The distribution of flavonoids in chloroplasts of twenty five species of vascular plants

A survey was made of the major flavonoids in whole leaf extracts and in chloroplast preparations from twenty five species of vascular plants including Anthophyta (20), Coniferophyta (1), Ginkophyta (1), Pterophyta (2), and Arthrophyta (1). The chloroplasts variously contained derivatives of flavones, C-glycosylflavones, flavonols, flavanones, isoflavones, 3-deoxyanthocyanidins, and anthocyanins. Twenty three species contain one or more flavonoids in isolated chloroplast, usually in a pattern quite similar to that found in whole-leaf extracts but occasionally showing enrichment of one or more flavonoids in the chloroplasts. Flavonoids are apparently absent from chloroplasts of Phaseolus aureus and Morus alba although whole-leaf extracts of these species are rich in quercetin derivatives.     

Knowledge of Colombian biodiversity: published and indexed

Documenting patterns of published studies on the biodiversity of megadiverse countries can offer valuable insights on global biodiversity knowledge. Here, I present results from a bibliometric analysis of 5,264 indexed publications on biodiversity in Colombia published during the period 1990–2011 and gathered by searching the Web of Knowledge database. I classified studies into six overlapping subjects: taxa lists, new taxa, new records, conservation, genetic diversity, and other. Publications were also classified by geographic location and the taxonomic group studied. I found variation in the number of studies per year, which presented a long-term trend of increasing volume. The 31 continental departments of Colombia and both the Atlantic and the Pacific oceans were represented in the studies, which included 98 taxonomic classes from 47 phyla. However, there were strong biases in taxonomic, geographic, and subject coverage. For instance, 75 % of studies focused on animals; and the Atlantic Ocean showed the highest number of studies, followed by Antioquia and Valle del Cauca departments. Genetic diversity and conservation were the least-studied subjects. I also found that Colombian researchers and Colombian institutions have played an important role in documenting the country’s outstanding biodiversity. However, Colombian biologists still prefer to publish in domestic or Latin American journals, which are mainly regional and have low international visibility. The patterns I present here can have important implications for optimizing and guiding research on Colombian biodiversity, and the paper concludes with some recommendations.     

Antioxidant activities of five polysaccharides from Inonotus obliquus

Five polysaccharides (IOP1b, IOP2a, IOP2c, IOP3a and IOP4) were isolated and purified from Inonotus obliquus by DEAE-Sepharose fast flow and SepharoseCL-6B column chromatography. Their chemical and physical characteristics were determined and antioxidant activities were investigated on the basis of hydroxyl radical assay, superoxide radical assay and ferric-reducing antioxidant power assay. The results showed that five polysaccharides exhibited antioxidant activities, and the higher content of uronic acid and proteinous substances, the stronger antioxidant activities of polysaccharides. Besides, molecular weights of polysaccharides also influence their antioxidant activities. IOP3a and IOP4 showed higher antioxidant properties than IOP1b, IOP2a and IOP2c.     

Antioxidant activity and cytotoxicity of methanol extracts from aerial parts of Korean salad plants

The aim of this investigation was to determine the content of total phenolics, antioxidant activity and cytotoxicity of methanol extracts from the aerial parts of 11 Korean medicinal salad plants. The highest total phenolic content of the methanol extracts was found in Aster scaber (17.1 mg 100 g(-1)), followed by Ixeris dentate (16.4 mg 100 g(-1)), Aster yomena (12.0 mg 100 g(-1)) and Sedum sarmentosum (9.1 mg 100 g(-1)) of FW. Methanol extracts of Ixeris dentate and Aster scaber at 50 microg mL(-1) exhibited the highest DPPH radical scavenging activity by 86.4 and 83.3%, respectively. It was registered a dose-dependent increase of DPPH free radical scavenging activity. Total phenolic content of the studied plant extracts was correlated with the DPPH radical scavenging activity. It was found by means of MTT assay, that cytotoxicity of the methanol extracts was the highest against HCT-116. Methanol extracts from Petasites japonicus (IC(50)<25.0 microg mL(-1)) showed the highest activity against HCT-116, following by Angelica gigas (34.75 microg mL(-1)), Erythronium japonicum (44.06 microg mL(-1)), and Aster scaber (54.87 microg mL(-1)). In conclusion, the studied salad plants have high total phenolics content and high antioxidant activity. These plants dose-dependently increased DPPH free radical scavenging activity. The total phenolics level was highly correlated with the free radical scavenging activity. Most of the studied salad plants have potent cytotoxicity activity. The results of this investigation suggest that the extracts of studied salad plants could be an addition to basic medicine for some diseases.     

