Identification, quantification and antioxidant activity of acylated flavonol glycosides from sea buckthorn (Hippophae rhamnoides ssp. sinensis).

A novel acylated flavonol glycoside: isorhamnetin (3-O-[(6-O-E-sinapoyl)-ß-D-glucopyranosyl-(1→2)]-ß-D-glucopyranosyl-7-O-α-L-rhamnopyranoside) (1), together with two known acylated flavonol glycosides: quercetin (3-O-[(6-O-E-sinapoyl)-ß-D-glucopyranosyl-(1→2)]-ß-D-glucopyranosyl-7-O-α-L-rhamnopyranoside) (2) and kaempferol (3-O-[(6-O-E-sinapoyl)-ß-D-glucopyranosyl-(1→2)]-ß-D-glucopyranosyl-7-O-α-L-rhamnopyranoside) (3) were isolated from the n-butanol fraction of sea buckthorn (Hippophae rhamnoides ssp. sinensis) berries for the first time by chromatographic methods, and their structures were elucidated using UV, MS, (1)H and (13)C NMR, and 2D NMR. Compounds 1-3 showed good scavenging activities, with respective IC50 values of 8.91, 4.26 and 30.90 µM toward the 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical; respective Trolox equivalent antioxidant capacities of 2.89, 4.04 and 2.44 µM µM(-1) toward 2,2'-azino-bis-3-ethyl-benzothiazoline-6-sulphonate (ABTS) radical. The quantitative analysis of the isolated acylated flavonol glycosides was performed by HPLC-DAD method. The contents of compounds 1-3 were in the range of 12.2-31.4, 4.0-25.3, 7.5-59.7 mg/100 g dried berries and 9.1-34.5, 75.1-182.1, 29.2-113.4 mg/100 g dried leaves, respectively.

Three new flavone C-glycosides from the aerial parts of Paraquilegia microphylla.

Three new flavone C-glycosides, paraquinins A-C, were isolated from the aerial parts of Paraquilegia microphylla (Royle) Dromm. et Hutch, a Tibetan medicine distributed in the Qinghai-Tibet plateau. On the basis of 1D and 2D NMR evidence, their structures were elucidated as acacetin-6-C-ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranoside (1), acacetin-6-C-α-L-rhamnopyranosyl-(1 → 2)-ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranoside (2), and acacetin-6-C-α-L-rhamnopyranosyl-(1 → 2)-(6'''-O-E-feruloyl)-ß-D-glucopyranosyl-(1 → 2)-ß-D-glucopyranoside (3).

Chemical constituents from Astilbe chinensis.

A new compound, 11-O-(3'-O-methylgalloyl)-bergenin (1), along with 11 known compounds (2-12), has been isolated from the rhizome of Astilbe chinensis. The chemical structure of compound 1 was determined by IR, MS, and NMR spectral data. All compounds were evaluated for the cytotoxic activity in vitro, and compound 4 showed a moderate cytotoxic activity against HepG2 cells.

Ligand fishing with functionalized magnetic nanoparticles coupled with mass spectrometry for herbal medicine analysis: ligand fishing for herbal medicine analysis.

The chemical composition of herbal medicines is very complex, and their therapeutic effects are determined by multi-components with sophisticated synergistic and/or suppressive actions. Therefore, quality control of herbal medicines has been a formidable challenge. In this work, we describe a fast analytical method that can be used for quality assessment of herbal medicines. The method is based on ligand fishing using human-serum-albumin-functionalized magnetic nanoparticles (HSA-MNPs) and mass spectrometry. To demonstrate the applicability of the proposed method, eight samples of Dioscorea panthaica were analyzed. The sampled plants were of both wild and cultivated origins. They grew at different geographical locations and were harvested at different times. The ligands bound to HSA-MNPs were isolated from the plant extracts and detected by using direct infusion electrospray ionization mass spectrometry (DI-ESI-MS). Chemical identity has been confirmed for five of the ligands isolated. From more than 15 peaks in the ESI-MS spectrum, 11 common peaks were selected for calculating the correlation coefficient and cosine ratio. The values of correlation coefficient and cosine ratio were >0.9824 and >0.9988, respectively, for all the samples tested. The results indicated a high level of similarity among the eight D. panthaica samples. Compared with chromatographic fingerprint analysis, the proposed HSA-MNP-based DI-ESI-MS/MS approach was not only fast and easy to carry out but also biological-activity-oriented, promising a more effective data interpretation and thus reliable assessment conclusions.

Rapid probe and isolation of bioactive compounds from Dioscorea panthaica using human serum albumin functionalized magnetic nano-particles (HSA-MNPs)-based ligand fishing coupled with electrospray ionization mass spectrometry.

The chemical diversity of secondary metabolites in medicinal plant makes it a huge challenge to isolate the bioactive compounds from herbal extracts, so quick recognition of the bioactive ones is of vital importance for improving the efficiency of isolation. In this study, a ligand fishing experiment based on human serum albumin functionalized magnetic nano-particles (HSA-MNPs) was performed to probe the bioactive components in a traditional Chinese medicinal plant, Dioscorea panthaica. The minor compounds fished out by HSA-MNPs were identified by electrospray ionization mass spectrometry (ESI-MS), and then separated from the extract of the whole plant by one or two steps of column chromatography under the guidance of ESI-MS. Four biologically active compounds, progenin II, progenin III, dioscin and gracillin, were isolated much faster than in the normal lengthy phytochemical procedure. The present study demonstrates that biological macromolecule (protein, enzyme, receptor, et al.) functionalized MNPs may serve as baits to recognize bioactive small molecules in complex herbal extracts. It is expected that a macromolecule functionalized MNPs-based ligand fishing experiment coupled with ESI-MS may accelerate the process of identification and isolation of bioactive components from medicinal plants, and thus benefit the speed of drug discovery.