Studies on Chemical Constituents from Dendranthema morifolium (Ramat.) Tzvel.: Structure Elucidation of Two New Triterpenoid Esters

Two new triterpenoid esters (1 and 2) and eleven known compounds were isolated from the ethyl ether extract of Dendranthema morifolium (Ramat.) Tzvel. By means of chemical correlation and spectral analyses (IR, FAB-MS, 1H-NMR, 13C-NMR), compounds 1 and 2 were established as 16β, 22α-dihydroxypseudotaraxasterol-3β-O-palmitate and lup-16β, 28-dihydroxy-3β-O-palmitate.     

The pollination biology of Calypso bulbosa var. Americana (Orchidaceae): Initial deception of bumblebee visitors

Summary The orchid Calypso bulbosa var. americana has deceptive flowers that provide no rewards for visitors. Near Banff, Alberta, the flowering period of this species is synchronized with the emergence of its pollinators, large bumblebee queens, in late spring. Calypso flowers appear to rely on the initial attraction and deception of newly-emerged naive bumblebees for pollination. Indirect evidence suggests that individual bees subsequently learn to avoid these flowers and that avoidance is learned quite rapidly. Avoidance behavior by pollinators is obviously detrimental to sexual reproduction in Calypso. This negative effect appears to be offset by the large number of seeds produced in plants which are effectively pollinated. A test of the hypothesis that Calypso flowers mimic flowers of the shooting star, Dodecatheon radicatum (Primulaceae) failed to provide evidence for mimicry.     

芦丁脂肪酸酯对Fe~(2+)诱导的卵磷脂氧化的抑制作用

通过酯化反应将一定长度的烃基链引入黄酮糖苷分子中可以提高糖苷的抗氧化活性。本文以反映脂质氧化修饰程度的硫代巴比妥酸反应物质（TBARS）的含量为监测指标,用可见光分光光度计比色法对比研究了三种新合成的芦丁脂肪酸酯——芦丁硬脂酸酯、芦丁月桂酸酯、芦丁正己酸酯及芦丁对Fe^2＋介导的卵磷脂氧化修饰的影响。结果表明三种芦丁脂肪酸酯均具有抗氧化活性,且芦丁月桂酸酯和芦丁正己酸酯的抗氧化活性均明显优于芦丁,其中芦丁正己酸酯具有最好的抗氧化活性。在芦丁分子中引入适宜长度的短烃基链可以改善其亲水亲脂平衡从而提高其抗氧化活性。     

A tetracyclic triterpenoid from Musa paradisiaca

The structure of a new tetracyclic triterpene isolated from the flowers of Musa paradisiaca was determined as (24R)-4α,14α,24-trimethyl-5α-cholesta-8,25(27)-dien-3β-ol.     

Anti-inflammatory activity of a new triterpenoid saponin from carthamus tinctorius linn

A new bioactive triterpenoid saponin 3beta-O-[beta-D-xylopyranosyl(1 --> 3)-O-beta-D-galactopyranosyl]-lup-12-ene-28 oic acid-28-O-alpha-L-rhamnopyranosyl ester compound (A), was isolated from the methanolic fraction of the roots of this plant by various colour reactions, chemical degradations and spectral analysis. Compound (A) showed anti-inflammatory activity.     

Anti-inflammatory activity of a new triterpenoid saponin from carthamus tinctorius linn

A new bioactive triterpenoid saponin 3β-O-[β-D-xylopyranosyl(1 → 3)-O-β-D-galactopyranosyl]-lup-12-ene-28 oic acid-28-O-α-L-rhamnopyranosyl ester compound (A), was isolated from the methanolic fraction of the roots of this plant by various colour reactions, chemical degradations and spectral analysis. Compound (A) showed anti-inflammatory activity.     

Subcellular distribution of free and ester-bound triterpene triols in Calendula officinalis flowers

In cellular subfractions obtained from Calendula officinalis ligulate flowers, the contents of individual free and ester-bound triterpene triols, as well as fatty acid components of the ester form, were determined. It was shown that triterpene triols are localized only in the chromoplast fraction, almost exclusively in a free form and in a very small amount as monoesters. The compositions of fatty acids esterifying triols were similar to those esterifying diols in chromoplasts.     

