7种黄檀属植物心材挥发油的成分分析及其抗菌活性

为了研究7种黄檀属（Dalbergia L.）植物心材的挥发性成分及其抗菌活性,采用水蒸气蒸馏法提取黄檀属植物心材的挥发性成分,气相色谱-质谱联用技术（GC-MS）对其化学成分进行分析;采用滤纸片琼脂扩散法测定挥发性成分的抗菌活性。结果表明,两粤黄檀检出9种成分,占总含量的98.93%;斜叶黄檀检出6种成分,占总含量的91.80%;交趾黄檀检出13种成分,占总含量的86.23%;海南黄檀检出9种成分,占总含量的94.86%;降香黄檀检出8种成分,占总含量的97.38%;东京黄檀检出8种成分,占总含量的97.72%;白沙黄檀检出23种成分,占总含量的79.45%。两粤黄檀和斜叶黄檀相对百分含量最大的成分为榄香素,分别为83.38%和73.03%;交趾黄檀中相对百分含量最大的成分为美迪紫檀素,为27.72%;海南黄檀中相对百分含量最大的成分为亚油酸,为42.80%;降香黄檀和东京黄檀中相对百分含量最大的成分为(7R,10S)-2,6,10-三甲基-7,10-环氧-2,11-十二碳-6-醇及其同分异构体,二者之和分别为60.37%和53.23%;白沙黄檀中已鉴定出且相对百分含量较大的成分为榄香素,为7.81%。黄檀属植物心材挥发性成分主要有苯丙素类、倍半萜类、黄酮类、脂肪酸类和甾体等,黄檀属植物心材的挥发性成分均对金黄色葡萄球菌具有抑制作用,部分挥发油对不同的农业病原菌具有一定的抑制作用。本研究为黄檀属植物的资源保护和开发利用提供了科学依据。     

茶多酚的抗菌活性

本文筛选了福氏痢疾杆菌、宋氏痢疾杆菌、金黄色葡萄球菌、绿胀杆菌、副伤寒杆菌及大肠杆菌等六种细菌,采用杯碟法对茶灰的提取物——茶多酚粗晶的抗菌活性进行测定。并与黄岑素作对照。结果表示:茶多酚对福氏痢疾杆菌等6种细菌的抑菌圈大于16mm 的浓度分别为1%、3%、与5%;而黄岑素对福氏痢疾杆菌等4种细菌的抑菌圈大于16mm 的浓度分别为10%与15%,并高达15%浓度的黄岑素药液对大肠杆菌无抑菌作用,对副伤寒杆菌的抑菌作用也不强。由此说明,茶多酚的抗菌活性比黄岑素强,抗菌谱也比黄岑素广。     

11种植物提取物对4种病原细菌的抑菌活性筛选

采用琼脂扩散法初步测试11种植物提取物对魔芋软腐病菌(Erwinia carotovora pv. carotovora)、猕猴桃溃疡病菌(Pseudomonas syringae pv. actinidiae)、白菜软腐病菌(Erwinia carotorora)、核桃细菌性黑斑病菌(Xanthomonas campestris pv.juglandis)4种病原细菌的抑制活性，进一步采用二倍稀释法测定高抑菌活性物质的最低抑菌浓度(MIC)，旨在为植物源杀细菌剂的研发提供线索。测定结果表明，1 000 μg/mL剂量下，大黄、博落回和狼毒提取物对魔芋软腐病菌具有较强抑制活性，对猕猴桃溃疡病菌抑制作用最好的是博落回和大黄提取物，对核桃黑斑抑菌效果最好的是蛇床提取物，均优于或相当于农用链霉素200 μg/mL的效果；二倍稀释法测试表明，大黄和博落回提取物对魔芋软腐病菌的MIC值分别为7.8、15.6 μg/mL；大黄和博落回提取物对猕猴桃溃疡病菌的MIC值分别为3.9、15.6 μg/mL。说明大黄、博落回和狼毒提取物均具有显著抑制植物病原细菌的活性，有开发为新型植物源杀细菌剂的潜力。     

