荷叶的抗氧化活性成分

荷叶为睡莲科植物莲(Nelumbo nucifera Gaertn)的干燥叶,是我国一种历史悠久的天然保健品.为阐明其抗氧化活性成分,采用正相、反相硅胶柱层析,凝胶柱层析和反相制备液相色谱等分离方法,从荷叶的甲醇提取物中分离得到18个化合物.通过波谱数据分别鉴定为荷叶碱(1),东莨菪内酯(2),黑麦草内酯(3),对甲氧基苯甲酸(4),(+)-梣皮树脂醇(5),阿魏酸(6),槲皮素(7),木犀草素(8),N-甲基阿西米诺宾(9),3,4-二羟基苯甲酸(10),4-羟基苯甲酸(11),(3S,5R,6R,7E,9S)-megastigman-7-ene-3,5,6,9-tetraol(12),儿茶素(13),腺嘌呤(14),异鼠李素-3-O-β-D-葡萄糖苷(15),异槲皮苷(16),槲皮素-3-O-β-D-吡喃木糖(1→2)-β-D-吡喃葡萄糖苷(17),槲皮素-3-O-β-D-葡萄糖醛酸苷(18),其中化合物2、4、5、8、10、11、14为首次从荷叶中分离得到.对其中的17个化合物进行了ABTS和DPPH自由基清除测试,化合物5-8,10,13,15-18表现出较强的抗氧化活性.本研究结果可为荷叶抗氧化活性的合理开发利用提供一定的科学依据.     

柳叶忍冬的化学成分研究

从柳叶忍冬95%乙醇提取物中首次分离并鉴定了20个化合物: ( )-cycloolivil (1)、( )-fraxiresinol (2)、prinsepiol(3)、软脂酸(4)、对甲基苯酚(5)、2,4-二羟基-3,6-二甲基苯甲酸甲酯(6)、洋芹素(7)、木犀草素(8)、5,7,4′-三羟基黄酮醇7-O-β-D-吡喃葡萄糖苷(9)、槲皮素(10)、染料木素(11)、5,4′-二羟基-7-甲氧基异黄酮(12)、染料木素5-O-β-D-吡喃葡萄糖苷(13)、5,4′-二羟基-7-甲氧基异黄酮5-O-β-D-吡喃葡萄糖苷(14)、5,7,4′-三羟基双氢黄酮7-O-β-D-吡喃葡萄糖苷(15)、丁二酸(16)、( )-儿茶素(17)、( -)-表儿茶素(18)、谷甾醇(19)和胡萝卜苷(20).应用波谱方法及与已知品对照进行结构鉴定.其中,化合物10、17和18是抑制血管紧张素转化酶的活性成分.表4参63     

唐菖蒲的化学成分研究

从唐菖蒲(Gladiolus gandavensis Van Houtte)球茎中分离得到23个化合物,应用波谱方法及与已知品对照的手段,将其鉴定为羽扇豆醇(1)、β-香树脂醇(2)、木栓酮(3)、木栓醇(4)、桦木醇(5)、(22E,24R)-24-methyl-5α-chol-esta-7,22-dien-3β-ol(6)、(E)-对羟基肉桂酸甲酯(7)、豆甾醇(8)、羽扇豆酮(9)、3β,27-dihydroxylup-12-ene(10)、齐墩果酸(11)、桦木酸(12)、1-甲基-3,8-二羟基-6,7-二氧亚甲基蒽醌-2-羧酸甲酯(13)、1-甲基-3,8-二羟基-6-甲氧基蒽醌(14)、1,7-二羟基-3,6-二甲氧基蒽醌(15)、(E)-对羟基肉桂酸(16)、咖啡酸乙酯(17)、β-胡萝卜苷(18)、2β,3β-二羟基-齐墩果-12-烯-23,28-二羧酸(19)、2β,3β,16α-三羟基-齐墩果-12-烯-23,28-二羧酸(20)、2β,3β-二羟基-齐墩果-12-烯-23,28-二羧酸-3-O-β-D-吡喃葡萄糖苷(21)、2β,3β,16α-三羟基-齐墩果-12-烯-23,28-二羧酸-3-O-β-D-吡喃葡萄糖苷(22)和咖啡酸(23).图1参20     

爵床的化学成分研究

为了研究爵床全草中具有血管紧张素转化酶抑制活性的化学成分,从爵床全草95%乙醇提取物中分离并鉴定了13个化合物:芹菜素(1)、槲皮素7-O-α-L-吡喃鼠李糖甙(2)、木犀草素7-O-β-D-吡喃葡萄糖甙(3)、洋芹素7-O-β-D-吡喃葡萄糖甙(4)、洋芹素7-O-新橙皮甙(5)、β-谷甾醇(6)、β-胡萝卜甙(7)、东莨菪素(8)、羽扇豆醇乙酸酯(9)、环桉烯醇(10)、木栓酮(11)、木栓醇(12)、积雪草酸(13).HPLC检测结果证明,该植物中还存在木犀草素(14)和槲皮素(15).其中化合物1、14和15为爵床中具有血管紧张素转化酶抑制活性的成分.图1表2参28     

