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Abstract Gut bacterial β-glucuronidase (GUS) can reactivate xenobiotics that exert enterohepatic circulation- triggered gastrointestinal tract toxicity. GUS inhibitors can alleviate drug-induced enteropathy and improve treatment outcomes. We evaluated the inhibitory effect of Polygonum cuspidatum Siebold & Zucc. and its major constituents against Escherichia coli GUS (EcGUS), and characterized the inhibitory mechanism of each of the components. Trans-resveratrol 4'-O-β-D-glucopyranoside (HZ-1) and (-)-epicatechin gallate (HZ-2) isolated from P. cuspidatum were identified as the key components and potent inhibitors. These two components displayed strong to moderate inhibitory effects on EcGUS, with Ki values of 9.95 and 1.95 μM, respectively. Results from molecular docking indicated that HZ-1 and HZ-2 could interact with the key residues Asp163, Ser360, Ile 363, Glu413, Glu504, and Lys 568 of EcGUS via hydrogen bonding. Our findings demonstrate the inhibitory effect of P. cuspidatum and its two components on EcGUS, which supported the further evaluation and development of P. cuspidatum and its two active components as novel candidates for alleviating drug-induced damage in the mammalian gut.
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Objective: To find out the active compounds of Yupingfeng San for the prevention and treatment of the coronavirus pneumoniadisease 2019 (COVID-19) using network pharmacology and molecular docking, with a purpose to find a better clinical use of Yupingfeng San. Methods: The effective ingredients and targets of Astragali Radix, Atractylodis Macrocephalae Rhizoma and Saposhnikoviae Radix were searched from the traditional Chinese medicine system pharmacology analysis platform (TCMSP) website, and the protein and protein interactive network of Yupingfeng San was established using the String database (PPI). Cytoscape 3.6.1 software was used for data analysis to extract the Hub network from the PPI network. The KEGG pathway analysis was performed using the String database and the molecular docking was performed using ChemOffice, PyMOL, and Auto Dock software. Results: A total of 45 effective ingredients were obtained with limited screening conditions [oral bioavailability (OB) ≥ 30%; drug-like (DL) ≥ 0.18], and 345 potential targets and 15 key targets of Yupingfeng San were screened. A total of 50 pathways were obtained by KEGG pathway analysis, among which 25 main pathways were selected, including PIK3R1 target regulation PI3K-Akt signaling pathway, Ras signaling pathway, HIF-1 signaling pathway, and MAPK signaling pathways and T cell receptor signaling pathways. Conclusion: The active compounds in Yupingfeng San can inhibit the combination between SARS-CoV-2 protein and angiotensin-converting enzyme II (ACE2), thus regulating multiple signal pathways (PIK3R1, IGF1R, etc), which plays a role in the prevention of COVID-19.
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Objective: A method for simultaneous determination of nine active organic acids [shikimic acid, catechinic, (-)- epicatechin, gallic acid, protocatechuic acid, 6-hydroxykynurenic acid (6HKA), p-hydroxybenzoic acid (PHBA), hydroxycinnamic acid, and caffeic acid] in Ginkgo biloba extracts (GBEs) by HPLC wavelength switching method was established, and its quality was evaluated by statistical analysis. Methods: An Inertsil ODS-3 C18 column (250 mm×4.6 mm, 5 μm) was used with a column temperature of 40 ℃ and a mobile phase gradient of acetonitrile-0.4% phosphoric acid. The detection wavelengths were 220 nm [shikimic acid, catechinic, (-)-epicatechin], 254 nm (gallic acid, protocatechuic acid, 6HKA, PHBA), 310 nm (hydroxycinnamic acid, caffeic acid), respectively. Results: Remarkable differences were found among the nine compositions in different producing areas samples. The samples from different manufacturers showed significant difference in organic acid compounds. There were great difference of the contents of organic acid in various batches from different manufacturers. The data were processed through unsupervised principal component analysis (PCA), cluster analysis (CA), correlation, and regression analysis to compare the quality differences. Catechinic, gallic acid, protocatechuic acid, and 6HKA were recognized as characteristic chemical markers that contributed most to reflect the difference between samples, and there were internal relations among these compounds. Conclusion: The established method was simple, accurate, and reliable with good precision, repeatability and stability, which can be used for the simultaneous determination of nine organic acid compounds. Through multivariate statistical analysis, the Q-markers that may affect the difference of GBEs were better identified, which can lay the foundation for the comprehensive quality control of GBEs. Meanwhile, the extracting process of GBEs were not uniform. The stability of process parameter in the enterprise was prepared to be further enhanced.
