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排序方式: 共有496条查询结果,搜索用时 31 毫秒
51.
In continual study on the heartwood of Rhamnus nakaharai, a new alaternin-8-O-glucoside, namely 1,2,6,8-tetrahydroxy-3-methylanthraquinone-8-O-β-glucopyranoside (1), together with some known compounds were further isolated and characterised by 1-D, 2-D NMR and other spectral evidences. The free radical scavenging and antityrosinase activities of the isolates, including alaternin (1a), emodin (2a), emodin-8-O-β-glucopyranoside (2), 6-methoxysorigenin-8-O-β-glucopyranoside (3) and 6-methoxysorigenin (3a) were tested. Alaternin (1a) exhibited to be mild DPPH radical scavenger with half as potent as vitamin C, while both alaternin (1a) and emodin-8-O-β-glucopyranoside (2) exhibited stronger SOD-like activity than that of BHA. 6-Methoxysorigenin (3a), a reported potential antioxidant, and its 8-O-glucoside (3) both performed significant inhibitory effect on mushroom tyrosinase with about twice as potent as kojic acid, the positive control. 相似文献
52.
A new isoflavone glycoside, (?)-tuberosin-3-O-β-D-glucopyranoside (1), along with 10 known compounds 1a-10, was isolated from Pueraria alopecuroides. Their structures were determined on the basis of spectral data including 1D and 2D NMR and HREIMS. These compounds were isolated from this plant for the first time. 相似文献
53.
Xuewei Ye Komal Anjum Tengfei Song Wenling Wang Siran Yu Haocai Huang 《Natural product research》2016,30(10):1156-1161
Five curvularin macrolides (1–5) were isolated from the cultured broth of marine actinomycete Pseudonocardia sp. HS7 that was obtained from the cloacal aperture of sea cucumber Holothuria moebii. The structures of these isolates were characterized as (11S,15R)-11-hydroxycurvularin (1), (11R,15R)-11-hydroxycurvularin (2), curvularin-7-O-α-D-glucopyranoside (3), trans-dehydrocurvularin (4) and curvularin (5) based on their NMR and HRESIMS data as well as chemical degradation. Compound 3 is a new macrolide with a rare α-D-glucopyranose substituent. Compounds 1–4, 5a and 5c (the acyl products of 5), suppressed the proliferation of all six tested cancer cell lines and 4 is the most active compound with IC50 values ranging from 0.59 to 3.39 μM. The 11-hydroxycurvularins 1 and 2 also showed antibacterial activity inhibiting the growth of Escherichia coli. 相似文献
54.
Yin-Di Zhu Jing-Yi Zhang Peng-Fei Li Hai-Feng Wu Nai-Liang Zhu Hai Jiang 《Natural product research》2016,30(9):1075-1080
Two new abietane diterpenoid glycosides, named clinopoditerpenes B (1) and C (2), were isolated from Clinopodium chinese. The structures of the new compounds were determined on the basis of extensive spectral analysis. Compound 1 exhibited cardioprotective effect against H2O2-induced apoptosis in H9c2 cells. 相似文献
55.
一种新的测定一维同核全相关的NMR技术 总被引:7,自引:3,他引:4
提出一种新的基于MDY混合脉冲的可测定一维同核全相关的核磁共振技术.称为一维自旋回波MDY相干转移(lD-SEMDY)实验.结果表明.它具有下列突出优点:一是不用Z-滤波技术就可以得到纯吸收型的一维全相关谱(lD-TOCSY).与同类技术相比,操作简便.可节省测定时间.应用范围较广;二是所测定亚谱中的信号归属通过改变混合时间和延迟时间可以得到确定;三是相干转移非常有效.远程磁化转移信号的灵敏度比较高,对弱偶合的自旋体系也可进行测定.以甙类化合物为例讨论了它在谱峰高度重叠的有机结构测定中的应用. 相似文献
56.
M. Lamidi T. Martin-Lopez E. Ollivier F. Crespin-Maillard L. Nze Ekekang G. Balansard 《Chromatographia》1995,41(5-6):581-584
Summary A reversed-phase HPLC determination of 11 saponins and an alkaloid glycoside inNauclea diderrichii bark is described. Quantitative analysis of quinovic acid 3-0-α-L-rhamnopyranoside which is one of the main saponins was
determined, using Chrysanthelline A as internal standard. The complete separation was achieved in 47 minutes. The method of
quantification was validated. 相似文献
57.
The key, versatile precursors N2-(N,N-dimethylaminomethylene)-1′-O-(4-methoxybenzyl)-3-[2-(4-nitrophenyl)ethyl]biopterin (29a) and its ciliapterin analog (29b) were prepared, respectively, from d-xylose (in 14 steps) and l-xylose (in 11 steps). Treatment of 29a and 29b with 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-β-d-glucopyranosyl bromide in the presence of silver triflate and tetramethylurea, followed by removal of the protecting groups, led to the first selective syntheses of limipterin (3) and tepidopterin (5), respectively. 相似文献
58.
A method for preparing homogeneous protein-imprinted polymer films with orientated immobilization of template is described. The template methyl parathion hydrolase (MPH) was modified with a peptide linker (Gly-Ser)5–Cys and was immobilized on a cover glass with a fixed orientation via the linker. The activity of the fusion enzyme (MPH-L) was evaluated by determining the product's absorbance at 405 nm (A405). Both the free and the immobilized MPH-L showed higher retention of the bioactivity than the wide type enzyme (MPH-W) as revealed by the A405 values for MPH-Lfree/MPH-Wfree (1.159/1.111) and for MPH-Limmobilized/MPH-Wimmobilized (0.348/0.118). The immobilized MPH-L also formed a more homogeneous template stamp compared to the immobilized MPH-W. The molecularly imprinted polymer films prepared with the immobilized MPH-L exhibited high homogeneity with low Std. Deviations of 80 and 200 from the CL intensity mean volumes which were observed for batch-prepared films and an individual film, respectively. MPH-L-imprinted polymer film also had a larger template binding capacity indicated by higher CL intensity mean volume of 3900 INT over 2500 INT for MPH-W-imprinted films. The imprinted film prepared with the orientated immobilization of template showed an imprinting factor of 1.7, while the controls did not show an imprinting effect. 相似文献
59.
60.
Cindy B. McReynolds Jun Yang Alonso Guedes Christophe Morisseau Roberto Garcia Heather Knych Caitlin Tearney Briana Hamamoto Sung Hee Hwang Karen Wagner Bruce D. Hammock 《Molecules (Basel, Switzerland)》2021,26(16)
There are few novel therapeutic options available for companion animals, and medications rely heavily on repurposed drugs developed for other species. Considering the diversity of species and breeds in companion animal medicine, comprehensive PK exposures in the companion animal patient is often lacking. The purpose of this paper was to assess the pharmacokinetics after oral and intravenous dosing in domesticated animal species (dogs, cats, and horses) of a novel soluble epoxide hydrolase inhibitor, EC1728, being developed for the treatment of pain in animals. Results: Intravenous and oral administration revealed that bioavailability was similar for dogs, and horses (42 and 50% F) but lower in mice and cats (34 and 8%, respectively). Additionally, clearance was similar between cats and mice, but >2× faster in cats vs. dogs and horses. Efficacy with EC1728 has been demonstrated in mice, dogs, and horses, and despite the rapid clearance of EC1728 in cats, analgesic efficacy was demonstrated in an acute pain model after intravenous but not oral dosing. Conclusion: These results demonstrate that exposures across species can vary, and investigation of therapeutic exposures in target species is needed to provide adequate care that addresses efficacy and avoids toxicity. 相似文献