锥头麻的化学成分研究

从锥头麻枝叶中分离到10个化合物:熊果酸(1)、2α,3β,19α三羟基12烯28乌苏酸(2)、羽扇豆醇(3)、β谷甾醇(4)、β胡萝卜苷(5)、大黄素8OβD吡喃葡萄糖苷(6)、5α,8α表二氧(22E,24R)麦角甾6,22二烯3β醇(7)、(2S,3S,4R,8E)2[(2′R)2′羟基二十四烷酰氨基]1,3,4三羟基8十八烷烯(8)、1OβD吡喃葡萄糖(2S,3S,4R,8Z)2[(2′R)2′羟基二十四烷酰氨基]3,4二羟基8十八烷烯(9)、1OβD吡喃葡萄糖(2S,3S,4R,8E)2[(2′R)2′羟基二十四烷酰氨基]3,4二羟基8十八烷烯(10),其中化合物9、10以混合物形式分离得到.应用波谱方法及与已知品对照的手段鉴定了它们的结构.图1表1参9     

黄海棠中的多酚类化学成分

金丝桃属(Hypericum)植物具有悠久的药用历史、丰富的植物资源、众多的生物活性.前期本研究组从金丝桃属植物中分离得到了一系列结构新颖的多环多异戊烯基取代的简苯三酚类化合物,为了能够发掘出更多结构新颖的天然产物,对云南哈巴雪山金丝桃属植物黄海棠(H.ascyron)地上部分中的多酚类化学成分进行研究.采用反复硅胶柱色谱、MCI、Sephades LH-20、制备型和半制备型高效液相色谱等分离手段从黄海棠中共分离纯化得到10个多酚类化合物.运用MS和NMR等波谱技术分别鉴定为槲皮素(1)、山奈酚(2)、3,8"-Biapigenin(3)、木樨草素(4)、2-(3,4-二羟基苯甲酰基)-2,4,6-三羟基-3(2H)-苯并呋喃酮(5)、2,4-二羟基-6-(3,4-二羟基苯甲酰氧基)-苯甲酸(6)、2,4-二羟基-6-(4-羟基苯甲酰氧基)-苯甲酸(7)、七叶内酯(8)、原儿茶酸(9)、原儿茶酸甲酯(10).化合物5-7为首次从藤黄科植物中分离得到,而化合物3、4、8、10为首次从该植物中分离得到.     

苍耳子的化学成分

苍耳子(Fructus Xanthii)是常用中药,主要用于慢性鼻炎的治疗,有一定的毒性.为明确苍耳子产生生物活性的物质基础,通过溶剂萃取、正、反相反复硅胶柱色谱及MCI柱色谱等方法,对苍耳子80%甲醇提取物进行分离纯化,用质谱、核磁共振谱等方法进行结构鉴定.从正丁醇萃取物中分离鉴定7个化合物:阿魏酸(1)、咖啡酸(2)、绿原酸(3)、4-O-咖啡酰奎宁酸甲酯(4)、6,7-二甲基-1,4-二氢-2,3-喹喔啉二酮(5)、咖啡酸胆碱酯(6)和4′-O-二氢红花菜豆酸钠盐-β-D-葡萄糖苷(7).其中,化合物4~7为首次从该植物中分离得到.图1参10     

短序醉鱼草的化学成分研究

为研究短序醉鱼草中具有血管紧张素转化酶(ACE)抑制活性的成分,从该植物地上部分95%乙醇提取物中首次分离并鉴定了11个化合物,分别是洋芹素(1)、芦丁(2)、槲皮素(3)、E-对-羟基肉桂酸(4)、β-谷甾醇(5)、β-胡萝卜甙(6)、豆甾醇(7)、3,4-二甲氧基肉桂酸(8)、木樨草素(9)、丁香醛(10)和华良姜素(11).化合物1、3和9显示一定的ACE抑制活性.图1表1参15     

血满草的化学成分(英文)

从血满草(Sambucus adnata Wall)全草的95%乙醇提取物中分离到16个化合物,应用波谱方法及与已知品对照的手段,将其鉴定为β-谷甾醇(1)、齐墩果酸(2)、槲皮素(3)、洋芹素(4)、木犀草素(5)、山奈酚(6)、α-香树脂醇乙酸酯(7)、α-香树脂醇(8)、咖啡酸乙酯(9)、棕榈酸甘油酯(10)、2,4-二羟基-3,6-二甲基苯甲酸甲酯(11)、没食子酸乙酯(12)、桦木酸(13)、丁二酸(14)、豆甾醇(15)、3,28,29-三羟基羽扇豆烷(16).其中,化合物3、4、5和9是抑制血管紧张素转化酶的活性成分.图1参38     

