毛竹和重组竹腐朽前后的表面颜色及耐腐性能

以毛竹和重组竹为研究对象,用绵腐卧孔菌(PV)、密粘褶菌(GT)两种褐腐菌和彩绒革盖菌(CV)、变色栓菌(TV)两种白腐菌进行腐朽试验,比较分析了毛竹和重组竹腐朽前后表面视觉性质及其质量损失差异。结果发现:毛竹和重组竹颜色均发生了显著变化,主要表现为明度(L~*)降低,色度值(C)、红绿轴色品指数(a~*)和黄蓝轴色品指数(b~*)显著增大,其中绵腐卧孔菌对毛竹及重组竹的色差影响最大。重组竹(耐绵腐卧孔菌)能达到Ⅰ级强耐腐水平;毛竹(耐绵腐卧孔菌)和重组竹(耐密粘褶菌和彩绒革盖菌)达到了Ⅱ级耐腐水平;毛竹(耐密粘褶菌、彩绒革盖菌和变色栓菌)和重组竹(耐彩绒革盖菌)为Ⅲ级稍耐腐水平。整体来看,重组竹对白腐菌和褐腐菌的耐腐效果好于毛竹。绵腐卧孔菌虽然对毛竹和重组竹的降解能力最弱,但对其颜色变化的影响却最大。扫描电镜可观察到彩绒革盖菌通过毛竹导管壁上的纹孔进入薄壁细胞、伴胞等,同时通过分泌木质素酶导致其细胞壁降解。     

Extraction of antioxidants from eucalyptus (Eucalyptus globulus) bark

The extraction of phenolic compounds from eucalyptus (Eucalyptus globulus) bark was examined with the aim of analyzing the potential of the extracts as natural antioxidants. Experiments were planned according to a 2³ factorial design to analyze the influence of temperature and Na₂SO₃ and NaOH concentrations in aqueous solutions on extraction yield, extract total phenols content, ferric reducing antioxidant power (FRAP), and number- and weight-average molecular weights. Extract total phenols content and FRAP antioxidant activity in the ranges 0.91–2.58?g gallic acid equivalent (GAE)/100?g oven-dried bark and 4.70–11.96?mmol ascorbic acid equivalent (AAE)/100?g oven-dried bark, respectively, demonstrated the potential of eucalyptus bark as a source of antioxidant compounds. Extraction at the highest temperature (100°C), the lowest Na₂SO₃ concentration (1.5% on oven-dried bark), and without NaOH provided the highest extract total phenols content and FRAP antioxidant activity. Those eucalyptus bark extracts with lower molecular weight showed higher antioxidant activity. Matrix-assisted laser desorption ionization time-of-flight and reverse-phase high-performance liquid chromatography electrospray ionization time-of-flight mass spectrometry revealed the presence of polygalloyl glucoses, catechin, epicatechin, ellagic acid, quercetin-3-o-rhamnoside, and isorhamnetin in eucalyptus bark aqueous extracts.     

In vitro antifungal activities of longan (Dimocarpus longan Lour.) seed extract

Longan, Dimocarpus longan Lour., contains polyphenolic compounds which exhibit several pharmacological properties. This study aims to evaluate antifungal activities of longan fruit extract in comparison to its active compounds. The results showed that longan seed exhibited antifungal activity against the opportunistic yeasts (Candida species and Cryptococcus neoformans). In contrast, longan pulp and whole fruit did not demonstrate any inhibitory effects. Ellagic acid showed the most potent antifungal activity followed by corilagin and gallic acid, respectively. Ellagic acid inhibited Candida parapsilosis and C. neoformans more effectively than Candida krusei and also some Candida albicans clinical strains. Baidam cultivar possessed higher antifungal activity (MIC=500-4000 μg/ml) as it contained higher contents of ellagic acid and gallic acid than Edor (MIC=1000-8000 μg/ml). For antibacterial activity, only corilagin and gallic acid possessed weak to moderate inhibitory effects against Staphylococcus aureus and Streptococcus mutans, respectively. Longan seed was then applied in the oral care products. Longan effervescent granule (5% extract) significantly reduced adhesion of C. albicans to acrylic strips. Mouthwash containing 0.5% extract exhibited good antifungal activity compared to a commercial product. These findings indicated that longan seed extract and its polyphenolic compounds can be used as an antifungal agent in oral care products for the treatment of opportunistic yeast infection.     