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Objective: To establish a rational method for Laportea bulbifera quality control. Methods: The fingerprint technique and multi-component quantitation were used to study the quality control of L. bulbifera by UHPLC. The 12 batches of L. bulbifera UHPLC fingerprint were evaluated by the evaluation system on similitude degree of chromatogram fingerprint of traditional Chinese medicine. Results: The quality control methods of Miao medicine L. bulbifera for simultaneous determination of 10 components (including neochlorogenic acid, cryptochlorogenic acid, chlorogenic acid, rutin, isoquercitrin, luteoloside, kaempferol-3-O-rutinoside, quercitrin, epigallocatechin and epicatechin) were established. The linear, precision, repeatability and stability are good. The standard recoveries were 95.89%-98.62%, with RSD less than 3%. The common mode of fingerprint was established after determination fingerprints of 12 batches of samples of L. bulbifera by UHPLC. There were 20 common peaks in these samples. The similarity of the 12 batches fingerprints were in the range from 0.805 to 0.931. Conclusion: The fingerprinting and multi-index content determination methods for quantitative control of Miao medicine L. bulbifera have high sensitivity, good accuracy, stability and reliability, which can provide a theoretical and experimental foundation for quantitative control of Miao medicine L. bulbifera.
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Objective: To screen the flavonoid constituents and targets of Litchi Semen in the intervention of progression and metastasis of colon adenocarcinoma (COAD). Methods: Through DRAR-CPI and SWISS database, potential targets of 19 flavonoids in Litchi Semen were searched. COAD gene expression data and clinical characteristic data from TCGA database were downloaded. Weighted gene co-expression network analysis (WGCNA) was used to establish the gene co-expression network and identify the co-expression module of COAD. The common targets of co-expression module and potential targets were used as the compound to interfere with the drug target of COAD. Protein interaction network analysis, KEGG and GO analysis were performed by String database. The Hub gene was extracted as potential biomarkers of COAD by the cytoHubba, and the interaction network of components, targets and pathways was established by the Cytoscape. The expressions of potential biomarkers were verified by HPA database, and the compounds were docked with the potential biomarkers. Results: A total of 18 co-expression modules were identified with seven of them were correlated with clinical features, such as survival time and tumor stage. Turquoise module was related to the development and transfer of COAD. 19 flavonoids in Litchi Semen acted on 380 potential targets. 34 targets repeated with turquoise module were selected as targets. GO analysis showed that the target points were enriched in 304 GO items, including 229 biological processes, 31 cell composition and 44 molecular functions; KEGG analysis showed that target points were enriched in cancer pathways, cell cycle, and progesterone-mediated 40 pathways including oocyte cancer pathway, cell senescence, and p53 signaling pathway. The genes of CDC25A, CDC25C, CCNB2 and AURKB were screened by cytoHubba as potential biomarkers which related to the progress and transfer of COAD. Compared with para-cancerous tissues, immunohistochemistry results obtained from HPA database showed that the protein expressions of CDC25C, AURKB and CCNB2 in COAD were increased significantly (P < 0.05), which were consistent with gene expression in TCGA data set. Narirutin, procyanidin A2, phloridzin and ent-epicatechin which were well combined to CDC25A, CDC25C and AURKB through hydrogen bond were screened. Conclusion CDC25A, CDC25C, CCNB2 and AURKB were the potential biomarkers closely related to the progression and metastasis of COAD. The mechanism of intervention of flavonoids in Litchi Semen on the progression and metastasis of COAD may be related to the regulation of biological processes, such as cell division, G2/M phase transformation of cell cycle, and the regulation of cancer pathway, p53 signaling pathway and other signaling pathways. Narirutin, procyanidin A2, phloridzin, ent-epicatechin and rutin could be treated as potential inhibitors of CDC25A, CDC25C and AURKB.
