Discovery and structural optimization of 9-O-phenylsulfonyl-berberines as new lipid-lowering agents.

Berberine is a quaternary isoquinoline alkaloid that exhibits potent hypoglycemic and hypolipidemic activity. Many medicinal chemists are currently working on structural modifications around the parent scaffold of berberine, expecting to further enhance its hypolipidemic activity and reducing its cytotoxicity. In this study, a focused berberine-like compound library containing 12,600 molecules was built via the introduction of various "drug-like" fragments at the C8 and C9 positions of berberine. Sixteen comopounds were hit by using the in-house QSAR models previously reported by our group. Considering synthesis feasibility and the cost of building-blocks, only four berberine analogs (library ID: 2028, 3847, 6033, and 12456) were selected and synthesized for investigating their lipid-lowering activities. Preliminary lipid-lowering study showed that compound 12456 with the phenylsulfonyl group at the C9 position had potent cholesterol inhibitory activity in HepG2 cells, superior to that of the parent compound berberine. Subsequently, a total of twenty-five 9-O-phenylsulfonyl-berberines (1a-1y) and twenty-four 9-O-phenylsulfonyl-tetrahydroberberine (2a-2x) were designed, synthesized, and evaluated by lipid-lowering experiments. The results displayed that most compounds exhibited more lipid-lowering activities than berberine. Among them, compound 1m inhibited cholesterol production close to 50% in both cell models when compared with the blank control; the inhibition of triglycerides exceeded 70%. Moreover, 1m also had significant pharmacological effects on the inhibition of LDLC and promotion of HDLC production, especially in the HepG2 cell model, in which the inhibitory rate against LDLC was close to 70% and the increase rate of HDLC was more than 75%. The hypolipidemic experiment of SD rats demonstrated that after 40 days of administration (1m, 15 mg/kg/d), blood cholesterol was reduced by 19.6%, triglycerides reduced by 34.52%, and LDLC reduced by 41.49%, when compared with the high-fat diet model (HFD). In addition, after 80 days of administration, the three indexes of 1m were still better than that of berberine. Oil Red O staining and H&E staining results showed that 1m exhibited potent lipid scavenging activity. All in all, 1m was discovered and identified as a potent lipid-lowering agent and a new berberine-like candidate, being evaluated by subsequent studies.

Discovery of C-9 Modified Berberine Derivatives as Novel Lipid-Lowering Agents.

Berberine (BBR), a kind of quaternary ammonium benzylisoquinoline alkaloids with multiple pharmacological activities, has been regarded as a promising lipid-lowering agent in the field of drug repurposing. Particularly, the chemical modification at the C-9 position of BBR can remarkably improve its lipid-lowering efficacy. In this study, thirteen novel BBR derivatives were rationally designed, synthesized, and evaluated by preliminary pharmacological tests. The results showed that most compounds exhibited more potent hypolipidemic activities when compared with BBR and simvastatin. Among these compounds, compound 2h-1 and 2h-2 exhibited better activity profiling in these four tests involving with inhibition of total cholesterol (TCHO), triglyceride (TG), and low-density lipoprotein cholesterol (LDLC) and the increase of high-density lipoprotein cholesterol (HDLC). Correspondingly, the BBR analogs with 9-O-cinnamic moiety probably exhibited potent lipid-lowering activity, and should be exploited as an important versatile template for the development of BBR-like lipid-lowering agents.

Structural Optimization of Caffeoyl Salicylate Scaffold as NO Production Inhibitors.

Chlorogenic acid (CGA) has been considered as one of important active components in a number of medicinal herbs. Recently our group demonstrated that caffeoyl salicylate scaffold derived from CGA can be employed for the development of novel anti-inflammatory agents. The most active compound D104 can be a very promising starting point for the further structural optimization. A series of novel caffeoyl salicylate analogs were designed, synthesized, and evaluated by preliminary biological evaluation. The obtained results showed that the two compounds B12 and B13 can not only inhibit production of nitric oxide (NO) in RAW264.7 cells induced by lipopolysaccharides (LPS) effectively, but also have high safety in in vitro cytotoxic test, which could be comparable with D104. Molecular docking study on the peroxisome proliferator-activated receptor γ (PPARγ) protein revealed that compounds B12 and B13 can follow the same binding mode with D104, and the carboxyl group of caffeoyl salicylate scaffold might play a key role in the interaction with protein target, which implied the carboxyl group should be retained in the further optimization.

