Hypoglycemic effect of Nitraria tangutorum fruit by inhibiting glycosidase and regulating IRS1/PI3K/AKT signalling pathway and its active ingredient identification by UPLC-MS.

The hypoglycemic effect of NTB-40 (40% ethanol fraction of Nitraria tangutorum fruit) in type I/II diabetic mice and its underlying mechanism and active ingredient structure were investigated. The postprandial blood glucose (PBG) lowering effect of NTB-40 treatment was confirmed by maltose, starch, and sucrose tolerance tests in alloxan-induced DM mice and sucrase and maltase inhibitory activities in vitro. More importantly, long-term dosing experiments in high-fat diet-STZ-induced diabetic mice further demonstrated that NTB-40 intervention could improve glycolipid metabolism disorder and insulin resistance (IR) by maintaining glucose homeostasis (FBG, OGTT, ITT, FINS, and HOMA-IR) and lipid homeostasis (TC, TG, HDL-C, LDL-C, and FFA), reducing inflammation (IL-6, IL-1ß, and TNF-α) and oxidative stress (SOD and MDA), ameliorating the liver's histological structural abnormalities, and modulating the IRS1/PI3K/AKT signaling pathway and downstream targets (FOXO1, GSK3ß, GLUT4) for decreasing hepatic gluconeogenesis and promoting glycogen synthesis and glucose uptake. All these results indicated that NTB-40 had an anti-diabetic effect by modulating the IRS1/PI3K/AKT signaling pathway and inhibiting α-glucosidase activity. Finally, the main chemical components of NTB-40, including phenolic acids, flavonoids, and alkaloids, were assigned by UPLC-Triple-TOF MS/MS.

Targeted isolation of cyclooxygenase-2 inhibitors from Saussurea obvallata using affinity ultrafiltration combined with preparative liquid chromatography.

Saussurea obvallata (S. obvallata) is widely used in Qinghai-Tibet Plateau with high medicinal and edible values of reducing inflammation. But, the individual components and mechanisms of action still ill-defined. In this work, an integrated method using affinity ultrafiltration combined with preparative liquid chromatography was developed to identify and separate cyclooxygenase-2 (COX-2) inhibitors from S. obvallata. The sample was pretreated using on-line medium pressure liquid chromatography to yield the active fraction. Then, the potential COX-2 ligands were screened out using affinity ultrafiltration from the targeted fraction and the identified compounds were isolated via preparative liquid chromatography. As a result, four main compounds, coniferin (1), syringin (2), roseoside (3) and grasshopper ketone (4) were targeted isolated with IC50 values of 12.34 ± 1.81, 4.04 ± 0.43, 13.91 ± 2.46 and 7.97 ± 1.21 µM, respectively. Results of this work demonstrated that the developed strategy was effective for the targeted separation of COX-2 inhibitors from natural product extracts.

Megastigmane sesquiterpenoids from Saussurea medusa and their anti-inflammatory activities.

Objectives: An ethanol extract of the whole plants of Saussurea medusa had been investigated to find novel anti-inflammatory sesquiterpenoids. Methods: Extensive spectroscopic data and chemical methods were applied to elucidate the structures of the compounds. Results: One new megastigmane sesquiterpenoid (1), along with 11 known analogues (2-12), were obtained from S. medusa. All isolates, except compounds 3 and 6, were mentioned from the studied plant for the first time. Compounds 1, 2, 4, 5, 7, 8 and 12 were firstly isolated from the genus Saussurea. Compounds 2, 9 and 10 were found to inhibit the lipopolysaccharide (LPS)-induced release of NO by RAW264.7 cells with IC50 values ranging from 21.1 ± 1.7 to 46.7 ± 1.9 µM. Furthermore, iNOS expression experiment was performed to examine the interactions between the active compounds and the iNOS enzyme.

Five New Diarylbutyrolactones and Sesquilignans from Saussurea medusa and Their Inhibitory Effects on LPS-induced NO Production.