128种南药植物提取物对6种病原菌的生长抑制作用

以水稻稻瘟病菌(Pyricularia oryzae Cav.)、香蕉枯萎病菌[(Fusarium oxysporum sp.cubense(E.F.Smith)Syn.et Han)]、香蕉炭疽病菌[Colletotrichum musae(Berk&Curt)Arx]、杧果炭疽病菌(Colletotrichum gloeosporioides PenZ)、辣椒炭疽病菌[Colletotrichum capsici(syd.)Butl.]和西瓜枯萎病菌(Fusarium oxysporum f.sp.niveum)6种病原菌为供试菌种,对47科128种南药植物的丙酮提取物进行室内抑菌活性试验。结果表明:有36种植物提取物对6种病原菌菌丝生长抑制率在60%以上;22种植物提取物对至少4种病原菌菌丝生长抑制率在80%以上;经方差分析,荜茇、艾纳香、白背叶、香茅、阴香、九里香、花椒、高良姜、益智、山柰、姜等11种植物提取物的抑菌效果与化学农药0.5mg/mL施保功的抑菌效果差异不显著。      

槟榔乙醇提取物对猪鸡五种致病菌的抑菌作用初探

采用倍比稀释法,评价了槟榔青果的乙醇提取物对猪鸡养殖中常见致病菌的抗菌作用。结果表明：提取物对鸡大肠杆菌、鸡沙门氏菌、鸡金黄色葡萄球菌、猪大肠埃希菌、猪金黄色葡萄球菌等5种致病菌有一定的抑菌作用,最低抑菌浓度(MIC)分别为62.5、31.25、31.25、62.5、62.5 g/L,而最低杀菌浓度(MBC)分别为125、62.5、62.5、125、125 g/L。     

广西山口8种红树林内生真菌的分离鉴定及抗菌活性菌株的筛选

采集广西山口8种红树林植物的多个部位,采用2种培养基分离培养红树林内生真菌;采用挖块法和琼脂扩散法对4种细菌和3种真菌进行抗菌试验。结果显示,从8种红树植物的根、茎、枝和叶上分离出104株内生真菌,叶片中共分出43株菌,数量最多。从白骨壤上分离得到菌株20株,占总菌株数的19.23%,比例最高。根据形态观察,内生真菌隶属8个类群及不产孢类,其中不产孢类46株,数量最多,其次是青霉属。抗菌试验筛选出20株内生真菌对至少1种指示菌具有抗菌活性。表明红树林内生真菌菌种资源丰富,这些菌株具有良好的抗菌活性,值得深入研究。     

20种植物提取物对南方根结线虫的毒杀活性

采用浸渍法测定13科20种植物乙醇提取物对南方根结线虫的毒杀活性。结果表明：酸豆、牛角瓜、番荔枝、苦楝乙醇提取物以10 mg/mL处理后24 h,供试2龄线虫校正死亡率分别为82.13%、85.71%、89.28%、89.28%,处理后48 h,校正死亡率分别为89.01%、96.34%、92.67%和96.34%,均具有强杀线虫活性;毒力测定结果表明：处理后24 h和48 h,4种提取物的LC50由小到大顺序为：酸豆＜牛角瓜＜番荔枝＜苦楝。     