RNA-Seq analysis and comparison of the enzymes involved in ionone synthesis of three cultivars of Osmanthus.

To comprehend the molecular mechanisms that control the differences in the composition of Osmanthus essential oils, the RNA-seq data and differentially expressed genes in different cultivar Osmanthus were studied. cDNA libraries of "jinqiugui," "baijie," and "rixianggui" were sequenced using Illumina HiSeq TM 2000. All of the enzymes involved in ionone synthesis were verified. DEGs were revealed and their enriched pathways were analyzed. A total of 20 DEGsencoding four enzymes that were potential candidates involved in ionone biosynthesis, as well as ispH, GPPS, ZDS, and CCD. It provided a way for Osmanthus oil monomer material to be synthesized in vitro.

[Comparison of three different thermophilic beta-glucosidases for baicalin transformation].

Three different beta-glycosidase sequences of Ttebgl3, Tpebgl1 and Tpengl3 from Thermotoga thermarum DSM 5069 and Thermotoga petrophila RKU-1 were analyzed. Also, the influence of temperature, pH, concentration of DMSO, metal ions and kinetic constant on catalytic conversion of baicalin had been compared. The results indicated that the optimal pH and optimum temperature for transformation of baicalin was 4.5 85 °C, 5.0 80 °C and 5.5 80 °C, respectively. The family GH3 beta-glycosidase Ttebgl3 and Tpebgl3 had the better DMSO tolerance. The activation effect of the metal ions on the catalytic conversion of baicalin was not obvious, and the inhibition of the GH3 family beta glucosidase was significantly stronger than that of the GH1 family. The kinetic constants of three different beta-glucosidases catalyzed baicalin were significantly different. The Km and Vmax values of Tpebgl1, Tpebgl3 and Ttebgl3 were 0.029 2 mmol·L⁻¹ 4.85 U·mg⁻¹, 0.268 6 mmol·L⁻¹ 121.04 U·mg⁻¹ and 0.391 8 mmol·L⁻¹ 308.90 U·mg⁻¹, respectively. Family GH3 beta-glycosidase converted more baicalin than family GH1 with the optimal conditions, 0.02 g baicalin, and the conversion rate was 68%, 97.3%, 97.31% respectively. The results of the study provided a guarantee for the transformation of baicalin.

[Preparation of baicalein using thermophilic and sugar-tolerant beta-glucosidase].

The reaction conditions of baicalin hydrolyzed into baicalein by a kind of thermophilic and sugar-tolerant beta-glucosidase were studied in this paper. The beta-glucosidase could catalyze baicalin into baicalein well in the acetic acid-sodium acetate buffer. The optimal enzyme activity was at 85 degrees C and pH 5.5. The enzyme was stable at the temperature less than 85 degrees C and pH range of 5-7.5. The maximum reaction rate V. and michaelis constant K. were 0.41 mmol x L(-1) x min(-1) and 3.31 mmol x L(-1) respectively. Different metal ions had different effects on the activity of enzyme. Na+ existing in acetic acid-sodium acetate buffer had an activation effect on enzyme. The enzyme activity was enhanced by the concentrations of glucose below 0.6 mol x L(-1), and was gradually inhibited when monosaccharide concentration was over 0.6 mol x L(-1). When the monosaccharide concentration reached 1.2 mol x L(-1), the inhibition rate of enzyme activity was about 50%, which showed good glucose tolerance. The good reaction conditions through the experiment have been determined as follows, the substrate: enzyme dose was 1 g: 0.2 mL, acetic acid-sodium acetate buffer pH 5.5, reaction temperature 85 degrees C, reaction time 10 h, and the enzymatic hydrolyzation ratio could reach 97%.

Design, synthesis, and biological activity of 9-O-cinnamoylberberines as novel lipid-lowering agents.

