Antimicrobial activity of endemic Crataegus tanacetifolia (Lam.) Pers and observation of the inhibition effect on bacterial cells

Up to now an increasing number of antibiotic-resistant bacteria have been reported and thus new natural therapeutic agents are needed in order to eradicate these pathogens. Through the discovery of plants such as Crataegus tanacetifolia (Lam.) Pers that have antimicrobial activity, it will be possible to discover new natural drugs serving as chemotherapeutic agents for the treatment of nosocomial pathogens and take these antibiotic-resistant bacteria under control. The objective of the present study was to determine antimicrobial activity and the activity mechanism of C. tanacetifolia plant extract. The leaves of C. tanacetifolia, which is an endemic plant, were extracted using methanol and tested against 10 bacterial and 4 yeast strains by using a drop method. It was observed that the plant extract had antibacterial effects on Bacillus subtilis, Shigella, Staphylococcus aureus, and Listeria monocytogenes among the microorganisms that were tested. Minimum inhibitory concentration (MIC) results obtained at the end of an incubation of 24 h were found to be > or =6.16 mg ml(-1) for B. subtilis, < 394 mg ml(-1) for Shigella, and > or =3.08 mg ml(-1) for L. monocytogenes and S. aureus and minimum bactericidal concentration (MBC) were found as > or =24.63 mg ml(-1) for B. subtilis, > or =394 mg ml(-1) for Shigella, > or =6.16 mg ml(-1) for L. monocytogenes, and > or =98.5 mg ml(-1) for S. aureus. According to the MBC results, it was found that the plant extract had bactericidal effects and in order to explain the activity mechanism and cell deformation of bacterial strains treated with plant extract, the scanning electron microscopy (SEM) was used. The results of SEM showed that the treated cells appeared shrunken and there was degradation of the cell walls. This study, in which the antibacterial effect of C. tanacetifolia was demonstrated, will be a base for further investigations on advanced purification and effect mechanism of action of its active compounds.     

Isolation and identification of oligomeric procyanidins from Crataegus leaves and flowers

Oligomeric procyanidins were isolated from the leaves and flowers of hawthorn (Crataegus laevigata). A trimer, epicatechin-(4β→8)-epicatechin-(4β→6)-epicatechin, and a pentamer consisting of (−)-epicatechin units linked through C-4β/C-8 bonds have been isolated from hawthorn for the first time, in addition to known procyanidins including dimers B-2, B-4 and B-5, trimers C-1 and epicatechin-(4β→6)-epicatechin-(4β→8)-epicatechin, and tetramer D-1. A fraction containing a hexamer was also found.     

野山楂茎化学成分研究

采用硅胶、AB-8大孔树脂和凝胶柱层析方法对野山楂茎化学成分进行分离纯化,并根据理化性质和光谱数据分析鉴定得到9个化合物,分别是:棕榈酸(1)、硬脂酸(2)、β-谷甾醇(3)、槲皮素(4)、芦丁(5)、熊果酸(6),β-胡萝卜甙(7),柠檬酸(8)和儿茶素(9)。除化合物4外,其余均首次从野山楂中分离得到。     

Allometric allocation in fruit and seed packaging conditions the conflict among selective pressures on seed size

Selective pressures on seed size could vary among the different stages of plant life cycles, so no simple relation could explain a priori its evolution. Here, we determined the relationships between seed size and two fitness components—seed dispersal and survival from predation—in a bird-dispersed tree, Crataegus monogyna. We interpret these relationships in relation to the patterns of mass allocation to fruit and seed components. Selection patterns were assessed at two levels (1) selection pressures on the parent tree; comparing seed dispersal efficiency among individual plants and (2) selection pressures at the individual seed level; comparing seed size variation (i) before and after dispersal, and (ii) before and after postdispersal seed predation. Dispersal efficiency (percentage of seed crop dispersed) was positively correlated with fruit mass and fruit width. Differences in crop size did not offset this effect, and larger seeds were overrepresented in the seed rain relative to the seed pool before dispersal. However, the advantage of larger seeds during the dispersal stage was cancelled later by an opposite selection pressure exerted by seed predators. As a result, smaller seeds had a higher probability of surviving postdispersal seed predation, establishing an evolutionary conflict imposed by the need for dispersal and the danger of being predated. Birds and rodents preferentially selected highly profitable fruits and seeds in terms of the relative proportion of their components. Larger fruits had a higher pulp to seed proportion than smaller ones, and all seeds had the same proportion of coat relative to the embryo-plus-endosperm fraction. Hence, although predator pressures were stronger than disperser ones, larger seeds invested proportionally less in structural defense than in dispersal.     

