Synthesis and absolute configuration of a new 3,4-dihydro-beta-carboline-type alkaloid, 3,4-dehydro-5(S)-5-carboxystrictosidine,isolated from Peruvian Uña de Gato (Uncaria tomentosa)

The structure including the absolute configuration of a new glucoalkaloid, 3,4-dehydro-5(S)-5-carboxystrictosidine, isolated from Peruvian U?a de Gato (Cat's Claw, original plant: Uncaria tomentosa), was confirmed by synthesis starting from secologanin and L-tryptophan.     

New oleanan-type triterpene and cincholic acid glycosides from Peruvian "Uña de Gato" (Uncaria tomentosa)

A new oleanan-type triterpene and three new cincholic acid glycosides were isolated from Peruvian "Una de Gato" (Cat's claw, plant of origin: Uncaria tomentosa), a traditional herbal medicine in Peru. Their structures were determined by spectroscopic analysis.     

A new gluco indole alkaloid, 3, 4-dehydro-5-carboxystrictosidine, from Peruvian Uña de Gato (Uncaria tomentosa)

A new gluco indole alkaloid, 3,4-dehydro-5-carboxystrictosidine, was obtained from Peruvian U?a de Gato (Cat's Claw, original plant: Uncaria tomentosa) together with two known gluco indole alkaloids. This compound was the first example of isolation of a gluco monoterpenoid indole alkaloid having a 3,4-dihydro-beta-carboline ring system from nature. A characteristic feature of the compound was the quick replacement of the methylene hydrogens on C-14 with deuterium that was observed when it was dissolved in CD3OD. We demonstrated a similar proton-deuterium exchange on a model compound, 1-methyl-3,4-dihydro-gamma-carboline, in CD3OD solution.     

Two new alkaloids from the leaves of Uncaria hirsuta Haviland

Two new alkaloids, uncaric acid A and hirsutaside A, were isolated from Uncaria hirsuta. Their structures were determined by spectroscopic evidences and chemical means.     

A metabolomics strategy for authentication of plant medicines with multiple botanical origins,a case study of Uncariae Rammulus Cum Uncis

Source authentication of herbal medicines was essential for ensuring their safety, efficacy and quality consistency, especially those with multiple botanical origins. This study proposed a metabolomics strategy for species discrimination and source recognition. Uncariae Rammulus Cum Uncis, officially stipulating the stems with hooks of five Uncaria species as its origins, was taken as a case study. Firstly, an untargeted MS^E method was developed by ultra‐high performance liquid chromatography hyphenated with quadrupole time‐of‐flight mass spectrometry for global metabolite characterization. Subsequently, data pretreatment was conducted by using Progenesis QI software and screening rules. The obtained metabolite features were defined as variables for statistical analyses. Principal component analysis and chemical fingerprinting spectra suggested that five official species were differentiated from each other except for Uncaria hirsuta and Uncaria sinensis. Furthermore, orthogonal partial least squares discrimination analysis was performed to discriminate confused two species, and resulted in the discovery of nine contributing markers. Ultimately, a Support Vector Machine model was developed to recognize five species and predict origins of commercial materials. The study demonstrated that the developed strategy was effective in discrimination and recognition of confused species, and promising in tracking botanical origins of commercial materials.     

岗稔提取物总酚含量测定方法的研究

总酚具有抗氧化、捕捉自由基、抑菌等作用,在食品加工、果蔬加工、贮藏、医药等方面都有应用价值。对岗稔果实中有效成分总酚进行提取,并测定其含量。为岗稔在实际产业中应用提供参考。     

Rauniticine-allo-oxindole B and rauniticinic-allo acid B, new heteroyohimbine-type oxindole alkaloids from the stems of Malaysian Uncaria longiflora var. pteropoda

Two new heteroyohimbine-type oxindole alkaloids, rauniticine-allo-oxindole B and rauniticinic-allo acid B, have been successfully isolated from the stems extract of Malaysian Uncaria longiflora var. pteropoda. The structures of the two new alkaloids were determined by spectroscopic analysis.     

