Antimicrobial and pesticidal activity of partially purified flavonoids of Annona squamosa

Foliar extracts of Annona squamosa (Family: Annonaceae) were screened for antimicrobial and insecticidal activity against the common microbial infestants of pulses and the stored grain pest pulse beetle, Callosobruchus chinensis (Coleoptera: Bruchidae). Flavonoids isolated from aqueous extracts of A squamosa showed antimicrobial activity against all the common microbial contaminants of pulses and 80% insecticidal activity against C chinensis at a concentration of 0.07 mg ml-1. Various physico-chemical tests, chromatographic and spectroscopic studies with partially purified aqueous extract indicated the presence of flavonol type flavonoids. This may provide a useful beginning for the development of botanical pesticides for post-harvest safeguard of pulses.     

氟虫腈衍生物-糖基偶合物的合成及其在蓖麻韧皮部的输导性研究

为提高氟虫腈在植物体内的输导性,利用葡萄糖、半乳糖与木糖作为导向基团对其进行了糖基化修饰,设计合成了3个含乙酰保护基的糖基-氟虫腈偶合物(a,b,c)和3个脱保护基的偶合物(d,e,f)。采用液相色谱法测定了其在蓖麻幼苗韧皮部中的输导积累性。结果表明:化合物a、b、c无韧皮部输导性,而d、e、f 则具有良好的韧皮部输导性;培养2 h后,收集的第3 h内韧皮部液中 d、e、f 的浓度分别为21.45、14.14 和14.82 μ mol/L。饲料拌毒法测定结果表明,与母体化合物氟虫腈(LC50为4.49 μ mol/L)相比,6个偶合物对亚洲玉米螟Ostrinia furnacalis的杀虫活性均有所下降,LC50值在47.54~78.00 μ mol/L之间。     

Compounds from Ageratum conyzoides: isolation, structural elucidation and insecticidal activity

This work aimed at identifying plant compounds with insecticidal activity against Diaphania hyalinata (L.) (Lepidoptera: Pyralidae), Musca domestica (L.) (Diptera: Muscidae), Periplaneta americana (L.) (Blattodea: Blattidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetaefolia L.), Jimson weed (Datura stramonium L.), 'baleeira' herb (Cordia verbenaceae L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.) and billy goat weed (Ageratum conyzoides L.). Firstly, the insecticidal activities of hexane and ethanol plant extracts were evaluated against adults of R. dominica. Among them, only the hexane extract of A. conyzoides showed insecticidal activity. The hexane extract of this plant species was therefore fractionated by silica gel column chromatography to isolate and purify its bioactive chemical constituents. Three compounds were identified using IR spectra, (1)H NMR, (13)C NMR, HMBC and NOE after gel chromatography: 5,6,7,8,3', 4', 5'-heptamethoxyflavone, 5,6,7,8,3'-pentamethoxy-4', 5'-methylenedioxyflavone and coumarin. The complete assignment of (13)C NMR to 5,6,7,8,3'-pentamethoxy-4', 5'-methylenedioxyflavone was successfully made for the first time. 5,6,7,8,3'-Pentamethoxy-4', 5'-methylenedioxyflavone did not show any insecticidal activity against the four insect species tested. 5,6,7,8,3', 4', 5'-Heptamethoxyflavone showed low activity against D. hyalinata and R. dominica and was not toxic to M. domestica or P. americana. In contrast, coumarin showed insecticidal activity against all four insect pest species tested, with the following order of susceptibility: R. dominica < P. americana < D. hyalinata < M. domestica after 24 h exposure.     