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Abstract Trichilia catigua A. Juss., Meliaceae, known as catuaba in Brazil, is traditionally used for the treatment of stress, sexual impotence and memory deficits. To our knowledge, there is no analytical method described in literature for simultaneous quantification of catuaba extract marker substances in biological matrices. The aim of this study was to develop and validate a bioanalytical method by LC-MS/MS to quantify epicatechin and procyanidin B2 in rat plasma after administration of standardized extract of T. catigua. Chromatographic separation was achieved with a C18 column, methanol and 0.1% aqueous formic acid at a flow rate of 0.25 ml/min. Detection was performed using electrospray ionization in negative mode. The lower limits of quantification were 5 ng/ml and 12.5 ng/ml for procyanidin B2 and epicatechin, respectively. Intra- and inter-day assays variability were less than 15%. The extraction recovery was 104% for epicatechin and 74% for procyanidin B2 using one-step liquid-liquid extraction with ethyl acetate. Epicatechin and PB2 were detected in plasma up to 300 min after oral administration of 400 mg/kg of standardized extract of T. catigua in rats. This rapid and sensitive method for the analysis of the epicatechin and procyanidin B2 in rat plasma can be applied to pharmacokinetic studies.
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Objective: A high performance liquid chromatography-ultraviolet-fluorescence (HPLC-UV-FLD) derivative system was established and the anti-oxidant activity of the extract of Gongcheng Tea was preliminarily evaluated by using a micro-injector imaging system combined with a fluorescent probe. Methods: Hydrogen peroxide assay and hydroxyl radical scavenging ability experiments were carried out on the anti-oxidant activity of Gongcheng Tea. The anti-oxidant components of Gongcheng Tea were screened by HPLC-UV-FLD post column derivation system and analyzed by an ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF MS). At the same time, the hydrogen peroxide scavenging activity of tea and active components were tested by a micro-injector imaging system combined with a hydrogen peroxide fluorescent probe (NBCD) in living Drosophila melanogaster. Results: The method was simple and rapid, and three main anti-oxidant compounds, epigallocatechin, epigallocatechin gallate, and epicatechin gallate were found in Gongcheng Tea. And it was found that they could significantly reduce the level of hydrogen peroxide in D. melanogaster. Conclusion: It laid a material basis for the further study of the anti-oxidant activity of Gongcheng Tea, and provided a reference for the screening of anti-oxidants in natural products.
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OBJECTIVE： To establish a method for simultaneous determination of 8 non-anthraquinone constituents in Rheum palmatum. METHODS： HPLC method was adopted. The determination was performed on Symmetry C18 column with mobile phase consisted of methanol-0.1％ phosphoric acid （gradient elution） at the flow rate of 1.0 mL/min. The column temperature was 30 ℃ and detection wavelength was 280 nm. Sample size was 30 μL. RESULTS： The linear range of gallic acid， catechin， epicatechin， resveratrol 4′-O-glucopyranoside， epicatechin gallate， resveratrol 4′-O-β-D-（6″-O-galloyl）-glucopyranoside， sennoside A， 4′-hydroxyphenyl-2-butanone-4′-O-β-D-（2″-O-galloyl-6″-O-p-hydroxy cinnamyl）-glucopyranoside were 6.16-2 464 ng（r＝0.999 9）， 37.4-14 960 ng（r＝0.999 9）， 7.635-3 054 ng（r＝0.999 7）， 7.63-3 052 ng（r＝0.999 9）， 8.32-3 328 ng（r＝0.999 9）， 11.5-4 600 ng（r＝0.999 9）， 16.08-6 432 ng（r＝0.999 9）， 29.3-11 720 ng（r＝0.999 9）， respectively. The limits of quantitation were 3.48， 4.30， 6.40， 4.40， 3.39， 2.87， 8.40 and 4.95 ng， respectively. The limits of detection were 2.32， 2.58， 2.40， 2.64， 2.26， 1.23， 4.20， 2.97 ng， respectively. RSDs of precision， stability and reproducibility tests were all lower than 5％. Recoveries were 94.32％- 100.54％（RSD＝2.78％，n＝6）， 91.15％-99.36％（RSD＝3.72％，n＝6）， 92.16％-98.04％（RSD＝2.39％，n＝6）， 93.41％-100.73％（RSD＝3.17％，n＝6）， 93.89％-98.40％（RSD＝1.99％，n＝6）， 92.61％-101.74％（RSD＝3.71％，n＝6）， 92.66％-103.40％（RSD＝3.76％，n＝6）， 95.45％-102.70％（RSD＝3.06％，n＝6）， respectively. CONCLUSIONS： The established method is simple， accurate and specific， and can be used for the simultaneous determination of 8 non-anthraquinone constituents in R. palmatum.
