Yulei Cui

Two-dimensional chromatography based on on-line HPLC-DPPH bioactivity-guided assay for the preparative isolation of analogue antioxidant compound from Arenaria kansuensis.

Traditional Tibetan medicine is important for discovery of drug precursors. However, information about the chemical composition of traditional Tibetan medicine is very limited due to the lack of appropriate chromatographic purification methods. In the present work, A. kansuensis was taken as an example and a novel two-dimensional reversed-phase/hydrophilic interaction liquid chromatography(HILIC) method based on on-line HPLC-DPPH bioactivity-guided assay was developed for the purification of analogue antioxidant compounds with high purity from the extract of A. kansuensis. Based on the separation results of many different chromatographic stationary phases, the first-dimensional (1D) preparation was carried on a RP-C18HCE prep column, and 2 antioxidant fractions were obtained from the 800mg crude sample with a recovery of 56.7%. A HILIC-XAmide prep column was selected for the second-dimensional (2D) preparation. Finally, a novel antioxidant β-carboline Alkaloids (Glusodichotomine AK) and 4 known compounds (Tricin, Homoeriodictyol, Luteolin, Glucodichotomine B) were purified from A. kansuensis. The purity of the compounds isolated from the crude extract was >98%, which indicated that the method built in this work was efficient to manufacture single analogue antioxidant compounds of high purity from the extract of A. kansuensis. Additionally, this method showed great potential in the preparation of analogue structure antioxidant compounds and can serve as a good example for the purification of analogue structure antioxidant carboline alkaloids and flavonoids from other plant materials.

Anti-inflammatory bioactive equivalence of combinatorial components β-carboline alkaloids identified in Arenaria kansuensis by two-dimensional chromatography and solid-phase extraction coupled with liquid–liquid extraction enrichment technology

Bioactive equivalent combinatorial components play a critical role in herbal medicines. However, how to discover and enrich them efficiently is a question for herbal pharmaceuticals researchers. In our work, a novel two-dimensional reversed-phase/hydrophilic interaction high-performance liquid chromatography method was established to perform real-time components trapping and combining for preparation and isolation of coeluting components. Arenaria kansuensis was taken as an example, and solid-phase extraction coupled with liquid-liquid extraction as a simple and efficient method for enriching trace components, reversed phase column coupled with hydrophilic interaction liquid chromatography XAmide column as two-dimensional chromatography technology for isolation and preparation of coeluting constituents, enzyme-linked immune-sorbent assay as bio-guided assay, and anti-inflammatory bioactivity evaluation for bioactive constituents. A combination of 12 β-carboline alkaloids was identified as anti-inflammatory bioactive equivalent combinatorial components from A. kansuensis, which accounts for 1.9% w/w of original A. kansuensis. This work answers the key question of which are real anti-inflammatory components from A. kansuensis and provides a fast and efficient approach for discovering and enriching trace β-carboline alkaloids from herbal medicines for the first time. More importantly, the discovery of bioactive equivalent combinatorial components could improve the quality control of herbal products and inspire a herbal medicine based on combinatorial therapeutics.

Erythritol Attenuates Postprandial Blood Glucose by Inhibiting α-Glucosidase

Diabetes mellitus (DM) is a serious metabolic disorder, where impaired postprandial blood glucose regulation often leads to severe health complications. The natural chemical erythritol is a C4 polyol approved by the U.S. Food and Drug Administration for use as a sweetener. Here, we examined a potential role for erythritol in the control of postprandial blood glucose levels in DM. An anti-postprandial hyperglycemia effect upon erythritol administration (500 mg kg-1) was demonstrated in alloxan-induced DM model mice by monitoring changes in blood glucose after intragastric administration of drugs and starch. We also found that erythritol most likely exerts its anti-postprandial hyperglycemic activities by inhibiting α-glucosidase in a competitive manner. This was supported by enzyme activity assays and molecular modeling experiments. In the latter experiments, it was possible to successfully dock erythritol into the catalytic pocket of α-glucosidase, with the resultant interaction likely driven by electrostatic interactions involving Asp215, Asp69, and Arg446 residues. This study suggests that erythritol may not only serve as a glucose substitute but also be a useful agent in the treatment of DM to help manage postprandial blood glucose levels.

Phenolics from Lagotis brevituba Maxim.

Abstract A phytochemical investigation on Lagotis brevituba led to the isolation and characterisation of 11 phenolic compounds: p-hydroxy-benzoic acid 1, methyl 3,4-dihydroxybenzoate 2, vanillic acid 3, protocatechuic acid 4, caffeic acid 5, glucose ester of (E)-ferulic acid 6, p-coumaric acid 7, vanillin 8, diosmetin-7-O-β-d-glucoside 9, chrysoeriol 10 and luteolin 11. Their structures were elucidated using spectroscopic methods and by comparison with data in the literature. Compounds 1–6 were first obtained from the genus Lagotis, and compounds 1–9 were isolated from L. brevituba for the first time. Compound 4 and 11 displayed remarkable antioxidant activities against DPPH radical (IC50 = 5.60 ± 0.09, 27.5 ± 0.06 mg/L, respectively), which were superior to positive control rutin. And compound 11 was also superior to rutin in ABTS assay (IC50 = 2.04 ± 0.13 mg/L).