准噶尔山楂种壳、种皮、种胚特性与种子休眠的关系

以准噶尔山楂种子为试验材料,检测其种壳和种皮的透水性及超微结构、种胚休眠特性及种子浸提液的抑制作用。结果表明：（1）准噶尔山楂种子具有胚休眠特性,种壳存在一定的机械束缚和透水障碍,存在内源抑制物质是引起准噶尔山楂种子休眠的主要原因。（2）酸蚀处理能使种壳表面结构破损,角质层脱落,种壳变薄,栅栏组织结构和细胞排列未发生变化,种孔增大,种子表面出现裂缝,但并不影响种子生活力。（3）准噶尔山楂种子甲醇浸提液的生物测定结果说明,准噶尔山楂种子的种壳、种皮和种胚均含有内源抑制物质,不同部位浸提液对白菜种子的发芽率、根长和苗高的抑制作用不同。     

Monoterpene and lignan glycosides in the leaves of Crataegus pinnatifida

In the present phytochemical study on the leaves of Crataegus pinnatifida, a new monoterpene glycoside, (3S,5R,6R,7E,9R)-3,6-epoxy-7-megastigmen-5,9-diol-9-O-β-Dglucopyranoside(6) and a new sesquilignan glycoside, acernikol-4’’-O-β-D-glucopyranoside (15), together with thirteen known compounds were isolated.     

Di-C-glycosylflavones from crataegus monogyna

Six di-C-glycosylapigenins have been characterized in leaves of Crataegus monogyna: vicenins- 1, -2 and -3: schaftoside; iso-, neo- and neoiso-schaftoside. This study corrects a previous misidentification of the flavonoid constituents of this tissue.     

Leaf hygrometer v. pressure chamber: a comparison of pressure–volume curve data obtained on single leaves by alternating measurements

Abstract. Data for the construction of pressure-volume curves were obtained by measuring water potentials of detached leaves repeatedly and alternately, with a pressure chamber and a leaf hygrometer. Good agreement between the parameters of the two resulting curves was observed. Regression lines on values after the loss of turgor were always more negative for the thermocouple data, with a maximum difference for the osmotic potential at full saturation of 0.25 MPa in Triticum and a minimum of 0.01 MPa in Populus. Neither the slopes of the regression lines nor the intercepts with the axes were statistically different. We see no reason for using one of these two unrelated methods as a standard against which the other is calibrated. Implications for the theory of pressure-volume curves are discussed.     

Comparing the composition and bioactivity of Crataegus Monogyna flowers and fruits used in folk medicine

Introduction – Studying local plant foods is of particular interest as they often contain high amounts of bioactive compounds. Furthermore, their nutritional and medicinal impact must be documented and supported with scientific studies. Crataegus monogyna is an example of ‘functional food’ traditionally used all over South European countries. Objective – A complete chemical and bioactive characterization of flower buds, flowers, unripe, ripened and over ripened fruits was performed. Methodology – Chemical characterization included determination of proteins, fats, ash, and carbohydrates, particularly sugars by HPLC‐RI, fatty acids by GC‐FID, tocopherols by HPLC‐fluorescence, phenolics, flavonoids, β‐carotene and ascorbic acid, by spectrophotometric techniques. Bioactivity was evaluated through screening of antioxidant properties: radical scavenging effects, reducing power, and inhibition of lipid peroxidation. Results – Flowers revealed the highest tocopherols and ascorbic acid contents, as also the best n‐6/n‐3 fatty acids ratio. Over ripened fruits showed the highest levels of carbohydrates, sugars and SFA. Unripe fruits presented the highest PUFA contents with the best PUFA/SFA ratio, as also the highest levels of phenolics and the most promising antioxidant properties (EC₅₀ < 20.83 µg/ml; even better than trolox). Conclusion – This study shows the potential of different parts of Crataegus monogyna as sources of several compounds, including nutrients and nutraceuticals. Moreover, it supports the documented nutritional and medicinal impact of this species. Copyright © 2010 John Wiley & Sons, Ltd.     

Typification of Crataegus crus-galli L. (Rosaceae) and nomenclatural notes on some related species of hawthorn

Lectotypification of Crataegus crus-galli permits the common ten-stamened entity of the northern United States and adjacent Canada to retain its name. The correct name for the related 20-stamen form, usually called C. fontanesiana, is C. tenax. Crataegus persimilis, lectotypified here, is shown to occur in Ontario as well as New York, having been previously misidentified as C. ?bushii and C. prunifolia in Ontario. A horticultural taxon usually (but improperly) called C. prunifolia is provided with a new cultivar name.