Design,synthesis and the evaluation of cholinesterase inhibition and blood-brain permeability of daidzein derivatives or analogs

In the present study, a series of derivatives and analogs of daidzein were designed and synthesized to investigate cholinesterase inhibition and blood–brain barrier permeability. The enzyme assay showed that most of the compounds containing a tertiary amine group exhibit moderate cholinesterase inhibition, 7-hydroxychromone derivatives (absence of B ring of daidzein scaffold) only have a weaker bioactivity, while those compounds without the tertiary amine group have no bioactivity. Among them compound 15a (4’-N,N-dimethylaminoethoxy-7-methoxyisoflavone) appeared the best inhibitory activity (IC₅₀: 2.14 ± 0.31 μmol/L) and higher selectivity for AChE over BuChE (Ratio: 7.07). It was selected for the further investigation by UPLC-MS/MS. The results show that C_Brain/Serum of compound 15a in mice was more than 2.87 within 240 min. This discovery may provide worthy information for the future development of central nervous drugs including but not limited to cholinesterase inhibitors.     

Recent advances with alkaline phosphatase isoenzymes and their inhibitors

Alkaline phosphatases are found in different living species and play crucial roles in various significant functions, such as hydrolyzing a variable spectrum of phosphate-containing physiological compounds, contributing to DNA synthesis, bone calcification, and attenuation of inflammation. They are homodimeric enzymes; each subunit contains one magnesium ion and two zinc ions crucial for the catalytic activity of the enzyme. Alkaline phosphatases exist in four distinct isoenzymes (placental, intestinal, germ cell, and tissue nonspecific alkaline phosphatases), which are expressed by four different genes; each one of them has distinguished functions. Any disturbance in the gene expression of alkaline phosphatase eventually induces serious disease conditions. Thus, the need to explore new lead inhibitors has increased recently. In this literature review, we aim to investigate the role of alkaline phosphatase in different diseases and physiological conditions and to study the structure–activity relationships of recently reported inhibitors. We focused on the lead compounds reported in the last 5 years (between 2015 and 2019).     

石杉碱类似物在体外对胆碱酯酶的抑制作用(英文)

用比色法测试表明,14个半合成类似物的抗AChE作用均弱于Hup-A,左旋二氢及四氢类似物的抗BuChE作用稍强于Hup-A,前者属混合型抑制剂,K_i值为0.12μmol·L~(-1)。后者属竞争型抑制剂,K_i值为0.56μmol·L~(-1)。二者不同于异氟磷,与AChE为可逆性结合。     

Synthesis and antioxidant activity of curcumin analogs

Numerous biological activities including antioxidant, antitumor, anti-inflammation, and antivirus of the natural product curcumin were reported. However, the clinical application of it was significantly limited by its instability, poor solubility, less body absorbing, and low bioavailability. This review focuses on the structure modification and antioxidant activity evaluation of curcumin. To study the structure–activity relationship (SAR), five series of curcumin analogs were synthesized and their antioxidant activity were evaluated in vitro. The results showed that electron-donating groups, especially the phenolic hydroxyl group are an essential component to improve the antioxidant activity.     

Design and synthesis of new tetrandrine derivatives and their antitumor activities

A series of tetrandrine derivatives were designed and synthesized using Suzuki coupling reaction. Eleven targeted compounds with over 50% inhibition against HL60 and A549 human cancer cell lines at 10 μM were further evaluated for the in vitro antitumor activities by MTT or SRB assay. The biological results revealed that some compounds exhibited potent antitumor activities. Thiophene derivative 6 and acetylphenyl derivative 5 were the most active ones against HL60 and A549 cell lines, with IC₅₀ values less than 5 μM, which thus could be considered as useful candidate for further development of new antitumor agents.     

The anti-inflammatory activity of several flavonoids isolated from Murraya paniculata on murine macrophage cell line and gastric epithelial cell (GES-1)

Context Murraya paniculata (L.) Jack (Rutaceae), Qianlixiang in Chinese, is distributed in China. As an important traditional Chinese medicine (TCM), it demonstrates many bioactivities, such as febrifuge, astringent, anti-dysenteric, and tonic.

