Applying molecular networking for targeted isolation of depsipeptides.

LC-HRMS/MS molecular networking enabled the targeted isolation of three new neoantimycin analogs (1, 3, 5) and two known ones (2, 4) from the culture broth of Streptomyces conglobatus RJ8. After derivatization into C1-hydroxyl form compounds (6-10) respectively, the absolute structures of 1-5 were clearly determined by analyzing the hydrolyzed components from 6-10. Compounds 2 and 3 were confirmed to be a pair of epimers with different stereochemistry at C-2, and so were 4 and 5. This is the first report of the isolation and characterization of epimers of NATs. The most abundant eight compounds we obtained were subjected to a cytotoxicity assay, 1 and 6 exhibited excellent cytotoxicity with the lowest IC50 value in the picomolar range against six human carcinoma cell lines while 7 and 8 showed potent cytotoxicity against PC-9 and PC-9/GR cell lines.

Corrigendum to "Selection of quality markers of Jasminum amplexicaule based on its anti-diarrheal and anti-inflammatory activities: Effect-target affiliation-traceability-pharmacokinetics strategy" [Chinese Herbal Medicines 11 (2019) 379-386].

[This corrects the article DOI: 10.1016/j.chmed.2019.08.002.].

Flavonoid analogues as urease inhibitors: Synthesis, biological evaluation, molecular docking studies and in-silico ADME evaluation.

A series of novel flavonoid analogues were designed and synthesized. The aimed compounds for urease inhibitory activities were clearly superior to the control drug thiourea (more than 10 times). Among these compounds, L2 (IC50 = 1.343 µM) and L12 (IC50 = 1.207 µM) exhibited the most excellent urease inhibitory activity in vitro. The molecular dockings of L2, L12 and L22 into urease were performed to explore the binding modes and their structure-activity relationship. Furthermore, these aimed compounds showed good druggable properties.

Liver metabolomics study reveals protective function of Phyllanthus urinaria against CCl4-induced liver injury.

Phyllanthus Urinaria L. (PUL) is a traditional Chinese medicine used to treat hepatic and renal disorders. However, the mechanism of its hepatoprotective action is not fully understood. In the present study, blood biochemical indexes and liver histopathological changes were used to estimate the extent of hepatic injury. GC/MS and LC/MS-based untargeted metabolomics were used in combination to characterize the potential biomarkers associated with the protective activity of PUL against CCl4-induced liver injury in rats. PUL treatment could reverse the increase in ALT, AST and ALP induced by CCl4 and attenuate the pathological changes in rat liver. Significant changes in liver metabolic profiling were observed in PUL-treated group compared with liver injury model group. Seventeen biomarkers related to the hepatoprotective effects of PUL against CCl4-induced liver injury were screened out using nonparametric test and Pearson's correlation analysis (OPLS-DA). The results suggested that the potential hepatoprotective effects of PUL in attenuating CCl4-induced hepatotoxicity could be partially attributed to regulating L-carnitine, taurocholic acid, and amino acids metabolism, which may become promising targets for treatment of liver toxicity. In conclusion, this study provides new insights into the mechanism of the hepatoprotection of Phyllanthus Urinaria.

Effect of Y6, an epigallocatechin gallate derivative, on reversing doxorubicin drug resistance in human hepatocellular carcinoma cells.

Cancer cells can acquire resistance to a wide variety of diverse and unrelated drugs, this phenomenon is termed multidrug resistance (MDR). Multidrug resistance has been an obstacle to the success of cancer chemotherapy. The present study investigated the reversal effect of Y6, a new compound obtained by chemically modifying the structure of epigallocatechin-3-gallate (EGCG) extracted from green tea. Y6 was proven to be effective in inhibiting cell proliferation and reversing drug resistance in doxorubicin (DOX) resistant human hepatocellular carcinoma cells (BEL-7404/DOX). BEL-7404/DOX cells were treated with either doxorubicin combination regimen (doxorubicin plus Y6 or epigallocatechin-3-gallate or verapamil separately) or doxorubicin alone. The results showed that cell proliferation was inhibited and late cell apoptosis increased in the combination treatment group, especially in the group treated with doxorubicin plus Y6. Further analysis revealed that the expressions of hypoxia-inducible factor-1α and multidrug resistance 1/P-glycoprotein decreased at both messenger RNA and protein levels by treatments with combined drugs compared to doxorubicin alone. Our results indicated that Y6, as a drug resistance reversal agent, increased the sensitivity of drug resistant cells to doxorubicin. The mechanisms of actions of Y6 in reversal effect were associated with the decreased expression of hypoxia-inducible factor-1α and multidrug resistance 1/P-glycoprotein.

Effect of Phyllanthus amarus Extract on 5-Fluorouracil-Induced Perturbations in Ribonucleotide and Deoxyribonucleotide Pools in HepG2 Cell Line.