Naturally occurring triterpenoid saponins

Naturally occurring new triterpenoid saponins reported from mid-1996 to March, 2007 are reviewed including their physical constants and plant sources, and are compiled in Table 1. New saponins are arranged in Table 1 on the basis of the skeletal structures of their aglycones, e.g., oleanane type, ursane type, lupane type, hopane type, taraxastane type, cycloartane type, lanostane type, tirucallane type, dammarane type, cucurbitane type, and holostane type. The known triterpenoid saponins and prosapogenins of the new saponins, the biological and pharmacological activities of which were published during 1996-2007, are also reviewed together with their plant sources listed in Table 2 according to the skeletal structures of their aglycones in the same fashion as in Table 1. The plant and animal sources of both new and known bioactive triterpenoid saponins are collected in Table 3 in alphabetical order. The biological and pharmacological activities such as antiallergic, antiatherosclerosis and antiplatelet, antibacterial, anticomplementary, antidiabetic, contraceptive, antifungal, anti-inflammatory, antileishmanial, antimalarial/antiplasmodial, anti-obesity, anti-proliferative, antipsoriatic, antispasmodic, antisweet, antiviral, cytotoxic/antitumor, detoxication, gastroprotective, haemolytic, hepatoprotective, immunomodulatory, anti-enzyme, anti-osteoporotic, insecticidal, insulin-like, membrane-porosity, molluscicidal, neuropharmacological, anti-endothelial dysfunction, snake venom antidote, and sweet activities of these saponins or derived prosapogenins are discussed briefly after Table 3.     

Floral morphological changes and reproductive success in deer weed (Lotus scoparius

Pollination-related and time-dependent floral morphological changes occur in a diverse set of angiosperm taxa and appear to be particularly common in species occupying resource-limited environments. In deer weed (Lotus scoparius), such floral modifications include a color change from yellow to orange and a folding of the banner petal down over the keel. These changes are rapidly induced by pollination, but will also occur much more slowly without pollination. Orange flowers typically lack nectar and pollen. We examined the reproductive success of these plants to test the hypothesis that retention of orange flowers increases pollinator visitation rate and fruit set while reducing costs to the pollinators. All of the common species of bee pollinators that visited deer weed easily distinguished between yellow and orange flowers at close range and preferentially probed yellow flowers. Retention of orange flowers by these plants resulted in a higher frequency of pollinator visits and a higher fruit set per flower than plants that lacked orange flowers. The number of flowers visited by each pollinator was lower on plants with a mixture of yellow and orange flowers, suggesting that the presence of orange flowers may reduce selfing. The possible selective pressures involved in the evolution of these mechanisms and their relation to stressful environments are also discussed.     

Effect of pollination success on floral longevity in the orchid Calypso bulbosa (Orchidaceae)

The lifespan of an individual flower is often affected by pollination success. Species differ regarding whether male function (pollen removal), female function (pollen deposition), or both trigger floral senescence. We studied senescence in the singleflowered, deceptive orchid Calypso bulbosa by manipulating the degree of male and female reproductive success. We found that deposition of any amount of pollen resulted in dramatic changes in shape and color within 4 d, whereas unmanipulated flowers and those that had had pollinia removed remained unchanged for 8-11 d after treatment. Selection may favor the reproductive function that is less easily satisfied as the trigger for senescence, because a flower that senesces after accomplishment of this function is likely to have already succeeded at the more easily satisfied one. Deceptive (i.e., rewardless) flowers are more likely to satisfy male than female function since the latter requires that a pollinator be fooled twice, first to pick up pollen and second to deposit it. A survey of naturally pollinated Calypso showed that male function, pollinium removal, was more likely to occur than female function, deposition (95% vs. 66% of visited flowers); thus floral senescence in Calypso is triggered by achievement of the function less likely to succeed. Studies of senescence triggers in species in which female function is more likely to be achieved than male are necessary to further test this hypothesis.     

Hydroxylation of the triterpenoid dipterocarpol with CYP106A2 from Bacillus megaterium

The bacterial steroid-hydroxylase CYP106A2 from Bacillus megaterium ATCC 13368 hydroxylates a variety of 3-oxo-Δ-4-steroids and has recently been shown to catalyse regioselective hydroxylation of the diterpene abietic acid, as well as the pentacyclic triterpene 11-keto-β-boswellic acid. The broad substrate spectrum of this enzyme makes it an excellent candidate for biotechnological application. Because the natural substrate of this enzyme is not known, we assumed that the whole substrate spectrum might not yet be fully discovered. The difference spectroscopy method was used to screen a natural product library of 502 compounds. Screening of the library resulted in the identification of twelve hits, among them eight potential and four known substrates for CYP106A2. Interestingly, when testing the potential substrates, product formation was obtained only with triterpenes, namely dipterocarpol and betulin. Dipterocarpol is the most promising compound for biotechnological application because it is a dammarane-type triterpenoid, as are the major bioactive compounds of ginseng. The dipterocarpol hydroxylation products were analysed by NMR and identified as 7β-hydroxydipterocarpol and 7β,11α-dihydroxydipterocarpol. To investigate the putative bioactive properties of these novel compounds, in vitro cytotoxicity assays with HeLa and COS-1 cells were performed. The substrate dipterocarpol and the dihydroxylated product did not show cytotoxic activity in our study. By contrast, the 7β-hydroxylated product was found to be cytotoxic to both tested cell lines. This study highlights the potency of CYP106A2 as a versatile biocatalyst for the bioconversion of natural products into pharmaceutically relevant bioactive products.     