Effect of seed treatment for laboratory germination of Albizia chinensis

Seeds of Albizia chinensis(Osb.) Merr. in addition to water were also treated with different treatments by incubating in ethyl alcohol, acetone, and petroleum ether at room temperature for different du...     

栲树皮乙醇提取物中多酚类化学成分的鉴定

采用Sephadex LH-20,MCI gel CHP 20P和Toyopearl Butyl-650C等柱色谱方法研究栲(Castanopsis fargesii Franch.)树皮乙醇提取物的化学成分。从栲树皮80%乙醇提取物中分离得到10个化合物,根据波谱数据分析鉴定化合物的结构,分别鉴定为苯甲酸、原儿茶酸、没食子酸、5-O-没食子莽草酸、3,5-二-O-没食子奎宁酸、表儿茶素、儿茶素、棓儿茶素、木麻黄鞣质和栗木鞣花素。所有的化合物均为首次从栲树中分离得到。     

Pistagremic acid,a glucosidase inhibitor from Pistacia integerrima

Pistacia integerrima Stewart in traditionally used as folk remedy for various pathological conditions including diabetes. In order to identify the bioactive compound responsible for its folk use in diabetes, a phytochemical and biological study was conducted. Pistagremic acid (PA) was isolated from the dried galls extract of P. integerrima. Strong α-glucosidase inhibitory potential of PA was predicted using its molecular docking simulations against yeast α-glucosidase as a therapeutic target. Significant experimental α-glucosidase inhibitory activity of PA confirmed the computational predictions. PA showed potent enzyme inhibitory activity both against yeast (IC₅₀: 89.12 ± 0.12 μM) and rat intestinal (IC₅₀: 62.47 ± 0.09 μM) α-glucosidases. Interestingly, acarbose was found to be more than 12 times more potent an inhibitor against mammalian (rat intestinal) enzyme (having IC₅₀ value 62.47 ± 0.09 μM), as compared to the microbial (yeast) enzyme (with IC₅₀ value 780.21 μM). Molecular binding mode was explored via molecular docking simulations, which revealed hydrogen bonding interactions between PA and important amino acid residues (Asp60, Arg69 and Asp 70 (3.11 Å)), surrounding the catalytic site of the α-glucosidase. These interactions could be mainly responsible for their role in potent inhibitory activity of PA. PA has a strong potential to be further investigated as a new lead compound for better management of diabetes.     

Antioxidant activity of extracts from the wood and bark of Port Orford cedar

Heartwood, sapwood, and inner and outer bark of Port Orford cedar were extracted with methanol, and the extracts evaluated for antioxidant activity. The total phenol content (TPC) of the extracts was determined by the Folin-Ciocalteu method and expressed as gallic acid equivalent (GAE). Butylated hydroxytoluene was used as a positive control in the free-radical-scavenging activity tests and ethylenediaminetetraacetic acid dihydrate disodium salt served as a positive control in the metal-chelating activity assay. All wood extracts showed significant freeradical-scavenging activity. In the radical-scavenging assay of 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (the ABTS assay), the inner bark extracts exhibited the strongest free-radical-scavenging activity. The 50% inhibitory concentrations (IC₅₀) in the radical-scavenging assay against 1,1-diphenyl-2-picrylhydrazyl hydrate radical (DPPH) of the heartwood, sapwood, and inner and outer bark extracts were 64.77, 29.03, 10.31, 19.87 μg·ml⁻¹, respectively. In the metal-chelating activity system, the sapwood extract demonstrated significant activity. The greatest TPC, 537.5 mg GAE/g dry extract, was detected in the inner bark. The lowest TPC of 136.9 mg GAE/g dry extract was observed in the heartwood dry extract. The results indicate that the antioxidant activities of the extracts are in accordance with the amounts of phenolics present; the inner and outer barks of Port Orford cedar are rich in phenolics and may provide good sources of antioxidants.     