The aim of this study was to investigate the antitumor activities of Phyllanthus amarus (PHA) and its potential of herb-drug interactions with 5-Fluorouracil (5-FU). Cell viability, ribonucleotides (RNs) and deoxyribonucleotides (dRNs) levels, cell cycle distribution, and expression of thymidylate synthase (TS) and ribonucleotide reductase (RR) proteins were measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, high performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS) method, flow cytometry and Western blot analysis, respectively. Our standardized PHA extract showed toxicity to HepG2 cells at high concentrations after 72 h exposure and induced G2/M cell cycle arrest. Combined use of 5-FU with PHA resulted in significant decreases in ATP, CTP, GTP, UTP and dTTP levels, while AMP, CMP, GMP and dUMP levels increased significantly compared with use of 5-FU alone. Further, PHA could increase the role of cell cycle arrest at S phase induced by 5-FU. Although PHA alone had no direct impact on TS and RR, PHA could change the levels of RNs and dRNs when combined with 5-FU. This may be due to cell cycle arrest or regulation of key enzyme steps in intracellular RNs and dRNs metabolism.

Effect of a novel synthesized sulfonamido-based gallate-SZNTC on chondrocytes metabolism in vitro.

The ideal therapeutic agent for treatment of osteoarthritis (OA) should have not only potent anti-inflammatory effect but also favorable biological properties to restore cartilage function. Gallic acid (GA) and its derivatives are anti-inflammatory agents reported to have an effect on OA (Singh et al., 2003) [1]. However, GA has much weaker antioxidant effects and inferior bioactivity compared with its derivatives. We modified GA with the introduction of sulfonamide to synthesize a novel sulfonamido-based gallate named sodium salt of 3,4,5-trihydroxy-N-[4-(thiazol-2-ylsulfamoyl)-phenyl]-benzamide (SZNTC) and analyzed its chondro-protective and pharmacological effects. Comparison of SZNTC with GA and sulfathiazole sodium (ST-Na) was also performed. Results showed that SZNTC could effectively inhibit the Interleukin-1 (IL-1)-mediated induction of metalloproteinase-1 (MMP-1) and MMP-3 and could induce the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1), which demonstrated ability to reduce the progression of OA. SZNTC can also exert chondro-protective effects by promoting cell proliferation and maintaining the phenotype of articular chondrocytes, as evidenced by improved cell growth, enhanced synthesis of cartilage specific markers such as aggrecan, collagen II and Sox9. Expression of the collagen I gene was effectively down-regulated, revealing the inhibition of chondrocytes dedifferentiation by SZNTC. Hypertrophy that may lead to chondrocyte ossification was also undetectable in SZNTC groups. The recommended dose of SZNTC ranges from 3.91µg/ml to 15.64µg/ml, among which the most profound response was observed with 7.82µg/ml. In contrast, its source products of GA and ST-Na have a weak effect in the bioactivity of chondrocytes, which indicated the significance of this modification. This study revealed SZNTC as a promising novel agent in the treatment of chondral and osteochondral lesions.

Synthesis and hypoglycemic activity of esterified-derivatives of mangiferin.

AIM: To synthesize three novel esterified-derivatives of mangiferin and evaluate their hypoglycemic activities. METHODS: Acetic, propionic, and butyric anhydride were reacted with mangiferin, respectively. The hypoglycemic activity of the derivatives was evaluated using a hyperglycemic mouse model induced by streptozotocin (STZ), and the islet cells were checked by biopsy inspection. RESULTS: 7, 2', 3', 4', 6'-penta-acetyl-mangiferin (PAM), 3, 6, 7, 2', 3', 4', 6'-hepta-propionyl-mangiferin (HPM) and 3, 6, 7, 2', 3', 4'-hexa-butyryl-mangiferin (HBM) were synthesized and their structures were identified by MS,(1)H, (13)C NMR, and 2D NMR. These three compounds were reported for the first time. PAM group (0.5, 0.25 mmol·kg(-1)), HPM group (0.5, 0.25 mmol·kg(-1)), and HBM group (0.5, 0.25, 0.125 mmol·kg(-1)) mice showed strong hypoglycemic activity (P < 0.01); mangiferin group (1, 0.5 mmol·kg(-1)), PAM group (0.125 mmol·kg(-1)) and HPM group (0.125 mmol·kg(-1)) showed marginal hypoglycemic activity (P < 0.05); mangiferin group (0.25 mmol·kg(-1)) had the potential for a hypoglycemic effect, although it did not demonstrate that statistically. In histological examination, the islet cells of the PAM, HPM, and HBM groups could recover from the STZ damage; islet cells of the mangiferin group could recover also, but less than the esterified-derivative groups. CONCLUSION: Derivatives could repair the damaged islet cells, and had higher lipid-solubility and stronger hypoglycemic activity than mangiferin itself. There existed a structure activity effect, and a solubility effect relationship: the larger esterification moieties, or the higher lipid-solubility, the stronger the hypoglycemic activity (no ester → acetyl → propionyl → butyryl). Esterified derivatives of mangiferin are potential compounds for new anti-diabetes drugs.

[Analysis of compositions of the essential oil from Curcuma aromatica by gas chromatography-mass spectrometry].