Five new diarylbutyrolactones and sesquilignans (1A/1B:  - 4: ), including one pair of enantiomers (1A/1B: ), together with 10 known analogues (5:  - 14: ), were isolated from the whole plants of Saussurea medusa. Compound 1: was found to possess an unusual 7,8'-diarylbutyrolactone lignan structure. Separation by chiral HPLC analysis led to the isolation of one pair of enantiomers, (+)-1A: and (-)-1B: . The structures of the new compounds were elucidated by extensive spectroscopic data. All compounds, except compounds 5, 7: and 9: , were isolated from S. medusa for the first time. Moreover, compounds 1:  -  4, 8: and 10:  - 14: had never been obtained from the genus Saussurea previously. Compounds (+)- 1A, 2, 5, 7: , and 9:  - 11: were found to inhibit the lipopolysaccharide (LPS)-induced release of NO by RAW264.7 cells with IC50 values ranging from 10.1 ± 1.8 to 41.7 ± 2.1 µM. Molecular docking and iNOS expression experiments were performed to examine the interactions between the active compounds and the iNOS enzyme.

Three Pairs of Novel Enantiomeric 8-O-4' Type Neolignans from Saussurea medusa and Their Anti-inflammatory Effects In Vitro.

Three pairs of novel enantiomeric 8-O-4' type neolignans (1a/1b−3a/3b), together with seven known analogues (4−10), were isolated from the whole plants of Saussurea medusa. Their structures were elucidated by extensive spectroscopic data analysis and electric circular dichroism (ECD) calculations after chiral separations. All compounds were obtained from S. medusa for the first time, and compounds 1−3 and 5−10 had never been obtained from the genus Saussurea previously. The anti-inflammatory activities of the compounds were evaluated by determining their inhibitory activities on the production of NO and inducible nitric oxide synthase (iNOS) expression in LPS-stimulated RAW 264.7 cells. Compounds (+)-1a, (−)-1b and 5−7 inhibited NO production and had IC50 values ranging from 14.3 ± 1.6 to 41.4 ± 3.1 µM. Compound 7 induced a dose-dependent reduction in the expression of iNOS in LPS-treated RAW 264.7 cells. Molecular docking experiments showed that all active compounds exhibited excellent docking scores (<−7.0 kcal/mol) with iNOS. Therefore, compounds (+)-1a, (−)-1b and 5−7 isolated from the whole plants of S. medusa may have therapeutic potential in inflammatory diseases.

Potential Use of Emerging Technologies for Preservation of Rice Wine and Their Effects on Quality: Updated Review.

Rice wine, a critical fermented alcoholic beverage, has a considerable role in different cultures. It contains compounds that may have functional and nutritional health benefits. Bacteria, yeasts, and fungi commonly found in rice wines during fermentation can induce microbial spoilage and deterioration of the quality during its distribution and aging processes. It is possible to control the microbial population of rice wines using different preservation techniques that can ultimately improve their commercial shelf life. This paper reviews the potential techniques that can be used to preserve the microbial safety of rice wines while maintaining their quality attributes and further highlights the advantages and disadvantages of each technique.

The Antibacterial Activity Mode of Action of Plantaricin YKX against Staphylococcus aureus.

We aimed to evaluate the inhibitory effect and mechanism of plantaricin YKX on S. aureus. The mode of action of plantaricin YKX against the cells of S. aureus indicated that plantaricin YKX was able to cause the leakage of cellular content and damage the structure of the cell membranes. Additionally, plantaricin YKX was also able to inhibit the formation of S. aureus biofilms. As the concentration of plantaricin YKX reached 3/4 MIC, the percentage of biofilm formation inhibition was over 50%. Fluorescent dye labeling combined with fluorescence microscopy confirmed the results. Finally, the effect of plantaricin YKX on the AI-2/LuxS QS system was investigated. Molecular docking predicted that the binding energy of AI-2 and plantaricin YKX was -4.7 kcal/mol and the binding energy of bacteriocin and luxS protein was -183.701 kcal/mol. The expression of the luxS gene increased significantly after being cocultured with plantaricin YKX, suggesting that plantaricin YKX can affect the QS system of S. aureus.

Hypoglycemic effects of Rhodiola crenulata (HK. f. et. Thoms) H. Ohba in vitro and in vivo and its ingredient identification by UPLC-triple-TOF/MS.

