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• <b>Saxifraga tangutica</b> Engl. is a promising source of antioxidants against DPPH and FRAP. • The 50% ethanol extract of S. <b>tangutica</b> showed strong antioxidative activity against DPPH and FRAP. • Eight phenols were isolated from S. <b>tangutica</b>; all of the compounds are reported for the first time from this plant. • The antioxidative S. <b>tangutica</b> extracts and isolated phenols supports the antioxidant of this plant.<br><b>Saxifraga tangutica</b> Engl., is a medicinal herb that grows on the Qinghai-Tibet Plateau. Extracts and phenols from the Qinghai population have been subjected to antioxidative assays against DPPH radical-scavenging and reducing power (FRAP). The 50% ethanol extract showed strong antioxidative activity against DPPH and FRAP, with IC50 ± SEM [μg/mL] values of 9.38 ± 0.46 and 15.46 ± 0.52, respectively. The antioxidative activity-guided fractionations were performed according to the DPPH and FRAP screening results. Fourteen fractions from the 50% ethanol extract showed dissimilar antioxidative activity against DPPH and FRAP of 8.16 ± 0.76 ∼ 38.42 ± 0.58 μg/mL and 13.22 ± 0.68 ∼ 61.47 ± 0.49 μg/mL. The chemical assay-guided separation of the active fractions (fractions 3, 6, 7 and 8) led to eight phenols: protocatechuic aldehyde (<b>1</b>), ethyl gallate (<b>2</b>), rhododendrin (<b>3</b>), <b>p</b>-hydroxyacetophenone (<b>4</b>), rhododendrol (<b>5</b>), protocatechuic acid ethyl ester (<b>6</b>), frambinone (<b>7</b>) and ethylparaben (<b>8</b>). All phenols are reported here for the first time from <b>S. tangutica</b> Engl. Protocatechuic aldehyde (<b>1</b>), ethyl gallate (<b>2</b>), rhododendrin (<b>3</b>) and protocatechuic acid ethyl ester (<b>6</b>) showed strong antioxidative activities (IC50 ± SEM [mM] between 8.79 ± 0.15 and 4.25 ± 0.47 and between 6.15 ± 0.48 and 2.83 ± 0.49) against DPPH and FRAP.

Objective: To investigate the chemical constituent from the roots of Gentiana straminea.; Methods: The constituents were separated by microporous resin,silica gel,Sephadex LH-20 and preparative column chromatography and their structures were elucidated by NMR and MS spectral methods.; Results: Twelve chemical constituents were isolated from the roots of Gentiana straminea and their structures were identified as daucosterol( 1),β-sitosterol( 2),ursolic acid( 3),sweroside( 4),swertiamarin( 5),gentiopicroside( 6),6’-O-acetyl-gentiopicroside( 7),6’-O-β-D-glucopyranosyl-sweroside( 8),protocatech uic aldehyde( 9),protocatechuic acid( 10),methyl gallate( 11) and dibutyl phthalate( 12).; Conclusion: The compounds 8,9,10,11 and 12 are obtained from this plant for the first time.;

A phytochemical investigation of <b>Saxifraga tangutica</b> led to the isolation of 11 compounds, including eight diarylheptanoids (<b>1</b>-<b>6</b>, <b>10</b> and <b>11</b>) and three phenylpropanoids (<b>7</b>-<b>9</b>). The chemical structures were established by extensive analysis of their MS and NMR spectroscopic data or comparison with literature data. In the present research, we report the isolated compounds <b>1</b>-<b>11</b>, for the first time, in the species <b>S. tangutica</b>. Moreover, compounds <b>1</b>, <b>2</b> and <b>4</b>-<b>11</b> have not been reported from any species in Saxifragaceae family. Furthermore, we discuss the chemotaxonomic significance of the isolated compounds.<br>• Eight diarylheptanoids and three phenylpropanoids have been isolated from <b>Saxifraga tangutica.</b> • Compounds <b>1</b>-<b>11</b> are firstly reported in the species <b>Saxifraga tangutica.</b> • Compounds <b>1</b>, <b>2</b> and <b>4</b>-<b>11</b> are firstly isolated from genus <b>Saxifraga</b> or family Saxifragaceae.