Objective: The objective of this study is to evaluate the anti-inflammatory effect of three flavonoids isolated from M. paniculata in lipopolysaccharide (LPS)-activated murine macrophage cell line and ethanol-induced gastric damage on gastric epithelial cell (GES-1).

Materials and methods Three identified flavonoids were isolated from stems and leaves of M. paniculata using ultra performance liquid chromatography (UPLC). Cell viability was measured with MTT, mouse peritoneal macrophages and GES-1 cells were incubated with 0, 0.01, 0.1, 1, 10, and 100?μM P1, P3 and P8 for 24, 48, and 72?h. The inhibitory effect of pretreatment with various concentrations of 5,7,3′,4′,5′-pentamethoxyflavone (P1), 5,7,3′,4′-tetramethoxyflavone (P3), or 5-desmethylnobiletin 5-hydroxy-6,7,8,3′,4′-pentameth-oxyflavone (P8) ranging from 0.03 to 30?μM on nitric oxide (NO) secretion was quantified by the Griess assay for 24 and 48?h, while interleukin-6 (IL-6) was measured by ELISA for 24 and 48?h.

Results The effects of P1, P3, and P8 on mouse peritoneal macrophages and GES-1 cells were not attributable to cytotoxic effects at the doses of 0–10?μM. The IC₅₀ value of P1 is 53.40?μM, P3 is 120.98?μM, and P8 is 10.73?μM. The concentration of the three flavonoids had the best effects of anti-inflammation upon NO inhibition at the dose of 3?μM. P3 had the highest inhibition on IL-6 production. The GES-1 cells pretreated with three flavonoids showed a significant increase in the level of NO (P1: 7.94?±?0.0635?μM, P3: 8.81?±?0.0159?μM, and P8: 8.51?±?0.0522?μM) at 24?h and a more significant increase at 48?h (P1: 9.34?±?0.0975?μM, P3: 11.9?±?0.0672?μM, and P8: 9.34?±?0.0454?μM).

Discussion and conclusion The current results suggested that the anti-inflammatory activity of three flavonoids was mainly manifested in the reduction of production of NO and IL-6 production. Analysis of the structure–activity relationship indicated that the double bond at C₂–C₃ and the position of the B ring at C₂/C₃ seemed to be indispensable for the anti-inflammatory activity.     

Chalcone hybrids and their antimalarial activity

Malaria, one of the most striking, re-emerging infectious diseases caused by the genus Plasmodium, places a huge burden on global healthcare systems. A major challenge in the control and eradication of malaria is the continuous emergence of increasingly widespread drug-resistant malaria, creating an urgent need to develop novel antimalarial agents. Chalcone derivatives are ubiquitous in nature and have become indispensable units in medicinal chemistry applications due to their diverse biological profiles. Many chalcone derivatives demonstrate potential in vitro and in vivo antimalarial activity, so chalcone could be a useful template for the development of novel antimalarial agents. This review covers the recent development of chalcone hybrids as antimalarial agents. The critical aspects of the design and structure–activity relationship of these compounds are also discussed.     

3,5-二亚苄基哌啶-4-酮类化合物的合成及其体外抗肿瘤活性

目的 合成3,5-二亚苄基哌啶-4-酮类化合物,并对其体外抗肿瘤活性进行初步评价。方法 以芳香醛、4-哌啶酮为原料,通过Claisen-Schmidt缩合制备目标化合物。采用MTT法测试目标化合物对人慢性粒细胞白血病急变细胞株K562增殖的抑制活性,考察部分化合物对多种肿瘤细胞株的抑制活性。结果与结论 合成了7个未见报道的3,5-二亚苄基哌啶-4-酮类化合物,其结构经¹H-NMR和MS谱确证;5个目标化合物的体外抗肿瘤活性明显强于姜黄素。     

Structure-based investigation of rat aldehyde oxidase inhibition by flavonoids

Abstract

1. Flavonoids are a group of polyphenolic plant metabolites most commonly known for their antioxidant activities. They also show inhibitory activities on molybdo-flavoenzymes family of enzymes which are involved in biotransformation of some exogenous and endogenous chemicals. Most notably, aldehyde oxidase (AO), a member of this family, is responsible for metabolism of some therapeutic agents. On the other hand, there are some therapeutics which inhibit AO. As flavonoids are ubiquitous in human diet and have potential to interact with AO, it is important to investigate their effects at the molecular details.

