980 research outputs found
Discovery of natural antiprotozoals from medicinal plants Saussurea costus and Carica papaya
No full textMedicinal plants have been an important source for the discovery of therapeutic agents for infectious diseases. In order to explore their potential an appropriate selection of plant species is important. In our attempt to find hits targeting antiprotozoal diseases, we utilized an extract library setting, and ethnomedicinal information. A library of 1800 plant and fungal extracts was screened for in vitro effects against Trypanosoma brucei rhodesiense STIB 900 strain and Plasmodium falciparum K1 strain. The ethyl acetate extract of Saussurea costus roots, and the methanolic extract of Carica papaya leaves were selected for further studies. HPLC-based activity profiling enabled the localization and identification of the active constituents of these plants extracts. Sensitive hyphenated analytical methods such as HPLC-PDA-ESI-TOF-MS and microprobe NMR were used for structure elucidation of the isolated compounds. X-ray crystallography was used in combination with electronic circular dichroism to determine the absolute configuration of selected compounds.
The ethyl acetate extract of S. costus roots potently inhibited the growth of T. b. rhodesiense in vitro. HPLC-based activity profiling led to the identification of four sesquiterpene lactones. Three structurally related sesquiterpene lactones that originated from different sources were also investigated. All compounds exhibited profound activity against T. b. rhodesiense with IC50 values between 0.8 – 21.9 µM. Cytotoxicity was tested on rat myoblast L-6 cells, where IC50 values of 1.6 to 19.4 µM were observed, and provided selectivity indices (SI) between 0.5 and 6.5. The most active compounds in this study were the germacranolides costunolide, parthenolide, and eupatoriopicrin.
The leaves of the Indonesian ethnomedicinal plant C. papaya are a known antimalarial remedy. So far, the active principles have not been investigated from a phytochemical and pharmacological point of view. HPLC-based activity profiling of the methanolic extract from C. papaya leaves against P. falciparum led to the discovery of five alkaloids and four flavonol glycosides. All compounds exhibited in vitro antimalarial activity against P. falciparum K1 strain, albeit to varying degrees. Three dimeric alkaloids showed potent activity with IC50 values ranging from 0.2 to 1.8 µM, and SI from 24.2 to 107.5. The isolated flavonol glycosides were less active, with IC50 values between 13.2 – 16.8 µM, and selectivity indices of more than 9. Lower activity was observed for the two monomeric alkaloids (IC50 = 77 µM). Carpaine (IC50 of 0.2 µM; SI of 107.5) was the most interesting compound in this study and was, hence, selected for further evaluation of its in vivo pharmacological properties using a 4-day suppressive assay on mice. However, only a reduction of parasitemia by 11.9% was observed. With the aid of X-ray crystallography and ECD calculation, the absolute configuration for carpaine was established as 1S,11R,13S,14S,24R,26S. Carpaine represents a new scaffold for anti-plasmodial drugs. An analysis of carpaine content by means of UPLC-MS/MS was pursued with 28 leaf samples from Indonesia and one from India. The carpaine content varied from 0.02 to 0.31%
Forgotten Edible alpine plants in the canton of Valais
No full textTradition possesses plenty of forgotten wild edible plants and may help researchers in the quest for new food varieties. Swiss alpine cantons, especially the canton of Valais, have still had a viable tradition. However, societal changes and extensive urbanization have caused this knowledge to be confined to lateral valleys. This contribution aimed to document wild edible plants which were collected in the canton of Valais. 38 informants originating from four different valleys of the canton (Val d’Entremont, Val d’Illiez, Val d’Hérens, and Val d’Anniviers) were interviewed with semi-directive interviews.
98 edible plant species, which belong to 38 families, were identified. Plants were classified in eight categories based on the way they were traditionally used including salads, cooked vegetables, spices, alcoholic drinks, teas, syrups, jams, and raw snacks. The categories with the highest number of citations were teas (18%), followed by cooked vegetables (16%), jams (16%), and raw snacks (16%). Taraxacum officinale, Sambucus nigra, Chenopodium bonus-henricus, and Urtica dioica were the most cited plants and most commonly used in the different valleys. Knowledge on edible plants is found from its origins in agriculture and activities as shepherds. Books written in the XIXth and early XXth centuries have documented these uses and have allowed identification of around 40 food plants, which had already fallen in oblivion (e.g. Bunium bulbocastanum).
