Short and Atom-Economic Enantioselective Synthesis of the σ1-Receptor Ligands (S)- and (R)-Fluspidine-Important Tools for Positron Emission Tomography Studies

Aryl bromides 2a and 2b bearing an alkynyl substituent in the o-position reacted with n-butyllithium and 1-benzylpiperidin-4-one in a one-pot Domino reaction to form ester 3 and aldehyde 5, respectively. Enantiomeric alcohols (R)-8 and (S)-8 were obtained by conjugate NaBH4 reduction of α,β-unsaturated ester 3 in the presence of chiral cocomplexes (R,R)-10 and (S,S)-10. Starting from orthoester 2a, the precursors (R)-8 and (S)-8 for the synthesis of fluspidine enantiomers (R)-1/[18F](R)-1 and (S)-1/[18F](S)-1 were obtained in only two reaction steps without additional steps for N-protection in an atom-economic manner in 95.6% ee and 97.2% ee, respectively.

The Gas-Phase Formation Mechanism of Dibenzofuran (DBF), Dibenzothiophene (DBT), and Carbazole (CA) from Benzofuran (BF), Benzothiophene (BT), and Indole (IN) with Cyclopentadienyl Radical

Benzofuran (BF), benzothiophene (BT), indole (IN), dibenzofuran (DBF), dibenzothiophene (DBT), and carbazole (CA) are typical heterocyclic aromatic compounds (NSO-HETs), which can coexist with polycyclic aromatic hydrocarbons (PAHs) in combustion and pyrolysis conditions. In this work, quantum chemical calculations were carried out to investigate the formation of DBF, DBT, and CA from the reactions of BF, BT, and IN with a cyclopentadienyl radical (CPDyl) by using the hybrid density functional theory (DFT) at the MPWB1K/6-311+G(3df,2p)//MPWB1K/6-31+G(d,p) level. The rate constants of crucial elementary steps were deduced over 600-1200 K, using canonical variational transition state theory with a small-curvature tunneling contribution (CVT/SCT). This paper showed that the production of DBF, DBT, and CA from the reactions of BF, BT, and IN with CPDyl involved six elementary steps: the addition reaction, ring closure, the first H shift, C-C cleavage, the second H shift, and elimination of CH3 or H. The cleavage of the C-C bond was regarded as the rate-determining step for each pathway due to the extremely high barrier. The 1-methyl substituted products were more easily formed than the 4-methyl substituted products. The main products were DBF and 1-methyl-DBF, DBT and 1-methyl-DBT, and CA and 1-methyl-CA for reactions of BF, BT, and IN with CPDyl, respectively. The ranking of DBF, DBT, and CA formation potential was as follows: DBT and methyl-DBT formation > DBF and methyl-DBF formation > CA, and methyl-CA formation. Comparison with the reaction of naphthalene with CPDyl indicated that the reactions of CPDyl attacking a benzene ring and a furan/thiophene/pyrrole ring could be inferred to be comparable under high temperature conditions.

Structurally Modified Cyclopenta[b]benzofuran Analogues Isolated from Aglaia perviridis

Four new cyclopenta[b]benzofuran derivatives based on an unprecedented carbon skeleton (1-4), with a dihydrofuran ring fused to dioxanyl and aryl rings, along with a new structural analogue (5) of 5‴-episilvestrol (episilvestrol, 7), were isolated from an aqueous extract of a large-scale re-collection of the roots of Aglaia perviridis collected in Vietnam. Compound 5 demonstrated mutarotation in solution due to the presence of a hydroxy group at C-2‴, leading to the isolation of a racemic mixture, despite being purified on a chiral-phase HPLC column. Silvestrol (6) and episilvestrol (7) were isolated from the most potently cytotoxic chloroform subfraction of the roots. All new structures were elucidated using 1D and 2D NMR, HRESIMS, IR, UV, and ECD spectroscopic data. Of the five newly isolated compounds, only compound 5 exhibited cytotoxic activity against a human colon cancer (HT-29) and human prostate cancer cell line (PC-3), with IC₅₀ values of 2.3 μM in both cases. The isolated compounds (1-5) double the number of dioxanyl ring-containing rocaglate analogues reported to date from Aglaia species and present additional information on the structural requirements for cancer cell line cytotoxicity within this compound class.