2. The inhibitory effects of 15 flavonoids on the activity of rat liver AO were assessed. Quantitative structure–activity relationship studies were performed using genetic algorithm coupled partial least square and stepwise multiple linear regression methods to elucidate the important structural properties responsible for the observed inhibitory effects. To further understand the mode of interaction between these flavonoids and AO, a homology model of the enzyme was built and flavonoids were docked into its active site. The most important amino acids involved in the interactions were identified.

3. Quercetin, myricetin and genistein were the most potent inhibitors establishing favorable interactions with the enzyme. However, the glycosylated flavonoids showed relatively weaker inhibition which may be attributed to their hindered binding into the active site of AO by bulky sugar groups.     

Improving potencies and properties of CD4 down-modulating CADA analogs

Introduction: CADA is a synthetic small molecule that inhibits HIV replication in cell cultures through down-modulating cell surface CD4 by inhibiting cotranslational translocation of nascent CD4 across the ER membrane in a signal sequence-specific manner. Analogs have been prepared mainly to increase potency and investigate the mechanism of action.

Areas covered: This article reviews progress on discovery of more potent CADA analogs, including symmetrical and unsymmetrical compounds, as well as fluorescent derivatives. The article also discusses some properties of CADA and a more potent analog (KKD023) that are relevant to drug development, including aqueous solubility, permeability, metabolism and oral bioavailability.

Expert opinion: Further studies on CADA analogs should focus on improving both potency and drug-like properties, and on elucidating the detailed mechanism of action. Solubility and permeability may be improved by reducing molecular weight, decreasing molecular flexibility and symmetry, or by a prodrug approach inducing active transport. Identifying the molecular mechanism of CD4 down-modulation may aid in assessing potential side effects of such immunomodulatory/anti-HIV drugs, and it could potentially lead to a general approach to designing drugs for specifically down-modulating other cell-surface proteins.     

Isatin dimers and their biological activities

Dimerization is a promising strategy to develop novel drug candidates that could extend the biological spectrum, enhance the activity, overcome drug resistance, as well as improve pharmacological, pharmacokinetic, and physicochemical profiles. Isatin dimers possess a broad spectrum of biological properties and the isatin dimer indirubin has already been used in the clinic, revealing the potential of isatin dimers as putative drugs. This review covers the recent advances of isatin dimers as pharmacologically significant scaffolds and the structure–activity relationship to set up the direction for the design and development of isatin dimers with higher efficiency and lower toxicity.     

Mechanisms of aggregation inhibition by aspirin and nitrate-aspirin prodrugs in human platelets

Objectives Aspirin is the mainstay of anti‐platelet therapy in the secondary prevention of cardiovascular disease. However, problems with aspirin safety and resistance demand clinical strategies based on multiple pharmacological approaches. Prodrugs of aspirin may offer beneficial effects in terms of gastro‐intestinal safety and multiple pharmacological approaches. However, the pharmacological profile of aspirin prodrugs in human platelets has not been completed yet. We aimed to compare the effects of aspirin and prodrugs of aspirin ( 1 – 5 ) on human platelet aggregation stimulated by ADP and collagen and associated receptor expression (GPIIb/IIIa and P‐selectin) in platelet‐rich plasma (PRP) and washed platelets (WP). Methods As aspirin is released from prodrugs following esterase hydrolysis we studied the expression and activity of butyrylcholineterase (BuChE) and carboxyesterase (CE) in plasma and platelets. The mechanism of prodrug‐induced platelet aggregation inhibition was explored by studying the effects of plasma and purified human BuChE on aggregation. Finally, the relative contribution of nitric oxide (NO) bioactivity to nitrate‐containing prodrugs of aspirin‐induced inhibition of aggregation was determined using 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ,) a selective inhibitor of the soluble guanylyl cyclase. Key findings ST0702, 2 , a nicotinic acid‐aspirin codrug was equipotent with aspirin with respect to inhibition of collagen‐induced platelet aggregation. Compound 4 , a NO releasing aspirin was the most potent inhibitor of ADP‐induced platelet aggregation, an effect partially reversed by ODQ. The platelet inhibitory effects of aspirin prodrugs were time‐dependent as the maximal inhibitory effects against collagen‐induced aggregation were achieved by aspirin at 2 min, 1 at 5 min and ST0702 at 15 min. The aspirin prodrugs were significantly less potent in WP than in PRP and the reverse was true of aspirin. In the presence of complete BuChE inhibition in PRP, there was almost complete loss of aspirin prodrug, but not aspirin anti‐aggregatory activity. Interestingly, CE activity was observed in WP and platelet lysate with pNPA substrate. Accordingly, 1 and ST0702 retained 50% and 100% anti‐aggregatory activity at maximal concentrations in WP, which was attenuated in the presence of esterase inhibitor phenylmethylsulphonyl fluoride. Conclusions The inhibitory effect of aspirin prodrugs in PRP is due to prodrug activation by BuChE. In contrast, the platelet‐inhibitory effects of aspirin prodrugs in WP may be mediated through the activity of platelet CE. Compound 4 , a NO‐containing aspirin prodrug, may exert dual inhibitory effects in platelets. Thus, aspirin prodrugs effectively inhibit human platelet aggregation and as such may be an alternative to conventional aspirin.     