Rhodiola crenulata (HK. f. et. Thoms) H. Ohba (RC), mainly distributed in the highly cold region of China, has long been used as a medicine/healthy food for eliminating fatigue and increasing blood circulation. This study aimed to evaluate the inhibitory effects of the RCRS extract on α-amylase and α-glucosidase (sucrase and maltase) in vitro and in vivo, and tentatively analyze and identify its chemical ingredients using UPLC-Triple-TOF/MS. The Rhodiola crenulata RCRS extract had strong inhibitory activities against α-amylase, sucrase and maltase with an IC50 of 0.031 mg mL-1, 0.142 mg mL-1 and 0.214 mg mL-1, respectively. Furthermore, the RCRS extract could significantly decrease the postprandial blood glucose (PBG) level of normal mice in a starch tolerance test, and reduce the PBG levels of diabetic mice in a starch/maltose/sucrose tolerance test. UHPLC-Triple-TOF-MS/MS analysis indicated that hydroxybenzoic acids, hydroxycinnamic acids, alcohol glycosides, flavonols and their derivatives were the main active ingredients in the RCRS extract. The results demonstrate that the RCRS extract of Rhodiola crenulata could be employed as a healthy food or medicine for controlling postprandial blood glucose levels.

Bioactivity-guided isolation of cyclooxygenase-2 inhibitors from Saussurea obvallata (DC.) Edgew. Using affinity solid phase extraction assay.

ETHNOPHARMACOLOGICAL RELEVANCE: Saussurea obvallata (DC.) Edgew. is a traditional Tibetan medicine used for the treatment of inflammation-related diseases, but the scientific validation was very limited. AIM OF THE STUDY: This study aimed to rapid screen and targeted isolate cyclooxygenase-2 (COX-2) inhibitors from S. obvallata extract. MATERIALS AND METHODS: An efficient ligand-fishing method based on affinity solid phase extraction (A-SPE) combining with HPLC was developed. The identified COX-2 inhibitors were separated using preparative liquid chromatography. In vitro COX-2 inhibition assays were employed to confirm the inhibitory activities of the isolated compounds. In addition, the effect of the isolated compounds on the production of prostaglandin E2 (PGE2) and the expression of COX-2 in LPS-induced RAW 264.7 were evaluated. RESULTS: A total of four phenylpropanoids, isolariciresinol, syringaresinol, pinoresinol and balanophonin were targeted isolated as COX-2 inhibitors with IC50 values of 36.4 ± 2.6 µM, 23.1 ± 1.8 µM, 3.6 ± 0.3 µM and 12.1 ± 0.9 µM, respectively. The isolated compounds significantly inhibited LPS-induced NO production in a dose-dependent manner. And, the results of the inhibitory effect on the release of PGE2 and the expression of COX-2 in LPS-induced macrophages were consistent with A-SPE analysis. CONCLUSION: The present work demonstrated that the developed A-SPE-HPLC method could successfully targeted isolated COX-2 inhibitors from S. obvallata extract. And, the isolation results indicated that the therapeutic effect of S. obvallata on inflammation-related diseases was partly based on the COX-2 active ingredients.

Targeted Separation of COX-2 Inhibitor from Pterocephalus hookeri Using Preparative High-Performance Liquid Chromatography Directed by the Affinity Solid-Phase Extraction HPLC System.

Pterocephalus hookeri, as a kind of popular traditional Tibetan medicine, is reputed to treat inflammatory related diseases. In the present work, a cyclooxygenase-2 functionalized affinity solid-phase extraction HPLC system was developed and combined with preparative-HPLC for rapidly screening and separating cyclooxygenase-2 ligand from P. hookeri extracts. Firstly, ligands of cyclooxygenase-2 were screened from extracts by affinity solid-phase extraction HPLC system. Then directed by the screening results, the recognized potential active compounds were targeted separated. As a result, the major cyclooxygenase-2 inhibitor of P. hookeri was obtained with a purity of >95%, which was identified as sylvestroside I. To test the accuracy of this method, the anti-inflammatory activity of sylvestroside I was inspected in lipopolysaccharide-induced RAW 264.7 cells. The results show that sylvestroside I significantly suppressed the release of prostaglandin E2 with dose-dependent, which was in good agreement with the screening result of the affinity solid-phase method. This method of integration of screening and targeted separation proved to be very efficient for the recognition and isolation of cyclooxygenase-2 inhibitors from natural products.