Berberine possesses a wide spectrum of lipid regulation, and yet it has poor physicochemical property and cytotoxicity as a drug candidate. In order to alleviate the problems, a total of twenty-one 9-O-cinnamoylberberines and twenty 9-O-cinnamoyltetrahydroberberines were designed, synthesized, and evaluated by in vitro cell viability experiment and four classical lipid-lowering assays involving with total cholesterol, triglyceride, low density lipoprotein cholesterol, and high density lipoprotein cholesterol. A structure-activity relationship study of these compounds resulted in the discovery of two promising candidate molecules (5p and 7u). Compound 5p displayed the most potent inhibitory effect for TG formation, with the inhibitory rates of 40.5% and 76.8% in 3T3-L1 cells and HepG2 cells, respectively. Compound 7u exhibited the most promoting activity for the production of HDLC, with the increasing rates of 52.6% and 70.5% in both models, respectively. These two attractive compounds can be further investigated as new lipid-lowering agents in follow-up researches.

A patent review of berberine and its derivatives with various pharmacological activities (2016-2020).

INTRODUCTION: Berberine (BBR), as one of the outstanding representatives of isoquinoline alkaloids, has been used as an antibacterial drug for a long time in China since ancient times. Currently, a large number of studies have been reported that berberine has a wide spectrum of pharmacological activities, such as anti-tumor, anti-inflammatory, hypoglycemic, hypolipidemic, anti-obesity, and the like. AREAS COVERED: This review systematically discussed important patents on berberine and berberine derivatives in terms of pharmacological activity between 2016 and 2020. These patents were mainly searched through the European Patent Office database and Web of Science. These berberine patents (~41) cover a wide range of applications, mainly including antitumor, anti-inflammatory, antibacterial, anti-metabolic disorder, and other newly reported pharmacological activities. EXPERT OPINION: Berberine is an important lead compound with great potential for optimization in drug development. However, there is a lack of research related to the biomolecular targets of BBR, which directly restricts the development of berberine in the pharmaceutical field. The problems involved with poor bioavailability and cytotoxicity are also worth considering in the development of berberine-based drugs. Accordingly, the increasing number of patents involving biomolecular targets in BBR's patent applications will be published as its related pharmacological mechanisms are further deciphered.

Cloning, Overexpression, and Characterization of a Thermostable, Organic Solvent-Tolerant Laccase from Bacillus pumilus ARA and Its Application to Dye Decolorization.

A thermostable and organic solvent-tolerant bacterial laccase from Bacillus pumilus ARA has been expressed heterologously and characterized, which shows potential decolorization capacity to various types of industrial synthetic dyes. The optimal temperature and pH were 85 °C and 3.5, respectively, while the purified recombinant laccase B.P.Lacc was stable under 55-75 °C and pH 5.0-8.0 conditions. The apparent kinetic parameters K m and V max of B.P.Lacc for ABTS as the substrate were 0.33 mM and 32.4 U/mg, respectively. Ethanol (1%, v/v) and methanol (2%, v/v) could stimulate the enzyme activity. The recombinant laccase retained over 95% of its initial activity in 10% (v/v) methanol. The optimal expression conditions for the laccase production of B.P.Lacc in LB medium were obtained: induction temperature of 25 °C, 0.4 mM Cu2+, and 1.0 mM IPTG added into the culture. After 5 h, the final laccase production was 1283 U/mL. Moreover, the laccase activity increased to 4822 U/mL after follow-up 2 h stationary cultivation, with about a 3.76-fold increase. The purified B.P.Lacc was able to efficiently decolorize synthetic dyes combined with mediators. Adding 1.0 mM ABTS, more than 90% of BRRB was decolorized by the enzyme, whether at pH 4.0 or pH 7.9. The outstanding enzymatic properties suggested that B.P.Lacc may be suitable for a wide application in future biodegradation fields.

Berberine: A Promising Natural Isoquinoline Alkaloid for the Development of Hypolipidemic Drugs.

Berberine, as a representative isoquinoline alkaloid, exhibits significant hypolipidemic activity in both animal models and clinical trials. Recently, a large number of studies on the lipid-lowering mechanism of berberine and studies for improving its hypolipidemic activity have been reported, but for the most part, they have been either incomplete or not comprehensive. In addition, there have been a few specific reviews on the lipid-reducing effect of berberine. In this paper, the physicochemical properties, the lipid-lowering mechanism, and studies of the modification of berberine all are discussed to promote the development of berberine as a lipid-lowering agent. Subsequently, this paper provides some insights into the deficiencies of berberine in the study of lipid-lowering drug, and based on the situation, some proposals are put forward.