Steryl esters and phenylethanol esters from Syringa komarowii

Three new steryl esters and a new phenylethanol ester, together with 22 known compounds were isolated from the aqueous ethanolic extract of the whole plants of Syringa komarowii. The new compounds were elucidated as stigmastane-3beta,6alpha-diol 3-O-tetradecanoate (1), stigmastane-3beta,6alpha-diol 3-O-palmitate (2), stigmastane-3beta,6alpha-diol 3-O-stearate (3), and 2-(4-hydroxyphenyl)-ethyl dotriacontanoate (4) on the basis of extensive spectral data and chemical evidences.     

Quantification of primary amine groups available for subsequent biofunctionalization of polymer surfaces

Biocompatible polymers are commonly functionalized with specific moieties such as amino groups to modify their surface properties and/or to attach bioactive compounds. A reliable method is usually required to characterize amino group surface densities. In this study, aminated polyethylene terephthalate (PET) films were generated via an aminolysis reaction involving either ethylenediamine molecules (EtDA), in order to vary easily the amino group density on PET surfaces, or 25 kDa polyvinylamine (PVAm) as an alternative reagent preventing bulk damages resulting from the aminolysis reaction. Among commonly used dyes for amino group quantification, Orange II and Coomassie Brillant Blue (CBB) were selected to quantify the extent of amine grafting resulting from these derivatization procedures. Rapid and convenient colorimetric assays were compared to surface atomic compositions obtained from X-ray photoelectron spectroscopy (XPS) measurements. Orange II was found to be the most appropriate dye for quantifying primary amine groups in a reliable and specific way. Due to its unique negative charge and low steric hindrance compared to CBB, the Orange II dye was very sensitive and provided reliable quantification over a wide range of amino group surface densities (ca. 5 to at least 200 pmol/mm(2)). In order to further validate the use of the Orange II dye for amino group quantification, a heterobifunctional linker reacting with amino groups was then grafted on modified PET surfaces. Interestingly, the good correlation between the densities of adsorbed Orange II and covalently grafted linkers suggests that the Orange II method is a relevant, reliable, easy, and inexpensive method to predict the amount of amino groups available for subsequent functionalization of polymer surfaces.     

Cytotoxic steroids from the trunk of Berberis koreana

A new steroid, itesmol 3-O-palmitate (1), along with two known steroids were isolated from the trunk of Berberis koreana. The structure of 1 was determined on the basis of spectroscopic analyses involving 2D NMR and chemical reactions. Compound 1 exhibited potential antiproliferative activity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines (respective IC(50) values of 7.41, 9.20, 4.53, and 12.91 μM).     

Potential sites of bioactive gibberellin production during reproductive growth in Arabidopsis

Gibberellin 3-oxidase (GA3ox) catalyzes the final step in the synthesis of bioactive gibberellins (GAs). We examined the expression patterns of all four GA3ox genes in Arabidopsis thaliana by promoter-beta-glucuronidase gene fusions and by quantitative RT-PCR and defined their physiological roles by characterizing single, double, and triple mutants. In developing flowers, GA3ox genes are only expressed in stamen filaments, anthers, and flower receptacles. Mutant plants that lack both GA3ox1 and GA3ox3 functions displayed stamen and petal defects, indicating that these two genes are important for GA production in the flower. Our data suggest that de novo synthesis of active GAs is necessary for stamen development in early flowers and that bioactive GAs made in the stamens and/or flower receptacles are transported to petals to promote their growth. In developing siliques, GA3ox1 is mainly expressed in the replums, funiculi, and the silique receptacles, whereas the other GA3ox genes are only expressed in developing seeds. Active GAs appear to be transported from the seed endosperm to the surrounding maternal tissues where they promote growth. The immediate upregulation of GA3ox1 and GA3ox4 after anthesis suggests that pollination and/or fertilization is a prerequisite for de novo GA biosynthesis in fruit, which in turn promotes initial elongation of the silique.     