Comprehensive screening and separation of cyclooxygenase-2 inhibitors from Pterocephalus hookeri by affinity solid-phase extraction coupled with preparative high-performance liquid chromatography.

Pterocephalus hookeri, a classical Tibetan herb, is mainly used to treat rheumatoid arthritis (RA) and contains various constituents potentially with cyclooxygenase-2 (COX-2) selective inhibition. A novel strategy for screening and target separating COX-2 inhibitors from the extracts of P. hookeri based on affinity solid-phase extraction (ASPE) column combined with preparative high-performance liquid chromatography (pre-HPLC) was successfully developed. The potential COX-2 inhibitors of P. hookeri were screened and recognized by the ASPE-HPLC system, which strategy is to analyze the compounds isolated by the ASPE column. Then, the active compounds were targeted separated by pre-HPLC according to real-time chromatograms. The control drugs celecoxib and glipizide were analyzed to verify the specificity and accuracy of the developed method. As a result, two pure compounds with COX-2 binding affinities were successfully separated from P. hookeri. They were characterized as swertisin and scopoletin using 1H- and 13C NMR spectroscopy, and the in vitro COX-2 inhibitory activities were verified. Compounds with COX-2 inhibitory activities could be screened and targeted separated from crude extracts by this strategy, which indicated that the proposed method was feasible, robust and effective for rapid separation of COX-2 inhibitors from natural products.

Enrichment and separation of high-polar compounds from Saussurea obvallata using solid-phase extraction combining with offline two-dimensional liquid chromatography.

The high-polar compounds from natural products are often used as medicines due to their good bioactivities. However, owing to the complexity and diversity of their structure, the separation of high-polar compounds is still a challenging work. For this, an efficient method for enrichment and separation of the high-polar compounds from Saussurea obvallata was developed. First, the target compounds were enriched from the total extract using a solid-phase extraction method. An offline two-dimensional liquid chromatography method was used for the separation of pure compounds from the enriched sample. After optimization of chromatographic conditions, high separation selectivity of target compounds was obtained on a polar-modified C18 column and a HILIC XAmide column. Hence, a two-dimensional reversed-phase × hydrophilic interaction liquid chromatography system was constructed and enlarged from the analytical level to the preparative level. In the first dimension, four fractions were obtained on the XCharge C18 column with a recovery rate of 71.2%. In the second-dimension preparation on the XAmide column, eight high-polar compounds with more than 96% purity were isolated. All compounds were isolated from Saussurea obvallata for the first time. The results demonstrated that this developed strategy is effective for preparative-scale isolation of high-polar compounds from natural products.

Alkaloids and phenolics identification in fruit of Nitraria tangutorum Bobr. by UPLC-Q-TOF-MS/MS and their a-glucosidase inhibitory effects in vivo and in vitro.

Nitraria tangutorum Bobr. (NTB), mainly distributed in the Qaidam Basin of Tibetan Plateau, have high economic, ecological and medicinal value. The chemical compositions in the NTB fruits were tentatively analyzed and characterized by applying UPLC-Q-TOF-MS/MS. Total 45 constituents, including 9 hydroxycinnamic acids derivatives, 12 flavonols, 4 flavonoids, 1 trolox derivative, 8 ß-carboline alkaloids, 4 tryptophan derivatives, and 7 other amino acid derivatives were identified by comparing with standard products, and analyzing their retention times, characteristic fragment ions and deprotonated molecule ions. The activity studies in vitro indicated that NTB-Z and NTB-C extracts had marked inhibitory effects against sucrase and maltase. Further sucrose/maltose/starch tolerance experiment demonstrated that both NTB-Z and NTB-C extracts at 400 mg/kg could markedly lower the postprandial blood glucose (PBG) level in diabetic animals. All these results indicated that the NTB fruits could be used as the functional health food or medicine for controlling postprandial blood glucose level.

Large-scale preparative isolation of bergenin standard substance from Saxifraga atrata using polyamide coupled with MCI GEL® CHP20P as stationary phases in medium pressure chromatography.