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Objective To investigate whether (-)-epicatechin plays a role in neurological repair on traumatic brain injury in mice.Methods The mice model of traumatic brain injury was established by modified weight drop method.Experimental mice were randomly (random number) divided into the injury+ (Veh) group and the injury + (-)-epicatechin (EC) group.At 3 days after operation,the expression of IL-1β and TNF-α were detected.The number of necrotic cells of the lesion area was detected by PI staining.At 28 days after SCI,Morris Water Maze test was performed to observe the ability of spatial learning and memory in mice.The expression of neurotrophic factors BDNF and NGF were examined by qRT-PCR.The expression of NeuN was detected by immunofluorescence staining.EdU staining was used to observe the neurogenesis in the SGZ region.Results Compared with the Veh group,EC treated group showed better spatial learning and memory ability in time spent in correct quadrant at day 27 and 28 [24 d:(26.333±5.037)％ vs (26.583±5.802)％,P=0.938;25 d (33.300±4.724)％ vs (29.767±3.347)％.P=0.166;26 d:(41.017±7.246)％ vs (32.800±8.145)％,P=0.095;27 d:(48.017±7.424)％ vs (35.267±6.748)％,P=0.011;28 d:(51.617±9.017)％ vs (41.116±6.467)％,P=0.043] and in latency to platform at day 27 and 28 [24 d:(62.967±5.494) s vs (63.917±7.027) s,P=0.800;25 d:(50.533±10.305) s vs (57.217±13.085) s,P=0.349;26 d:(40.333± 10.526) s vs (50.133±11.039) s,P=0.147;27 d:(28.717±4.137) s vs (44.533±7.181) s,P=0.001;28 d:(21.950±6.889) s vs (37.567±5.974) s,P=0.002].There was a decreased expression of IL-lβ and TNF-α and increased level of neurotrophic factor BDNF and NGF after EC treatment in EC treatment group,compared to the veh treatment group [IL-1β and TNF-α:(42.690±3.057) ng/mL and (750.167±51.941) ng/mL vs (71.670±4.996) ng/mL and (1 085.167±68.535) ng/mL,P=0.000 6 and 0.003;BDNF and NGF:0.543±0.033 and 0.334±0.041 vs 0.756±0.088 and 0.514±0.047,P=0.048 and 0.017)].EC decreased the cell death near injury area (54.833±5.486 vs 74.000±5.323,P=0.031),increased NeuN positive cells (76.667±6.386 vs 42.167±5.237,P=0.002),and increased neurogenesis in SGZ area (12.667±0.760 vs 7.500±1.258,P=0.031).Conclusions (-)-Epicatechin plays an important role in functional recovery after traumatic brain injury in mice.The underlying mechanisms are closely related to inhibited inflammation,enhanced neurotrophic factors and improved neurogenesis.
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AIM To establish a quantitative analysis of multi-components by single marker(QAMS) method for the content determination of six catechins in Xinnaojian Capsules (Tablets) (tea extract).METHODS The analysis of 50％ methanol extract of this drug was performed on a 35 ℃ thermostatic Shimadzu Wonda Cract ODS-2 column (4.6 mm ×250 mm,5 μm),with the mobile phase comprising of 0.5％ acetic acid (A)-acetonitrile (B) flowing at 1.0 mL/min in a gradient elution manner,and the detection wavelength was set at 280 nm.With epigallocatechin gallate as an internal standard,the relative correction factors of epigallocatechin,catechin,epicatechin,gallocatechin gallate and epicatechin gallate were calculated,from which the content determination was made.RESULTS Six constituents showed good linear relationships within their own ranges (r ≥ 0.999 8),whose average recoveries were 96.00％-98.47％ with the RSDs of 2.09％-2.91％.The results obtained by QAMS method approximated those obtained by external standard method.CONCLUSION This simple and reliable method can be used for the quality control of Xinnaojian Capsules (Tablets).