Antifungal activity of extracts from five Egyptian wild medicinal plants against late blight disease of tomato

This study was carried out to evaluate the antifungal potential of water and ethanol extracts from aerial parts of five wild medicinal plants collected from Sinai Peninsula, Egypt, and the extracts were tested in vitro and in vivo against Phytophthora infestans, the causal agent of late blight disease of tomato. The five wild medicinal plants used for the study were Asclepias sinaica, Farsetia aegyptia, Hypericum sinaicum, Phagnalon sinaicum and Salvia aegyptiaca. Ethanol extracts were more effective on the pathogen than water extracts at all concentrations used. Water and ethanol extracts of all plants tested reduced mycelial growth and inhibited spore germination of the pathogen with varying degrees. Water and ethanolic extracts also reduced the disease infection with pathogen comparing with control in detached leaves technique. In all experiments, extracts of A. sinaica and F. aegyptia were most effective on the pathogen than other plant extracts. In plot experiment, the water and ethanolic extracts of A. sinaica and F. aegyptia gave the most reduction of late blight disease severity comparing with control. Also, data indicated that after the application of plant extracts, there was an increase in fruit yield of tomato corresponding with the reduction of disease severity . Scanning electron microscopy revealed a negative alteration of pathogen hyphae treated with A. sinaica extract at 20%. This concentration of the same plant extract also reflected in dramatic changes in the cyto-morphology of pathogen hyphae as observed by transmission electron microscopy. These changes resulted in an increase in vacuolisation and lipid contents with consequent reduction of cytoplasm with alteration of cell wall and plasmalemma. The overall results suggested that the use of these Egyptian wild medicinal plant extracts was promising, effective and environment-friendly management measure against Phytophthora blight of tomato and thus, may be used in the production of organically grown vegetables.     

Antioxidant and acetylcholinesterase inhibitory activity of selected southern African medicinal plants

Alzheimer's disease (AD) is the most common type of dementia in the aging population. Enhancement of acetylcholine levels in the brain is one means of treating the disease. However, the drugs presently used in the management of the disease have various drawbacks. New treatments are required and in this study, extracts of Salvia tiliifolia Vahl. (whole plant), Chamaecrista mimosoides L. Greene (roots), Buddleja salviifolia (L.) Lam. (whole plant) and Schotia brachypetala Sond. (root and bark) were evaluated to determine their polyphenolic content, antioxidant and acetylcholinesterase inhibitory (AChEI) activity. The DPPH and ABTS assays were used to determine antioxidant activity and Ellman colorimetric method to quantify AChEI activity. Although all four plants showed activity in both assays, the organic extracts of C. mimosoides root was found to contain the highest AChEI activity (IC₅₀ = 0.03 ± 0.08 mg/ml) and B. salviifolia whole plant had the highest antioxidant activity (ABTS; IC₅₀ = 0.14 ± 0.08 mg/ml and DPPH; IC₅₀ = 0.23 ± 0.01 mg/ml). The results suggest that the tested plant species may provide a substantial source of secondary metabolites, which act as natural antioxidants and acetylcholinesterase inhibitors, and may be beneficial in the treatment of AD.     