A new diarylheptanoid, (5S)-1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxyheptan-3-one-5-O-β-D-6-Oacetylglucoside (<i>1</i>), together with two known diarylheptanoids, (5S)-1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxyheptan-3-one-5-O-β-D-glucopyranoside (<i>2</i>) and hirsutanonol (<i>3</i>), were isolated from Saxifraga tangutica. The structures of <i>1-3</i> were elucidated using 1D and 2D NMR spectral data, including high-resolution mass spectra (HR-ESI-MS). It was found that the new compound was acetyl-substituted (5S)-1,7-bis-(3,4-dihydroxyphenyl)-5-hydroxyheptan-3-one-5-O-β-D-glucopyranoside.

Traditional Tibetan medicine (TTM) has been valuable for the identification of new therapeutic leads. Nevertheless, reports about the chemical constituents of TTM are meager owing to the lack of suitable purification techniques. In this study, an off-line two-dimensional reversed-phase/hydrophilic interaction liquid chromatography (2D RP/HILIC) technique guided by on-line HPLC-DPPH has been established for the isolation of pure antioxidants from the extract of Dracocephalum heterophyllum . According to the chromatographic recognition outcome of the HPLC-DPPH system, the first-dimensional (1D) separation on the Megress C18 preparative column yielded 6 antioxidative fractions (61.4% recovery) from the ethyl acetate fraction (6.1 g). In the second-dimensional (2D) separation, a HILIC XAmide preparative column was employed. In total, 8 antioxidants were isolated from D. heterophyllum with a purity of >95%, which indicated the efficiency of the developed method to prepare antioxidative compounds with high purity from plant extracts. In addition, this method was highly efficient for the preparation of structural analogues of the antioxidative polyphenols and could be applied for the purification of structural analogues from other resources. [ABSTRACT FROM AUTHOR]

Trypsin from the pancreas of Tibetan sheep was purified to 7.4-fold by ammonium sulphate and acetone precipitation, followed by Sephacryl S-200 (Whatman, Maidstone, England) and Sephadex G-75 (Whatman) gel filtration, with an 23.2-fold increase in specific activity and 13.6% yield. The final enzyme preparation was nearly homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and the molecular weight of the enzyme was estimated to be approximately 27 kDa by SDS-PAGE. Trypsin-like enzymes had maximal activities at around pH 9.0 and 60C for the hydrolysis of Nα-ρ-Tosyl–L–arginine methyl ester hydrochloride (TAME). Trypsin was unstable above 60C and below pH 4.0, and was stabilized by calcium ions. Purified trypsin had a Michaelis–Menten constant (Km) and catalytic constant (Kcat) of 0.53 mM and 206 s−1, respectively, when TAME was used as the substrate. The specific trypsin inhibitors, soybean trypsin inhibited, Nα-ρ-tosyl-L-lysine chloromethyl ketone and phenyl methyl sulfonyl fluoride, strongly inhibited the activity of trypsin, while other protease inhibitors exhibited negligible inhibition. The result suggests that major proteinase in the pancreas of Tibetan sheep was trypsin-like serine proteinase. PRACTICAL APPLICATIONS Tibetan sheep is one of the unique livestock resources in western China. It was found that the trypsin extraction and purification from waste pancreas have the biological characteristics of the heat resistance, alkali resistance, high specific activity and high hydrolysis efficiency. It does not only serve as a better research tool enzyme, but is also widely applied in the food, pharmaceutical, textile and other industries. This paper provides the scientific research basis of the development of the waste pancreas for the Tibetan sheep, therefore reducing environmental pollution.

