Nitrogen Availability and Defense of Tomato Against Two-spotted Spider Mite

The aim of this work was to study how nitrogen availability affects within-plant allocation to growth and secondary metabolites and how this allocation affects host selection by herbivores. Tomato plants (Lycopersicon esculentum) were grown at six levels of nitrogen availability. When nitrogen availability increased, plant relative growth rate increased, but tissue carbon/nitrogen ratio in the second oldest true leaf and allocation to large glandular trichomes (type VI) as well as to the defense compounds rutin and chlorogenic acid decreased. Leaf protein concentration increased. Two-spotted spider mite (Tetranychus urticae) females responded significantly to these changes: in dual choice tests they preferred leaf disks from plants grown at high nitrogen availability, with a low C/N ratio. This preference persisted in an olfactometer in which the mites were offered only the odors released by leaves with damaged trichomes. We conclude that in a tomato leaf increased nitrogen availability leads to decreased allocation to defenses, and that repellent volatiles released by trichomes play a key role in affecting leaf selection by two-spotted spider mite females.     

Effect of Nighttime Temperature on Tomato Plant Defensive Chemistry

Given that the amplitude of diurnal temperature fluctuations has been decreasing, mainly via warmer night temperatures, we examined the effects of nighttime temperature on concentration of the catecholic phenolics chlorogenic acid and rutin in tomato plants. A two-factor design, with carbon dioxide (350 ppm and 700 ppm) and nighttime temperature (14, 15, 16, 17, and 18°C, with a 26°C daytime temperature) was used. Compared to the lower carbon dioxide level, for whole plants the concentration of phenolics was lower at the higher carbon dioxide level, but patterns for plant parts differed. Nighttime temperature did not affect concentration of phenolics for whole plants, but it did influence concentration of the phenolics for plant parts, although not in predictable ways. Furthermore, the pattern of concentration of chlorogenic acid was somewhat different from that of rutin. The amount of change in concentration of these allelochemicals is likely sufficient to have substantial effects on insect herbivores. We conclude that nighttime temperature affects concentration of allelochemicals in tomato plants in significant ways.     

BIOTECHNOLOGY AND BIOENGINEERING Roles of biomolecules in the biosynthesis of silver nanoparticles: Case of gardenia jasminoides extract

Rapid development of biosynthesis of metal nanoparticles using plants has attracted extensive interests to further investigate this novel and eco-friendly method. In the biosynthesis process, the plant may act as reducing agent, capping agent or shape directing agent. However, identifying specific roles of various components in the plant is challenging. In this study, we use biosynthesis of silver nanoparticles with Gardenia jasminoides Ellis ex-tract to address this issue. The formation process of silver nanoparticles is investigated and the nanoparticles are characterized with the ultraviolet-visible spectroscopy, Fourier transform infrared spectra and scanning electron mi-croscopy. The results indicate that the Gardenia jasminoides Ellis extract can reduce silver ions to form silver nanoparticles, stabilize the nanoparticles, and affect the growth of silver nanocrystal to form silver nanowires. Only geniposide in the extract exhibits good shape-directing ability for silver nanowires. It is found that bovine albumin is a potential capping agent, whereas rutin, gallic acid and chlorogenic acid possess reducing and capping ability.     

Interaction of nuclear polyhedrosis virus with catechols: Potential incompatibility for host-plant resistance against noctuid larvae

Two major orthodihydroxy phenolics ofLycopersicon esculentum, rutin and chlorogenic acid, have previously been identified as potential sources of host-plant resistance against the tomato fruitwormHeliothis zea. We report here the possible incompatibility of these chemically based resistance factors with viral control ofH, zea. We have found that both rutin and chlorogenic acid significantly inhibited the infectivity of nuclear polyhedrosis viruses. Chlorogenic acid, when added to tissue culture medium containing TN-368 ovarian cells, inhibited the infectivity of a multiply embedded virus (AcMNPV) by over 86%. Rutin or chlorogenic acid, when fed toH. zea, inhibited the infectivity of a singly embedded nuclear polyhedrosis virus (HzSNPV), with the greatest degree of inhibition occurring at low doses of viral inoculum. Additionally, the ingestion of these phytochemicals significantly prolonged the survival time of virally infectedH. zea larvae. These results suggest that the effectiveness of nuclear polyhedrosis viruses in controllingH. zea populations may be adversely affected by varieties ofL. esculentum with significant levels (eg. 3.5 mol/g wet weight) of rutin or chlorogenic acid.     

