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991.
From the alcoholic extract of the whole plants of Serratula strangulata ,two new compounds,named strangusin-A(1) and strangusin-B(2) have been isolated and their structures were established by spectroscopic method. 相似文献
992.
Preparation,characterization and application of powdered activated carbon‐cellulose acetate phthalate mixed matrix membrane for treatment of steel plant effluent 下载免费PDF全文
Preparation, characterization and industrial application of a mixed matrix membrane (MMM) using powdered activated carbon (PAC) in cellulose acetate phthalate (CAP) have been reported in this study. The objective of this work is to fabricate a less energy intensive, highly selective (to phenolic compounds) adsorptive membrane with high throughput in a scalable platform for simultaneous removal of organic as well chemical oxygen demand (COD) from a steel plant effluent. The membrane with 25 wt% PAC has maximum adsorption capacity of phenol 35 mg/g at pH 5.5. Effluent with total phenolic compounds (23 mg/g) and COD of 5200 mg/l is treated in continuous cross‐flow configuration. Breakthrough time is 44 hr for a filtration area of 0.008 m2 with total phenol concentration in permeate as per World Health Organization (WHO), 1 mg/l. Throughput of the system is high, 40 l/m2 hr at transmembrane pressure drop 276 kPa and cross‐flow rate 20 l/hr. Maximum rejection of phenol is obtained at low pressure and cross‐flow rate. Removal of phenolic compounds is achieved by adsorption by PAC in CAP matrix and satisfactory reduction of COD and complete removal of non‐volatile solids are due of sieving mechanism. A simple chemical regeneration method is proposed to recover the permeate flux beyond 90%. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
993.
In the present paper, for the first time, we are interested to separate and identify some bioactive fractions isolated from the roots of a Saharan plant Anabasis articulata, which is widely used in traditional medicine against cancer. The crude methanolic extract of the roots was fractionated on column chromatography, and eluted with dichloromethane/methanol each time with increasing polarity of methanol; 17 fractions were separated. One of these fractions named F12 showed more antioxidant activity to scavenge DPPH free radical with percentage inhibition of 95.29%. F12 was separated by thin-layer chromatography (TLC) to give 12 compounds. A second preparative TLC of compound 2, which has antioxidative activity of 74.92%, provided the three phenolic acids M1, M2 and M3, analysed by high-performance liquid chromatography and UV–visible spectrophotometry. 相似文献
994.
Anna K. F. Albertson Prof. Jean‐Philip Lumb 《Angewandte Chemie (International ed. in English)》2015,54(7):2204-2208
Lignan natural products comprise a broad spectrum of biologically active secondary metabolites. Their structural diversity belies a common biosynthesis, which involves regio‐ and chemoselective oxidative coupling of propenyl phenols. Attempts to replicate this oxidative coupling have revealed significant challenges for controlling selectivity, and these challenges have thus far prevented the development of a unified biomimetic route to compounds of the lignan family. A practical solution is presented that hinges on oxidative ring opening of a diarylcyclobutane to intercept a putative biosynthetic intermediate. The effectiveness of this approach is demonstrated by the first total synthesis of tanegool in 4 steps starting from ferulic acid, as well as a concise synthesis of the prototypical furanolignan pinoresinol. 相似文献
995.
Faridah Osman Nobuyuki Maeta Masato M. Ito Chien-Min Lin Hong Cheu Lin 《Liquid crystals》2017,44(14-15):2355-2365
A series of non-linear S-shaped liquid crystal oligomers wherein the molecule consists of biphenylene moiety as a central core unit and two symmetrical side arms azobenzene moieties joined to catechol as a linkage group have been successfully synthesised and characterised. The members in this series possess different inner spacer with carbon number n ranging from 4 to 9 while the outer spacer length located in azobenzene moieties are remains unaltered. The members with even parity exhibit monotropic phase, whereas homologues with odd parity display enantiotropic phase. The appearance of nematic, smectic A and smectic B phases was validated with texture observation under polarised light and X-ray diffraction (XRD). The XRD study on the S-shaped oligomer indicates that the arrangement of smectic phase exists as an intercalated structure. The S-shaped oligomer shows photoisomerisation properties in solution whereby the trans to cis isomerisation for this molecule is accomplished 1140 s, whereas reverse process under thermal back reaction occurred in 4620 min. 相似文献
996.
Lysanne Salomon Peter Lorenz Marek Bunse Otmar Spring Florian C. Stintzing Dietmar R. Kammerer 《Molecules (Basel, Switzerland)》2021,26(6)
In the present study, Achillea atrata L. and A. millefolium L. were compared for the first time with regard to their phenolic compound profile and antioxidant activity by applying the 2,2-diphenyl-picryl hydrazyl radical assay. For this purpose, aerial plant parts were consecutively extracted with solvents of increasing polarity (dichloromethane, n-butanol, ethyl acetate), revealing that the A. atrata ethyl acetate fraction showed the highest antioxidant activity with an IC50 value of 12.2 ± 0.29 µg/mL compared to 17.0 ± 0.26 µg/mL for A. millefolium. Both species revealed the presence of luteolin, apigenin, centaureidin, and nevadensin exclusively in this most polar fraction, which are known as effective 2,2-diphenyl-picryl hydrazyl radical scavengers. The antioxidant capacity of the aforementioned fractions strikingly correlated with their total phenolic contents, which was highest in the ethyl acetate fraction of A. atrata. Characterization of the metabolite profiles of both Achillea species showed only marginal differences in the presence of key compounds, whereas the concentrations of individual compounds appeared to be species-specific. Our results suggest that A. atrata, based on its compound pattern and bioactivity characteristics, has similar qualities for phytotherapy as A. millefolium. 相似文献
997.