Prenylated Phenol and Benzofuran Derivatives from Aspergillus terreus EN-539, an Endophytic Fungus Derived from Marine Red Alga Laurencia okamurai

Three new prenylated phenol derivatives, terreprenphenols A–C (1–3), along with four known related compounds (4–7), were isolated from Aspergillus terreus EN-539, an endophytic fungus obtained from the marine red alga Laurencia okamurai. The structures of these compounds were established by extensive analysis of 1D/2D NMR data, mass spectrometric data, and optical rotation (OR). The corresponding relationship between absolute configuration and optical rotation for known compounds anodendroic acid (4) and asperterreusine C (5) was ambiguous in literature, and their absolute configurations were therefore discussed and confirmed for the first time by time-dependent density functional (TDDFT) ECD and OR calculations. Compounds 1–7 inhibited some common aquatic bacteria with MIC values ranging from 2 to 64 μg/mL.

Identifying Phlorofucofuroeckol-A as a Dual Inhibitor of Amyloid-β25-35 Self-Aggregation and Insulin Glycation: Elucidation of the Molecular Mechanism of Action

Both amyloid-β (Aβ) and insulin are amyloidogenic peptides, and they play a critical role in Alzheimer's disease (AD) and type-2 diabetes (T2D). Misfolded or aggregated Aβ and glycated insulin are commonly found in AD and T2D patients, respectively, and exhibit neurotoxicity and oxidative stress. The present study examined the anti-Aβ25-35 aggregation and anti-insulin glycation activities of five phlorotannins isolated from Ecklonia stolonifera. Thioflavin-T assay results suggest that eckol, dioxinodehydroeckol, dieckol, and phlorofucofuroeckol-A (PFFA) significantly inhibit Aβ25-35 self-assembly. Molecular docking and dynamic simulation analyses confirmed that these phlorotannins have a strong potential to interact with Aβ25-35 peptides and interrupt their self-assembly and conformational transformation, thereby inhibiting Aβ25-35 aggregation. In addition, PFFA dose-dependently inhibited d-ribose and d-glucose induced non-enzymatic insulin glycation. To understand the molecular mechanism for insulin glycation and its inhibition, we predicted the binding site of PFFA in insulin via computational analysis. Interestingly, PFFA strongly interacted with the Phe1 in insulin chain-B, and this interaction could block d-glucose access to the glycation site of insulin. Taken together, our novel findings suggest that phlorofucofuroeckol-A could be a new scaffold for AD treatment by inhibiting the formation of β-sheet rich structures in Aβ25-35 and advanced glycation end-products (AGEs) in insulin.

New Hydrazinothiazole Derivatives of Usnic Acid as Potent Tdp1 Inhibitors

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is a promising therapeutic target in cancer therapy. Combination chemotherapy using Tdp1 inhibitors as a component can potentially improve therapeutic response to many chemotherapeutic regimes. A new set of usnic acid derivatives with hydrazonothiazole pharmacophore moieties were synthesized and evaluated as Tdp1 inhibitors. Most of these compounds were found to be potent inhibitors with IC₅₀ values in the low nanomolar range. The activity of the compounds was verified by binding experiments and supported by molecular modeling. The ability of the most effective inhibitors, used at non-toxic concentrations, to sensitize tumors to the anticancer drug topotecan was also demonstrated. The order of administration of the inhibitor and topotecan on their synergistic effect was studied, suggesting that prior or simultaneous introduction of the inhibitor with topotecan is the most effective.