芸薹属植物抗菌核病的研究进展

从芸薹属植物菌核病的发病原因、侵染过程及侵染方式，菌核病的致病机理和芸薹属植物的抗病机制等方面，以油菜为例综述菌核病的抗性遗传及抗菌核病的研究进展。     

艾纳香中的黄酮类化合物及其抗菌活性

为明确艾纳香抗菌药效物质基础,采用硅胶柱色谱, 凝胶色谱和反相色谱等技术从艾纳香乙酸乙酯部位中分离获得15个单体化合物,经波谱学鉴定分别为：3,3°,5-三羟基-4°,7-二甲氧基二氢黄酮 (1)、4°,5-二羟基-3,3°,7-三甲氧基黄酮 (2)、艾纳香素 (3)、3,5,3°,4°-四羟基-7-甲氧基黄酮 (4)、香叶木素 (5)、3°,4°,5-三羟基-3,7-二甲氧基黄酮 (6)、异鼠李素 (7)、chrysosplenol C (8)、金丝桃苷 (9)、异槲皮苷 (10)、3°,5,7-三羟基-4°-甲氧基二氢黄酮 (11)、sakuranetin (12)、pilloin (13)、5,7,3°,4°-四羟基-3-甲氧基黄酮 (14)、5-羟基-3,7,3°,4°-四甲氧基黄酮 (15),其中化合物7、11、12和13为首次从该植物中分得。抗菌活性评价结果显示：化合物1、3、6、8和12对3株细菌具有不同程度的抑制活性,其中化合物3对金黄色葡萄球菌抑制活性最强, 最低抑菌浓度MIC值为32 μg/mL。     

浅谈菠萝叶纤维抑菌物质研究

以菠萝叶纤维为研究对象,选用5种不同溶剂提取纤维中的活性成分进行定性分析,以大肠杆菌为指示菌,评价其抑菌效果。结果表明：通过定性分析发现石油醚、氯仿、乙酸乙酯、丙酮以及水5段提取物中分别含有酚类、黄酮类、生物碱及香豆素等抗菌成分。     

茜草不同极性提取物的体外抑菌活性研究

本文采用k-b纸片法研究了茜草不同极性溶剂提取物的抑菌作用,结果表明,石油醚提取物浓度为50mg／ml时,抑菌率为25．03％;乙酸乙酯层提取物浓度为50mg／mL时抑制率最高,为48．64％;丙酮层提取物浓度为50mg／mL时抑制率最高,为61．59％;甲醇层提取物浓度为50mg／mL时抑制率最高,为46．09％。     

Antibacterial activity of plant extracts obtained with alternative organics solvents against food-borne pathogen bacteria

The objectives of this study were: the chemical characterization of extracts from seven plants (Larrea tridentata, Flourensia cernua, Lippia graveolens, Agave lechuguilla, Yucca filifera, Opuntia ficus-indica, and Carya illinoensis) which are acclimated to the Mexican semi-desert. The extracts were obtained using Soxhlet method by water, ethanol and an infusion method using alternative organic solvents (lanolin and cocoa butter), in addition it was evaluated the antibacterial activity of semi-desert plant extracts against Enterobacter aerogenes, Escherichia coli, Salmonella typhi and Staphylococcus aureus. Chemical characterization of plant extracts showed that they are rich in secondary metabolites; cocoa butter was the non-conventional solvent which it was possible to obtain the highest content of total tannins. It was not possible to identify saponins in those extracts where non conventional solvents were used. While in extract where non conventional solvents were used, it was only possible to detect the presence of terpenes in creosote bush and prickly pear extracts. S. aureus was the bacterial strain that showed the highest growth inhibition as consequence of the plant extracts. The use of semi-desert plant extracts obtained using organic solvents are a good alternative for food-borne pathogen bacteria control because all the bacterial growth decreased with the tested extracts.     