Antihypoxic activities of constituents from Arenaria kansuensis

BACKGROUND In previous investigation, we have identified antioxidative effects of water-soluble ethanolic extracts (named as AKE) from Arenaria kansuensis and inferred that these extracts or their constituents may also have antihypoxic activity. A. kansuensis has been widely used in traditional Tibetan medicine for altitude sickness (AS) and has been known as the herb of anti-inflammatory and hypoxia resistance for a long time. PURPOSE The purpose of this study is to evaluate protective effects of AKE and its major constituents against hypoxia-induced lethality in mice and RSC96 cells. STUDY DESIGN AND METHODS Hypoxia-induced lethality in mice was investigated by 3 experimental animal models of hypoxia. Meanwhile, we established a RSC96 cell model of hypoxia which applied to screen and assess the anti-hypoxic activity of compounds isolated from A. kansuensis. RESULTS Results indicated that AKE dose-dependently prolonged survival time of hypoxia induced lethality in mice compared to vehicle group and exhibited significantly anti-hypoxic effect. AKE also enhanced the number of red blood cells (RBC) and the concentration of hemoglobin (HB). 8 compounds were bio-guided separated and purified from AKE based on the animal model and cell model of hypoxia. Among which pyrocatechol (C16) and tricin 7-O-β-d-glucopyranoside (C13) were confirmed to express better protective effects on cell damage induced by hypoxia, suggesting that these two compounds are major active constituents of AKE for anti-hypoxia. CONCLUSION This study demonstrated that pyrocatechol and tricin 7-O-β-d-glucopyranoside could be therapeutic candidates for treatment of AS. It is the first time to find the major active constituents of AKE for anti-hypoxia. Meanwhile, a RSC96 cell model of hypoxia was established to screen anti-hypoxic activity of compounds for the first time.

Efficient Separation of Four Antibacterial Diterpenes from the Roots of Salvia Prattii Using Non-Aqueous Hydrophilic Solid-Phase Extraction Followed by Preparative High-Performance Liquid Chromatography

An efficient preparative procedure for the separation of four antibacterial diterpenes from a Salvia prattii crude diterpenes-rich sample was developed. Firstly, the XION hydrophilic stationary phase was chosen to separate the antibacterial crude diterpenes-rich sample (18.0 g) into three fractions with a recovery of 46.1%. Then, the antibacterial fractions I (200 mg), II (200 mg), and III (150 g) were separated by the Megress C18 preparative column, and compounds tanshinone IIA (80.0 mg), salvinolone (62.0 mg), cryptotanshinone (70.0 mg), and ferruginol (68.0 mg) were produced with purities greater than 98%. The procedure achieved large-scale preparation of the four diterpenes with high purity, and it could act as a reference for the efficient preparation of active diterpenes from other plant extracts.

Anti-alcohol liver disease effect of Gentianae macrophyllae extract through MAPK/JNK/p38 pathway

The hepatoprotective effect of Gentianae macrophyllae root extract (GME) on alcoholic liver disease (ALD) was evaluated through ethanol induced ALD animal model.

Trace anti-inflammatory β-carboline alkaloid identified in Arenaria kansuensis by two-dimensional chromatography coupled with UniElut C18AEX based solid-phase extraction re-enrichment technology

Traditional Chinese medicine is important for discovery of drug precursors. However, information about trace chemical composition of them is very limited due to the lack of appropriate enrichment and chromatographic purification methods In our work, A. kansuensis was taken as an example, a novel two-dimensional reversed-phase/hydrophilic interaction liquid chromatography coupled with UniElut C18AEX solid-phase extraction re-enrichment method based on anti-inflammatory bioactivity-guided assay was developed for gathering and purifying trace β-carboline alkaloids with high purity from the ethyl acetate extract of A. kansuensis. Extraction with ethyl acetate as the first enrichment method, then, a UniElut C18AEX column was employed to re-enrich trace fraction which was hardly detected by diode array detector during high performance liquid chromatography analysis, eighteen grams of UniElut C18AEX was used as sorbent material to pack a 60mL pipette tip for the extraction of β-carboline alkaloids from 100mL of ethyl acetate sample. The whole extraction process was finished in 10min, and the volume of eluent used was only 120mL. The enriching fraction (100mg) was used for the following two-dimensional purification. First-dimensional preparation was carried on a RP-Megress-C18 prep column, and four anti-inflammatory fractions were obtained from the 100mg re-enriching sample with a recovery of 66.9%. A HILIC-XAmide prep column was selected for the second dimensional preparation. Finally, two pair of analogue β-carboline alkaloids and one other β-carboline alkaloid were purified from A. kansuensis. The purity of the isolated compounds was ≫>98%, which indicated that the method was efficient to re-enrich and manufacture single trace β-carboline alkaloids with high purity from A. kansuensis. Additionally, this method showed great potential to serve as a good example for the purification and enrichment of analogue structure anti-inflammation carboline alkaloids from other plant materials.