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AIM To establish a RP-HPLC method for the simultaneous content determination of four constituents in Canarii Fructus.METHODS The analysis of Canarii Fructus methanol extract was performed on a 30 ℃ thermostatic Hypersil ODS column (4.6 mm × 200 mm,5 μm),with the mobile phase comprising of acetonitrile0.1％ phosphoric acid flowing at 1.0 mL/min in a gradient elution manner,and the detection wavelength was set at 237 nm.RESULTS Gallic acid,protocatechuic acid,chlorogenic acid and epicatechin displayed good linear relationships within the ranges of 0.525-10.500 μg/mL (r =0.999 9),0.700-14.000 μg/mL (r =0.999 9),0.575-11.500 μg/mL (r =0.999 9) and 0.550-11.000 μg/mL (r =0.999 9),whose average recoveries were 99.05％ (RSD=1.4％),98.73％ (RSD=0.8％),98.69％ (RSD=1.3％) and 99.47％ (RSD=1.1％),respectively.CONCLUSION This simple,sensitive and relible method can be used for the quality control of Canarii Fructus.
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Objective: To evaluate the polyphenol extracted from Litchi chinensis and quantify the content of four kinds of polyphenol therein, the combination of fingerprint and quantitative analysis of multi-components by single marker (QAMS) was used. Methods: A total of 22 batches of extract from Litchi chinensis were assayed by RP-UPLC to establish a common mode of fingerprints. For achieving QAMS, a method was developed by selecting epicatechin as internal reference and the relative correction factor of the three components, procyanidin A2, procyanidin B2, and epicatechin-(4β→8,2β→O→7)-epicatechin-(4β→8)-epicatechin (PC-C), to determine their contents. The feasibility and accuracy of QAMS were evaluated by comparing the contents of four polyphenols determined with two different methods, QAMS and external standard method. Results: Nineteen common peaks were identified in the characteristic fingerprint, nine components, including the known principal components, procyanidine B2 (peak 6), epicatechin (peak 8), PC-C (peak 9), procyanidine A2 (peak 15), three trimers of procyanidine type A (peaks 12, 16, and 17), a dimer of procyanidine type A (peak 19) and a dimer of procyanidine type B (peak 14), were verified in 22 batches of Litchi chinensis extract. Good similarities with correlation coefficients higher than 0.9 were found in 22 batches fingerprints. There was no significant difference between calculated value and detected value of the four ingredients in 22 batches, by QAMS and external standard method. Conclusion: The results showed that the combined method of fingerprint and QAMS for quality control is accurate and feasible and provide reference method to evaluate the quality of extracts from Litchi chinensis.
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Objective: To study the chemical constituents from the 70% ethanolic extracts of Aesculus chinensis seeds. Methods: The compounds were isolated by D101 macroporous adsorptive resins, silica gel, Sephadex LH-20, and preparative-HPLC and their structures were identified by chemical methods and spectroscopic analyses. Results: Ten compounds were isolated from the 70% ethanolic extracts of A. chinensis seeds. They were 2R,3R-3,7,3'-trihydroxy-5'-methoxyflavane-5-O-β-glucopyranoside (1), quercetin-4'-O-β-D-glucopyranoside (2), quercetin-3'-O-β-D-glucoside (3), quercetin-3-O-[β-D-xylopyranosyl (1-2)]-β-D- glucopyranoside (4), quercetin-3-O-[β-D-glucopyranosyl (1-4)]-α-L-rhamnopyranoside (5), kaempferol-3-O-[β-D-glucopyranosyl (1-4)]-α-L-rhamnopyranoside (6), kaempferol-3-O-[β-D-xylopyranosyl (1-2)]-β-D-glucopyranoside (7), kaemferol-3-O-[β-D- xylopyranosyl (1-2)] [β-D-glucopyranosyl (1-3)]-β-D-glucopyranoside (8), (-)-epicatechin (9), and quercetin (10). Conclusion: Compounds 1 and 2 are obtained from genus Aesculus Linn. for the first time, and compounds 3-9 are isolated from A. chinensis for the first time.