New antifungal flavone glycoside from Butea monosperma O. Kuntze

A new bioactive flavone glycoside was isolated from the methanol soluble fraction of the flowers of Butea monosperma O. Kuntze, which was identified as 5,7-dihydroxy-3,6,4'-trimethoxyflavone-7-O-alpha-L-xylopyranosyl-(1-->3)-O-alpha-L-arabinopyranosyl-(1-->4)-O-beta-D-galactopyranoside (1) by several colour reactions, chemical degradations and spectral analysis. The compound 1 shows antimicrobial activity against various fungal species.     

Ovule and Embryo Sac Development in Malus pumila L. cv. Cox's Orange Pippin, from Dormancy to Blossom

Ovule and embryo sac development in the flowers of Cox's OrangePippin apple (Malus pumila L.) were studied from dormancy topetal fall using both scanning electron and light microscopy.The relative timing was established between these developmentsand the external development of the flower bud and flower. Malus pumila L. cv. Cox's Orange Pippin, apple, Cox, SEM, ovule development, anatomy, histology     

Localization accuracy of two electromagnetic tracking systems in prostate cancer radiotherapy: A comparison with fiducial marker based kilovoltage imaging

The aim of this study was to evaluate the localization accuracy of electromagnetic (EM) tracking systems RayPilot (Micropos Medical AB) and Calypso (Varian Medical Systems) in prostate cancer radiotherapy. The accuracy was assessed by comparing couch shifts obtained with the EM methods to the couch shifts determined by simultaneous fiducial marker (FM) based orthogonal kilovoltage (kV) imaging. Agreement between the methods was compared using Bland-Altman analysis. Interfractional positional stability of the FMs, RayPilot transmitters and Calypso transponders was investigated. 582 fractions from 22 RayPilot patients and 335 fractions from 26 Calypso patients were analyzed. Mean (± standard deviation (SD)) differences between RayPilot and kV imaging were 0.3 ± 2.2, −2.2 ± 2.4 and −0.0 ± 1.0 mm in anterior-posterior (AP), superior-inferior (SI) and left-right (LR) directions, respectively. Corresponding 95% limits of agreement (LOA) were ±4.3, ±4.7 and ±2.1 mm around the mean. Mean (±SD) differences between Calypso and kV imaging were −0.2 ± 0.6, 0.1 ± 0.5 and −0.1 ± 0.4 mm in AP, SI and LR directions, respectively, and corresponding LOAs were ±1.3, ±1.0 and ±0.8 mm around the mean. FMs and transponders were stable: SD of intermarker and intertransponder distances was 0.5 mm. Transmitters were unstable: mean caudal transmitter shift of 1.8 ± 2.0 mm was observed. Results indicate that the localization accuracy of the Calypso is comparable to kV imaging of fiducials and the methods could be used interchangeably. The localization accuracy of the RayPilot is affected by transmitter instability and the positioning of the patient should be verified by other setup techniques. The study is part of clinical trial NCT02319239.     

The Behavior and Interactions of Birds Visiting Erythrina fusca Flowers in the Colombian Amazon1

I observed 22 species of birds visiting flowering Erythrina fusca trees at Matamatá, Amazonas, Colombia. The large orange flowers of E. fusca are adapted for pollination by birds and are protected from illegitimate visits by a petal that covers the nectaries and anthers until displaced by a foraging bird. Experiments with flowers bagged to exclude potential pollinators demonstrated that the flowers do not open without assistance. At Matamatá, parrots are the most frequent visitors to flowering E. fusca, and two species, Dusky‐headed Parakeet (Aratinga weddellii) and Cobalt‐winged Parakeet (Brotogeris cyanoptera), appear to be the main pollinators. This is only the fourth report of Neotropical parrots acting as pollinating agents. At least five other parrot species fed on the nectar or flowers of E. fusca but destroyed the flowers in the process. Orange‐backed Troupials (Icterus jamacaii) were the only other species observed opening E. fusca flowers nondestructively and are likely to be pollinators. Hummingbirds were common visitors to E. fusca flowers and some species were found to carry E. fusca pollen; however, hummingbirds were unable to open the flowers themselves and relied on other visitors to open the flowers for them. The number of hummingbird visits to a flowering E. fusca tree was positively correlated with the number of visits by parrots and icterids, but not with the number of mature flowers, indicating that legitimate visitors facilitate access by hummingbirds.