Joana P. B. Rodrigues ngela Fernandes Maria Inês Dias Carla Pereira Tnia C. S. P. Pires Ricardo C. Calhelha Ana Maria Carvalho Isabel C. F. R. Ferreira Lillian Barros 《Molecules (Basel, Switzerland)》2021,26(7)
Ruscus aculeatus L. is a subshrub used in traditional medicine in different parts of the world, namely in Europe and the Iberian Peninsula. According to reported folk knowledge, the aerial parts are mainly used as diuretics and the underground organs are used for the treatment of disorders of the urinary system and as a laxative. In this work, the aerial part and the roots and rhizomes of R. aculeatus were chemically characterized with regard to the content of phenolic compounds and bioactive properties. Aqueous (infusions and decoctions) preparations and hydroethanolic extracts from the two mentioned parts of the plant were prepared. Nine phenolic compounds were detected in all the extracts. Apigenin-C-hexoside-C-pentoside isomer II was the major compound in aqueous extracts and, in the hydroethanolic extract was quercetin-O-deoxyhexoside-hexoside followed by apigenin-C-hexoside-C-pentoside isomer II. All extracts revealed antioxidant activity and potential to inhibit some of the assayed bacteria; aqueous extracts of the aerial part and infusions of roots and rhizomes did not show cytotoxic effects on a non-tumor primary cell culture. This preliminary study provides suggestions of the biological potential associated with the empirical uses and knowledge of this species, in particular its bioactivities. 相似文献
998.
Marcela Holl Aneta Bílkov Pavel Jakubec Stanislava Kokov Hana Ko
ov Vl
kov Dalibor atínský Frantiek vec Hana Sklenov 《Molecules (Basel, Switzerland)》2021,26(11)
The new screening method for rapid evaluation of major phenolic compounds in apples has been developed. Suitability of coupling HPLC/UHPLC separation with the diode-array detection and universal charged aerosol detection with respect to the presence of interfering substances was tested. Characteristics of both detection techniques were compared and method linearity, limits of detection and quantitation, and selectivity of them determined. Student t-test based on slopes of calibration plots was applied for the detailed comparison. The diode-array detection provided the best results regarding sensitivity and selectivity of the developed method in terms of evaluation of phenolics profiles. The response of the charged aerosol detector was negatively affected by co-eluting substances during rapid-screening analyses. Coulometric detection was used for advanced characterization of extracts in terms of antioxidant content and strength to obtain more complex information concerning sample composition. This detection also allowed evaluation of unidentified compounds with antioxidant activity. HPLC/UHPLC separation using a combination of diode-array and coulometric detectors thus represented the best approach enabling quick, yet complex characterization of bioactive compounds in apples. 相似文献
999.
DPPH, superoxide and nitric oxide radical scavenging activities and total phenolic content (TPC) of some less known plants, distributed in Burdur-Antalya provinces and consumed both as food and for the medicine, Asplenium ceterach L. (golden herb), Valeriana dioscoridis Sm. (valerian), Doronicum orientale Hoffm. (tiger herb), Cota pestalozzae (Boiss.) Boiss. (camomile), Eremurus spectabilis M. Bieb. (foxtail lily), Asphodeline lutea (L.) Rchb. (asphodel) and Smyrnium connatum Boiss. and Kotschy (hemlock) were investigated. As a result, the highest 2,2-diphenyl-1-picril hydrazyl (DPPH) radical scavenging activity was determined in C. pestalozzae extract (IC50 = 18.66 μg mL? 1), the highest superoxide and nitric oxide radical scavenging activity was determined in A. ceterach extract (IC50 = 145.17 and 372.03 μg mL? 1). The highest TPC was determined in A. ceterach extract (59,26 μg mL? 1) as gallic acid equivalent. Further bioactivity and phytochemistry studies on these plants may enlighten new drug discovery researches. 相似文献
1000.
Sixteen subsequent fractions were prepared from the ethyl acetate fraction of Zanthoxylum bungeanum leaves after bio-guided chromatographic separation. The HPLC profiles and antioxidant activity of the various fractions indicated that the content of eight phenolic compounds (chlorogenic acid, epicatechin, rutin, hyperoside, trifolin, quercitrin, afzelin and quercetin) and antioxidant activity vary significantly, and high concentrations of a combination of eight phenolic compounds would result in an increase of the antioxidant activity. These results suggested that the eight compounds could be used as chemical markers for quality assessment of Z. bungeanum leaves. Correlation between chromatographic fingerprint and antioxidant activity of the fractions showed that quercitrin and hyperoside play crucial roles in the antioxidant activity, and they can be seen as the milestone for quality control. The findings also suggested that five obtained fractions (E-3-3, E-2-4, E-7, E-5 and E-4) could become useful supplements for functional food ingredients and health-related products. 相似文献