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Objective To establish an HPLC fingerprint method of Sanlejiang Oral Liquid (SOL) and determine the contents of its main components, combining with clustering analysis for quality consistency evaluation of different batches, so as to provide a reference for the quality control. Methods Welchrom C18 (250 mm × 4.6 mm, 5 μm) column was adopted, the mobile phase consisted of 0.1% phosphoric acid water-methanol with gradient elution at the flow rate of 1.0 mL/min, and the detection wavelength was 270 nm, the column temperature was 25 ℃. HPLC fingerprint of SOL was established and determination method of gallic acid, gallocatechin, epicatechin, corilagin, and ellagic acid were studied methodologically. Results The fingerprint chromatography included 22 mutual peaks. At the same time, the 10 batches of SOL fingerprints were analyzed by similarity software, the similarity among the batches was more than 0.95. Based on the tetention time of master compounds, five components [gallic acid (peak 3), gallocatechin (peak 8), epicatechin (peak 15), corilagin (peak 16), and ellagic acid (peak 21)] were identified and quantified. The contents of gallic acid, gallocatechin, epicatechin, corilagin, and ellagic acid in 10 batches of Sanlejiang Oral Liquid were 5.743 2- 7.538 0, 0.492 9-0.847 1, 0.529 7-0.804 8, 0.937 5-1.756 5, and 0.352 7-0.554 5 mg/mL, respectively. Conclusion The established method is simple in good separation and reproducibility, achieving the qualitative and quantitative research for SOL, and thus can provide a reference for the standard and evaluation of quality of SOL.
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ABSTRACT The fruits of Litchi chinensis Sonn., Sapindaceae, are renowned for their biological activities. However, their leaves are poorly explored, although they represent an important source of vegetable raw material with biological properties as antioxidant, anti-inflammatory and antinociceptive. An HPLC method was developed and validated for the simultaneous quantification of epicatechin and procyanidin A2 in the leaf hydroethanolic extract of L. chinensis. The markers and other unidentified components were separated on a Luna Phenomenex C18 column (250 mm × 4.6 mm, 5 µm) with mobile phase composed of acetonitrile: water pH 3.0 (with sulfuric acid), in a gradient run; at 1.0 ml min-1, 30 ºC and 278 nm for detection. The method was linear over an epicatechin and procyanidin A2 concentration range of 10–100 µg ml-1. The Limit of Quantification for epicatechin and procyanidin A2 were 1.7 and 2 µg ml-1, respectively. The Relative Standard Deviation (%) values for markers (intra- and inter-day precision studies) were <4.0% and the accuracy was 100 ± 5%. The method was applied to ten samples collected in the state of Santa Catarina (Brazil), which showed 14.8–44.5 and 44.8–69.6 mg g-1 of epicatechin and procyanidin A2, respectively. The proposed method could be a valuable tool for quality assessment of L. chinenis leaves as well as their herbal derivatives.
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Phytochemical investigation of the ethanol extract of stem bark and leaves of Ximenia americana L. revealed the presence of epicatechin and quercetin, respectively. This is the first report of the occurrence of epicatechin in this genus. The extracts, fractions and isolated compounds of X. americana were subjected to an in vitro antioxidant activity assay by the DPPH method (2,2-diphenyl-1-picrylhydrazyl). The EC50 values were calculated and the results indicate that the ethyl acetate fractions of the stem bark and leaves have high antioxidant activity and a high content of total phenols. The high antioxidant activity of these fractions is justified by the presence of epicatechin and quercetin.
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Objective To develop a double-wavelength HPLC method for the simultaneous determination of neogambogic acid,gambogic acid,( +)-catechin and L-epicatechin in Litong pill. Methods The quantitative analysis was carried out on C18 column(250 mm×4.6 mm,5 μm).A linear elution of methanol-acetonitrile(4: 1)and 0.2% phosphoric acid solution was adopted at the flow rate of 1.1 mL·min-1 ,with the detection wavelength set at 360 nm for neogambogic acid and gambogic acid,and at 280 nm for(+)-catechin and L-epicatechin. Results The linear ranges of neogambogic acid,gambogic acid,(+)-catechin and L-epicatechin were 5.85-117.00 μg·mL-1(r= 0.999 5),8.95-179.00 μg·mL-1(r= 0.999 8),6.90-138.00 μg·mL-1(r= 0.999 7),and 5.30-106.00 μg·mL-1(r = 0.999 9),respectively.The average recoveries were 97.82%(RSD= 1.21%),98.72%(RSD = 1.30%),96.96%(RSD = 0.84%)and 99.26%( RSD = 1.46%)for neogambogic acid, gambogic acid,(+)-catechin and L-epicatechin,respectively. Conclusion The method is simple,accurate,reproducible and may be used for the simultaneous determination of neogambogic acid,gambogic acid,(+)-catechin and L-epicatechin in Litong pill.