绿原酸和芦丁的提取工艺研究进展

综述了杜仲中绿原酸和芦丁的提取研究进展。重点介绍了绿原酸和芦丁的溶剂提取、物理强化提取、离子液体提取等方面研究,并展望了其提取工艺的发展趋势和应用潜能。     

Effect of Eleven Antioxidants in Inhibiting Thermal Oxidation of Cholesterol

Eleven antioxidants including nine phenolic compounds (rutin, quercetin, hesperidin, hesperetin, naringin, naringenin, chlorogenic acid, caffeic acid, ferulic acid), vitamin E (α‐tocopherol), and butylated hydroxytoluene (BHT) were selected to investigate their inhibitory effects on thermal oxidation of cholesterol in air and lard. The results indicated that the unoxidized cholesterol decreased with heating time whilst cholesterol oxidation products (COPs) increased with heating time. The major COPs produced were 7α‐hydroxycholesterol, 7β‐hydroxycholesterol, 5,6β‐epoxycholesterol, 5,6α‐epoxycholesterol, and 7‐ketocholesterol. When cholesterol was heated in air for an hour, rutin, quercetin, chlorogenic acid, and caffeic acid showed a strong inhibitory effect. When cholesterol was heated in lard, caffeic acid, quercetin, and chlorogenic acid demonstrated inhibitory action during the initial 0.5 h (p < 0.05), with caffeic acid being the best inhibitor. Hesperetin, naringenin, caffeic acid, ferulic acid, vitamin E, and BHT could decrease the peroxide value during the initial 0.5 and 1 h (p < 0.05) in lard. It seemed that 200 ppm antioxidant could not obviously retard the long‐term oxidation of cholesterol and lard under high temperature, but caffeic acid, quercetin, and chlorogenic acid displayed great untapped potential to prevent thermal oxidation of cholesterol 0.5 h at least. For the sake of health and flavor, fast stir‐frying over a high flame is recommended. If baking or deep fat frying food in oil, it is best to limit cooking time to within 0.5 h.     

Protective action of midgut catalase in lepidopteran larvae against oxidative plant defenses

Catalase activity was detected in the midgut tissues and regurgitate of several lepidopteran pests of the tomato plant. Greatest activity in the midgut was detected in larvalHelicoverpa zea, followed bySpodoptera exigua, Manduca sexta, andHeliothis virescens. We present evidence that catalase, in addition to removing toxic hydrogen peroxide, may inhibit the oxidation of plant phenolics mediated by plant peroxidases. Small amounts of larval regurgitate significantly inhibited foliar peroxidase activity via removal of hydrogen peroxide. Treatment of foliage with purified catalase nearly eliminated peroxidase activity and was superior as a larval food source compared to untreated foliage. Tomato foliar peroxidases oxidize an array of endogenous compounds including caffeic acid, chlorogenic acid, rutin, coumaric acid, cinnamic acid, and guaiacol. The oxidized forms of these compounds are potent alkylators of dietary and/or cellular nucleophiles (e.g., thiol and amino functions of proteins, peptides, and amines). When tomato foliar protein was pretreated with peroxidase and chlorogenic acid and incorporated in artificial diet, larval growth was reduced compared to larvae fed untreated protein. Thus, the diminution of peroxidase activity and removal of hydrogen peroxide by catalase may represent an important adaptation to leaf-feeding. The secretion of catalase in salivary fluid during insect feeding is also suggested to be a potential mechanism for reducing hydrogen peroxide formation as an elicitor of inducible plant defenses.     

绿原酸提取纯化方法的研究进展

绿原酸是植物体内一种重要的次生代谢产物,作为一种活性物质广泛存在于高等双子叶植物和蕨类植物中.由于其具有抑菌消毒、活血降压、抗氧化、防衰老等功效,因而成为生物活性物质研究的热点之一.从绿原酸的提取和分离纯化两方面进行综述,并就传统提取法、物理场提取法和生物酶解法3种方法进行重点阐述,旨在为绿原酸的应用提供参考和依据.     

