A new flavonol glycoside from the aerial parts of Astragalus vulneraria

A new flavonol glycoside, isorhamnetin 3-O-beta-D-apiofuranosyl-(1-->2)-alpha-L-rhamnopyranosyl-(1-->6)]-beta-D-galactopyranoside, and the known diglycoside, isorhamnetin 3-O-alpha-L-rhamnopyranosyl-(1-->6)-beta-D-galactopyranoside were isolated from the aerial parts of Astragalus vulneraria. Characterization of the two compounds was done by spectroscopic methods (1D and 2D NMR, and FAB-MS).     

Gas chromatographic-mass spectrometric analysis of essential oils from Pimpinella aurea, Pimpinella corymbosa, Pimpinella peregrina and Pimpinella puberula gathered from Eastern and Southern Turkey

Essential oils from fruits, stems and leaves and roots of Pimpinella aurea DC., P. corymbosa Boiss., P. peregrina L. were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) techniques. Fruits and aerial parts of P. puberula (DC.) Boiss were also evaluated. A total of 140 different compounds were identified, and significant qualitative and quantitative differences were observed among the samples. In fact, the main constituents of each species were different and only the oils extracted from roots shared the same principal compound, epoxy pseudoisoeugenyl-2-methyl butyrate (26.8-42.8%). The other fractions were dominated by different sesquiterpene compounds although in three of them, P. aurea stem and leaves, P. puberula fruits and P. puberula stems and leaves, monoterpene constituents also appear as main ones.     

Tryptamine derived amides with thiazole ring system from Thermoactinomyces strain TA66-2

A moderately thermophilic actinomycete strain, which was identified as Thermoactinomyces strain TA66-2, was isolated from hot-spring water. Fermentation, followed by solvent partition and chromatographic separations, resulted in the isolation of two new and two known molecules. The structures of the new compounds were elucidated as 2-(1-Propionylaminoethyl)thiazole-4-carboxylic acid [2-(1H-indol-3-yl)ethyl]amide and 2-(1-Acetylaminoethyl)thiazole-4-carboxylic acid [2-(1H-indol-3-yl)-ethyl]amide by using spectral methods (1D-, 2D-NMR and LC-ESI-MS).     

Performance enhancement of the power penalty in DWDM FSO communication using DPPM and OOK modulation

This paper presents the design and performance enhancement of the power penalty (PP) in a dense wavelength division multiplexing based on free space optical communication (FSOC) link using digital pulse position modulation (DPPM) and on–off keying (OOK) modulation. Such a system has a high performance, low cost, robust and power efficient, reliable, excessive flexibility, and higher data rate for access networks. The system performance is evaluated for an 8-channel wavelength-division-multiplexing for hybrid fiber FSOC system at 2.5 Gbps on widely accepted modulation schemes under various atmospheric turbulence (AT) regimes conditions. The performance of system is introduced in terms of PP, bit-error rate (BER), transmission distance and the average received optical power. The numerical results shows that the improvement of the PP using DPPM modulation of 0.2–3.0 dB for weak turbulence (WT) regimes for BER of 10^?6 and above 20, 25 dB for strong turbulence (ST) regimes are reported for BER of 10^?6 and 10^?9, as respectively (depending on the AT level). Further, we develop of improvement the PP caused by multiple-access interference about 6.686 dB which is predicted for target BER of 10^?9 in WT and 1 dB at target BER of 10^?6 in ST when the 8 user are active on the system of optical network units. Additionally, the optical power budget and margin losses of a system are calculated with different link length. The proposed approach of DPPM merges superiority with higher enhancement of PP about 0.8 dB for BER equal 10^?9 at FSO link length l_fso?=?2000 m compared to OOK at 1 dB for WT. An improvement of 2 dB is observed using the DPPM scheme over an OOK due to capability of detect pulses under background noise conditions with increased receiver sensitivity.     

Trojanosides I-K: new cycloartane-type glycosides from the aerial parts of Astragalus trojanus.