In this study, polyamide and MCI GEL® CHP20P were employed as stationary phases in medium pressure chromatography (MPC) for the efficient preparative separation of bergenin from Saxifraga atrata. Ethanol-water, methanol-water, and acetonitrile-water mobile phases all showed good enrichment capacity for bergenin fraction when polyamide was used as a stationary phase. After 5 cycles of polyamide MPC using acetonitrile/water, 1.2 g of bergenin fraction was isolated from 180 g Saxifraga atrata herb. Further purification of this fraction was conducted using MCI GEL® CHP20P styrene-divinylbenzene beads. The bergenin fraction was separated into two fractions, and after three runs of MPC, 714.2 mg of bergenin with purity above 99% was obtained. The results demonstrate that the combination of polyamide and styrene-divinylbenzene MPC can be utilized for preparative isolation of compounds from natural products with high yield and purity.

Two new polycyclic polyprenylated acylphloroglucinols derivatives from Hypericum acmosepalum.

Polycyclic polyprenylated acylphloroglucinols (PPAPs) were mainly obtained from the plants of Hypericum genus of Guttiferae family, and possessed intriguing chemical structures and appealing biological activities. Two new PPAPs derivatives, hyperacmosin C (1) and hyperacmosin D (2) were isolated from H. acmosepalum. Their structures were established by NMR, HREIMS, and experimental electronic circular dichroism spectra. Besides, compound 1 showed significant hepatoprotective activity at 10 µM against paracetamol-induced HepG2 cell damage and compound 2 could moderately increase the relative glucose consumption.

Multivariate statistical and comparison analysis of chemical constituents in Arenaria kansuensis Maxim. from different regions in Qinghai-Tibet Plateau.

INTRODUCTION: Arenaria kansuensis Maxim. (AKM) is one of the most valued medicinal and edible herbs widely used in Qinghai-Tibet Plateau and there is also a large number of AKM bioactive constituents for health benefits of human beings. However, few works have referred to phytochemical content, fingerprint analysis and quality control of AKM. Therefore, the establishment of validated analytical methods is urgently needed for fingerprint comparison and quantitative analysis of AKM multicomponent. OBJECTIVES: To determine quantitatively and compare the phytochemical constituents of AKM located at different areas. METHODOLOGY: The chemical constituents in AKM samples were separated, identified, and quantified by high-performance liquid chromatography (HPLC) with a diode array detector. The discrimination and separation models for the chemical constituents were developed by chemometric analysis. RESULTS: The flavones and ß-carboline alkaloids were rich in AKM herbs, and the overall pattern of phytochemical profiles was the same, while the significant differences were detected in the total flavonoids, total ß-carboline alkaloids and individual contents, especially the predominant compounds such as tricin and arenarine B. This demonstrated that ecogeographical origin gave an important impact on phytochemical compositions which could be considered as reliable parameters for classifying the AKM resources. Moreover, the contents of AKM constituents were higher in July and/or August than other months of the year, and there were no significant differences in the main phytochemical contents between cultivated and wild AKM herbs. CONCLUSION: This study could provide credible data and method for geographical origin trace, comprehensive evaluation and further utilization of AKM resources.

Preparative isolation of 1,1-diphenyl-2-picrylhydrazyl inhibitors from Ribes himalense using medium-pressure and two-dimensional reversed-phase/reversed-phase liquid chromatography guided by an online HPLC-1, 1-diphenyl-2-picrylhydrazyl assay.

The lack of suitable chromatographic purification methods makes it a challenge to effectively isolate the chemical components of traditional Tibetan medicines. Ribes himalense is a rarely studied Tibetan medicine, reputed to have free radical-scavenging effects. In the present work, we utilized it as a model herb to highlight an approach for the separation of 1,1-diphenyl-2-picrylhydrazyl inhibitors via medium-pressure chromatography and two-dimensional reversed-phase/reversed-phase interaction liquid chromatography under the guidance of an online high-performance liquid chromatography-1,1-diphenyl-2-picrylhydrazyl assay. Finally, we obtained two free radical inhibitors (>95% purity) from the R. himalense extract. This is the first report of the rapid isolation of these free radical inhibitors from R. himalense. This method can be useful in quality standard assessment and further pharmacological activity research, and may be used as a reference for the composition research of various natural products.