Mixture-Amount Design and Response Surface Modeling to Assess the Effects of Flavonoids and Phenolic Acids on Developmental Performance of Anastrepha ludens

Host plant resistance to insect attack and expansion of insect pests to novel hosts may to be modulated by phenolic compounds in host plants. Many studies have evaluated the role of phenolics in host plant resistance and the effect of phenolics on herbivore performance, but few studies have tested the joint effect of several compounds. Here, we used mixture-amount experimental design and response surface modeling to study the effects of a variety of phenolic compounds on the development and survival of Mexican fruit fly (Anastrepha ludens [Loew]), a notorious polyphagous pest of fruit crops that is likely to expand its distribution range under climate change scenarios. (+)- Catechin, phloridzin, rutin, chlorogenic acid, and p-coumaric acid were added individually or in mixtures at different concentrations to a laboratory diet used to rear individuals of A. ludens. No effect was observed with any mixture or concentration on percent pupation, pupal weight, adult emergence, or survival from neonate larvae to adults. Larval weight, larval and pupal developmental time, and the prevalence of adult deformities were affected by particular mixtures and concentrations of the compounds tested. We suggest that some combinations/concentrations of phenolic compounds could contribute to the management of A. ludens. We also highlight the importance of testing mixtures of plant secondary compounds when exploring their effects upon insect herbivore performance, and we show that mixture-amount design is a useful tool for this type of experiments.     

Do Foliar Phenolics Provide Protection to Heliothis virescens from a Baculovirus?

The effects of chlorogenic acid on larval survival and growth of the tobacco budworm Heliothis virescens and larval susceptibility to Helicoverpa zea nucleopolyhedrovirus (HzSNPV) were studied with an artificial diet and transgenic tobacco Nicotiana tabacum. Survival of neonates on over- or underexpressed phenylalanine ammonia-lyase (PAL) transgenic tobacco lines was positively correlated with the level of chlorogenic acid. Larval weight was not correlated with the level of chlorogenic acid in tobacco foliage. On the other hand, larval weights on artificial diet supplemented with chlorogenic acid were negatively correlated with chlorogenic acid concentration. Second instars treated on virus-treated (10 occlusion bodies/larva) tobacco leaf disks for 24 hr and then reared on tobacco leaves showed higher survival time and increased mortality on lines with increasing levels of chlorogenic acid. However, viral-related larval mortality on artificial diet was negatively correlated with dietary chlorogenic acid. These results illustrate the inadequacy of artificial diet studies in establishing causal relationships among plant chemistry, herbivores, and natural enemies.     

高效液相色谱法同时测定云南白花木瓜不同部位中5个成分的含量

建立了一种采用高效液相色谱(HPLC)法同时测定白花木瓜中绿原酸、芦丁、金丝桃苷、齐墩果酸、熊果酸的质量浓度的方法,比较了果皮、果肉中绿原酸、芦丁、金丝桃苷、齐墩果酸、熊果酸质量浓度的差异.结果显示,在以A相(甲醇)和B相(体积分数为16％乙腈,体积分数为0.3％磷酸水溶液)为流动相的梯度洗脱条件下,绿原酸、芦丁、金丝...     

Polyphenol content and modulatory activities of some tropical dietary plant extracts on the oxidant activities of neutrophils and myeloperoxidase

Young leaves of Manihot esculenta Crantz (Euphorbiaceae), Abelmoschus esculentus (Malvaceae), Hibiscus acetosella (Malvaceae) and Pteridium aquilinum (Dennstaedtiaceae) are currently consumed as green vegetables by peoples in sub-Saharan Africa, Latin America, Asia and their migrants living in Western Europe. Sub-Saharan peoples use Manihot, Abelmoschus and Hibiscus also in the folk medicine to alleviate fever and pain, in the treatment of conjunctivitis, rheumatism, hemorrhoid, abscesses, ... The present study investigates the effects of aqueous extracts of those plants on the production of reactive oxygen species (ROS) and the release of myeloperoxidase (MPO) by equine neutrophils activated with phorbol 12-myristate 13-acetate (PMA). The ROS production was measured by lucigenin-enhanced chemiluminescence (CL), and the release of total MPO by an ELISA method. The study also investigates the effect of the extracts on the activity of MPO by studying its nitration activity on tyrosine and by using a new technique called SIEFED (Specific Immunological Extraction Followed by Enzymatic Detection) that allows studying the direct interaction of compounds with the enzyme. In all experiments, the aqueous extracts of the plants developed concentration-dependent inhibitory effects. A moderate heat treatment did not significantly modify the inhibitory capacity of the extracts in comparison to not heated ones. Total polyphenol and flavonoid contents were determined with an HPLC-UV/DAD analysis and a spectroscopic method using Folin-Ciocalteu reagent. Some polyphenols with well-known antioxidant activities (caffeic acid, chlorogenic acid, hyperoside, rosmarinic acid and rutin) were found in the extracts and may partly explain the inhibitory activities observed. The role of those dietary and medicinal plants in the treatment of ROS-dependent inflammatory diseases could have new considerations for health.     