Amidino-Rocaglates: A Potent Class of eIF4A Inhibitors

Rocaglates share a common cyclopenta[b]benzofuran core that inhibits eukaryotic translation initiation by modifying the behavior of the RNA helicase, eIF4A. Working as interfacial inhibitors, rocaglates stabilize the association between eIF4A and RNA, which can lead to the formation of steric barriers that block initiating ribosomes. There is significant interest in the development and expansion of rocaglate derivatives, as several members of this family have been shown to possess potent anti-neoplastic activity in vitro and in vivo. To further our understanding of rocaglate diversity and drug design, herein we explore the RNA clamping activity of >200 unique rocaglate derivatives. Through this, we report on the identification and characterization of a potent class of synthetic rocaglates called amidino-rocaglates. These compounds are among the most potent rocaglates documented to date and, taken together, this work offers important information that will guide the future design of rocaglates with improved biological properties.

Synthesis and Biological Evaluation of (+)-Usnic Acid Derivatives as Potential Anti-Toxoplasma gondii Agents

Six series of (+)-usnic acid derivatives were synthesized. The IC₅₀ values of these compounds were determined in T. gondii infected HeLa cells (μM) and in HeLa cells (μM), and their selectivity indexes (SI) were calculated. In vitro, most of the derivatives tested in this study exhibited more anti activity than that of the parent compound (+)-usnic acid and the positive control drugs. Among these derivatives, methyl (E)-(1-(6-acetyl-7,9-dihydroxy-8,9b-dimethyl-1,3-dioxo-3,9b-dihydrodibenzo[b,d]furan-2(1H)-ylidene)ethyl)phenylalaninate (D3) showed the most effective anti-T. gondii activity (selectivity >2.77). In comparison with the clinically used positive control drugs sulfadiazine (selectivity 1.15), pyrimethamine (selectivity 0.89), spiramycin (selectivity 0.72), and the lead compound (+)-usnic acid (selectivity 0.96), D3 showed better results in vitro. Furthermore, D3 and (E)-6-acetyl-7,9-dihydroxy-8,9b-dimethyl-2-(1-(quinolin-6-ylamino)ethylidene)dibenzo[b,d]furan-1,3(2H,9bH)-dione (F3) had greater inhibitory effects on T. gondii (inhibition rates 76.0% and 64.6%) in vivo in comparison to spiramycin (inhibition rate 55.2%); in the peritoneal cavity of mice, the number of tachyzoites was significantly reduced (p < 0.001) in vivo. Additionally, some biochemical parameters were measured and spleen indexes were comprehensively evaluated, and the results indicated that mice treated with both compound D3 and compound F3 showed reduced hepatotoxicity and significantly enhanced antioxidative effects in comparison to the normal group. Granuloma and cyst formation were effected by the inhibition of compound D3 and compound F3 in liver sections. Overall, these results indicated that D3 and F3 for use as anti-T. gondii agents are promising lead compounds.

Rapid Characterization of Chemical Components in Edible Mushroom Sparassis crispa by UPLC-Orbitrap MS Analysis and Potential Inhibitory Effects on Allergic Rhinitis