Molecular Dynamics Analysis of Binding Sites of Epidermal Growth Factor Receptor Kinase Inhibitors.

The development of an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) is an ongoing and challenging research field. However, the dynamic motion of the binding site of EGFR has not been accurately depicted, hindering the improvement of EGFR TKI. For this reason, about 33 protein complexes (32 EGFR proteins plus 1 ErbB4 protein) were carefully curated and subsequently studied for dynamic movements of their binding sites by molecular dynamics simulations in this study. The analysis of root mean square deviation (RMSD) revealed that T790M mutation can make an impact on dynamic motion of binding sites; the RMSD value of the EGFR binding site was unrelated to inhibitory activity. The analysis of the radius of gyration (R g) revealed that T790M can slightly shrink the value of R g, thereby influencing the shape of the EGFR binding site. More interestingly, the R g value can exhibit weak correlation with inhibitory activity of most inhibitors. The relationship between R g and biological activity deserve our serious interest since the best scoring function, Xscore, cannot distinguish highly active EGFR inhibitors. The root mean square fluctuation (RMSF) analysis of key residues derived from binding sites indicated that the most flexible residue was ASP800 with a large RMSF value against the steady residue ALA743 with a small RMSF value, and two other residues (MET793 and LEU844) were supposed to be involved with molecular recognition. In short, the obtained results would be more effective for guiding the development of a novel EGFR kinase inhibitor.

Discovery of 7,9-Disulfatetrahydroberberine as Novel Lipid-Lowering Agents.

Berberine (BBR), a well-known alkaloid, exhibits various pharmacological activities, especially hypolipidemic activity, which has attracted much interest from medicinal chemists in the past decade. However, little progress was made on the structural modification of BBR for improving lipid-lowering activity, mainly due to its unclear biological target and low safety. In this study, a new scaffold of 7,9-disulfatetrahydroberberine was discovered unexpectedly, provided with extremely low cytotoxicity. Hence, a novel series of highly safe 7,9-disulfatetrahydroberberines were designed, synthesized, and evaluated for their hypolipidemic activities. In order to investigate the significance of the 9-position substituent, another new series of 7-sulfatetrahydroberberines were designed and synthesized. Lipid-lowering experiments showed that among these compounds, 5f exhibited the best lipid-lowering activity based on two cell models, 3T3-L1 cells and HepG2 cells. Compared with the blank control, the inhibition rate of compound 5f against total cholesterol was over 60%, the inhibition rate against triglyceride was over 70%, the inhibition rate against low-density lipoprotein cholesterol was approximately 75%, and the inhibition rate against high-density lipoprotein cholesterol was close to 50%, which were far superior to the positive control BBR. This result also verified the feasibility of the development of BBR as a lipid-lowering drug via disubstituted modification at the 7- and 9-position.

Structures and bioactivities of seven flavonoids from Osmanthus fragrans 'Jinqiu' essential oil extraction residues.

Osmanthus fragrans are well-known for their fragrance, but it is wasteful if to discard O. fragrans flower after extracting their essential oils. In this paper, we found that O. fragrans flower residues were rich in flavonoids. Six flavonoids and one phenylethanoid glycoside were isolated from the ethanol extract of O. fragrans flower residues, identified as quercetin (1), rutin (2), verbascoside (3), genistin (4), kaempferol (5), isorhamnetin (6) and naringin (7). In bioactivity study, kaempferol (IC50 = 1.43 µg/mL) showed the best anti-inflammatory activity. Isorhamnetin, quercetin, kaempferol, verbascoside and rutin (the values of IC50 were 18.30, 11.05, 16.88, 20.21 and 22.76 µg/mL, respectively) showed excellent DPPH free radical scavenging activity. Verbascoside performed relatively well at inhibiting the growth of both CT26 colonic carcinoma cells (IC50 = 46.87 µg/mL) and HepG2 hepatocarcinoma cells (IC50 = 30.58 µg/mL). In addition, quercetin and kaempferol showed strong anti-proliferation activity against HepG2 cells.

Consensus scoring model for the molecular docking study of mTOR kinase inhibitor.