OBJECTIVE: To analyze the compositions of the essential oil from the rhizome of Curcuma aromatica in Guangxi. METHODS: The essential oil from the rhizome of Curcuma aromatica was extrated by steam distillation and analysed by GC-MS. RESULTS: 50 chemical constituents accounting for 93.11% of total content were identified. CONCLUSION: The main components are eucalyptol (53.86%), neocurdione (9.89%), linalool (4.24%), camphor (3.14%), alpha-terpineol (2.94%) and germacrone (2.89%).

[Analysis of essential oil from Mahonia duclouxiana].

OBJECTIVE: To analyze the compositions of essential oil from Mahonia duclouxiana. METHODS: The essential oil was extracted by steam distillation, its chemical components were analyzed by GC-MS, and principal component was confirmed by GC. RESULTS: 80 peaks were detected and 41 components have been identified, which made up more than 90% of total essential oil. The major component was 4-Terpineol (43.73%), the other high content components were alpha-Terpineol (5.23%), (Z)-3-Hexen-1-ol (4.78%), Linalool (4.04%), etc. CONCLUSION: The chemical components of essential oil of from Mahonia duclouxiana by GC-MS for the first time. This study provided science basis for further research development of Mahonia duclouxiana.

[Study on the volatile oil of Murraya exotica].

OBJECTIVE: To study the volatile oil of Murraya exotica. METHODS: The volatile oil of Murraya exotica was extracted by steam-stilling and was identified by GC-MS-DS. RESULTS: More than 90 compounds were separated, and 59 compounds were identified, accounting for 93.9% of the total essential oil of Murraya exotica. The major constituents of volatile oil were bicyclogermacrene (26.0%), beta-caryophyllene (20.8%), alpha-caryophyllene (5.8%), delta-cadinene (4.7%), spathulenol (4.3%), trans-alpha-bergamotene (4.1%), germacrene D (3.7%), beta-bisabolene (3.0%), ar-Curcumene (2.5%). CONCLUSION: The major components of Murraya exotica are the terpenoids, including 80.6% of sesquiterpenoids and 11.9% of monoterpenoids. Bicyclogermacrene is identified in Murraya genus for the first time.

Study of the metabolites of bencycloquidium bromide racemate, a novel anticholinergic compound, in rat bile by liquid chromatography-tandem mass spectrometry.

A sensitive and specific liquid chromatographic-electrospray ionization (ESI) tandem ion trap mass spectrometric method has been developed for identification of bencycloquidium bromide (BCQB) and its metabolites in rat bile. Six healthy rats were administrated a single dose (3.0 mg kg(-1)) of BCQB by intraperitoneal (i.p.) injection. The bile were sampled from 0 h to 24 h and purified by using a C(18) solid- phase extraction (SPE) cartridge, then the purified bile samples were separated on a reversed-phase C(18) column using acetonitrile/40 mM ammonium acetate buffer (containing 0.1% formic acid) as mobile phase at gradient elution and detected by an on-line MS(n) detector. Identification and structural elucidation of the metabolites were performed by comparing the changes in molecular weight (Deltam) and full scan MS(n) spectra with those of the parent drug. Eight metabolites (such as hydroxylated and oxidized metabolites) and the parent drug were found in rat bile. Eight metabolites of BCQB were identified and hydroxylated metabolites were the major metabolites. The metabolic pathways of BCQB in vivo are proposed for the first time.

[A new flavonol glycoside from Baeckea Frutescens L].

To study the chemical constituents of the traditional Chinese herb Baeckea Frutescens L., a new flavonol glycoside, named 6, 8-dimethylkaempferol-3-O-alpha-L-rhamnoside (1), together with seven known compounds: quercetin (2), quercetin-3-O-alpha-L-rhamnoside (3), myricetin (4), myricetin-3-O-alpha-L-rhamnoside (5), gallic acid (6), ursolic acid (7) and 1,3-dihydroxy-2-(2'-methoxylpropionyl)-5-methoxy-6-methylbenzene (8) were isolated by using silica gel column chromatography, polyamide column chromatography and recrytallization. Their structures were identified on the basis of physicochemical properties and spectroscopic analysis. Among them, compounds 2-7 were isolated from this plant for the first time and compound 8 was first isolated from plant.

[Study on quality analysis of essential oil from twig and leaf of Baeckea frutescens].

OBJECTIVE: To provide scientific methods for quality criterion by studying the chemical components of essential oil from Baeckea frutescens. METHOD: The chemical components of essential oil from B. frutescens were identified by GC-MS-DS, TLC and capillary GC. The relative contents of main components were determined by area normalization. RESULT: More than 50 peaks were separated, and 38 components were identified, which accounted for over 94% of the total GC peaks areas of the essential oil. The methods for quality evaluation of essential oil from B. frutescens by TLC and capillary GC were established. CONCLUSION: The chemical components of essential oil from B. frutescens collected from different habitats and collecting periods have common characteristics as well as differences. Some components, such as linalool, can be used as a standard and chromatography fingerprint to analyze the quality of essential oil from B. frutescens.