Sparassis crispa is a kind of edible fungus widely grows in the north temperate zone, which shows various medicinal properties. Due to the complexity of chemical constitutes of this species, few investigations have acquired a comprehensive configuration for the chemical profile of it. In this study, a strategy based on ultra-high performance liquid chromatography (UPLC) combined with Orbitrap mass spectrometer (MS) was established for rapidly characterizing various chemical components in S. crispa. Through the summarized MS/MS fragmentation patterns of reference compounds and systematic identification strategy, a total of 110 components attributed to six categories were identified for the first time. Moreover, allergic rhinitis (AR) is a worldwide inflammatory disease seriously affecting human health, and the development of drugs to treat AR has been a topic of interest. It has been reported that the extracts of S. crispa showed obvious inhibitory effects on degranulation of mast cell- and allergen-induced IgE and proinflammatory mediators, but the active components and specific mechanism were still not clear. Src family kinases (SFKs) participate in the initial stage of allergy occurrence, which are considered the targets of AR treatment. Herein, on the basis of that self-built chemical database, virtual screening was applied to predict the potential SFKs inhibitors in S. crispa, using known crystal structures of Hck, Lyn, Fyn, and Syk as receptors, followed by the anti-inflammatory activity evaluation for screened hits by intracellular calcium mobilization assay. As results, sparoside A was directly confirmed to have strong anti-inflammatory activity with an IC50 value of 5.06 ± 0.60 μM. This study provides a useful elucidation for the chemical composition of S. crispa, and demonstrated its potential inhibitory effects on AR, which could promote the research and development of effective agents from natural resources.

Pharmacokinetics of salvianolic acid B, rosmarinic acid and Danshensu in rat after pulmonary administration of Salvia miltiorrhiza polyphenolic acid solution

A sensitive and accurate LC-MS/MS method was established for quantifying salvianolic acid B (Sal B), rosmarinic acid (Ros A) and Danshensu (DA) in rat plasma. Salvia miltiorrhiza polyphenolic acid (SMPA), active water-soluble ingredients isolated and purified from Salvia miltiorrhiza Bge included Sal B, Ros A and DA. The pharmacokinetic analysis of Sal B, Ros A and DA after pulmonary administration of SMPA solution to rat was performed by LC-MS/MS. Results from the pharmacokinetic studies showed that the peak concentration of DA was 21.85 ± 6.43 and 65.39 ± 3.83 ng/mL after pulmonary and intravenous administration, respectively. DA was not detected at 2 h after administration. The absolute bioavailabilities of Sal B and Ros A were respectively 50.37 ± 27.04 and 89.63 ± 12.16% after pulmonary administration of 10 mg/kg SMPA solution in rats. The absolute bioavailability of Sal B increased at least 10-fold after pulmonary administration, compared with oral administration. It was concluded that the newly established LC-MS/MS method was suitable for describing the pharmacokinetic characteristics of Sal B, Ros A and DA in rat after pulmonary administration of SMPA solution. The data from this study will provide a preclinical insight into the feasibility of pulmonary administration of SMPA.

Overcoming deterrent metabolites by gaining essential nutrients: A lichen/snail case study

Specialised metabolites in lichens are generally considered repellent compounds by consumers. Nevertheless, if the only food available is lichens rich in specialised metabolites, lichenophages must implement strategies to overcome the toxicity of these metabolites. Thus, the balance between phagostimulant nutrients and deterrent metabolites could play a key role in feeding preferences. To further understand lichen-gastropod interactions, we studied the feeding behaviour and consumption in Notodiscus hookeri, the land snail native to sub-Antarctic islands. The lichen Usnea taylorii was used because of its simple chemistry, its richness in usnic acid (specialised metabolite) and arabitol (primary metabolite) and its presence in snail habitats. Choice tests in arenas with intact lichens versus acetone-rinsed lichens were carried out to study the influence of specialised metabolites on snail behaviour and feeding preference. Simultaneously, usnic acid and arabitol were quantified and located within the lichen thallus using HPLC-DAD-MS and in situ imaging by mass spectrometry to assess whether their spatial distribution explained preferential snail grazing. No-choice feeding experiments, with the pure metabolites embedded in an artificial diet, defined a gradual gustatory response, from strong repellence (usnic acid) to high appetence (D-arabitol). This case study demonstrates that the nutritional activity of N. hookeri is governed by the chemical quality of the food and primarily by nutrient availability (arabitol), despite the presence of deterrent metabolite (usnic acid).