Herbivore-Induced Defenses in Tomato Plants Enhance the Lethality of the Entomopathogenic Bacterium, <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> var. <Emphasis Type="Italic">kurstaki</Emphasis>

Plants can influence the effectiveness of microbial insecticides through numerous mechanisms. One of these mechanisms is the oxidation of plant phenolics by plant enzymes, such as polyphenol oxidases (PPO) and peroxidases (POD). These reactions generate a variety of products and intermediates that play important roles in resistance against herbivores. Oxidation of the catecholic phenolic compound chlorogenic acid by PPO enhances the lethality of the insect-killing bacterial pathogen, Bacillus thuringiensis var. kurstaki (Bt) to the polyphagous caterpillar, Helicoverpa zea. Since herbivore feeding damage often triggers the induction of higher activities of oxidative enzymes in plant tissues, here we hypothesized that the induction of plant defenses would enhance the lethality of Bt on those plants. We found that the lethality of a commercial formulation of Bt (Dipel® PRO DF) on tomato plants was higher if it was applied to plants that were induced by H. zea feeding or induced by the phytohormone jasmonic acid. Higher proportions of H. zea larvae killed by Bt were strongly correlated with higher levels of PPO activity in the leaflet tissue. Higher POD activity was only weakly associated with higher levels of Bt-induced mortality. While plant-mediated variation in entomopathogen lethality is well known, our findings demonstrate that plants can induce defensive responses that work in concert with a microbial insecticide/entomopathogen to protect against insect herbivores.     

An Overview on Dietary Polyphenols and Their Biopharmaceutical Classification System (BCS)

Polyphenols are natural organic compounds produced by plants, acting as antioxidants by reacting with ROS. These compounds are widely consumed in daily diet and many studies report several benefits to human health thanks to their bioavailability in humans. However, the digestion process of phenolic compounds is still not completely clear. Moreover, bioavailability is dependent on the metabolic phase of these compounds. The LogP value can be managed as a simplified measure of the lipophilicity of a substance ingested within the human body, which affects resultant absorption. The biopharmaceutical classification system (BCS), a method used to classify drugs intended for gastrointestinal absorption, correlates the solubility and permeability of the drug with both the rate and extent of oral absorption. BCS may be helpful to measure the bioactive constituents of foods, such as polyphenols, in order to understand their nutraceutical potential. There are many literature studies that focus on permeability, absorption, and bioavailability of polyphenols and their resultant metabolic byproducts, but there is still confusion about their respective LogP values and BCS classification. This review will provide an overview of the information regarding 10 dietarypolyphenols (ferulic acid, chlorogenic acid, rutin, quercetin, apigenin, cirsimaritin, daidzein, resveratrol, ellagic acid, and curcumin) and their association with the BCS classification.     

Microwave-assisted extraction of chlorogenic acid from flower buds of Lonicera japonica Thunb.

An efficient microwave-assisted extraction (MAE) technique has been developed to recover chlorogenic acid from flower buds of Lonicera japonica Thunb. The yield of chlorogenic acid rapidly reached 6.14% within 5 min under the optimal MAE conditions, i.e. 50% ethanol as extraction solvent, 1:10 (w/v) of the solid/liquid ratio and 60 °C of extraction temperature. The MAE showed obvious advantages in terms of short duration and high efficiency to recover chlorogenic acid from raw plant materials in comparison with conventional heat-reflux extraction. The mechanism of the enhanced extraction by microwave assistance was discussed by observing cell destruction of plant material after MAE treatment by scanning electron microscopy. The results showed that the plant materials were significantly destroyed due to the cell rupture after MAE treatment.     

