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31.
32.
AbstractConvolvulus trabutianus Schweinf. & Muschl. is an endemic plant from northern Sahara used in folk medicine. Herein we report, the isolation, characterization and evaluation of the radical scavenging properties of twenty three compounds from different extracts of this species by on-line HPLC-ABTS?+ screening. These compounds include nine phenolic acids: 2, 6, 10–16, two phytosterols: 3–4, four coumarins: 5, 7–9, two quinic acids: 21 and 22 and six flavonoids: 1, 17–20 and 23 among which the most active were: 10, 16, 21 and 22. All the extracts showed a significant antioxidant activity on-line. These results were validated off-line by ORAC and TEAC assays. Four compounds: 1, 5, 18 and 19 were described for the first time from the Convolvulaceae family, whereas compounds 2, 6, 8, 10, 13 and 21 were new for the genus Convolvulus. 相似文献
33.
HPLC-separation using a reversed-phase system is described for phytosterols, pentacyclic triterpenoid acids, -diols and –ketones. 相似文献
34.
Chemical investigation of the cultures of a sponge-derived fungus Simplicillium sp. YZ-11 led to the isolation of a new minor diketopiperazine alkaloid cyclo-(2-hydroxy-Pro-Gly) (1) and a natural lactone (S)-dihydro-5-[(S)- hydroxyphenylmethyl]-2(3H)-furanone (2), together with five known ergostane-type sterols (3–7). Their structures were established based on extensive spectroscopic methods (1H and 13C NMR, 1H-1H COSY, HSQC and HMBC) and optical rotation analysis. 相似文献
35.
Jingming Wu Ruikang HuJunqi Yue Zhaoguang YangLifeng Zhang 《Journal of chromatography. A》2009,1216(7):1053-1058
Injection-port derivatization combined with solid-phase extraction (SPE) was developed and applied for the first time to determine five types of fecal sterols (coprostanol, cholestanol, epicholestanol, epicoprostanol and cholesterol) with gas chromatography–mass spectrometry (GC–MS). In this method, silylation of fecal sterols was performed with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) at GC injection-port. The factors influential to this technique such as injection-port temperature, purge-off time, derivatization reagent (BSTFA) volume, and the type of organic solvent were investigated. In addition, the conditions of SPE (including the type of SPE cartridge, the type of elution organic solvent) were also studied. After SPE followed by injection-port silylation by GC–MS, good linearity of analytes was achieved in the range of 0.02–10 ng/mL with coefficients of determination, R2 > 0.995. Good reproducibility was obtained with relative standard deviation less than 19.6%. The limits of detection ranged from 1.3 ng/mL to 15 ng/mL (S/N = 3) in environmental water samples. Compared with traditional off-line silylation of fecal sterols performed with water bath (60 °C, 30 min), this injection-port silylation method is much simpler and convenient. The developed method has been successfully applied for the analysis of fecal sterols from real environmental water samples. 相似文献
36.
13
C NMR spectra were studied and signals were assigned for C atoms of steroids 1-7 相似文献
37.
38.
Nine compounds including six cycloartane glycosides cyclosieversiosides A, B, F, G, and H and astrasieversianin IX; β-sitosterol, β-sitosterol β-D-glucopyranoside, and D-3-O-methyl-chiro-inositol were isolated and identified from roots of Astragalus sieversianus Pall. (Leguminosae) growing in the Republic of Kyrgyzstan.
Presented at the 6th International Symposium on the Chemistry of Natural Compounds (SCNC, Ankara, Turkey, June 28–29, 2005.
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Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 253–256, May–June, 2008. 相似文献
39.
E. A. Dikusar V. I. Potkin S. K. Petkevich R. V. Kaberdin N. G. Kozlov A. V. Bazhanov N. V. Kovganko 《Chemistry of Natural Compounds》2004,40(3):230-234
Previously unknown (Z)-3,4,4,4-tetrachlorobut-2-enoates 1b-20b were prepared in 77-88% yields by reaction in the presence of pyridine of 3,3,4,4,4-pentachlorobutanoic acid chloride with cetyl alcohol (1a), terpenols and terpenone oximes (2a-13a), sterols (14a and 15a), diosgenin (16a), and plant phenols and their oximes (17a-20a). 相似文献
40.
N. M. Shevchenko Yu. V. Burtseva T. N. Zvyagintseva T. N. Makar′eva O. S. Sergeeva A. M. Zakharenko V. V. Isakov Nguyen Thi Linh Nguyen Xuan Hoa Bui Minh Ly Pham Van Huyen 《Chemistry of Natural Compounds》2009,45(1):1-5
Sterols and polysaccharides of green alga Caulerpa lentillifera grown under laboratory conditions and in mariculture and polysaccharides of green alga C. sertularioides grown under natural conditions were studied. The sterol fraction consisted of C27-C29 steroidal alcohols with Δ5-unsaturation in the steroid core regardless of the growth conditions. The dominant (79.9%) steroid component of the sterol
fraction was clionasterol. The water-soluble fraction of C. lentillifera grown under laboratory conditions was a mixture of 1,4-α- and 1,3-β-D-glucans and protein. The same fraction isolated from C. lentillifera grown in mariculture contained only protein. The water-soluble fraction of C. sertularioides grown under natural conditions contained 1,3;1,6-β-D-galactan sulfated at C2. The principal components of the base-soluble polysaccharide fractions from all algae samples were
1,4-α-D-glucans.
Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 5-8, January-February, 2009. 相似文献