Spent Grain from Malt Whisky: Assessment of the Phenolic Compounds

In order to extract antioxidant phenolic compounds from spent grain (SG) two extraction methods were studied: the ultrasound-assisted method (US) and the Ultra-Turrax method (high stirring rate) (UT). Liquid to solid ratios, solvent concentration, time, and temperature/stirring rate were optimized. Spent grain extracts were analyzed for their total phenol content (TPC) (0.62 to 1.76 mg GAE/g SG DW for Ultra-Turrax pretreatment, and 0.57 to 2.11 mg GAE/g SG DW for ultrasound-assisted pretreatment), total flavonoid content (TFC) (0.6 to 1.67 mg QE/g SG DW for UT, and 0.5 to 1.63 mg QE/g SG DW for US), and antioxidant activity was measured using 2,2-diphenyl-2-picrylhydrazyl (DPPH) free radical (25.88% to 79.58% for UT, and 27.49% to 78.30% for UT). TPC was greater at a high stirring rate and high exposure time up to a certain extent for the Ultra-Turrax method, and at a high temperature for the ultrasound-assisted method. P-coumaric acid (20.4 ± 1.72 mg/100 SG DW for UT, and 14.0 ± 1.14 mg/100 SG DW for US) accounted for the majority of the phenolic found compounds, followed by rosmarinic (6.5 ± 0.96 mg/100 SG DW for UT, and 4.0 ± 0.76 mg/100 SG DW for US), chlorogenic (5.4 ± 1.1 mg/100 SG DW for UT, and non-detectable for US), and vanillic acids (3.1 ± 0.8 mg/100 SG DW for UT, and 10.0 ± 1.03 mg/100 SG DW for US) were found in lower quantities. Protocatechuic (0.7 ± 0.05 mg/100 SG DW for UT, and non-detectable for US), 4-hydroxy benzoic (1.1 ± 0.06 mg/100 SG DW for UT, and non-detectable for US), and caffeic acids (0.7 ± 0.03 mg/100 SG DW for UT, and non-detectable for US) were present in very small amounts. Ultrasound-assisted and Ultra-Turrax pretreatments were demonstrated to be efficient methods to recover these value-added compounds.     

Supercritical fluid extraction of oxindole alkaloids from Uncaria tormentosa

Supercritical fluid extraction of oxindole alkaloids from Uncaria Tormentosa is described. The extraction was performed with supercritical carbon dioxide alone and with supercritical carbon dioxide modified with 10% metanol, and the extracts were analyzed by GC/MS and HPLC/MS.     

High accuracy ultrasonic monitoring of electrochemical processes

Ultrasonic testing (UT) can be used for non-intrusive corrosion monitoring. In this paper, we firstly show that UT is not only capable of monitoring wall-thickness losses, but can also be exploited for tracking electrodeposition processes. All ultrasonic measurements reported are in agreement with analytical predictions and optical surface profile measurements. Since UT is highly sensitive to the coupling conditions and the relative acoustic properties of substrates and deposited materials, it can become an effective tool for studying the interface phenomena in which dissolution and deposition compete. Examples of these include passivation layer formation and scale deposition which are corrosion-inhibiting electrochemical processes.     

Chromatographic and spectroscopic methods for the identification of alkaloids from herbarium samples of the genus Uncaria.

A combination of thin-layer chromatography, gas-liquid chromatography, ultraviolet spectroscopy and mass spectrometry techniques for the alkaloid screening of herbarium samples of the genus Uncaria (Rubiaceae) is described. Some sixty alkaloids are distinguished by the screening procedure, and they represent heteroyohimbine, oxindole, roxburghine, simple beta-carboline, pyridino-indolo-quinolizidinone and gambirtannine types.     

Conduritol F glucosides and terpenoid glucosides from Cynanchum liukiuense and distribution of conduritol F glucosides in several Asclepiadaceous plants

Conduritol F 3-0- and 4-O-glucosides were obtained from Cynanchum liukiuense, along with conduritol F which was identified in all Asclepiadaceous plants examined, Tylophora tanakae, Asclepias curassavica and A. fruticosa, as well as in Marsdenia tomentosa. The pattern of the glucosidic linkage to conduritol F differed between individual species, 2-O-glucoside from T tanakae and M. tomentosa, 3-O-glucoside from A. curassavica, but none from A. fruticosa. Along with conduritol F glucosides, an 11-glucosyloxy-megastigmane and a monoterpenoid glucoside were isolated from C. liukiuense.     