白背黄花稔Sida rhombifolia的生物活性及化学成分研究

用石油醚和乙酸乙酯分别对白背黄花稔 Sida rhombifolia L.地上部分的乙醇提取物进行萃取,得不同萃取相;测定了乙醇提取物及不同萃取相对白纹伊蚊 Aedes albopictus Skuse 4龄幼虫和福寿螺 Ampullaria gigas Spix的毒杀活性。结果表明,乙醇提取物和乙酸乙酯相对白纹伊蚊4龄幼虫的杀虫活性明显,而石油醚相和乙醇提取物对福寿螺的杀螺活性较好。对乙酸乙酯相进一步分离得到11个化合物,经核磁共振氢谱(1H NMR)和碳谱(13C NMR)鉴定其分别为已知化合物:间-羟基苯甲酸(1)、棕榈酸1-甘油酯(2)、丁香酸(3)、没食子酸(4)、 β -谷甾醇(5)、豆甾醇(6)、东莨菪内酯(7)、山奈酚(8) 、5-羟基-7,4'-二甲氧基二氢黄酮(9)、3- O - β -D-葡萄糖-(6- O -对羟基反式香豆酰基)-山奈素苷(10)和 β -谷甾醇-3- O -葡萄糖苷(11)。其中化合物 2 对白纹伊蚊4龄幼虫具有较好的杀虫活性,24 h和48 h的LC50值分别为28.66和13.50 μg/mL。     

Insecticidal activity of deoxypodophyllotoxin, isolated from Juniperus sabina L, and related lignans against larvae of Pieris rapae L

In the course of screening for naturally occurring insecticides from plants from the northwestern part of China, a petroleum ether extract of Juniperus sabina L was found to show insecticidal activity against fifth-instar larvae of Pieris rapae L. From the extract, an insecticidal compound was isolated by bioassay-guided fractionation. The compound was identified as deoxypodophyllotoxin (1) by comparison of its spectroscopic characteristics with literature data. In bioassays, 1 showed antifeedant activity against fifth-instar larvae of P rapae at 0.05-1.00 g litre(-1) and its AFC50 (concentration for 50% antifeedant activity) values at 12 and 48h were 0.170 and 0.060 g litre(-1), respectively. In that concentration range, all treated insects died within 48 h after treatment and compound 1 showed delayed insecticidal activity. At 0.015-0.100 g litre(-1), 1 showed insecticidal activity, with an LC50 of 0.020 g litre(-1). The related compound deoxypicropodophyllotoxin (2), however, showed lower antifeedant and insecticidal activities than 1 in bioassay. This indicated that the trans-lactone ring is an important moiety for enhancing activity in these compounds. Comparison of the insecticidal activities of 1 and another related compound, podophyllotoxin (3), suggested that varying the substituent at C-4 is an exciting possibility for synthesizing more potent analogues.     

Activity of Ricinus communis (Euphorbiaceae) and ricinine against the leaf-cutting ant Atta sexdens rubropilosa (Hymenoptera: Formicidae) and the symbiotic fungus Leucoagaricus gongylophorus

The focus of this study was the identification of compounds from plant extracts for use in crop protection. This paper reports on the toxic activity of fractions of leaf extracts of Ricinus communis L (Euphorbiaceae) and isolated active compounds in the leaf-cutting ant Atta sexdens rubropilosa Forel and its symbiotic fungus Leucoagaricus gongylophorus (Singer) M?ller. The main compounds responsible for activity against the fungus and ant in leaf extracts of R communis were found to be fatty acids for the former and ricinine for the ants.     

松油烯-4-醇对淡色库蚊的熏蒸毒力及对其Na+ ,K+ -ATP酶的抑制作用

为进一步探讨杀虫植物砂地柏Sabina vulgaris Ant.精油中主要杀虫活性成分—松油烯-4-醇(terpinen-4-ol)对卫生害虫的生物活性,测定了该物质对淡色库蚊Culex pipiens Pallens及其Na+,K+-ATP酶活性的影响。结果表明:松油烯-4-醇对淡色库蚊具有较强的熏蒸作用,其LC50值为6.79 mg/L, 在LC80剂量下其击倒中时(KT50)为6.92 min;淡色库蚊Na+,K+-ATP酶活性测定的最佳反应条件为pH值7.42、温度35.5℃、底物浓度0.7 mmol/L;离体和活体情况下,松油烯-4-醇均可显著抑制淡色库蚊Na+,K+-ATP酶的活性,其I50值为32.02 μg/mL。Na+,K+-ATP酶可能是松油烯-4-醇对淡色库蚊的杀虫作用靶标。     

Efficacy of leaf extract fractions of Glycyrrhiza glabra L. against downy mildew of cucumber (Pseudoperonospora cubensis)