Synthesis and biological evaluation of resveratrol derivatives with anti-breast cancer activity

Resveratrol is a natural phytoestrogen produced by plants to protect themselves from injury, UV irradiation, and fungal attack. The main active structure is E-resveratrol, which has many pharmacological activities. As the structure of resveratrol is similar to the natural estrogen 17β-estradiol and the synthetic estrogen E-diethylstilbestrol, resveratrol is used in reducing the incidence of breast cancer. However, the therapeutic application of resveratrol is limited due to its low bioavailability. To improve its bioavailability and pharmacological activity, some resveratrol derivatives have been designed and synthesized by substitutions of methoxy, hydroxyl, and other functional groups or heterocyclic esterification either on the “A” or “B” ring, and double bonds were replaced by imine bonds and isometric heterocycles such as naphthyl and imidazole, or synthetic resveratrol oligomers. The structures, synthetic routes, and evaluation of the biological activities of these compounds are discussed. These are aimed at providing some references for the study of resveratrol derivatives in anti-breast cancer treatment.     

Molecular modeling and QSAR-based design of histamine receptor ligands

Background: The histamine receptors have therapeutic relevance in treatment of several diseases with the more recently discovered H₃ and H₄ receptors offering opportunity as new therapeutic drug targets. Thus, it is of interest to develop new, potent and therapeutically relevant drugs with no side effects. Molecular modeling techniques may play an important role in quickly designing new ligands with a likelihood of exhibiting the corresponding pharmacological profile. Objective: The article describes the findings obtained from this approach for all of the histamine receptors with special emphasis on the H₃ and H₄ receptors. Conclusion: There have been several new studies in the past years aimed at developing new histamine receptor ligands on the one hand and at explaining pharmacological profiles on molecular level on the other. For these purposes, not only molecular modeling techniques, but also synthesis, pharmacological characterization, molecular biological and physical techniques are useful. This combination of several different theoretical and experimental techniques allows getting a more detailed insight into the interaction of histamine receptor ligands with histamine receptors and developing new drugs.     

Coumarin-containing hybrids and their antibacterial activities

Infections caused by Gram-positive and -negative bacteria are one of the foremost causes of morbidity and mortality globally. Antibiotics are the mainstay of therapy for bacterial infections, but the emergence and wide spread of drug-resistant pathogens have already become a huge issue for public healthcare systems. The coumarin moiety, which is ubiquitous in nature, could bind to the B subunit of DNA gyrase in bacteria and inhibit DNA supercoiling by blocking the ATPase activity; hence, coumarin derivatives possess potential antibacterial activity. Several coumarin-containing hybrids such as coumermycin A1, clorobiocin, and novobiocin have already been used in clinical practice for the treatment of various bacterial infections; thus, it is conceivable that hybridization of the coumarin moiety with other antibacterial pharmacophores may provide opportunities for the development of novel antibiotics. This review outlines the advances in coumarin-containing hybrids with antibacterial potential in the recent 5 years and the structure–activity relationships are also discussed.     

