Latest ArticlesBased on the principle of molecular hybridization, fifteen compounds were designed and synthesized through the combination of aminothiazoloxime and phosphonate fragment. The results showed that these compounds had better inhibitory effects on the tested bacteria. In particular, the activities of compounds Ⅲf and Ⅲi against S. aureus, E. coli, methicillin-resistant S. aureus (MRSA) and fluoroquinolone-resistant E. coli (FREC) were the most significant, the minimal inhibitory concentration (MIC) of Ⅲf was 1, 8, 4, 16 μg·mL-1 respectively, and the MIC of Ⅲi was 4, 4, 16, 8 μg·mL-1 respectively, which were slightly lower than that of the control drug oxacillin, and their anti-E. coli, MRSA and FREC activities were superior to that of the control drug oxacillin. Their activities to S. aureus were close to that of oxacillin, and to E. coli, MRSA and FREC were superior to that of oxacillin, which is worthy of further study.
A novel pair of Z/E isomeric compounds with unprecedented carbon skeleton were isolated from an aqueous extract of Aspongopus chinensis Dallas by macroporous resin, silica gel, and semi-preparative high performance liquid chromatography (HPLC). Their structures were identified by nuclear magnetic resonance (NMR), Infrared spectroscopy (IR), Mass spectroscopy (MS) and other spectroscopic methods as (Z)-3-(but-1″-en-1″-yl)-1-(2ʹ-hydroxyethyl)-4-propylpyridin-1-ium, namely aspongopyridine A, and (E)-3-(but-1″-en-1″-yl)-1-(2ʹ-hydroxyethyl)-4-propylpyridin-1-ium, namely aspongopyridine B, respectively. Besides, the anti-inflammatory, anti-tumor, acetylcholinesterase inhibition and butyrylcholinesterase inhibition activities of the compounds 1 and 2 were evaluated. The results showed that compounds 1 and 2 have no anti-inflammatory, anti-tumor, and butyrylcholinesterase inhibition activities instead of weak acetylcholinesterase inhibition activity.
Thirty-one phenolic constituents were isolated and purified from the 95% ethanol extract of Sanguisorbae Radix by using various chromatographic techniques, including macroporous resin, silica gel, ODS, Sephadex LH-20 and semi-preparative HPLC. Their structures were elucidated by physicochemical properties, spectroscopic data (MS and NMR) and electronic circular dichroism (ECD) spectra, and identified as 3-methoxyl-2S, 3S-epoxyflavanone (1a), 3-methoxyl-2R, 3R-epoxyflavanone (1b), longifoin B (2), longifoin C (3), eriodictyol (4), naringenin (5), liquiritigenin (6), 5, 3ʹ-dihydroxy-7, 4ʹ-dimethoxyflavanone (7), naringenin-7-O-β-D-glucopyranoside (8), dihydroquercetin (9), dihydrokaempferol (10), (-)-garbanzol (11), (2R, 3R)-4-methoxyl-distylin (12), kaempferol (13), quercetin (14), α, 4, 2′, 4′-tetrahydroxydihydrochalcone (15), phloretin (16), (+)-catechin (17), ethyl (+)-cyanidan-3-ol-8-carboxylate (18), phyllocoumarin (19), methyl 3-methoxy-4, 5-dihydroxybenzoate (20), 4, 5-dimethoxy-3-hydroxybenzoic acid methyl ester (21), 3, 4′-di-O-methylellagic acid (22), 3, 4, 3′-O-trimethylellagic acid (23), 3, 3ʹ, 4ʹ-O-trimethylellagic acid-4-O-β-D-xyloside (24), (3R)-thunberginol C (25), resveratrol (26), 1-hydroxypinoresinol (27), (7S, 8S)-3-methoxy-3′, 7-epoxy-8, 4′-oxyneoligna-4, 9, 9′-triol (28), emodin-8-O-β-D-glucoside (29), phloracetophenone (30) and 4-(4′-hydroxyphenyl)-butan-2-one (31). Among them, compound 1a and 1b is a pair of new flavonoid enantiomers, compounds 2 and 3 are a pair of new epimers, while compounds 4, 5, 6, 9, 10, 13, 16 and 26 were obtained from S. officinalis for the first time, compounds 7, 8, 27, 30 and 31 were isolated for the first time from the S. officinalis genus, and compounds 11, 12, 15, 18, 19, 25, 28 and 29 were isolated for the first time from the Rosaceae. The antioxidant activities of compounds 1-24 were evaluated by activating the Nrf2 transcriptional pathway, which were measured by the dual-luciferase reporter gene assay in 293T cells. Compounds 4, 6-10, 12, 14, 17, 19, 20 and 22-24 showed significant Nrf2 agonistic effect compared with the control group at 25 μmol·L-1, which provided reference for the research of their antioxidant activity.
