Nutraceutical Activity of Anthocyanins from the Edible Berries of Rhamnus pompana

We present the inhibitory properties of the R. pompana anthocyanin fraction (RPAF) and its major constituents on alpha-glucosidase (AG), pancreatic lipase (PL), HMG-CoA reductase, and ornithine decarboxylase (ODC). The effect of RPAF was also evaluated in ICR male mice subjected to oral glucose tolerance test (OGTT) and hypercaloric/atherogenic diet for 30 days. RP-HPLC/MS profiling revealed that RPAF contained five major anthocyanins and induced slight inhibition on PL and HMG-CoA reductase (IC₅₀, 245–338 μg mL⁻¹) whereas strong activity on AG and ODC (IC₅₀, 130–133 μg mL⁻¹) was observed. Kinetic studies and molecular docking with pelargonidin-3-O-rutinoside (P3R) on ODC, revealed changes in K_m (0.9514–0.9746 mM) and V_max (1.96–2.32 μmol mg⁻¹ min⁻¹) suggesting mixed inhibition and molecular interaction with two active sites of ODC. P3R showed antiproliferative activity (IC_50, 46.5 μM) and decreased polyamine accumulation in DLD-1 cells. The results of OGTT confirmed that RPAF regulates postprandial glucose levels in diabetic animals which experienced a significant glucose depletion (30 %; p<0.001) from 30 to 120 min post-treatment. Prolonged supplementation of RPAF caused significant decrease (p<0.001) in plasma glucose, total cholesterol, LDL-c and triglycerides as well as significant increase (p<0.001) of HDL-c compared with normoglycemic untreated animals.     

Size-uneven competition and resource availability: A factorial experiment on seedling establishment of three Mediterranean species

Abstract

A factorial experiment was conducted in order to test whether the ranking of competitive ability at seedling stage is affected by different resource availability and competition asymmetry levels. Seedlings of three Mediterranean species (Rhamnus alaternus, Ampelodesmos mauritanicus and Cistus incanus) were grown at two competition intensities with different water and nutrient levels. Plants responses were expressed as mortality, biomass production and plant architecture. Data were also analysed by an index of competitive response intensity. A clear ranking of competitive response was observed, with Rhamnus > Ampelodesmos > Cistus. Competition was affected both by water and nutrient availability, but none of these factors modified competitive ranking. Seedling competition behaviour appeared to be related to species successional roles.     

Ecology and ecosystem impacts of common buckthorn (<Emphasis Type="Italic">Rhamnus cathartica</Emphasis>): a review

In this review, we synthesize the current knowledge of the ecology and impacts of Rhamnus cathartica L., a shrub from Europe and Asia that is a successful invader in North America. Physiological studies have uncovered traits including shade tolerance, rapid growth, high photosynthetic rates, a wide tolerance of moisture and drought, and an unusual phenology that may give R. cathartica an advantage in the environments it invades. Its high fecundity, bird-dispersed fruit, high germination rates, seedling success in disturbed conditions, and secondary metabolite production may also contribute to its ability to rapidly increase in abundance and impact ecosystems. R. cathartica impacts ecosystems through changes in soil N, elimination of the leaf litter layer, possible facilitation of earthworm invasions, unsubstantiated effects on native plants through allelopathy or competition, and effects on animals that may or may not be able to use it for food or habitat.     

鼠李属一新种

发表了鼠李属一新种,即崂山鼠李Rhamnus laoshanensis D. K. Zang.     

Vegetation Management for Promoting Ecosystem Resilience in Fire-Prone Mediterranean Shrublands

Dense shrublands constitute highly hazardous fuels in Mediterranean countries. The combination of agricultural land abandonment and fire occurrence in many Mediterranean areas has led to a landscape dominated by shrublands where resprouter species are scarce or absent. Major goals in the management of these areas are to reduce both the fuel loads and their continuity and increase the resilience of the ecosystems by introducing resprouter species. We investigated the performance of one-year-old seedlings of native resprouters, that is, Pistacia lentiscus , Quercus ilex , and Rhamnus alaternus , in a combination of vegetation clearing and mulching with brush chipping in three sites with high amount of fuel load. The planting holes inside the shrublands showed lower radiation and soil surface temperature than those in the cleared areas, whereas soil water content was higher in the mulched holes than in the unmulched ones, especially when water availability was lowest. Seedling survival of Q. ilex and R. alaternus significantly increased within the shrubland; P. lentiscus showed the opposite effect, but its survival was enhanced by the mulching treatment. The three species grew faster in the cleared plots although, unexpectedly, mulching showed a negative effect on Q. ilex relative growth rate in diameter. Our results suggest that the combination of fuel control and reforestation as techniques for shrubland management is an appropriate option, at least in the short term, to redirect vegetation dynamics toward later successional stages, improving ecosystem resilience by the introduction of woody resprouter species.     

Comparison of three different extraction methods and HPLC determination of the anthraquinones aloe‐emodine,emodine, rheine,chrysophanol and physcione in the bark of Rhamnus alpinus L. (Rhamnaceae)

Introduction – Rhamnus alpinus L. (Rhamnaceae), a traditional plants in the flora of the Abruzzo region, is known to contain active anthraquinone secondary metabolites. However, the content of anthraquinones varies among R. alpinus samples depending on collection season and site. Thus, using simple, reliable and accurate analytical methods for the determination of anthraquinones in R. alpinus extracts allows comparative study of different methods of extraction. Objective – After a partial validation of an HPLC method for the simultaneous determination of five anthraquinones, aloe‐emodine, rheine, emodine, chrysophanol and physcione, in the bark of R. alpinus, we compared three different methods of extraction. Methodology – Anthraquinones were extracted from the bark of R. alpinus using different techniques (methanol maceration, ultrasonic and supercritical CO₂ extraction). Separation and quantification of anthraquinones were accomplished using a reversed‐phase C₁₈ column with the mobile phase of H₂O–methanol (40 : 60, v/v, 1% formic acid) at a wavelength of 254 nm. The qualitative analyses were also achieved at wavelength of 435 nm. Results – All calibration curves were linear over the concentration range tested (10–200 mM) with the determination coefficients ≥0.991. The detection limits (S/N = 3) were 5 mM for each analytes. All five anthraquinones were found in the samples tested at concentrations reported in experimental data. Conclusion – The described HPLC method and optimised extraction procedure are simple, accurate and selective for separation and quantification of anthraquinones in the bark of R. alpinus and allow evaluation of the best extraction procedure between the tested assays. Copyright © 2009 John Wiley & Sons, Ltd.