Two traditional edible plants (Phyteuma orbiculare and Cirsium spinosissimum) were submitted to a thorough phytochemical investigation. Each plant was successively extracted with dichloromethane and methanol. Extracts were subjected to HPLC-MS DAD analyses and pure constituents were isolated by preparative and semi-preparative methods (Diaion HP-20, liquid-liquid extraction, Sephadex LH-20, open column on silica gel, preparative and semi-preparative columns on C18). The molecular structures of the isolated compounds were elucidated by chemical and spectroscopic methods. In addition, substances relevant for nutrition (e.g. vitamins, fatty acids, minerals, and major polyphenols) were quantified.
The first species investigated was the round-headed rampion (Phyteuma orbiculare L., Campanulaceae). The sweet flowers of the plant were consumed by shepherds as raw snacks, whereas nutty-tasting leaves (rosettes) were eaten as a salad. No phytochemical studies or biological data had been published for the entire genus Phyteuma.
23 substances including different polyphenols, fatty acids, and triterpenes were identified from dried aerial parts. Phytochemical investigations also revealed the presence of two novel saponins, phyteumosides A and B. The aglycon of phyteumoside A possessed an unprecedented skeleton that could be rationalized as an incompletely cyclized onoceroid triterpene, whereas that of phyteumoside B was a new 17-polypodene skeleton. Identification of these two substances was achieved by compilation of chemical and enzymatic hydrolyses, followed MS/MS, GC-MS, NMR and X-rays analyses. In addition to these two new substances, a new dimeric phenylpropanoid glycosylate derivative (tangshenoside VII) could be isolated and elucidated.
Concerning the quantification of substances relevant for nutrition, Phyteuma orbiculare contained interesting amounts of ascorbic acid, beta-carotene, polyphenols, polyinsaturated fatty acids, calcium, magnesium and potassium
This food plant, which possesses interesting nutritive properties and favorable breeding predispositions, could be an interesting candidate for further agronomic development. However, species of the same genus have a larger biomass and it was interesting to compare their phytochemical profile. HPLC-MS DAD analyses revealed similar metabolite profiles for P. spicatum, P. ovatum, and P. orbiculare but showed differences for P. hemisphaericum.
The second plant to be investigated was a thistle, Cirsium spinosissimum (Asteraceae). Surrounding leaves and the pappus hairs were removed before consumption, and the receptacle was eaten in early summer time. Taste of the receptacle is similar to that of an artichoke, and its consistency is tender.
A total of 20 substances including polyphenols, a monoterpene lactone, fatty acids and a spermine derivative were identified. Major polyphenols were linarin and pectolinarin and have been previously isolated from other Cirsium species.
This plant contains vitamins and polyunsaturated fatty acids in low amounts, and an interesting level of potassium. Cirsium spinosissimum is not really convenient for further cultivation due to its spiny morphology.
Other alpine edible plants selected during this work could be interesting with regard to their chemical composition, and for future breeding. They should be the main focus of further investigations. The establishment of alpine plants as new food crops would represent a diversification of the activities in mountain agriculture
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Analysis of University Researcher Collaboration Networks using co-authorship
No full textSocial network analysis gives evidence for the connections between groups of individuals. It is these connections that channel flow of information and the sharing of knowledge. As universities move towards more interdisciplinary modes of research and funding, an effective network that links its entire cohort of active researchers is vital. This project conducted a co-authorship network analysis and a path length analysis on a small institutional database. The major advantage of our analysis over other similar work is that we used author's background details in supporting our analysis and generated co-authorship graphs with authors' names and groups. The network metrics have been compared and contrasted to similar work conducted with large-scale cross-institutional databases in several domains. We found the most of metrics are not affected by the network size and showed that the ECS community is a small-world network with similar knowledge sharing to those communities formed by an entire discipline
Mosquito Larvicidal Constituents from Lantana Viburnoides SP Viburnoides Var Kisi (A. rich) Verdc (Verbenaceae).