Four pyrazines were isolated from the n-butanol fraction of Hypecoum erectum L. by using various chromatographic methods, including MCI gel, ODS, silica gel and semi-preparative HPLC. The structures of the isolated compounds were identified as hyperectpyrazin A (1), 1′S-(6-methylpyrazin-2-yl)-ethane-1′, 2′-diol (2), 2-hydroxymethyl-6-methylpyrazin (3) and pyrazine-2-carboxylic acid (4) by spectroscopy methods (1D NMR, 2D NMR, UV, IR, MS, etc.). The absolute configuration of compound 2 was determined by using the Mo2(OAc)4 induced CD analysis for the first time. Compound 1 was a new compound, compounds 2-4 were isolated from H. erectum for the first time. Compounds 1-4 were evaluated for their inhibition against acetylcholinesterase and nitric oxide generation induced by lipopolysaccharide-RAW264.7 macrophage cells. At a concentration of 50 μmol·L-1, compounds 2 and 4 displayed inhibitory effects on acetylcholinesterase with the inhibition rates of 44.40% and 43.99%, respectively.
The correct pairing of disulfide bonds maintains the correct folding mode and high-level structure formation of peptides and protein drugs, which is crucial for the quality control of products. In order to ensure that the disulfide bonds are correctly paired, disulfide bond analysis is an essential part of peptides and protein drug characterization. Mass spectrometry can be used to analyze disulfide bonds. However, insulin and its analogues have two pairs of disulfide bonds without restriction enzyme cutting site. Conventional collision-induced dissociation (CID) and high-energy induced cleavage (HCD) cannot accurately locate the complex disulfide bond. In our study, three methods were used to localize the complex disulfide, including enzyme digestion combined with key peptide fragment in source decay (ISD) fragmentation method, enzyme digestion combined with partial reduction alkylation method, intact protein source ISD and electron transfer dissociation (ETD) cleavage method, The applicability of insulin aspart, insulin lispro and insulin glargine were also investigated. This study provides a new way for the quality control of disulfide bonding mode of insulin and its analogues, and also provides a reference for the disulfide bond localization of peptides or proteins containing this complex disulfide bond.
To establish and optimize a method for the detection of recombinant human midkine (rhMK) activity and verify its methodology, cell counting kit-8 (cck-8) method was used to measure the proliferation activity of rat knee chondrocytes. The specificity, accuracy, precision, linearity and robustness of the method were also verified in this study. The established method was proven to have good specificity because the buffer of rhMK and recombinant human interleukin-1 receptor antagonist have no obvious active effect; the recoveries of the samples with relative activities of 50%, 75%, 100%, 125%, 150% were in the range of 80.0% to 124.0% by statistical analysis, the relative standard deviations (RSD) of relative potency were all within 20%, the linear correlation coefficient, R2 ≥ 0.98, suggesting that the accuracy, precision and linearity of the method were good; the robustness correlation coefficient, R2 ≥ 0.92 and the ratio of maximum to minimum of sigmoidal dose-response were no less than 1.5, indicating that robustness of the methods was good. In conclusion, a bioactivity measurement method for rhMK was established and fully validated in this study and it provides a reliable method for the bioactivity analysis of rhMK routine samples during the development. This study was approved by the Animal Care and Use Committee of Shanghai Model Organisms Center, Inc. (approval number: 2019-0008-06).
This study aimed to identify the related substances of phloroglucinol injection by two-dimensional liquid chromatography quadrupole time-of-flight mass spectrometry (2D-LC-Q-TOF/MS). The first-dimensional separation was carried out on an HSS T3 (250 mm × 4.6 mm, 5 μm) column by gradient elution using 1.36 g·L-1 potassium dihydrogen phosphate buffer solution (pH adjusted to 3.0 with diluted phosphoric acid) and acetonitrile as the mobile phases. The separated components were then trapped in switch valve tube lines respectively and delivered to the second-dimensional desalting gradient elution which was performed with a BDS C18 (100 mm × 4.6 mm, 2.4 μm) column using 0.1% formic acid and methanol as the mobile phases. After rapid desalting, electrospray-ionization quadrupole time-of-flight high resolution mass spectrometry was used for determining the accurate masses and elemental compositions of the parents and their product ions for both phloroglucinol and its related substance. Structures of the related substances were then figured out by mass spectrometry elucidation, organic reaction mechanism analysis, and/or comparison with reference substances. Under the established analytical conditions, phloroglucinol and its related substances were adequately separated, 17 main related substances were detected and identified in the injection and its stressed samples for the first time. The identification results can provide reference for the quality control of phloroglucinol injection.