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OBJECTIVE:To establish a method for the content determination of L-epicatechin in Actinidiae arguta. METHODS:HPLC was performed on the column of Kromasil C18 with mobile phase of acetonitrile-0.2%Acetic acid solution(15:85,V/V)at a flow rate of 1.0 ml/min,detection wavelength was 210 nm,column temperature was 25 ℃,and the volume injection was 10 μl. RESULTS:The linear range of L-epicatechin was 10.47-167.52 μg/ml(r=0.999 9);RSDs of precision,stability and reproducibility tests were lower than 2%;average recovery was 98.07%-101.71%(RSD=1.39%,n=6). CONCLUSIONS:The method is simple, accurate and reliable,and suitable for the content determination of L-epicatechin in A. arguta.
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To develop a RP-HPLC method for the determination of catechin (C),epicatechin (EC),gallic acid (GA)and procyanidin B2 (PCB2 )in procyanidins and compare the contents of C,EC,GA and PCB2 in procyani-dins purchased from different manufacturers.A RP-HPLC method was developed and the determination was car-ried out on a Hypersil ODS2 column (4.0 mm ×200 mm,5 μm).The mobile phase consisted of methanol and 2% acetic acid with gradient elution and the detection wave-length was at 280 nm.There was a good linear rela-tionship between concentration and the peak area in the range of 0.1-50 μg/mL (r =0.998 6)for catechin,0.1-50 μg/mL (r =0.994 5)for epicatechin,0.05-50 μg/mL (r =0.999 9)for gallic acid and 0.1-50 μg/mL (r =0.992 2)for procyanidin B2 ,respectively.The average recoveries of catechin,epicatechin,gallic acid and PCB2 were 98.36%,98.21%,89.60% and 98.47%,respectively and the RSDs were 1.39%,0.84%,2.12% and 2.46%,respectively.The method is simple,accurate,reproducible and can be used for assay of C,EC,GA,PCB2 in procyanidins.There was a great difference in the content of four substance in procyanidins purchased from dif-ferent manufacturers.
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To study the effects of sanguisorba tannins and saponins compatibility at different proportions [tannins-saponins (1∶1) and tannins-saponins(8∶1)] after intragastric administration (50 mg•kg⁻¹) on pharmacokinetic parameters of catechin, epicatechin and ziyuglycoside Ⅰ in rats by using pharmacokinetic techniques and methods. Kinetica 5.0 software was used to calculate the pharmacokinetic parameters. The results showed that the specificity, linearity, recovery rate, precision and stability of the established detection method were in line with the test requirements. When the sanguisorba tannins and eaponins were combined at the rate of 1∶1, Vd and CL of catechin and epicatechin were increased significantly（P<0.05); MRT was significantly shortened(P<0.05); Cmax and AUC were significantly reduced(P<0.05). When the sanguisorba tannins and saponins were combined at the rate of 8∶1, Vd and CL of catechin and epicatechin were significantly reduced(P<0.05); MRT was significantly prolonged(P<0.05); Cmax and AUC were increased significantly(P<0.05). In addition, with the increase in proportion of sanguisorba tannins in the compatibility, Cmax and AUC of ziyuglycoside Ⅰ were increased significantly(P<0.05); Vd and CL were significantly reduced(P<0.05), Tmax was obviously lagging behind, and MRT was also significantly prolonged(P<0.05). In our present study, catechin, epicatechin and ziyuglycoside Ⅰ showed good pharmacokinetic behavior in rats when sanguisorba tannins and saponins were combined at the rate of 8∶1 in compatibility, which could be used as a reference for the proportion in sanguisorba tannins and saponins compatibility.