Electrochemistry of chlorogenic acid: experimental and theoretical studies

Cyclic voltammetry, chronoamperometry and rotating disk electrode voltammetry as well as quantum chemical methods, are used for electrochemical study of chlorogenic acid, as an important biological molecule. The standard formal potential, diffusion coefficient, and heterogeneous electron transfer rate constant of chlorogenic acid in aqueous solution are investigated. Acidic dissociation constant of chlorogenic acid is also obtained. Quantum mechanical calculations on oxidation of chlorogenic acid in aqueous solution, using density functional theory are presented. The change of Gibbs free energy and entropy of oxidation of chlorogenic acid are calculated using thermochemistry calculations. The calculations in aqueous solution are carried out with the use of polarizable continuum solvation method. Theoretical standard electrode potential of chlorogenic acid is achieved to be 0.580 V versus standard calomel electrode (SCE) which is in agreement with the experimental value of 0.617 V obtained experimentally in this work. The difference is consistent with the values we previously reported for other quinone derivatives.     

Rejection of host plant by larvae of cabbage butterfly: Diet-dependent sensitivity to an antifeedant

Garden nasturtium,Tropaeolum majus (Tropaeolaceae), is an acceptable host plant for the cabbage butterfly,Pieris rapae. Eggs are readily laid on the plant and hatching larvae feed and develop into normal pupae and adults. However, when second- to fifth-instar larvae were transferred from cabbage to nasturtium, they refused to feed and starved to death. Similar results were obtained when larvae were transferred from other host plants to nasturtium. However, larvae that were reared on nasturtium readily accepted cabbage as a new host plant. We have demonstrated the presence of strong antifeedants in nasturtium foliage and identified the most prominent active compound as chlorogenic acid. However, larvae reared on nasturtium had limited sensitivity, and larvae reared on a wheat germ diet were completely insensitive to the antifeedants. Larvae apparently develop sensitivity to the deterrent as a result of feeding on other host plants, whereas continuous exposure to the deterrent causes habituation or suppression of sensitivity development. The results demonstrate that dietary experience can dramatically affect the response of an insect to a potentially antifeedant compound in a plant.     

Survival and Development of Tobacco Hornworm Larvae on Tobacco Plants Grown Under Elevated Levels of Ozone

Tobacco plants, Nicotiana tabacum were grown under different levels of ozone (O₃) in open-top chambers. Ozone concentrations were established by charcoal filtration, which reduced O₃ to approximately one-half ambient, or by the addition of O₃ to unfiltered air to increase concentrations to approximately 1.4 or 1.7 times ambient O₃. Survival of tobacco hornworm, Manduca sexta, larvae was increased when second instars were fed tobacco leaves grown in chambers with elevated levels of O₃. Second instars also gained significantly more weight when they were fed for one week on plants exposed to elevated levels of O₃ than when they were fed plants grown in charcoal-filtered air. Ozone-treated tobacco plants had higher levels of total nitrogen (primarily reduced nitrogen) and soluble carbohydrates (sugars), and lower levels of leaf-surface components, starch, nicotine, and rutin. Increased survival and growth response of hornworm larvae to elevated O₃ levels in these experiments suggests that similar responses could occur in the southeastern US tobacco production areas where O₃ levels can be high enough to injure tobacco plants.     

从金银花中提取绿原酸的工艺研究

尝试了多种从金银花中提取绿原酸的工艺流程,但结果都不能令人满意。从实验中总结了许多关于绿原酸的性质,从而设想用乙醇和水组成的混合溶剂作提取剂,用盐酸作电离抑制剂,水浴加热回流。并利用绿原酸在热乙醇和冷乙醇中溶解度相差非常大的特点,使其在热乙醇中溶解而在冷乙醇中析出,从而达到分离的目的。并研究了实验中乙醇浓度、溶剂用量、水浴温度、回流时间以及pH值对提取绿原酸的影响,用正交设计选取了最佳工艺。结果表明,最佳提取条件为：40%乙醇（体积分数）、溶剂用量为12倍、水浴温度80℃、回流时间2.5h、pH值6。     

烟草和烟气中酚类物质检测技术研究进展

烟草中的多酚类物质(如绿原酸、芸香苷和莨菪亭)对烟草品质有重要影响,卷烟烟气中的简单酚类物质(如邻、间、对-苯二酚、苯酚、邻、间、对-甲酚)是烟气主要有害成分之一;烟草和烟气中酚类物质的分析检测及其相互转化规律一直是国内外烟草行业研究的热点方向之一。总结了近年来烟草中主要的多酚物质和烟气中主要的简单酚的分析检测方法以及多酚与简单酚之间的转化研究进展。