五种柏科植物挥发油成分的GC-MS分析

柏科植物是园林绿化中常用的常绿树种,具有种数多、分布广的特点。该研究采用水蒸气蒸馏法提取5种柏科植物叶片中的挥发油,利用气相色谱-质谱(GC-MS)与计算机检索联用技术对其化学成分进行分析和鉴定,并用面积归一法测定各组分的相对含量。结果表明:用水蒸气蒸馏法提取柏科植物挥发油得油率较高,除偃柏外4种柏树的得油率都在0.5%以上;5种柏科植物挥发油中共检测出了80种萜类物质,其中日本花柏中萜类物质最多含有54种,日本扁柏次之含有51种,柏木含有47种,线柏含有42种,偃柏则只含有35种;挥发油中含量较高的成分有乙酸龙脑酯、α-蒎烯、3-蒈烯、D-柠檬烯、松油烯-4-醇、桧烯和萜品油烯等,一些植物还含有龙脑、β-月桂烯、石竹烯、β-紫罗兰酮和Verticiol等一些重要的药用成分;柏科植物挥发油具有成分及相对含量差异大、成分较简单、化合物种类以萜烯类为主的特点。研究结果可为进一步开发利用柏科植物资源提供理论依据。     

Evaluation of five clustering algorithms for biodiversity surrogates

Conservation planning requires knowledge of the distribution of all species in the area of interest. Surrogates for biodiversity are considered as a possible solution. The two major types are biological and environmental surrogates. Here, we evaluate four different methods of hierarchical clustering, as well as one non-hierarchical method, in the context of producing surrogates for biodiversity. Each clustering method was used to produce maps of both surrogate types. We evaluated the representativeness of each clustering method by finding the average number of species represented in a set of sites, one site of each domain, which was carried out with Monte-Carlo permutations procedure. We propose an additional measure of surrogate performance, which is the degree of evenness of the different domains, e.g., by calculating Simpson's diversity index. Surrogates with low evenness leave little flexibility in site selection since often some of the domains may be represented by a single or very few sites, and thus surrogate maps with a high Simpson's index value may be more relevant for actual decision making. We found that there is a trade-off between species representativeness and evenness. Centroid clustering represented the most species, but had very low values of evenness. Ward's method of minimum variance represented more species than a random choice, and had high evenness values. Using the typical evaluation measures, the Centroid clustering method was most efficient for surrogate production. However, when Simpson's index is also considered, Ward's method of minimum variance is more appropriate for managers.     

Antioxidant activity of extract from Polygonum cuspidatum

Numerous diseases are induced by free radicals via lipid peroxidation, protein peroxidation and DNA damage. It has been known that a variety of plant extracts have antioxidant activities to scavenge free radicals. Whether Polygonum cuspidatum Sieb. et Zuce has antioxidant activity is unknown. In this study, dried roots of Polygonum cuspidatum were extracted by ethanol and the extract was lyophilized. Free radical scavenging assays, superoxide radical scavenging assays, lipid peroxidation assays and hydroxyl radical-induced DNA strand scission assays were employed to study antioxidant activities. The results indicate that the IC50 value oí Polygonum cuspidatum extract is 110 microg/ml in free radical scavenging assays, 3.2 microg/ml in superoxide radical scavenging assays, and 8 microg/ml in lipid peroxidation assays, respectively. Furthermore, Polygonum cuspidatum extract has DNA protective effect in hydroxyl radical-induced DNA strand scission assays. The total phenolics and flavonoid content of extract is 641.1 +/- 42.6 mg/g and 62.3 +/- 6.0 mg/g. The results indicate that Polygonum cuspidatum extract clearly has antioxidant effects.     