The discovery of mammalian target of rapamycin (mTOR) kinase inhibitors has always been a research hotspot of antitumor drugs. Consensus scoring used in the docking study of mTOR kinase inhibitors usually improves hit rate of virtual screening. Herein, we attempt to build a series of consensus scoring models based on a set of the common scoring functions. In this paper, twenty-five kinds of mTOR inhibitors (16 clinical candidate compounds and 9 promising preclinical compounds) are carefully collected, and selected for the molecular docking study used by the Glide docking programs within the standard precise (SP) mode. The predicted poses of these ligands are saved, and revaluated by twenty-six available scoring functions, respectively. Subsequently, consensus scoring models are trained based on the obtained rescoring results by the partial least squares (PLS) method, and validated by Leave-one-out (LOO) method. In addition, three kinds of ligand efficiency indices (BEI, SEI, and LLE) instead of pIC50 as the activity could greatly improve the statistical quality of build models. Two best calculated models 10 and 22 using the same BEI indice have following statistical parameters, respectively: for model 10, training set R2=0.767, Q2=0.647, RMSE=0.024, and for test set R2=0.932, RMSE=0.026; for model 22, raining set R2=0.790, Q2=0.627, RMSE=0.023, and for test set R2=0.955, RMSE=0.020. These two consensus scoring model would be used for the docking virtual screening of novel mTOR inhibitors.

Design, synthesis, and anti-inflammatory activity of caffeoyl salicylate analogs as NO production inhibitors.

Chlorogenic acid (CGA) has been reported to exhibit potent anti-inflammatory activity. However, the development of anti-inflammatory agent based on CGA has not been investigated. In this paper, a series of caffeoyl salicylate compounds derived from CGA were designed, synthesized, and evaluated by LPS-induced nitric oxide synthase inhibition and QRT-PCR technique. Most compounds showed modest activity to inhibit production of nitric oxide (NO) in RAW 264.7 cells induced by lipopolysaccharides (LPS). Among these compounds, QRT-PCR and western blotting results indicated that compounds 6b, 6c, 6f, 6g and D104 that possess 5-member ring or 6-member ring caused a significant inhibition against expression of the iNOS2 in LPS-induced macrophages. In addition, cytotoxic assay displayed most derivatives have good safety in vitro. This new promising scaffold could be further exploited for the development of anti-inflammatory agent in the future.

High-level expression of recombinant thermostable ß-glucosidase in Escherichia coli by regulating acetic acid.

In the fermentation progress, fermentation parameters including the feed rate, induction temperature, and induction pH evidently regulate the accumulation of acetic acid generated by recombinant E. coli in the medium. The production of thermostable ß-glucosidase (Tpebgl3) was increased by optimizing the parameters mentioned step by step. The optimal conditions were obtained with the highest enzyme expression (560.4U/mL) and the maximum DCW (65g/L) at the pre-induction specific growth rate of 0.2h-1 followed by a post-induction specific growth rate (0.18h-1); induction temperature is 39°C; the pH is 7.2; the concentration of acetic acid was maintained all along below 0.9g/L. Results show it is necessary for the synthesis of Tpebgl3 to regulate the accumulation of acetic acid at the premise of feeding to meet the normal growth of E. coli. The production of Tpebgl3 by recombinant E. coli is the highest reported to date.

Combined Molecular Docking, 3D-QSAR, and Pharmacophore Model: Design of Novel Tubulin Polymerization Inhibitors by Binding to Colchicine-binding Site.

Interference with dynamic equilibrium of microtubule-tubulin has proven to be a useful tactics in the clinic. Based on investigation into the structure-activity relationship (SAR) studies of tubulin polymerization inhibitors obtained from several worldwide groups, we attempted to design 691 compounds covering several main heterocyclic scaffolds as novel colchicine-site inhibitors (CSIs). Evaluated by a series of combination of commonly used computer methods such as molecular docking, 3D-QSAR, and pharmacophore model, we can obtain the ultimate 16 target compounds derived from five important basic scaffolds in the field of medicinal chemistry. Among these compounds, compound A-132 with in silico moderate activity was synthesized, and subsequently validated for preliminary inhibition of tubulin polymerization by immunofluorescence assay. In additional, the work of synthesis and validation of biological activity for other 15 various structure compounds will be completed in our laboratory. This study not only developed a hierarchical strategy to screen novel tubulin inhibitors effectively, but also widened the spectrum of chemical structures of canonical CSIs.