An ethanolic leaf extract of Glycyrrhiza glabra L. (licorice) was highly effective in former bioassays and semi-commercial trials in controlling cucumber downy mildew (efficacy up to 99.0?% in bioassays and 83.0?% in semi-commercial trials). In order to elucidate the active ingredients and the mode of action, licorice leaf extract was fractionated into six fractions of defined substance classes, of which the fraction containing acidic substances (F6) showed highest efficacy (97.6?%). The calculated EC₅₀ values after a probit analysis of concentration series of crude extract and fraction F6 were concentrations of 1.0?% (crude extract) and 0.6?% (fraction F6). Interestingly, the slopes of the resulting graphs were significantly different, pointing to different modes of action for the two treatments. Three flavonoid compounds could be detected. The substances were glabranin, licoflavanon and pinocembrin. All three are known for their antimicrobial and antifungal capacity against plant and human pathogens. Besides these flavonoids, results, such as the different EC₅₀ values, indicated that other compounds may be involved in the activity of fraction F6 against P. cubensis on cucumber.     

蓖麻不同部位蓖麻碱的含量及其杀虫活性

采用高效液相色谱(HPLC)外标法测定并比较了蓖麻Ricinus communis不同部位和不同生长期蓖麻叶中蓖麻碱的含量,并研究了其对甜菜夜蛾Spodoptera exigua的毒杀效果。结果表明,蓖麻不同部位中蓖麻碱的含量差异较大,由高到低依次为叶(1.005%)>籽壳(0.568%)>饼粕(0.451%)>茎(0.429%)>籽仁(0.235%);不同生长期蓖麻叶中蓖麻碱的含量也存在很大差别,其中鲜绿叶中的含量最高。提取的蓖麻碱对甜菜夜蛾具有良好的毒杀效果,施药72 h后对2龄幼虫的LC50值为0.35 mg/mL。     

硬毛棘豆根的抑菌活性成分研究

为明确硬毛棘豆Oxytropis hirta Bunge根的农用抑菌活性成分,用75％乙醇浸提硬毛棘豆根,得到粗提物;再分别以石油醚、乙酸乙酯与正丁醇为溶剂对粗提物进行萃取,得到不同溶剂萃取相;通过活性追踪法对抑菌活性好的乙酸乙酯相运用现代柱层析与波谱学技术进行了分离与结构鉴定,并对所分离的化合物进行了抑菌活性评价.结...     

牛筋草内生菌砖红链霉菌CSF09杀虫成分鉴定及活性初步研究

为了从微生物中筛选天然杀虫活性化合物,从牛筋草中分离到1株具有杀虫活性的内生放线菌砖红链霉菌Streptomyces lateritius CSF09。采用大孔吸附树脂提取和硅胶柱层析技术,从CSF09菌株发酵液中分离到1个杀虫活性成分,通过质谱和核磁共振波谱鉴定了其化学结构,并初步测定了该化合物对3龄粘虫幼虫和家蝇成虫的杀虫活性。结果表明:该菌株发酵液中的杀虫活性成分为4-甲氧基水杨醛,发酵单位约为13 mg/L;4-甲氧基水杨醛对家蝇和粘虫均表现出一定的触杀活性,其中对家蝇的LD50值为1.51 μg/头,对粘虫毒力较弱,以10 μg/头剂量处理时校正死亡率仅为36.6%;4-甲氧基水杨醛杀虫活性的突出特性是作用迅速,其击倒中时（KT50）大多在5 min以内。研究表明,4-甲氧基水杨醛具有一定的卫生杀虫剂开发应用潜力。     

Identification and use of a wild plant with antimicrobial activity against Ralstonia solanacearum, the cause of bacterial wilt of potato

Fresh aerial tissue and roots of 14 wild plants in Okinawa prefecture were investigated for their antimicrobial activity against Ralstonia solanacearum , which causes bacterial wilt of potato. A 70% aqueous ethanol extract of fresh aerial tissue of Geranium carolinianum L. showed strong antimicrobial activity against R. solanacearum . This extract also showed antimicrobial activity against the pathogens causing common scab of potato and soil rot of sweet potato. The antimicrobial substance could be extracted with hot water, and was effective against R. solanacearum in soil. In the field test, a treatment combining incorporation of dried aerial tissue into the soil and solarization was highly effective for control of bacterial wilt of potato. These findings suggest that G. carolinianum L. could be used as a biological agent for the control of bacterial wilt of potato.     