Synthesis of Usnic Acid Derivatives and Evaluation of Their Antiproliferative Activity against Cancer Cells

Usnic acid is a secondary metabolite abundantly found in lichens, for which promising cytotoxic and antitumor potential has been shown. However, knowledge concerning activities of its derivatives is limited. Herein, a series of usnic acid derivatives were synthesized and their antiproliferative potency against cancer cells of different origin was assessed. Some of the synthesized compounds were more active than usnic acid. Compounds 2a and 2b inhibited survival of all tested cancer cell lines in a dose- and time-dependent manner. Their IC₅₀ values after 48 h of treatment were ca. 3 μM for MCF-7 and PC-3 cells and 1 μM for HeLa cells, while 3a and 3b revealed antiproliferative activity only against HeLa cells. All active usnic acid derivatives induced G0/G1 arrest and a drop in the fraction of HeLa cells in the S and G2/M phases. Compounds 2a and 2b decreased the clonogenic potential of the cancer cells evaluated and induced cell cycle arrest at the G0/G1 phase and apoptosis in MCF-7 cells. Moreover, they induced massive cytoplasmic vacuolization, which was associated with elevated dynein-dependent endocytosis, a process that has not been reported for usnic acid and indicates a novel mechanism of action of its synthetic derivatives. This work also shows that naturally occurring usnic acids are promising lead compounds for the synthesis of derivatives with more favorable properties against cancer cells.

Mycousfurans A and B, Antibacterial Usnic Acid Congeners from the Fungus Mycosphaerella sp., Isolated from a Marine Sediment

Mycousfurans (1 and 2), two new usnic acid congeners, along with (−)-mycousnine (3), (−)-placodiolic acid (4), and (+)-usnic acid (5), were isolated using high-performance liquid chromatography-ultraviolet (HPLC-UV)-guided fractionation of extracts of Mycosphaerella sp. isolated from a marine sediment. The planar structures of 1 and 2 were elucidated using 1D and 2D NMR spectra. The relative configurations of the stereogenic carbons of 1 and 2 were established via analysis of their nuclear Overhauser spectroscopy (NOESY) spectra, and their absolute configurations were determined using a comparison of experimental and calculated electronic circular dichroism (ECD) spectra. Compounds 1 and 2 were found to have antibacterial activity, showing moderate activity against Kocuria rhizophila and Staphylococcus aureus.

Voltammetric, spectroscopic, and cellular characterization of redox functionality of eckol and phlorofucofuroeckol-A: A comparative study

Interest in phlorotannins has increased in recent years largely due to antioxidant capacity, however, the redox mechanism of phlorotannins is still obscure. In the present study, the electrochemical oxidation mechanisms of eckol (EL) and phlorofucofuroeckol-A (PFF-A), two representative phlorotannin compounds, were comparatively analyzed in a wide pH range using cyclic and differential pulse voltammetry as well as spectroscopic assay. The voltammetric study revealed that EL and PFF-A were successively oxidized in three pH-dependent steps. Moreover, it was found that the PFF-A presented a stronger proton and electron transferring activity as compared to EL since PFF-A exhibited lower acid-base dissociation constant (pKa ) value and higher heterogeneous rate constant (kbh ) value in the first oxidation step. These property were further evidenced by comparison of direct antioxidant activity (i.e., superoxide anion and peroxide radicals) as well as indirect antioxidant activity (i.e., mRNA expression of two phase II enzymes) between EL and PFF-A. PRACTICAL APPLICATIONS: Phlorotannins from edible algae have been regarded as novel antioxidants those presented high application potential in food industry. Even though antioxidant activity of phlorotannin compounds have been widely investigated in both in vitro and in vivo studies, very few reports focused on electron transferring functionality which is chemical basis for antioxidant process. Herein, the oxidative mechanisms of two representative phlorotannins were comparatively analyzed using multiple electrochemical methods. This is hopefully to give information on the chemical meaning behind the antioxidant activity of dietary phlorotannins.