A new flavonol acylglycoside from the fruits of Nitraria tangutorum Bobr.

Phytochemical investigation on the ethanol extract of the fruits of Nitraria tangutorum Bobr. led to the isolation of a new flavonol acylglycoside tangutoside (7) and six known ones including p-formylphenol (1), 3-formylindole (2), rutin (3), prionitisid B (4), quercitrin (5) and flazin (6). Among them, compounds 2, 4, and 5 were isolated from Nitraria tangutorum Bobr. for the first time. Their structures were identified by spectroscopic methods and by comparison with data reported in the references. The compounds 3, 4, 5, and 7 were demonstrated to possess strong DPPH radical scavenging ability with IC50 values of 31.45 µg/mL, 19.21 µg/mL, 59.30 µg/mL, and 44.54 µg/mL, respectively.

Identification of phenolic compounds in fruits of Ribes stenocarpum Maxim. By UHPLC-QTOF/MS and their hypoglycemic effects in vitro and in vivo.

The gooseberry (Ribes stenocarpum Maxim. (CBZ)) is a wild and noncommercially cultivated berry fruit widely distributed in the Tibetan Plateau. The phenolic constituents from the berry fruit of CBZ were firstly identified by employing UPLC-QTOF MS. A total of 41 compounds, including hydroxycinnamic acids, hydroxybenzoic acids, flavonols and dihydroflavonol, were identified in view of their molecular weight, characteristic fragment ions and retention times. Further in vitro enzyme assay indicated that CBZ fruit extract could strongly and effectively inhibited a-glucosidase and α-amylase, with the IC50 values of 0.013 mg/mL and 0.005 mg/mL, respectively. In addition, the starch/maltose/sucrose tolerance experiment demonstrated that the CBZ fruit extract could reduce the sucrose mediated postprandial blood glucose (PBG) levels in normal mice, and significantly lower starch/maltose/ sucrose mediated PBG levels in diabetic mice. These results suggested that this berry fruit could be used as a dietary supplement, or drug for the control of hyperglycemia.

Anti-rheumatoid arthritis effects of iridoid glucosides from Lamiophlomis rotata (Benth.) kudo on adjuvant-induced arthritis in rats by OPG/RANKL/NF-κB signaling pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Lamiophlomisrotata (Benth.) Kudo. has been used to treat trauma bleeding, rheumatism, yellow water disease in traditional Chinese medicine. AIM: The aim of this work was to evaluate the anti-rheumatoid arthritis (RA) activities and underlying mechanisms of the total iridoid glucosides (TIG) from Lamiophlomisrotata (Benth.) Kudo. METHODS: The chemical constituents of TIG was analyzed by high-performance liquid chromatography (HPLC) with seven reference compounds (penstemonoside, chlorotuberside, shanzhiside methyl ester, phloyoside, 7-epliamalbide, phlorigidoside C and lamalbide). The anti-rheumatoid arthritis effects of TIG were investigated by arthritis indexes and paw swelling degrees, as well as histopathological and Micro-CT analysis in adjuvant-induced arthritis (AIA) rats. The impacts of TIG on the level of inflammatory cytokines (IL-1ß, TNF-α, IL-6, IFN-γ, IL-17 and IL-10), and the regulation of OPG/RANKL/NF-κB pathways were determined by the ELISA and western blot, respectively. RESULTS: TIG significantly reduced the arthritis indexes and paws swelling in AIA rats, attenuated the inflammation and bone destruction in joint tissues, reduced the generation of pro-inflammatory cytokines IL-1ß, TNF-α, IL-6, IFN-γ and IL-17, as well as increased the generation of anti-inflammatory cytokine IL-10 in serum. Moreover, TIG markedly inhibited the expression of p-IKK-α, p-IκB and p-p65, and decreased the ratio of OPG/RANKL in the synovial tissues. CONCLUSION: TIG possessed significant anti-RA activities on adjuvant-induced arthritis, which might be ascribed to the regulation of inflammatory cytokines IL-1ß, TNF-α, IL-6, IFN-γ IL-17 and IL-10, as well as inhibition of OPG/RANKL/NF-κB signaling pathways.