Disease development and PR-protein activity in wheat (Triticum aestivum) seedlings treated with plant extracts prior to leaf rust (Puccinia triticina) infection

The potential to control leaf rust (Puccinia triticina; pathotype UVPt9) in vivo in susceptible (Thatcher) and resistant (Thatcher/Lr15) near-isogenic wheat (Triticum aestivum) lines by foliar applications of crude plant leaf extracts from Tulbaghia violacea and Agapanthus africanus, as well as a commercially available natural product, ComCat^®, and a Lupinus albus seed suspension (SS) was investigated. In vitro activities of the PR-proteins, β-1,3-glucanase, chitinase and peroxidase were quantified in these two wheat lines under both non-infected and infected conditions. Although foliar application of the different plant extracts accelerated the activities of all three enzymes in resistant infected wheat plants, it was only the A. africanus extract that increased the in vitro activities of the three apoplastic pathogenesis-related proteins significantly in both susceptible and resistant wheat cultivars, whether uninfected or infected. The latter resulted in the reduction of pustule and necrotic lesion formation in the susceptible and resistant wheat lines, respectively. Foliar treatment of wheat seedlings with either ComCat^® or SS had no effect on pustule and necrotic lesion formation. The A. africanus crude extract also had a significant in vitro inhibitory effect on both leaf rust spore germination and subsequent germ tube development.     

Efficacy of medicinal plant extracts against Formosan subterranean termite, Coptotermes formosanus

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is among the most devastating termite pests. Natural products derived from plant extracts were tested in a discovery programme for effective, environment friendly termite control agents. Screening for anti-termitic activity of plant extracts with some known medicinal attributes could lead to the discovery of new agents for termite control. The aim of this study was to investigate the anti-termitic activity of crude leaf hexane, ethyl acetate, acetone and methanol extracts of Andrographis lineata Wallich ex Nees. (Acanthaceae), Andrographis paniculata (Burm.f.) Wall. ex Nees. (Acanthaceae), Argemone mexicana L. (Papaveraceae), Aristolochia bracteolata Lam. (Aristolochiaceae), Datura metel L. (Solanaceae), Eclipta prostrata L. (Asteraceae), Sesbania grandiflora (L.) Pers. (Fibaceae) and Tagetes erecta L. (Compositae) against C. formosanus. An impregnated filter paper no-choice bioassay method was followed. All the crude extracts showed anti-termitic activity in a dose-dependent manner and exhibited a significant activity after 24 h and 48 h of exposure; the highest termite mortality was found in leaf hexane extract of A. bracteolata, ethyl acetate extract of A. paniculata, D. metel, E. prostrata, methanol extract of A. lineata and D. metel after 24 h (LD₅₀ = 363, 371, 298, 292, 358 and 317 ppm; LD₉₀ = 1433, 1659, 1308, 1538, 1703 and 1469 ppm), respectively. The hexane extract of T. erecta, acetone extract of A. mexicana, methanol extract of S. grandiflora and T. erecta showed activity after 48 h (LD₅₀ = 245, 253, 289, 409 ppm; LD₉₀ = 1378, 1511, 1508 and 2425 ppm), respectively. Among the natural products tested, may provide a renewable source of safe natural wood preservatives. These findings corroborate traditional insecticidal application of selected plants and the results can be extended for the control of termites. The primary objective of the present study was to identify novel, natural chemotypes from biologically active crude plant extracts that may be useful as part of termite treatment regimens in their natural form or as synthons for structure-activity studies in the future. The results reported here open the possibility of further investigations of efficacy on their anti-termitic properties of natural product extracts.     

Antifungal properties of Agapanthus africanus L. extracts against plant pathogens