Phytochemical Constituents of Arenaria kansuensis

The whole plant of Arenaria kansuensis (Caryophyllaceae), a very important Chinese folk medicine, has been used to treat influenza, lung inflammation, jaundice, and rheumatism [1]. However, very few studies have been reported on the chemical constituents of the plant.Until now, the allocated substances previously isolated from A. kansuensis were mostly flavonoids, -carboline alkaloids, terpenoids, steroids, and phenylpropanoids [2]. As part of our continuing studies on bioactive compounds from A. kansuensis, we have carried out an investigation of the chemical constituents of the plant. Our phytochemical investigation led to the isolation of 10 compounds (1–10) from A. kansuensis, among which compounds 1, 6, 7, and 8 were isolated from a natural source for the first time; compounds 1, 2, 5, 6, 7, 8, and 10 were also isolated from A. kansuensis for the first time. The same for indole derivatives and phenethylamine derivatives, which were also isolated from A. kansuensis for the first time. The structures of 1–10 were all elucidated by spectroscopic methods, including 13C NMR, 1H NMR, and MS techniques. As far as we know, prior to this study, 13C NMR data of compounds 1, 7, and 8 have not been reported. This is the first time that the data mentioned have been confirmed. Another three compounds (3, 4, and 9) are known chemical constituents previously isolated from A. kansuensis. The isolated compounds were identified as 1-(9H-pyrido[3,4-b]indol-1-yl)ethane-1,2-diol (1) [3], cordysinin C (2) (light yellow powder, HR-ESI-MS m/z 213.1209 [M + H]+ (calcd for C13H13N2O, 213.1208) [4]), arenarine B (3) (pale yellow powder, HR-ESI-MS m/z 242.1102 [M]+ (calcd for C14H14N2O2, 242.1107) [5]), arenarine D (4) (light yellow powder, HR-ESI-MS m/z 226.0102 [M]+ (calcd for C13H10N2O2, 226.0107) [5]), -carboline-1-carboxylic acid (5) (yellow powder, HR-ESI-MS m/z 212.1102 [M]+ (calcd for C12H8N2O2, 212.1105) [6]), 1-(1-hydroxyethyl)pyrido[3,4-b]indole-3-carboxylate (6) (yellow powder, HR-ESI-MS m/z 270.1102 [M]+ (calcd for C15H14N2O3, 270.1101) [7]), N-hydroxyindole-3-carboxylic acid (7) [8], 4-hyroxy-3-methoxy-phenethylamine (8) [9], tricin (9) (yellow powder, HR-ESI-MS m/z 330.0702 [M]+ (calcd for C17H14O7, 330.0706) [10]), and tricin 7-O-Dglucopyranoside (10) (yellow powder, HR-ESI-MS m/z 492.0502 [M]+ (calcd for C23H24O12, 492.0501) [11]). Plant Material. The whole herbs of A. kansuensis were collected from Daban Mountain (101 24 2.8 E, 37 20 50.5 N, altitude 3990 m), Qinghai Province, China in September 2014. A voucher specimen (No. 0322810) has been deposited at the Key Laboratory of Tibetan Medicine Research, Chinese Academy Sciences, Xining, China. Extraction and Isolation. The dried and powdered whole plant (10 kg) was extracted with 83% aqueous ethanol (100 L 3) for 24 h to give a concentrated extract. The concentrated extract was suspended in water (3 L) and successively extracted with EtOAc (3 L 3) and n-BuOH (3 L 3) to yield concentrated extracts of the EtOAc (AKE, 865 g) and n-BuOH (AKB, 101 g) fractions. The concentrated EtOAc fraction (AKE, 865 g) was subjected to MCI column (6 90 cm) chromatography (CC) eluting with MeOH–H2O (9:1); the eluent was monitored by thin-layer chromatography (TLC) until nothing appeared on the TLC. The concentrated fraction was successively subjected to silica gel (SiO2) column (8 150 cm) chromatography (CC) eluting with CH2Cl2–MeOH–H2O (7:3:0.5); the eluent was monitored by thin-layer chromatography (TLC) until nothing appeared on the TLC. The concentrated fraction was successively prepared using semi-preparation dynamic axial compression columns (DAC-HB50, RP-C18, 5 65 cm, elueting parameter: MeOH–H2O, 30–70% gradient elution for