袋花忍冬的化学成分研究

从袋花忍冬全草95%乙醇提取物中首次分离得到16个化合物.应用波谱方法及与已知品对照,将其鉴定为E-p-coumaryl hexacosanate(1)、β-谷甾醇(2)、2,6-dihydroxyhumula-3(12),7(13),9(E)-triene(3)、十六烷酸1-甘油酯(4)、(20S,22E,24R)-5α,8α-表二氧-麦角甾-6,22-二烯-3β-醇(5)、环阿尔廷-25-烯-3β,24ξ-二醇(6)、二十四烷酸(7)、2,4-二羟基-3,6-二甲基苯甲酸甲酯(8)、乌苏酸(9)、柚皮素(10)、胡萝卜苷(11)、木犀草素(12)、柏双黄酮(13)、咖啡酸(14)、洋芹素(15)和木犀草素-7-O-β-D-葡萄糖苷(16).其中木犀草素(12)和咖啡酸(14)为袋花忍冬中具有ACE抑制活性的化合物.图1参13     

Rapid,recurring, structured survey versus bioblitz for generating biodiversity data and analysis with a multispecies abundance model

A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.     

Compliance with and ecosystem function of biodiversity offsets in North American and European freshwaters

Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.     

A palaeo-hydrogeological model for arsenic contamination in southern and south-east Asia

An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.     

Cost‐effective conservation of an endangered frog under uncertainty

How should managers choose among conservation options when resources are scarce and there is uncertainty regarding the effectiveness of actions? Well‐developed tools exist for prioritizing areas for one‐time and binary actions (e.g., protect vs. not protect), but methods for prioritizing incremental or ongoing actions (such as habitat creation and maintenance) remain uncommon. We devised an approach that combines metapopulation viability and cost‐effectiveness analyses to select among alternative conservation actions while accounting for uncertainty. In our study, cost‐effectiveness is the ratio between the benefit of an action and its economic cost, where benefit is the change in metapopulation viability. We applied the approach to the case of the endangered growling grass frog (Litoria raniformis), which is threatened by urban development. We extended a Bayesian model to predict metapopulation viability under 9 urbanization and management scenarios and incorporated the full probability distribution of possible outcomes for each scenario into the cost‐effectiveness analysis. This allowed us to discern between cost‐effective alternatives that were robust to uncertainty and those with a relatively high risk of failure. We found a relatively high risk of extinction following urbanization if the only action was reservation of core habitat; habitat creation actions performed better than enhancement actions; and cost‐effectiveness ranking changed depending on the consideration of uncertainty. Our results suggest that creation and maintenance of wetlands dedicated to L. raniformis is the only cost‐effective action likely to result in a sufficiently low risk of extinction. To our knowledge we are the first study to use Bayesian metapopulation viability analysis to explicitly incorporate parametric and demographic uncertainty into a cost‐effective evaluation of conservation actions. The approach offers guidance to decision makers aiming to achieve cost‐effective conservation under uncertainty.     

Threats to intact tropical peatlands and opportunities for their conservation

Large, intact areas of tropical peatland are highly threatened at a global scale by the expansion of commercial agriculture and other forms of economic development. Conserving peatlands on a landscape scale, with their hydrology intact, is of international conservation importance to preserve their distinctive biodiversity and ecosystem services and maintain their resilience to future environmental change. We explored threats to and opportunities for conserving remaining intact tropical peatlands; thus, we excluded peatlands of Indonesia and Malaysia, where extensive deforestation, drainage, and conversion to plantations means conservation in this region can protect only small fragments of the original ecosystem. We focused on a case study, the Pastaza‐Marañón Foreland Basin (PMFB) in Peru, which is among the largest known intact tropical peatland landscapes in the world and is representative of peatland vulnerability. Maintenance of the hydrological conditions critical for carbon storage and ecosystem function of peatlands is, in the PMFB, primarily threatened by expansion of commercial agriculture linked to new transport infrastructure that is facilitating access to remote areas. There remain opportunities in the PMFB and elsewhere to develop alternative, more sustainable land‐use practices. Although some of the peatlands in the PMFB fall within existing legally protected areas, this protection does not include the most carbon‐dense (domed pole forest) areas. New carbon‐based conservation instruments (e.g., REDD+, Green Climate Fund), developing markets for sustainable peatland products, transferring land title to local communities, and expanding protected areas offer pathways to increased protection for intact tropical peatlands in Amazonia and elsewhere, such as those in New Guinea and Central Africa which remain, for the moment, broadly beyond the frontier of commercial development.     

