1,720,985 research outputs found
Analysis of the constituents of aqueous preparations of Stachys recta by HPLC-DAD and HPLC-ESI-MS
No full textIn the present study a method based on liquid chromatography with diode array detection (HPLC/DAD) coupled to an electrospray ionization (ESI) interface for the simultaneous determination of phenolic constituents in three aqueous preparations of the herbal medicinal drug Stachys recta. The developed assay was simple and effective and permitted the quality control of S. recta decoctions and infusion. Overall, 30 constituents were detected and identified, belonging mainly to three classes of compounds: caffeoylquinic acids, phenylethanol glycosides and flavonoids. 15 of them were quantified having a lower limit not less than 0.02% of the lyophilized extracts. Only seven of them were previously reported in this species, while 23 were identified for the first time as constituents of S. recta. HPLC-DAD-ESI-MS analysis provided evidence for the certain identification of the main constituents and in some cases of their isomers. Eight constituents were isolated and their structure elucidated by HPLC-ESI-MS and 1D- and 2D-NMR spectroscopy. Among the investigated preparations, the infusion seems to be the best method to extract the native constituents of the plant, while decoction is a more aggressive treatment and causes partial degradation of some acylated flavonoids. © 2010 Elsevier B.V
Rapid and efficient purification of naphthodianthrones from St. John's wort extract by using liquid-liquid extraction and SEC
No full textHypericin and pseudohypericin, the main naphthodianthrones present in Hypericum species are among the most promising natural products, but the research concerning their biological activities is hindered by their low content in the plant. In this paper a method for the rapid isolation of hypericin and pseudohypericin from Hypericum perforatum hydro-alcoholic dried extracts has been developed. Briefly, the method consists of a partition of the extract between organic and aqueous layers and further purification of the richest extract in naphthodianthrones with Sephadex LH-20 column chromatography. A final separation of hypericin from pseudohypericin was achieved using Sephadex LH-60 column chromatography. All partitions were carried out in triplicate and monitored by LC-MS and NMR analyses. The best results were obtained by successive extraction with n-hexane, Et2O and EtOAc. A three-step fractionation resulted in 98% content in total naphthodianthrones. To the best of our knowledge this is the first report on the separation of hypericin from pseudohypericin using size exclusion chromatography. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Analysis of the constituents and quality control of Viola odorata aqueous preparations by HPLC-DAD and HPLC-ESI-MS
No full textIn the present study, a method based on liquid chromatography with diode array detection (HPLC-DAD) coupled to an electrospray ionisation (ESI) interface was developed for the determination of the constituents in the aqueous preparations of Viola odorata L. flowering tops. The developed assay was fast, simple and effective and permitted the quality control of the preparations. The aim of this work was to assess the qualitative and quantitative profile of the investigated preparations, which find until today wide applications in food and cosmetic industry, and to propose a validated method for their quality control. Characteristic constituents of V. odorata flowers are considered to be the anthocyanins; however, a detailed literature research showed that data concerning their chemical content are scarce. HPLC-DAD-ESI-MS analyses supported by extensive preparative chromatographic investigations and 2D NMR analyses revealed the predominance of complex flavonol glycosides and permitted the complete characterisation of the content of V. odorata preparations. This is the first report of detailed analysis of the chemical composition of V. odorata flowers. © 2010 Springer-Verlag
Analysis and stability of the constituents of Curcuma longa and Harpagophytum procumbens tinctures by HPLC-DAD and HPLC-ESI-MS
No full textIn the present study two methods based on liquid chromatography with diode array detection (HPLC-DAD) coupled to an electrospray ionisation (ESI-MS) interface were developed for the determination of constituents in the tinctures (60%, v/v, DER 1:5) of turmeric (Curcuma longa L.) and Devil's claw (Harpagophytum procumbens L.). The developed simple and effective assays permitted the quality control of both tinctures. The aim of this work was to assess the qualitative and quantitative profile of the constituents of two widely marketed commercial preparations and to evaluate chemical stability of their marker constituents during accelerated thermal stability test by HPLC analysis. Characteristic constituents of C. longa rhizomes are the curcuminoids, whereas characteristic constituents of H. procumbens are acylated iridoid glycosides and phenylethylalcohols. Constituents of Devil's claw tincture (mainly iridoids) were more stable than curcuminoids of turmeric. © 2011 Elsevier B.V
GC-MS analysis of the volatile constituents of the essential oil and aromatic waters of Artemisia annua L. at different developmental stages
No full textArtemisia annua L. (Asteraceae) still represents the only source of artemisinin, considered as one of the most important drugs for the treatment of malaria and which, more recently, has been shown to be effective against numerous types of tumors. The foliage and inflorescence of A. annua also yield an essential oil upon hydrodistillation. This oil has been evaluated at different development stages (pre-flowering and flowering) by GC/MS. The volatile oil from plants at full blooming showed numerous constituents, with germacrene D (21.2%), camphor (17.6%), β-farnesene (10.2%), β-caryophyllene (9%), and bicyclogermacrene (4.2%) among the main ones. Aromatic waters, after extraction with n-hexane, showed the presence, among others, of camphor (27.7%), 1,8-cineole (14%), artemisia ketone (10.1%), α-terpineol (6.1%), trans-pinocarveol (5.4%), and artemisia alcohol (2%). From plants at the pre-flowering stage, aromatic waters were obtained with camphor (30.7%), 1,8-cineole (12.8%), artemisia alcohol (11.4%), artemisia ketone (9.5%), alpha-terpineol (5.8%), and trans-pinocarveol (3.0%) as the main constituents. The qualitative and quantitative profiles of the two aromatic waters were similar. These results permitted the conclusion to be made that A. annua could be harvested a long time before the onset of flowering to obtain higher yields of artemisinin or could be allowed to attain maturity to obtain valuable yields of volatile
Complete 1H (600 MHz) and 13C NMR Spectral Assignment of 3,4-bis[(3,4-Dimethoxyphenyl)methyl]dihydro-(3R-trans)-2(3H)-furanone (Matairesinol Dimethyl Ether), a Naturally Occurring Dibenzylbutyrolactone Lignan.
No full textComposition of the essential oil of fennel teas obtained by classical infusion or microwave decoction of unbroken and crushed fruits and by some pre-packaged teabags and instant teas
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Chemical composition of the essential oil and volatile constituents from aromatic waters of Balsamita suaveolens Pers
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