An orthogonally (80.3%) preparative two-dimensional hydrophilic interaction chromatography/reversed-phase liquid chromatography method has been established for the isolation and purification of flavonoids from Saxifraga tangutica. Initially, flavonoids were enriched by means of a middle-pressure chromatographic tower (containing middle chromatogram isolated gel). In the first dimension, a XION preparative column was used to separate the flavonoid fractions under the guidance of characteristic ultraviolet absorption spectra of flavonoids and nine flavonoid fractions were obtained. Then, the coeluted flavonoid fractions were selected for further purification via reversed-phase liquid chromatography with the parent ion peak of quercetin (303), kaempferol (287), or isorhamnetin (317). Several flavonoids could be separated from each hydrophilic interaction chromatography fraction; furthermore, flavonoids with poor resolution in one-dimensional liquid chromatography were isolated in two-dimensional liquid chromatography due to the orthogonality. In addition, this technique was valuable for trace flavonoids, which were concentrated in the first stage and separated in the second stage. In total, 18 flavonoids with either quercetin, kaempferol, or isorhamnetin parent nuclei were targetedly obtained, and 15 flavonoids were obtained for the first time from S. tangutica. These results established that the off-line two-dimensional hydrophilic interaction chromatography/reversed-phase liquid chromatography technique was efficient for the isolation of flavonoids from Saxifraga tangutica.

In a search for naturally occurring antibacterial compounds in medicinal plants, six hitherto unknown thiophene acetylenes, named 10,11-threo-xanthopappin D, 10,11-erythro-xanthopappin D, 10,11-cis-xanthopappin B, 5-(but-4-chloro-3-hydroxy-1-ynyl)-2-(Z)-pent-3-ene-1-ynylthiophene, 5-(but-4-chloro-3-hydroxy-1-ynyl)-2-(E)-pent-3-ene-1-ynylthiophene, 5-(but-3,4-dihydroxy-1-ynyl)-2-(Z)-pent-3-ene-1-ynylthiophene and two furanosesquiterpenes, as well as fifteen known compounds, were isolated from Xanthopappus subacaulis, which has been used as a traditional Tibetan medicine in China. A biosynthetic pathway to thiophene acetylenes was proposed and, the isolated compounds were tested for their antibacterial activity against five bacteria. Within the series of thiophene acetylenes tested, 10,11-threo-xanthopappin D with a threo configuration exhibited strong activity against Bacillus subtilis, with a minimum inhibitory concentration (MIC) of 7.25μg/mL, whereas 10,11-erythro-xanthopappin D with erythro configuration possessed broad-spectrum antibacterial activity against Escherichia coli, Bacillus cereus, Staphylococcus aureus and Erwinia carotovora, with MICs of 12.5, 15.5, 7.25 and 7.25μg/mL, respectively. Meanwhile, the compounds 10,11-cis-xanthopappin B, xanthopappin B, 5-(but-4-chloro-3-hydroxy-1-ynyl)-2-(Z)-pent-3-ene-1-ynylthiophene and 5-(but-4-chloro-3-hydroxy-1-ynyl)-2-(E)-pent-3-ene-1-ynylthiophene substituted with a Cl atom at C-14 showed moderate inhibitory activity against E. coli, B. cereus, S. aureus, E. carotovora and B. subtilis, with MICs ranging from 31.25 to 62.5μg/mL. The structures of these compounds were elucidated through the comprehensive analysis of spectroscopic data, including UV, IR, MS and NMR.

Traditional Tibetan medicine is important for discovery of drug precursors. However, knowledge of the chemical composition of traditional Tibetan medicines is very limited due to the lack of appropriate chromatographic purification methods. In the present work, Salvia prattii was taken as an example, and an off-line hydrophilic interaction liquid chromatography/reversed-phase liquid chromatography preparative method was developed for the purification of phenylpropanoids with high purity from a crude sample of Salvia prattii. Based on the separation results of four different chromatographic stationary phases, the first-dimensional preparation was performed on an XAmide preparative column with the crude sample concentration of 62.0 mg/mL, and five main fractions were obtained from the 12.4 g crude sample with a recovery of 54.8%. An XCharge C18 preparative column was applied in the second-dimensional preparation to further isolate the phenylpropanoids from the redissolved first-dimensional fractions with concentration of approximately 50.0 mg/mL. The purities of the phenylpropanoids isolated from the crude sample of Salvia prattii were higher than 98%, indicating that the method was efficient for the purification of phenylpropanoids with high purity from Salvia prattii. Additionally, this method showed great potential in the preparation of phenylpropanoids and can serve as a good example for the purification of phenylpropanoids from other plant materials.