Crude extracts of various Agapanthus africanus plant parts were screened in vitro against eight economically important plant pathogenic fungi. Radial mycelial growth was inhibited significantly (P<0.05) in five test organisms, while Pythium ultimum, and to a lesser extent Fusarium oxysporum and Alternaria alternata, showed a degree of tolerance. Subsequently, these crude extracts were tested in vivo in the greenhouse against Mycosphaerella pinodes, the cause of black spot or Ascochyta blight in peas. Fourth internode leaves were removed from 4-week-old pea plants, placed on moist filter paper in Petri dishes and inoculated with a M. pinodes spore suspension 30 min before and after treatment with the extracts. The control of Ascochyta blight by different concentrations of the crude extracts was measured in terms of lesion size over a 6-d period at 20 °C in a growth cabinet. All crude extracts significantly reduced lesion development caused by M. pinodes when leaves were inoculated with spores both before and after treatment with the extracts. Neither of the extracts showed any phytotoxic reaction on the leaves, even at the highest concentration applied. A combined aerial part crude extract of A. africanus was additionally evaluated against sorghum covered (Sporisorium sorghi) and loose (Sporisorium cruentum) kernel smuts under field conditions over two seasons. The extract and a standard fungicide, Thiram that served as a positive control, were applied as seed treatments 1 h after artificially inoculating separate sets of sorghum seed with smut spores. Inoculated, but untreated seeds served as a negative control. The extract reduced the incidence of both loose and covered kernel smuts significantly (P<0.05) and compared favourably with the prescribed fungicide, Thiram. Both treatments resulted in significant yield increases compared to the untreated control. From these results it was concluded that the aerial part crude extract of A. africanus possesses sufficient in vivo antifungal activity to warrant a further investigation.     

Antifungal activity of leaf extracts from South African trees against plant pathogens

The antifungal activity of acetone, methanol, hexane and dichloromethane leaf extracts of six plant species (Bucida buceras, Breonadia salicina, Harpephyllum caffrum, Olinia ventosa, Vangueria infausta and Xylotheca kraussiana) were evaluated for antifungal activity against seven plant pathogenic fungal species (Aspergillus niger, Aspergillus parasiticus, Colletotricum gloeosporioides, Penicillium janthinellum, Penicillium expansum, Trichoderma harzianum and Fusarium oxysporum). These plant species were selected from 600 evaluated inter alia, against two animal fungal pathogens. All plant extracts were active against the selected plant pathogenic fungi. Of the six plant species, B. buceras had the best antifungal activity against four of the fungi, with minimum inhibitory concentration (MIC) values as low as 0.02 mg/ml and 0.08 mg/ml against P. expansum, P. janthinellum, T. harzianum and F. oxysporum. Some of the plant extracts had moderate to low activity against other fungi, indicating that the activity is not based on a general metabolic toxicity. P. janthinellum, T. harzianum and F. oxysporum were the most sensitive fungal species, with a mean MIC of 0.28 mg/ml, while the remaining four fungi were more resistant to the extracts tested, with mean MICs above 1 mg/ml. The number of active compounds in the plant extracts was determined using bioautography with the listed plant pathogens. No active compounds were observed in some plant extracts with good antifungal activity as a mixture against the fungal plant pathogens, indicating possible synergism between the separated metabolites, B. salicina and O. ventosa were the most promising plant species, with at least three antifungal compounds. Leaf extracts of different plant species using different methods (acetone, hexane, DCM and methanol) had antifungal compounds with the same R_f values. The same compounds may be responsible for activity in extracts of different plant species. Based on the antifungal activity, crude plant extracts may be a cost effective way of protecting crops against fungal pathogens. Because plant extracts contain several antifungal compounds, the development of resistant pathogens may be delayed.     

Antifungal activity of liquid waste obtained from the detoxification of steam-exploded plant biomass against plant pathogenic fungi