Changes in soil carbon during the establishment of a hardwood plantation in subtropical Australia

Soil carbon (C) pools are not only important to governing soil properties and nutrient cycling in forest ecosystems, but also play a critical role in global C cycling. Mulch and weed control treatments may alter soil C pools by changing organic matter inputs to the forest ecosystem. We studied the 12-month mulch and weed control responses on the chemical composition of soil organic C and the seasonal dynamics of water extractable organic C (WEOC), hot water extractable organic C (HWEOC), chloroform-released organic C (CHCl₃-released C), and acid hydrolysed organic C (acid hydrolysable C) in a hardwood plantation of subtropical Australia. The results showed that compared with the non-mulch treatment, the mulch treatment significantly increased soil WEOC, HWEOC, and CHCl₃-released C over the four sampling months. The weed control treatment significantly reduced the amount of HWEOC and CHCl₃-released C compared with the no weed control treatment. Neither the mulch nor weed control treatment significantly affected soil acid hydrolysed organic C. There were no significant seasonal variations in soil WEOC, HWEOC, CHCl₃-released C, and acid hydrolysed organic C in the hardwood plantation. Solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy was used to study the structural chemistry of soil C pools in hydrofluoric acid (HF) treated soils collected 12 months after the mulch and weed control treatments were applied. Overall, O-alkyl C was the dominant C fraction, accounting for 33–43% of the total NMR signal intensity. The mulch treatment led to higher signal intensity in the alkyl C spectral region and A/O-A ratio (the ratio of alkyl C region intensity to O-alkyl C region intensity), but lower signal intensity in the aryl C and aromaticity. Compared with the no weed control treatment, the weed control treatment reduced signal intensity in the aryl C and aromaticity. Together, shifts in the amount and nature of soil C following the mulch and weed control treatments may be due to the changes in organic matter input and soil physical environment.     

天然低共熔溶剂提取杜仲叶绿原酸及其抗氧化活性

以杜仲叶为原料,采用超声波辅助天然低共熔溶剂(NADES)提取杜仲叶绿原酸并考察其抗氧化活性.首先筛选出较优的天然低共熔溶剂体系,然后在单因素试验的基础上通过响应面优化提取工艺,并考察杜仲叶绿原酸的抗氧化活性.研究结果表明:较优的溶剂体系由甜菜碱、L-乳酸与水组成,各组分的物质的量比为1:1:4,低共熔溶剂中水用量为5...     

木质纤维成分的乙酸分离方法及表征

研究了一种用含有少量硫酸的乙酸溶液分离杨木成分的方法。考察了反应时间、乙酸浓度、液比和催化剂浓度对木材成分分离的影响。对分离出的木材三种成分进行了表征。结果表明,分离杨木成分的较佳条件为:硫酸浓度0.3%,液比6,反应时间3h和乙酸浓度90%。残渣的主要成分是α-纤维素和半纤维素。水不溶沉淀物(乙酰化木质素)的重均分子量分布在341到253之间,分散性系数分布在1.1到1.2这一窄范围内。糖分析结果表明,可溶性成分主要来源于半纤维素,以单糖形式存在。     

Changes in structural and chemical components of wood delignified by fungi

Summary Cerrena unicolor, Ganoderma applanatum, Ischnoderma resinosum and Poria medulla-panis were associated with birch wood that had been selectively delignified in the forest. Preferential lignin degradation was not uniformly distributed throughout the decayed wood. A typical white rot causing a simultaneous removal of all cell wall components was also present. In the delignified wood, 95 to 98% of the lignin was removed as well as substantial amounts of hemicelluloses. Scanning and transmission electron microscopy were used to identify the micromorphological and ultrastructural changes that occurred in the cells during degradation. In delignified areas the compound middle lamella was extensively degraded causing a defibration of cells. The secondary wall, especially the S₂ layer, remained relatively unaltered. In simultaneously white-rotted wood all cell wall layers were progressively removed from the lumen toward the middle lamella causing erosion troughs or holes to form. Large voids filled with fungal mycelia resulted from a coalition of degraded areas. Birch wood decayed in laboratory soil-block tests was also intermittently delignified. Selective delignification, sparsely distributed throughout the wood, and a simultaneous rot resulting in the removal of all cell wall components were evident. Scanning electron microscopy appears to be an efficient technique for examining decayed wood for fungi with the capacity to selectively delignify wood.The authors would like to thank Kathy Zuzek for technical assistance and Dr. M. Larsen, Forest Prod. Lab., Madison, for identifying the sporophores of Poria medulla-panis. This research was founded in part by a grant from the USDA Forest Service, Forest Products Laboratory and from the Graduate School, University of Minnesota     

Bioactivities of caffeic acid methyl ester (methyl-(E)-3-(3,4-dihydroxyphenyl)prop-2-enoate): a hydroxycinnamic acid derivative from Solanum melongena L. fruits