Three new cycloartane-type triterpene glycosides have been isolated from the aerial parts of Astragalus trojanus. The structures were established mainly by a combination of one- and two-dimensional NMR techniques [1H-1H-correlation spectroscopy (COSY), 1H-13C-heteronuclear multiple quantum correlation spectroscopy (HMQC), and 1H-13C-heteronuclear multiple-bond correlation spectroscopy (HMBC)] and high resolution electrospray ionization mass spectrometry (HR-ESI-MS) as 3-O-beta-(2',3'-di-O-acetyl)-D-xylopyranosyl-6-O-beta-D-glucopyranosyl-16-O- acetoxy-20(R),24(S)-epoxycycloartane-3beta,6alpha,16beta,25-tetrol, 3-0-[alpha-L-rhamnopyranosyl-(1-->2)-beta-(3',4'-di-O-acetyl)-D-xylopyranosyll-6-O-beta-D-xylopyranosyl-20(R),24(S)-epoxycycloartane-3p,6alpha,16beta,25-tetrol, 3-O-beta-D-xylopyranosyl-6,16-di-O-beta-D-glucopyranosyl-20(R)24(S)-epoxycycloartane-3beta,6alpha,16beta,25-tetrol.     

Separation ofAstragalus saponins by reversed phase high performance liquid chromatography and evaporative light scattering detection

Summary A new HPLC method permitted the separation of 13 triterpene lycosides isolated from differentAstragalus species within 40 min. A water/acetonitrile gradient was used as eluent and 5 μm RP-18 material as stationary phase. By using an evaporative light scattering (ELS) detector, the main saponins ofA. membranaceus could be detected at levels as low as 20.0 μg·mL⁻¹. This method facilitated distinction of differentAstragalus species as well as the analyses of market products containingA. membranaceus. The results showed variations from 0.019 to 0.184% in the total saponin content of the market products.     

Separation ofCimicifuga racemosa triterpene glycosides by reversed phase high performance liquid chromatography and evaporative light scattering detection

Summary The main triterpene glycosides ofCimicifuga racemosa were separated by reversed phase HPLC, using a C-18 column, Evaporative Light Scattering (ELS) detection and a grient system consisting of water, acetonitrile and reagent alcohol. Within 35 min three main glycosides could be separated and quantified in the methanolic root extract with detection limits of 10.5, 15.6 and 31.6 μg·mL⁻¹ respectively. The method was successfully used, to analyzed differentCimicifuga racemosa market products, as well as to distinguish between otherCimicifuga samples from China.     

A study on electrodeposited Ni x Fe1−x alloy films

Ni _x Fe_1−x (0.22 ≤x ≤ 0.62) alloy films were grown by electrodeposition technique. A shift in diffraction peaks of NiFe and Ni₃Fe was detected with increasing Ni content. The highest positive magnetoresistance ratio was detected as 5% in Ni0.₅₁Fe0.₄₉. Positive and negative anisotropic magnetoresistance were observed in longitudinal and transverse geometries respectively. The highest anisotropic magnetoresistance ratio of 9.8% was also detected in Ni0.₅₁Fe0.₄₉. The angular variation of magnetoresistance was studied. Magnetisation loop curves show that NiFe alloy films have a linear decreasing anisotropy constant with increasing Ni deposit content and show a decreasing behavior of coercivity which indicates soft magnetic property with increasing Ni deposit content     

Secondary metabolites from Phlomis oppositiflora

In addition to rare phenylethanoid triglycosides, myricoside and its dimetylether derivative serratumoside A {3-hydroxy,4-methoxy-beta-phenylethoxy-O-beta-D-apiofuranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->3)-4-O-feruloyl-beta-D-glucopyranoside}, a new phenylethanoid glycoside, myricoside-3"-O-methylether {3,4-dihydroxy-beta-phenylethoxy-O-beta-D-apiofuranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->3)-4-O-feruloyl-beta-D-glucopyranoside} along with a new neolignan glucoside, (7S, 8R)-dehydroconiferyl alcohol-8-5'-dehydroconiferyl aldehyde 4-O-beta-D-glucopyranoside were isolated from the aerial parts of Phlomis oppositiflora. The structures of the new compounds were identified by means of spectroscopic (UV, IR, 1D- and 2D-NMR, and LC-ESIMS) methods.     

Cimiracemoside a: A new cyclolanostanol xyloside from the rhizome of Cimicifuga racemosa

A new 9,19-cyclolanostane-type triterpene xyloside (1), from the rhizomes of Cimicifuga racemosa, has been isolated together with four known saponins; cimiaceroside A, 25-O-methylcimigenol-3-O-beta-D-xylopyranoside, 27-deoxyactein and 23-O-acetylshengmanol-3-O-beta-D-xylopyranoside. The structure of the new compound was established as 16beta,23:22beta,25-diepoxy-12-acetoxy-3beta,23,24b eta-trihydroxy-9,19-cyclolanost-7-ene-3-O-beta-D-xylopyranoside . For the structure elucidation, 1D- and 2D-NMR experiments and high resolution electrospray ionization Fourier transformation mass spectrometry (HRESIFTMS) were used.