苦参杀虫抑菌活性成分研究

苦参(SophoraflavescensAit)为豆科槐属灌木,分布广泛,是我国历史悠久的传统药物之一,主要功效清热、杀虫、利尿、祛湿[1]。苦参在农业上的应用,近几年引起人们的重视,有1.1%苦参碱醇溶液等几个产品获得登记。但多数研究只是停留在苦参的粗提物直接用于病虫害防治上,对苦参的生物活性与其成分的联系研究甚少。本文以生物活性追踪试验为指导,从苦参提取物中分离到2个主要杀虫抑菌活性化合物,参考文献报道的波谱数据,确定其结构分别为苦参酮(Kurarinone)(I)和槐属二氢黄酮G(SophoraflavanoneG)(II)。I　R=OCH3　　II　R=H1　结果与讨…     

Larvicidal activity against Plutella xylostella of cordycepin from the fruiting body of Cordyceps militaris

The insecticidal activities of methanol extracts of Cordyceps militaris Link (Ascomycotina: Clavicipitaceae) cultured on fresh pupae of Bombyx mori L against 3rd-instar larvae of Plutella xylostella L were examined using direct contact application. The larvicidal activity was more pronounced in an extract of C militaris fruiting body than in an extract of the pupae separated from the culture. The biologically active constituent of the Cordyceps fruiting body was characterized as cordycepin (3'-deoxyadenosine) by spectroscopic analysis. Responses varied according to dose, exposure time and application method. In a leaf-dipping test, cordycepin at 500 mg litre-1 caused no mortality at 1 DAT (day after treatment) but 78 and 100% mortality at 2 and 4 DAT, respectively, whereas 34 and 88% mortality at 3 and 5 DAT, respectively was observed at 300 mg litre-1. Cordycepin caused body colour change from pale green to dark brown and eventually body lysis. These results suggested that the larvicidal action may be attributable to a direct effect rather than an inhibitory action on chitin synthesis. There was a significant difference in insecticidal activity of cordycepin between leaf dipping (500 mg litre-1) with 100% mortality and topical application (10 micrograms per larva) with 0% mortality, suggesting that cordycepin has stomach action. Cordycepin merits further study as a potential P xylostella control agent or as a lead compound.     

杠柳的不同溶剂提取分离物对小菜蛾幼虫的拒食和毒杀作用

以生物活性跟踪法测定了杠柳Periploca sepium Bunge 的不同溶剂提取液及其不同馏份对小菜蛾幼虫的拒食和毒杀活性。结果表明,杠柳根皮的乙醇提取液和氯仿提取液对小菜蛾具有较强的拒食和毒杀活性,该生物活性高于石油醚提取液。乙醇提取物水溶后分别用苯、正丁醇溶剂萃取。生物测定结果显示,苯萃取物对小菜蛾的活性最高,表明其活性成分主要分布在苯萃取物中。苯萃取物通过硅胶柱层析分离,淋洗液为石油醚、石油醚/乙酸乙酯不同比例混合液、乙酸乙酯、乙酸乙酯/甲醇不同比例混合液和甲醇,根据颜色和极性,将收集到的淋洗液分成8个馏份,其中5、6、7号3个馏份对小菜蛾幼虫具有强烈的拒食和毒杀作用,其200倍液对小菜蛾幼虫的拒食率分别为99.8%、99.1%和98.6%,校正死亡率分别为92.1%、91.5%和100%。     