Based on UPLC-Q-orbitrap-MS and biological network analysis tools, the mechanism of Xihuang Pill in improving hyperplasia of mammary glands was systematically analyzed. The rat model of hyperplasia of mammary glands was established by intramuscular injection of estradiol benzoate and progesterone. LC-MS tissue metabolomics was used to explore the key metabolites and metabolic pathways of Xihuang Pill in improving hyperplasia of mammary glands in rat. The network analysis of the key metabolites regulated by Xihuang Pill was carried out by integrating biological network analysis tools, focusing on the key metabolic pathways, and exploring the potential targets of Xihuang Pill to improve hyperplasia of mammary glands. Compared with the control group, there were significant differences in the content of 49 differential metabolites in the tissues of the model group (P < 0.05). Xihuang Pills could significantly call back 17 metabolites such as L-alanine, threonine, indole-3-carboxylic aldehyde, lysine, arginine, alanylleucine, glycyltyrosine, γ-glutamyl leucine, vitamin B3, serine leucine, threonine leucine, isoleucine glutamic acid, γ-glutamyl tyrosine, decanoyl-L-carnitine, uric acid, leucylleucine, S-adenosyl-methionine. Further network analysis and literature research on the key metabolites regulated by Xihuang Pills showed that the AGE-RAGE signaling pathway may be one of the important pathways for Xihuang Pills to improve hyperplasia of mammary glands. STAT3, MAPK1, EGFR, CASP3, CASP8, PRKCA and JUN in the AGE-RAGE signaling pathway may be potential targets for Xihuang Pills to improve hyperplasia of mammary glands. The animal experiment operations involved in this paper follow the provisions of the Animal Ethics Committee of Gansu University of Traditional Chinese Medicine and pass the ethical review of animal experiments (approval number: 2022-705).
Hydrogen peroxide (H2O2) and nitric oxide (NO) has a short half-life, low bioavailability, poor tumor targeting and systemic adverse reactions in the physiological environment. In this study, phacoemulsification and nano-precipitation were used to synthesize didecyl dimethyl ammonium bromide (DDAB)/polylactic acid nanoparticles (PLA), then L-arginine (L-Arg) and glucose oxidase (GOx)-loaded nanoparticles (GADP) were prepared, and the in vitro antitumor activity was investigated.The particle size, potential, embedding rate and the ability to produce H2O2/NO of the nanoparticles were investigated. Meanwhile, in vitro cell cytotoxicity against human hepatoma cells (HepG2) was evaluated.The results showed that the prepared L-Arg-DDAB/PLA (ADP) nanoparticles were spherical particles. And the particle size and zeta potential were (225.7 ± 6.33) nm and (+23.5 ± 0.12) mV, respectively. The adsorption rate of GOx was 87.23% ± 0.02%. The drug loading of L-Arg was 15.6% ± 0.22%. The pH value of glucose solution and the amount of H2O2 showed that GADP had good catalytic activity. In vitro cytotoxicity experiments showed that blank nanoparticles were nontoxic, while the drug-loaded nanoparticles presented enhanced antitumor effect on HepG2 cells. And can inhibit tumor cell migration. The low dose nano-scale NO delivery system GADP can effectively inhibit the migration of tumor cells and kill tumor cells, thus producing therapeutic benefits.
To optimize the formulation and technology of oxymatrine-astragaloside Ⅳ coloaded liposomes (Om-As-Lip) based on quality by design (QbD) principles, and further to verify the feasibility of its amplification process, Om-As-Lip was prepared by ethanol injection combined with pH gradient method. The critical material attributions of Om-As-Lip were evaluated by dual-risk analysis tools and Plackett-Burman design (PBD). The formulation of Om-As-Lip was further optimized with the Box-Behnken design (BBD). The design space was also established based on the contour plots of BBD. In order to further investigate the amplification process of Om-As-Lip, the critical process parameters of high-pressure homogenization (HPH) were optimized by single-factor test, and the quality of the final product was also evaluated. The results of risk analysis and PBD confirmed that the astragaloside concentration, cholesterol concentration, and phospholipid ratio (HSPC∶SPC) were the ctitical material attributes. The model established by BBD had a good predictability, and the optimized mass ratio of As to phospholipids was 1∶40, cholesterol to phospholipids was 1∶10, HSPC to SPC was 51∶9. The design space of Om-As-Lip was as follows: the ratio of cholesterol to phospholipids was 1∶12-1∶5 and HSPC to SPC was 1∶7-17∶3. The optimized high-pressure homogenization pressure was 600 bar, temperature was 4 ℃, and cycle times was 6 times for HPH-Om-As-Lip. The quality of Om-As-Lip prepared based on the QbD concept can meet the expected CQAs, and the formulation and technology established can provide a reliable experimental basis for its future development and applications.