The antifungal activity of steam-exploded liquid waste (SELW) produced by the detoxification of steam-exploded biomass of Miscanthus sinensis, Arundo donax and wheat straw for 2nd generation industrial bioethanol production was studied against plant pathogenic fungi for the first time. Quantification of fermentation inhibitors (2-furaldehyde, 5-hydroxymethylfurfural, acetic and formic acid) was carried out by standard methods. Mycelial growth inhibition and conidial germination of eight fungal strains [Alternaria alternata, Botrytis cinerea, Colletotrichum acutatum, Cladosporium fulvum, Fusarium oxysporum f. sp. lycopersici (FOL), F. oxysporum f. sp. melonis (FOM), F. solani f. sp. pisi and Verticillium dahliae] were evaluated in vitro at different dilution rates (1:2, 1:4 and 1:8) for each SELW. Disease suppressiveness was assessed in vivo in eight horticultural pathosystems (A. alternata/tomato, B. cinerea/tomato, C. acutatum/strawberry, C. fulvum/tomato, FOL/tomato, FOM/melon, F. solani f. sp. pisi/pea and V. dahliae/eggplant) under greenhouse conditions. Pathogen suppression by each SELW, applied both in spray form on to tomato leaves and skins of tomato and strawberry, and by means of dipping method in watering suspensions on to seedling root systems of tomato, melon, pea and eggplant, was evaluated at dilution rates of 1:2, 1:4 and 1:8 using irrigation water during curative and preventive treatments. Investigations carried out in vitro showed that M. sinensis SELW was more suppressive than wheat straw SELW, and A. donax SELW was less suppressive than wheat straw SELW at the lowest dilution rates. Relationships between the concentration of 2-furaldehyde, acetic and formic acid present in SELWs and their antifungal effect were found. Moreover, B. cinerea, C. fulvum, V. dahliae, A. alternata, C. acutatum and F. solani f. sp. pisi were more effectively inhibited than FOL and FOM. Investigations performed in vivo showed that SELWs of M. sinensis and wheat straw can be diluted at a 1:2 rate and used for controlling six fungal diseases during preventive treatments. In particular, they can be used by dipping of the root systems during transplanting in the case of F. solani f. sp. pisi/pea and V. dahliae/eggplant; on the other hand, they can be nebulized on to the leaves and fruits before symptoms appearance in the case of A. alternata/tomato, B. cinerea/tomato, C. acutatum/strawberry and C. fulvum/tomato. This study is of particular interest because it points out how these SELWs could be employed in horticultural crop protection in Southern Italy, thereby making it possible to effectively combine industrial production of 2nd generation biofuels with sustainable horticulture under greenhouse conditions.     

白千层精油的化学成分与抑菌活性研究

研究白千层精油的化学成分及其对植物病原真菌的抑菌活性,为环境友好型农药的研发及白千层的综合应用提供理论依据。采用气相色谱-质谱（GC-MS）联用技术分析了白千层精油的化学成分,并用菌丝生长速率法测定了白千层精油对4种植物病原真菌的抑菌活性。从白千层精油中分离鉴定出74种化学成分,占总含量的97.28%,其主要化学成分是左旋-α-蒎烯（2.07%）、β-月桂烯（1.05%）、1,8-桉叶素（67.29%）、萜品烯（2.52%）、芳樟醇（2.36%）、α-松油醇（7.93%）和(+)-g-桉叶油醇（1.26%）等。进一步研究表明,白千层精油在5.0~10.0 μL/mL浓度范围对立枯丝核菌菌丝生长抑制率为100%;处理2 d时,白千层精油在2.5~10.0 μL/mL浓度下对小孢拟盘多毛孢菌、水稻稻瘟病菌和香蕉枯萎病菌的菌丝生长抑制率达71.59%以上,其抑菌作用均随着处理浓度的增加而增强,随着白千层精油处理时间的延长,对3种植物病原菌表现出较好的持效性。白千层精油对立枯丝核菌、小孢拟盘多毛孢菌、水稻稻瘟病菌和香蕉枯萎病菌均具有较强的抑菌活性,在农用抗菌剂应用中有较好的应用潜力。     

茶树花皂苷提取分离、化学结构及生物活性研究进展

茶树花皂苷作为茶资源中重要的功能成分日益受到人们的关注。本文对至今已发现的21种茶树花皂苷单体的分离鉴定、纯化方法、化学结构进行了详细的综述。并总结了其肠胃保护，抗血脂、抗血压，减肥等生物功能，分析了这些生物活性与皂苷的构效关系。并对茶树花皂苷发展趋势提出了展望。