Antioxidant activity of thiosulfinates derived from garlic

Garlic extract significantly inhibited the oxidation of methyl linoleate in homogeneous acetonitrile solution, whereas the antioxidant effect of allicin-free garlic extract, prepared by removing allicin by prepared by removing allicin by preparative HPLC, was much lower than that of the garlic extract. These results suggest that the antioxidant properties are mostly attributed to the presence of allicin in the garlic extract. Allicin a major component of the thiosulfinates in garlic extract, was found to be effective for inhibiting methyl linoleate oxidation, but its efficiency was less than that of alpha-tocopherol. Next, the reactivity of allicin toward the peroxyl radical, which is a chain-propagating species, was investigated by direct ESR detection. The addition allicin to 2,2'-azobis(2,4-dimethylvaleronitrile)-peroxyl radical solution caused the signal intensity of the peroxyl radical to dose-dependently decrease, indicating that allicin is capable of scavenging the the peroxyl radical and acting as an antioxidant. Finally, we studied the structure-anioxidant activity relationship for thiosulfinates and suggested that the combination of the allyl group (-CH2CH=CH2) and the -S(O)S- group is necessary for the antioxidant action of thiosulfinates in the garlic extract. In addition, one of the two possible combinations, -S(O)S-CH2CH=CH2, was found to make a much larger contribution to the antioxidant activity of the thiosulfinates than the other, CH2=CH-CH2-S(O)S-.     

水母胶原蛋白抗氧化活性研究

提取水母胶原蛋白,观察其体内外抗氧化作用。体外采用邻苯三酚自氧化法观察水母胶原蛋白对超氧阴离子(·O2-)的清除作用,采用Fenton反应体系观察对羟自由基(·OH)的清除作用;体内观察水母胶原蛋白对小鼠血清、肝脏、大脑中超氧化物歧比酶(SOD)、过氧化氢酶(CAT),丙二醛(MDA)含量的影响。结果表明:水母胶原蛋白对·O2-、·OH具有良好的清除作用,呈一定的剂量依赖关系,能明显提高小鼠血清、肝脏、大脑中的SOD、CAT含量,能在一定程度上降低血清、肝脏、大脑中的MDA水平。因此,水母胶原蛋白具有显著的抗氧化生物活性。     

Antioxidant activity of dihydrofurocoumarins from Corydalis heterocarpa

The aim of this paper is to report the results of investigations into the antioxidant effect of dihydrofurocoumarins (1–6), isolated from the salt marsh plant Corydalis heterocarpa. The scavenging activities of the isolated compounds against DPPH radicals, hydroxyl radicals, and superoxide radicals were evaluated by electron spin resonance. The protective activities of these compounds against hydroxyl radical-mediated genomic DNA damage and peroxynitrite-mediated dihydrorhodamine oxidation were also investigated. The experimental results show that most compounds had antioxidant activity but their capabilities differed a little for the different indicators. Among them, compound 6 exerted the strongest antioxidant activity at a concentration of 100 μM/mL for all tested bioassay systems, compared with other compounds.     

Introduction: twenty five years of the Gibbs Conference on Biothermodynamics

In 2011, the Gibbs Conference on Biothermodynamics will celebrate its 25th anniversary. Since the inaugural meeting in 1987, it has brought together laboratories that lived, breathed and argued about the molecular logic of macromolecular machines. The participants have a deep commitment to understanding the nature of physico-chemical forces that govern regulation of biological systems, and share a passion for applying linkage theory. The collective goal is to understand how ligand binding, subunit assembly and conformational change drive what we observe as physiological processes such as regulated transport, enzyme cascades, gene regulation, membrane permeability, viral infection, intracellular trafficking and folding of macromolecules.In this special issue, articles by former organizers of the Gibbs Conference showcase the current breadth and depth of the field of biothermodynamics, and how thoroughly it is integrated with the study of macromolecular structures, computational modeling and physiological studies of human health and disease.     

