was comparable with that of 3.954g essential oil from D. latiflorus and 4.117g B. multiplex (Lour.)Raeuschel leaves. The antioxidant activity of essential oil from I. tessellatus leaves was the lowest. The antioxidant activity of 20.655g essential oil from I. tessellatus leaves was comparable with that of 1g TBHQ.The phenolic group and the ring structure of essential oils were important structural basis of antioxidant activities of essential oils from bamboo leaves. The data indicated that essential oils obtained from B. vittata leaves, P. pubescens leaves, D. latiflorus leaves, and B. multiplex (Lour.)Raeuschel leaves may be used as natural antioxidant.5. The essential oils from bamboo leaves were diluted into a series of concentration of sample solutions: 5.0 mg·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 Staphyloccocus aureus, Bacillus subtili, Escherichia coli, Candida albicans, Aspergillus flavus and Aspergillus niger were tested by using filter paper method. After 24 hours' culture, the essential oils from P. yixingensis leaves and I. latifolius leaves had strong inhibitory effect on B. subtilis, and the essential oils from D. yunnanicus leaves and D. amoenus leaves had better inhibition action to S. aureus, B. subtilis and E. coli at high concentration (25 mg·mL-1). The essential oils from D. yunnanicus leaves, D. amoenus leaves, P. yixingensis leaves and I. latifolius leaves had moderate inhibitory effect on C. albicans, A. flavus and A. niger at 25 mg·mL-1.Based on a comprehensive analysis, The essential oils from D. yunnanicus leaves, D. amoenus leaves and I. latifolius leaves had inhibition action to S. aureus, B. subtili, E. coli, C. albicans, A. flavus and A. niger , and the essential oils from P. yixingensis leaves had inhibition action to S. aureus, B. subtili, E. coli and C. albicans. The higher the concentration of the essential oils, the better the antibacterial activity. The essential oils extracted from one kind of bamboo leaves have different inhibition action to six strains, and essential oils extracted from different species of bamboo leaves have different inhibition action to one kind of strain. The antibacterial effects of essential oils from bamboo leaves on bacteria are better than fungi.There were some unsaturated compounds in the essential oils from bamboo leaves, which could display a series of physiological activities, owing to unsaturated double bond. The essential oils from D. yunnanicus leaves, D. amoenus leaves, P. yixingensis leaves and I. latifolius leaves rich in (z)-3-hexen-1-ol, 2-octanol, 6,10,14-trimethyl-2-pentadecanone, ionone, 2-hexenal, benzeneacetaldehyde and nonanal showed inhibition action to six strains. The chemical components from essential oils, including (z)-3-hexen-1-ol, 2-octanol, 6,10,14-trimethyl-2-pentadecanone, ionone, 2-hexenal, benzeneacetaldehyde and nonanal, were important material base of antibacterial effects of essential oils from bamboo leaves. The hydroxy and the unsaturated double bond were important structural basis of antibacterial effects of essential oils from bamboo leaves. The essential oil from bamboo leaves was the crude extraction, which was composed of multi-ingredient. The antibacterial activities of essential oils from bamboo leaves were due to the synergistic effect of multi-ingredient. The data indicated that essential oils obtained from D. yunnanicus leaves, D. amoenus leaves, P. yixingensis leaves and I. latifolius leaves may be used as natural fungicide.
|
PDF Full Text Request