Feeding deterrent and growth inhibitory effects of caffeic acid methyl ester (CME) isolated from the fruit extract of eggplant, Solanum melongena L. along with two known phenolic acids, caffeic acid (CA) and chlorogenic acid (CG) and azadirachtin (taken as active control), were evaluated against Spodoptera litura Fab. and Achaea janata L. (Lep., Noctuidae). The structure of CME was determined on the basis of extensive spectroscopic (UV, FTIR, ¹H, and ¹³C NMR) data analysis. CME has exhibited strong feeding deterrent activity against S. litura and A. janata larvae with ED₅₀ values of 52.02 and 41.02 μg/cm² leaf area, respectively. CA and CG were relatively less effective compounds when compared with CME. The results also revealed that the isolated compound CME caused marked larval growth inhibition in S. litura and A. janata larvae after 7 days of feeding on a treated diet. The effect on growth of larvae was concomitant with the reduced feeding and digestibility of ingested food. So the activities of digestive proteases within the midgut of larvae were examined using specific substrates to understand the digestive physiology in the larval guts. The bulk of the activity was associated with serine proteases comprising trypsin-, chymotrypsin-, and elastase-like enzymes, which decreased in diets containing CME, whereas, interestingly increased with CG. From the results, we conclude that CME isolated from S. melongena fruit extract shows feeding deterrent and larval development inhibitory activities that may prove useful in the management of S. litura and A. janata larvae.     

酚羟基保护法合成硬脂酰单宁酸酯及其抗氧化性能评价

为解决单宁酸(TA)亲水性强亲油性弱的问题,以单宁酸为原料,利用苄基溴将单宁酸的部分酚羟基保护后得到单宁酸苄基醚(TBE),再以硬脂酸酐为酰基化试剂,吡啶为催化剂,N_2保护下反应,引入长链脂肪烃;最后在弱酸条件下将苄基水解脱去,制得硬脂酰单宁酸酯(C_(18)-TA)。采用均匀实验优化合成条件,傅里叶红外光谱(FT-IR)、紫外光谱(UV)、核磁共振(~1H NMR)表征了C_(18)-TA的结构,并通过C_(18)-TA清除·DPPH的能力和抗油脂氧化能力评价其抗氧化性能。结果表明:优化最佳合成条件为单宁酸1 g,硬脂酸0.6 g,吡啶1.5 mL,反应温度80℃,回流时间265 min,得到的C_(18)-TA产率可达87.98%。使用酚羟基保护法制得的C_(18)-TA不仅改善了单宁酸的表面活性,而且保留了单宁酸中多数的酚羟基,抗氧化能力明显高于单宁酸和丁基羟基茴香醚(BHA),质量浓度为0.05~0.25 g/L,对·DPPH的清除率为91.96%~97.39%;对亚麻籽油的抗氧化值(POV)升高缓慢,0~30 d为3.82~17.72 mmol/kg。     

Bilberry extract protect restraint stress-induced liver damage through attenuating mitochondrial dysfunction

The aim of the present study is to investigate the protective effect of bilberry extract on liver damage in restraint stressed mice. A remarkable increase in alanine aminotransferase (ALT) and reactive oxygen species (ROS) levels was observed in stressed mice. Treatment with bilberry extract restored ALT and ROS to normal levels, and enhanced mitochondrial complex II activity that was lowered in restraint stressed mice. The mitochondrial electron transfer chain (ETC)-related gene expression was measured by RT-PCR, and a significant up-regulation of complex II mRNA was observed for SDHA, B, C and D mRNA in bilberry extract-treated group compared with that in stressed group. Bilberry extract administration also profoundly elevated the Na⁺-K⁺-ATPase activity and mitochondria membrane potential (?Ψ_m), which was reduced in the stressed group. Bilberry extract exhibited protective effect by scavenging free radicals and attenuating mitochondrial dysfunction in the liver of restraint stressed mice. It may be used as a promising therapeutic agent in preventing and delaying the life-related disease.     

A new anxiolytic fatty acid from Aethusa cynapium

The present investigation was carried out with a view to separate bioactive constituent from Aethusa cynapium. Bioactivity guided fractionation of the anxiolytic methanol extract has led to the isolation of a novel unsaturated fatty acid. Structure of the acid characterized by UV, IR, 1H NMR, C13 NMR, MS techniques was found to be trideca-7, 9, 11-trienoic acid. Antianxiety activity was confirmed using the mCPP-induced hypolocomotion test. This new fatty acid—trideca-7,9,11-trienoic acid, isolated from A. cynapium was found to be responsible for the antianxiety activity of the plant.     