Insecticidal activity of five Chinese medicinal plants against Plutella xylostella L. larvae

Twenty-five extracts of five Chinese medicinal plant species were screened for insecticidal activity against the diamondback moth, Plutella xylostella L., larvae by a leaf dipping bioassay method. The ethyl acetate, ethanol, and acetone extracts of Veratrum nigrum L. root and rhizome, the ethyl acetate extract of Phytolacca americana L. root, and the petroleum ether extract of Pseudolarix kaempferi Gord. root bark were effective against P. xylostella. Among them, the ethyl acetate extract of V. nigrum showed the strongest insecticidal activity against the second and third instar larvae of P. xylostella, with LC₅₀ values of 225 and 335 ppm, respectively. The other extracts gave little or no insecticidal activity against P. xylostella. These results indicated that V. nigrum may be a promising naturally occurring agent for P. xylostella larval control, and that the organic solvent used for plant extraction can affect its insecticidal activity.     

转基因植物对农业生物多样性的影响

论述了近年来转基因植物对农业生态系统生物多样性影响的研究进展．主要在遗传多样性、物种多样性和生态系统多样性3个层次上予以评述．包括转基因植物对作物遗传多样性的影响;转基因植物的外源基因向杂草和近缘野生种转移;转基因抗虫植物对目标害虫的影响。抗除草剂转基因植物对作物和杂草的影响,抗病毒转基因植物对病毒的影响;转基因植物对非目标生物的影响,对土壤生态系统的影响等．     

Antioxidant and antitopoisomerase activities in plant extracts of some Colombian flora from La Marcada Natural Regional Park

Many plants have been used to treat some diseases and infections since time immemorial, and this potential has been exploited by the pharmaceutical industry in the search of new analgesic, anticarcinogenic and antimicrobial agents, among other active agents. In order to contribute with bioprospection studies on the Colombian flora, 35 extracts from 13 plant species belonging to seven families (Apocynaceae, Cactaceae, Costaceae, Eremolepidaceae, Passifloraceae, Solanaceae and Urticaceae) were collected from La Marcada Natural Regional Park (LMNRP), Colombia. Dichloromethane, n-hexane and aqueous-methanol crude extracts were prepared and evaluated for their activity against Saccharomyces cerevisiae RS322N, R52Y and RS321 strains in the yeast mutant assay and their antioxidant capacity through the DPPH test. The dichloromethane extract from Myriocarpa stipitata (Urticaceae) showed moderate inhibitory activity against the three S. cerevisiae strains tested. The capacity of the dichloromethane extract from M. stipitata to inhibit the enzyme topoisomerase I and to cause DNA damage was inferred from these results. In the DPPH assay, the n-hexane crude extract from Costus sp. (Costaceae) showed good antioxidant activity (48%); in addition, the crude dichloromethane and aqueous-methanol extracts from Rhipsalis micrantha (Cactaceae) showed moderate antioxidant activity with percentage of 29 and 21%, respectively.     

Antioxidant activity of extract from Polygonum aviculare L

Free radicals induce numerous diseases by lipid peroxidation, protein peroxidation, and DNA damage. It has been reported that numerous plant extracts have antioxidant activities to scavenge free radicals. Whether Polygonum aviculare L. (Polygonaceae) has antioxidant activity is unknown. In this study, dried Polygonum aviculare L. was extracted by ethanol, and the extract was lyophilized. The antioxidant activities of extract powder were examined by free radical scavenging assays, superoxide radical scavenging assays, lipid peroxidation assays and hydroxyl radical-induced DNA strand scission assays. The results show that the IC50 value of Polygonum aviculare L. extract is 50 microg/ml in free radical scavenging assays, 0.8 microg/ml in superoxide radical scavenging assays, and 15 microg/ml in lipid peroxidation assays, respectively. Furthermore, Polygonum aviculare L. extract has DNA protective effect in hydroxyl radical-induced DNA strand scission assays. The total phenolics and flavonoid content of extract is 677.4 +/- 62.7 microg/g and 112.7 +/- 13 microg/g. The results indicate that Polygonum aviculare L. extract clearly has antioxidant effects.