Human Influence and Classical Biogeographic Predictors of Rare Species Occurrence

Biogeographic theory predicts that rare species occur more often in larger, less‐isolated habitat patches and suggests that patch size and connectivity are positive predictors of patch quality for conservation. However, in areas substantially modified by humans, rare species may be relegated to the most isolated patches. We used data from plant surveys of 81 meadow patches in the Georgia Basin of Canada and the United States to show that presence of threatened and endangered plants was positively predicted for patches that were isolated on small islands surrounded by ocean and for patches that were isolated by surrounding forest. Neither patch size nor connectivity were positive predictors of rare species occurrence. Thus, in our study area, human influence, presumably due to disturbance or introduction of competitive non‐native species, appears to have overwhelmed classical predictors of rare species distribution, such that greater patch isolation appeared to favor presence of rare species. We suggest conservation planners consider the potential advantages of protecting geographically isolated patches in human‐modified landscapes because such patches may represent the only habitats in which rare species are likely to persist. Influencia Humana y Predictores Biogeográficos Clásicos de la Ocurrencia de Especies Raras     

Seasonal dynamics of macro-algae in the South Lake of Tunis

The macro-algae communities observed in the south lake of Tunis are characterized by the predominance of nitrophilous algae which are in the order of biomass importance:Ulva, Cladophora andEnteromorpha. We have noted seasonal changes of alga distribution. The wind appears to be one of the most important factors influencing this distribution. The total biomass reaches a maximum in the spring. Rapid decomposition of the biomass leads to a severe ecological imbalance, resulting in crises of anoxia and fish death. A restoration project has already started. It aims at removal of contaminated muds and the introduction of a new circulation system. The main objectives of this work were to collect information on the distribution and biomass of the phytobenthic communities as a first step in the constitution of a database for further comparison.     

Patterns and biases of climate change threats in the IUCN Red List

International Union for Conservation of Nature (IUCN) Red List assessments rely on published data and expert inputs, and biases can be introduced where underlying definitions and concepts are ambiguous. Consideration of climate change threat is no exception, and recently numerous approaches to assessing the threat of climate change to species have been developed. We explored IUCN Red List assessments of amphibians and birds to determine whether species listed as threatened by climate change display distinct patterns in terms of habitat occupied and additional nonclimatic threats faced. We compared IUCN Red List data with a published data set of species’ biological and ecological traits believed to infer high vulnerability to climate change and determined whether distributions of climate change‐threatened species on the IUCN Red List concur with those of climate change‐threatened species identified with the trait‐based approach and whether species possessing these traits are more likely to have climate change listed as a threat on the IUCN Red List. Species in some ecosystems (e.g., grassland, shrubland) and subject to particular threats (e.g., invasive species) were more likely to have climate change as a listed threat. Geographical patterns of climate change‐threatened amphibians and birds on the IUCN Red List were incongruent with patterns of global species richness and patterns identified using trait‐based approaches. Certain traits were linked to increases or decreases in the likelihood of a species being threatened by climate change. Broad temperature tolerance of a species was consistently related to an increased likelihood of climate change threat, indicating counterintuitive relationships in IUCN assessments. To improve the robustness of species assessments of the vulnerability or extinction risk associated with climate change, we suggest IUCN adopt a more cohesive approach whereby specific traits highlighted by our results are considered in Red List assessments. To achieve this and to strengthen the climate change‐vulnerability assessments approach, it is necessary to identify and implement logical avenues for further research into traits that make species vulnerable to climate change (including population‐level threats).     

Parasitic wasps orient to green leaf volatiles

Summary Undamaged plants emit low levels of green leaf volatiles (GLVs), while caterpillar-damaged and artificially damaged plants emit relatively higher levels of certain GLVs. Female braconid parasitoids,Microplitis croceipes, oriented to both damaged plants and to individual GLVs in no-choice tests in a wind tunnel, but seldom oriented to undamaged plants. Female ichneumonid parasitoids,Netelia heroica, also oriented to individual GLVs in a wind tunnel. Males of both wasp species failed to orient to the GLVs. These data show that leaf-feeding caterpillars can cause the release of GLVs, and that parasitic wasps can respond to these odors by flying upwind (chemoanemotactic response), which brings the wasps to their caterpillar hosts. This supports the hypothesis that plants communicate with members of the third trophic level,i.e., plants under herbivore attack emit chemical signals that guide natural enemies of herbivores to sites of plant damage. In this interaction, the GLVs serve as tritrophic plant-to-parasitoid synomones. That parasitoids from two different wasp families oriented to GLVs suggests that the response may be widespread among the Hymenoptera.Mention of a commercial or proprietary product does not constitute an endorsement by the U.S. Department of Agriculture