大孔吸附树脂对杜仲叶中绿原酸、总黄酮的分离研究

通过对静态吸附容量和洗脱效果的选择，从10种大孔吸附树脂中确定出最适于杜仲叶中绿原酸、总黄酮分离的XDA-5树脂。研究了用该树脂吸附分离杜仲叶中绿原酸和总黄酮的方法，得出以下结论：1)杜仲叶绿原酸和总黄酮的最佳分离工艺为：上柱液pH值为2-3，静态吸附时间8h，绿原酸最佳洗脱剂为10％～15％乙醇溶液，黄酮洗脱剂为50％-70％乙醇溶液，流速为每分钟流出液体积相当于吸附剂体积的8％；2)10％～15％乙醇洗脱液经真空浓缩后，其固形物得率为4．85％，绿原酸含量为36．65％；3)50％～70％乙醇洗脱液经真空浓缩后，其固形物得率为4．98％，总黄酮含量为28．34％。     

Antioxidant activity of extracts from <Emphasis Type="Italic">Calocedrus formosana</Emphasis> leaf,bark, and heartwood

Calocedrus formosana Florin (Cupressaceae) is an endemic tree to Taiwan. To evaluate the antioxidant activity of the plant extracts from heartwood, bark, and leaf of C. formosana, assays for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities, as well as prevention of DNA strand cleavage were performed in this study. Similar IC₅₀ values against the DPPH radical were found for the heartwood and bark extracts at approximately 23µg/ml. Moreover, the heartwood extract exhibited the highest inhibitory activity against superoxide radicals among the test samples; a 2.3-fold lower value of IC₅₀ for superoxide radical inhibition was found in the heartwood extract relative to that of (+)-catechin. Much less effect on inhibition of DPPH and superoxide radicals was found from the leaf extract of C. formosana. More than 70% of superoxide radicals were inhibited in the presence of 10µg/ml heartwood extract, whereas only 15% inhibition was obtained from the leaf extract. The heartwood extract, at a dose of approximately 0.5mg/ml, apparently completely prevented the X174 supercoiled DNA cleavage induced by ultraviolet photolysis of H₂O₂, as judged by agarose gel electrophoresis. This report also suggests that the antioxidant activities of the plant extracts of C. formosana are in good correlation with their phenolic contents.     

Waxes composition of Quercus suber reproduction cork from different Spanish provenances

Summary The chemical composition of waxes was studied in Quercus suber cork planks collected in seven localities of the three main production areas of Spain. Waxes were extracted with chloroform (CHCl₃) and the extract was submitted to saponification in order to obtain the neutral and acid fractions. The trimethylsilyl derivatives of both fractions were analysed by GC-MS. The seven populations cannot be distinguished by their total contents of waxes (Chloroform extract) and of the neutral and acid fraction. This lack of differences could be due to the important variability among samples of each population. The neutral fraction was mainly composed of fatty alcohols (all the even members from C₁₈ to C₂₆, with traces of the intermediate odd members and some unsaturated groups) and triterpenes (11 components, among them friedelin, betulin and cerin were identified) and a very small amount of monocarboxylic fatty acids (C₁₆ and C₂₄ members) was also present. The main group of components of the acid fraction was that of fatty acids (saturated even C₁₄–C₂₄ and odd C₁₅, C₁₇, C₂₁ members, accompanied by a great amount of unsaturated terms and some ω-hydroxyacids, 18-hydroxy-9,12-octadecadienoic and 18-hydroxy-9-octadecenoic acids). Four triterpenes and the C₂₀ and C₂₄ alcohols were also detected in the acid fraction. Significant differences were found among the corks of the various provenances in the global contents of alcohols and triterpenes and in these individual components contents of the neutral fraction. Concerning the differences among the various provenances in the contents of the groups of fatty acids, alcohols, and triterpenes in the acid fraction, a higher number of differences were obtained in the comparisons of the contents of acids and triterpenes, whereas the differences were practically null in the case of the alcohols. When the differences were studied considering the individual compounds, the relation with the behaviour of the contents of the groups of components was not as clear as it happens in the neutral fraction. In this case, the differences were scarcer and they did not show a unique pattern, neither in the components, nor the populations. There is no correspondence in the differences among the provenances regarding the components of the neutral fraction or those of the acid fraction. No clear relationship was found between the geographical proximity of the provenances and chemical similarity of the waxes composition. Received 12 December 1997