来自大兴安岭凋落物的绿僵菌及其相近菌属真菌的生物活性

为研究绿僵菌Metarhizium及其相近菌属真菌的生物活性,采用形态学和分子生物学的方法对来自大兴安岭凋落物的肉色基思菌Keithomyces carneus（曾用名：肉色绿僵菌M.carneum）与马氏马昆德菌Marquandomyces marquandii（曾用名马昆德绿僵菌M. marquandii）以及金龟子绿僵菌Metarhizium anisopliae进行了鉴定,并分析了它们对3种害虫、4种植物病原菌的活性。杀虫活性测定表明,肉色基思菌与马氏马昆德菌对双斑萤叶甲Monolepta hieroglyphica、玉米蚜Rhopalosiphum maidis、绿豆象Callosobruchus chinensis具有侵染能力,为非寄主专化型真菌。抑菌活性测定表明,肉色基思菌对立枯丝核菌Rhizoctonia solani,水稻白叶枯病菌Xanthomonas oryzae pv. oryzae等病原菌具有抑菌活性。本研究揭示了3种供试真菌具有防治双斑萤叶甲的潜力,也发现了肉色基思菌与马氏马昆德菌的生防潜力,为它们进一步开发利用打下了基础。     

Fumigant activity of plant essential oils and components from horseradish (Armoracia rusticana), anise (Pimpinella anisum) and garlic (Allium sativum) oils against Lycoriella ingenua (Diptera: Sciaridae)

Plant essential oils from 40 plant species were tested for their insecticidal activities against larvae of Lycoriella ingénue (Dufour) using a fumigation bioassay. Good insecticidal activity against larvae of L. ingenua was achieved with essential oils of Chenopodium ambrosioides L., Eucalyptus globulus Labill, Eucalyptus smithii RT Baker, horseradish, anise and garlic at 10 and 5 microL L(-1) air. Horseradish, anise and garlic oils showed the most potent insecticidal activities among the plant essential oils. At 1.25 microL L(-1), horseradish, anise and garlic oils caused 100, 93.3 and 13.3% mortality, but at 0.625 microL L(-1) air this decreased to 3.3, 0 and 0% respectively. Analysis by gas chromatography-mass spectrometry led to the identification of one major compound from horseradish, and three each from anise and garlic oils. These seven compounds and m-anisaldehyde and o-anisaldehyde, two positional isomers of p-anisaldehyde, were tested individually for their insecticidal activities against larvae of L. ingenua. Allyl isothiocyanate was the most toxic, followed by trans-anethole, diallyl disulfide and p-anisaldehyde with LC(50) values of 0.15, 0.20, 0.87 and 1.47 microL L(-1) respectively.     

12种除草剂对玉米田鸭跖草的防效

采用田间小区试验方法,测定12种除草剂对玉米田鸭跖草的防效。在玉米3~5叶期、鸭跖草3~7叶期进行茎叶喷雾处理,施药后观察鸭跖草的药害症状并定时调查除草效果。试验结果表明:氯氟吡氧乙酸、苯唑草酮、硝磺草酮以及含有以上成分的复配制剂对鸭跖草有较高防效。因此,防除玉米田鸭跖草可选择氯氟吡氧乙酸、苯唑草酮、硝磺草酮等除草剂单剂或含有以上成分的除草剂混剂。     

Insecticidal activity of the enantiomers of fipronil

The two enantiomers of the insecticide fipronil were made by preparative HPLC. The insecticidal activities of the racemic mixture and the two enantiomers against selected agricultural or household pests (cotton stainer, Dysdercus cingulatus F; grain weevil, Sitophilus granarius L and house fly, Musca domestica L) were determined. There was no significant difference in acute or residual activity between the racemic mixture and the enantiomers of fipronil, indicating that there is no preferred chiral form of the compound in these key species of important insects. This observation clearly suggests that there is no major scope for marketing the insecticide in a one-enantiomer form.     

藜不同溶剂提取物的杀蚜活性

以萝卜蚜为试虫,对4种不同溶剂藜提取物的杀蚜活性进行了研究。结果表明,石油醚和乙醇提取物的杀虫活性最为显著,对萝卜蚜有很强的触杀和拒食作用,石油醚提取物72 h的平均拒食率为73.33%,拒食中浓度AFC_(50)为61.731 mg/mL,触杀校正死亡率为97.69%,LC_(50)为22.431 mg/mL;乙醇提取物72 h的触杀校正死亡率为93.82%,LC_(50)为34.698 mg/mL,与对照组具有显著差异。此外,藜其他溶剂提取物也表现出一定的杀蚜活性。