THE SYNTHESIS OF URUSHIOL TITANIUM CHELATE POLYMERS AND THEIR STRUCTURAL CHARACTERISTICS

The synthetic method and structural characteristics of urushiol-titanium chelates (UT) and urushiol-titanium chelate polymer for anticorrosive coatings have been studied.Two kinds of coating films made from UT polymer show excellent physico-mechanical properties and possess good chemical resistance to strong acids and alkalis, many kinds of salt solutions and organic solvents, stable at high temperature.     

Advancement of light-element neutron depth profiling at the University of Texas

The University of Texas (UT) at Austin has collaborated with the National Institute of Standards and Technology for comparisons of concentration versus depth profiles of samples containing ¹⁰B. Technology sharing from NIST has allowed UT to avoid many initial set backs such that significant advancements in the UT-NDP facility’s experimental and analytical methodology have been achieved. UT has analyzed two samples loaned to them from NIST. The collaborative effort between the two institutions has given the UT-NDP facility the proper tools to begin profiling more advanced samples in hopes of meeting the capabilities set by NIST in the NDP field. The UT-NDP facility was able to profile a borosilicate surface deposit onto silicon such that the concentrations of ¹⁰B at various depths of the deposit were determined and fit well to a Pearson distribution.     

Flavonoid Glycosides from the Aerial Part of Lespedeza tomentosa

Chemistry of Natural Compounds - The aerial part of Lespedeza tomentosa (Thunb.) Maxim. growing in southern Primorsky Krai, Russian Federation, yielded 10 identified flavonoid glycosides, eight of...     

Constituents of Leaves of Uncaria Hirsuta Haviland

Nine compounds, ursolic acid (1), β-sitosteryl glucoside (2), umbelliferone (3), uncarine-A (4), chlorogenic acid (5), rutin (6), neohesperidin (7), quercitrin (8)and afzelin (9) were isolated and characterized from fresh leaves of Uncaria hirsuta. Their structures were elucidated by spectral methods. Among them, uroslic acid (I) exhibited a cytotoxic principle of this plant.     

Unified theory of the exciplex formation/dissipation

The natural extension and reformulation of the unified theory (UT) proposed here makes it integro-differential and capable of describing the distant quenching of excitation by electron transfer, accompanied with contact but reversible exciplex formation. The numerical solution of the new UT equations allows specifying the kinetics of the fluorescence quenching and exciplex association/dissociation as well as those reactions' quantum yields. It was demonstrated that the distant electron transfer in either the normal or inverted Marcus regions screens the contact reaction of exciplex formation, especially at slow diffusion.     

A new pimarane from Mitrephora tomentosa

A new diterpenoid named (-)-8beta-hydroxypimar-15-en-18-oic acid was isolated, along with (-)-kaur-16-en-19-oic acid, 13,14-dihydrooropheic acid and beta-sitosterol, from the bark of Mitrephora tomentosa.     

毛白杨环氧水解酶的异源表达及其在催化拆分手性环氧化物中的应用

对已公布的全基因组进行检索发现,杨树(Populus tomentosa)至少含有24个预测为可溶性环氧水解酶的基因.从中选取了7个可能的环氧水解酶基因进行克隆,通过扩增得到其中5个毛白杨(Populus tomentosa Carr)环氧水解酶基因.序列分析显示,它们与已克隆的巨大芽胞杆菌环氧水解酶的同源性仅为24%～26%.对该系列基因进行了在E.coli中的异源表达,并将得到的5个环氧水解酶(PTEH1～5)用于缩水甘油苯基醚和对硝基苯乙烯氧化物的酶促水解反应.结果发现,其中3个重组酶具有显著的环氧水解酶活性.进一步研究表明,PTEH1和PTEH2对于缩水甘油苯基醚显示了一定的反常规的(R)-选择性,而PTEH5则优先水解(S)-构型的缩水甘油苯基醚.因此,毛白杨中环氧水解酶表现出多样性.