Clinical efficacy of once-daily micronized purified flavonoid fraction 1000 mg tablet in patients with symptomatic chronic venous disease

Aim: To investigate the clinical efficacy of micronized purified flavonoid fraction (MPFF) 1000?mg given as a single 1000?mg tablet once daily in patients suffering from chronic venous disease (CVD) vs MPFF 500?mg twice daily.

Methods: In an international, randomized, double-blind, parallel-group study, patients classified C0s to C4 according to Clinical Etiological Anatomic Pathophysiologic [CEAP] classification and with leg pain graded as superior to 4?cm on a 10-cm visual analog scale (VAS), were treated for 8 weeks with either MPFF 1000?mg once daily or MPFF 500?mg twice daily. The present post-hoc analysis focuses on the effect of treatment over time in patients randomized to the MPFF 1000?mg group. Leg pain was assessed at each follow-up visit by VAS. VAS scores over time were compared between each visit using paired Student t-tests.

Results: In total, 87 patients out of 174 were randomized to the MPFF 1000?mg group. Mean age?±?SD was 49.1?±?12.2 years, most of the patients were female (81.6%), the main CEAP classes of the most affected leg were C1 (20.7%), C2 (39.1%), C3 (33.33%), and the mean duration of CVD was 14.6?±?10.9 years. Patients with previous CVD treatment represent 27.6% of the patients. A MPFF 1000?mg tablet once daily was associated with a significant and continuous reduction in leg pain throughout the treatment period: –1.54?cm (±1.45) from baseline to week 2 (p?<?.01), –1.11?cm (±1.06) from week 2 to week 4 (p?<?.01), –1.57?cm (±1.05) from week 4 to week 8 (p?<?.01).

Conclusions: The new MPFF 1000?mg dose regimen in once daily tablets was associated with a rapid and continuous reduction in leg pain throughout the 8-week treatment period.     

In vitro potential modulation of baicalin and baicalein on P-glycoprotein activity and expression in Caco-2 cells and rat gut sacs

Context Previous studies have shown that Scutellariae Radix, the dried root of Scutellaria baicalensis Georgi (Labiatae), has a certain inhibitory effect on P-glycoprotein (P-gp), but the effects of its main active constituents on P-gp are still ambiguous.

Objectives In vitro studies were performed to investigate the effects of its main active constituents (baicalin and its aglycone, baicalein) on the activity and expression of P-gp in intestine using Caco-2 cells and rat gut sacs.

Materials and methods In Caco-2 cell experiments, the effects of baicalin and baicalein on P-gp activity were investigated using a P-gp substrate, rhodamine 123 and non-substrate fluorescein Na, by determining their intracellular fluorescence accumulation, and their effects on P-gp expression were determined using flow cytometry. In addition, rat gut sac model was selected to investigate the effects of baicalin and baicalein on the transport of verapamil, a classical P-gp substrate. The gut sacs of male Sprague–Dawley rats were filled with 0.4?mL the test solution contained verapamil (0.2575?mg/mL) and the drugs [baicalin and baicalein, at concentrations of 1/8 IC₅₀ (59.875, 41.5?μg/mL), 1/4 IC₅₀ (119.75, 83?μg/mL) and 1/2 IC₅₀ (239.5, 166?μg/mL)], and then incubated in Tyrode’s solution for a period of time. After termination of the incubation, the incubated solution was processed for the subsequent detection.

Results According to the results of MTT assay, the IC₅₀ values of verapamil, baicalin and baicalein were 104, 479, 332?μg/mL, respectively. The obtained results from the two models were confirmed mutually. As a result, baicalin exhibited no obvious effect on intracellular accumulation of Rh-123, and almost had no effect on P-gp expression and verapamil transportation, while baicalein significantly increased intracellular accumulation of Rh-123 (p?<?0.01), down-regulated P-gp expression (p?<?0.01) and increased the transport of verapamil (p?<?0.05).

Discussion and conclusion The results indicated that baicalein may be a P-gp inhibitor, which presented obvious inhibitory effects on P-gp activity and expression level. A comparison of the structures of baicalin and baicalein indicates that the existence of glucosyl plays a decisive role in influencing the activity and expression of P-gp.