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Lantana viburnoides sp viburnoides var kisi is used in Tanzania ethnobotanically to repel mosquitoes as well as in traditional medicine for stomach ache relief. Bioassay-guided fractionation and subtraction bioassays of the dichloromethane extract of the root barks were carried out in order to identify the bioactive components for controlling Anopheles gambiae s.s. mosquito larvae. Twenty late III or early IV instar larvae of An. gambiae s.s. were exposed to various concentrations of the plant extracts, fractions, blends and pure compounds, and were assayed in the laboratory by using the protocol of WHO 1996. Mean mortalities were compared using Dunnett's test (p < 0.05) and lethal concentration calculated by Lackfit Inversel of the SAS programme. The crude extract (LC50 = 7.70 ppm in 72 h) and fractions exhibited different level of mosquito larvicidal activity with subtraction of some fractions resulting in activity enhancement. The active fractions contained furanonaphthaquinones regio-isomers (LC50 = 5.48-5.70 ppm in 72 h) and the lantadene triterpenoid camaric acid (LC50 = 6.19 ppm in 72 h) as active principles while the lupane triterpenoid betulinic acid (LC50 < 10 ppm in 72 h) was obtained from the least active fraction. Crude extracts and some fractions had higher or comparable larvicidal activity to the pure compounds. These results demonstrate that L. viburnoides sp viburnoides var kisi extracts may serve as larvicides for managing various mosquito habitats even in their semi-purified form. The isolated compounds can be used as distinct markers in the active extracts or plant materials belonging to the genus Lantana
Measurement of the branching fraction
No full textThe B
0
s
→ J/ψK
0
S
branching fraction is measured in a data sample corresponding to 0.41 fb−1
of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to
the penguin contributions affecting the sin 2β measurement from B
0
→ J/ψK
0
S
. The time-integrated
branching fraction is measured to be B(B
0
s
→ J/ψK
0
S
) = (1.83±0.28)×10−5
. This is the most precise
measurement to date
Structure-Elucidating Total Synthesis of the (Polyenoyl)tetramic Acid Militarinone C§
No full textThe (polyenoyl)tetramic acid militarinone C (1) heads a family of seven members. Before our work, the configuration of C-5 was unknown whereas the configurations of C-8′ and C-10′ were either (R,R) or (S,S). We synthesized the four stereoisomers of constitution 1, which conform with these insights. This included cross-coupling both enantiomers of the western building block (8) with both enantiomers of the eastern building block (9). The specific rotations of the resulting 1 isomers suggested that natural 1 is configured like the coupling partners (S)-8 and (R,R)-9. This conclusion was corroborated by degrading natural 1 to alcohol 35 and by proving its configurational identity with synthetic (R,R)-35
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Prompt charm production in pp collisions at √<span style="text-decoration:overline">s</span>=7 TeV
No full textCharm production at the LHC in pp collisions at s√=7 TeV is studied with the LHCb detector. The decays D0→K−π+, D+→K−π+π+, D⁎+→D0(K−π+)π+, D+s→ϕ(K−K+)π+, Λ+c→pK−π+, and their charge conjugates are analysed in a data set corresponding to an integrated luminosity of 15 nb−1. Differential cross-sections dσ/dpT are measured for prompt production of the five charmed hadron species in bins of transverse momentum and rapidity in the region 0<pT<8 GeV/c and 2.0<y<4.5. Theoretical predictions are compared to the measured differential cross-sections. The integrated cross-sections of the charm hadrons are computed in the above pT-y range, and their ratios are reported. A combination of the five integrated cross-section measurements gives
σ(cc¯)pT<8 GeV/c,2.0<y<4.5=1419±12(stat)±116(syst)±65(frag) μb,
where the uncertainties are statistical, systematic, and due to the fragmentation functions
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