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.

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.

[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.

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.

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.

[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%.