A Comparative Study of the Anticancer Activity and PARP-1 Inhibiting Effect of Benzofuran-Pyrazole Scaffold and Its Nano-Sized Particles in Human Breast Cancer Cells

Breast cancer is considered the most common and deadly cancer among women worldwide. Nanomedicine has become extremely attractive in the field of cancer treatment. Due to the high surface to volume ratio and other unique properties, nanomaterials can be specifically targeted to certain cells and tissues to interact with the living systems. The strategic planning of this study is based on using the nanoprecipitation method to prepare nanoparticles BZP-NPs (3.8-5.7 nm) of the previously prepared benzofuran-pyrazole compound (IV) BZP which showed promising cytotoxic activity. The capacity of BZP and BZP-NPs to suppress the growth of human breast tumor MCF-7 and MDA-MB-231 cells was evaluated using MTT assay. The IC50 doses of BZP and BZP-NPs targeting normal breast cells MCF-12A exceeded those targeting the cancer cells by >1000-fold, demonstrating their reasonable safety profiles in normal cells. Furthermore, cell cycle analysis, apoptosis induction detection, assessment of p53, Bcl-2, caspase-3, and PARP-1 levels of BZP and its nano-sized-BZP-NPs particles were also evaluated. Although the obtained results were in the favor of compound IV in its normal-sized particles, BZP-NPs appeared as a hit compound which showed improved cytotoxicity against the tested human breast cancer cells associated with the induction of pre-G1 apoptosis as well as cell cycle arrest at G2/M phase. The increase in caspase-3 level, upregulation of p53, and downregulation of Bcl-2 protein expression levels confirmed apoptosis. Furthermore, ELISA results exhibited that BZP-NPs produced a more favorable impact as a PARP-1 enzyme inhibitor than the parent BZP.

Quantitative imaging of anion exchange kinetics in halide perovskites

Ion exchange, as a postsynthetic transformation strategy, offers more flexibilities in controlling material compositions and structures beyond direct synthetic methodology. Observation of such transformation kinetics on the single-particle level with rich spatial and spectroscopic information has never been achieved. We report the quantitative imaging of anion exchange kinetics in individual single-crystalline halide perovskite nanoplates using confocal photoluminescence microscopy. We have systematically observed a symmetrical anion exchange pathway on the nanoplates with dependence on reaction time and plate thickness, which is governed by the crystal structure and the diffusion-limited transformation mechanism. Based on a reaction-diffusion model, the halide diffusion coefficient was estimated to be on the order of [Formula: see text] This diffusion-controlled mechanism leads to the formation of 2D perovskite heterostructures with spatially resolved coherent interface through the precisely controlled anion exchange reaction, offering a design protocol for tailoring functionalities of semiconductors at the nano-/microscale.

Design and Synthesis of Poly(ADP-ribose) Polymerase Inhibitors: Impact of Adenosine Pocket-Binding Motif Appendage to the 3-Oxo-2,3-dihydrobenzofuran-7-carboxamide on Potency and Selectivity

Poly(adenosine 5'-diphosphate-ribose) polymerase (PARP) inhibitors are a class of anticancer drugs that block the catalytic activity of PARP proteins. Optimization of our lead compound 1 (( Z)-2-benzylidene-3-oxo-2,3-dihydrobenzofuran-7-carboxamide; PARP-1 IC50 = 434 nM) led to a tetrazolyl analogue (51, IC50 = 35 nM) with improved inhibition. Isosteric replacement of the tetrazole ring with a carboxyl group (60, IC50 = 68 nM) gave a promising new lead, which was subsequently optimized to obtain analogues with potent PARP-1 IC50 values (4-197 nM). PARP enzyme profiling revealed that the majority of compounds are selective toward PARP-2 with IC50 values comparable to clinical inhibitors. X-ray crystal structures of the key inhibitors bound to PARP-1 illustrated the mode of interaction with analogue appendages extending toward the PARP-1 adenosine-binding pocket. Compound 81, an isoform-selective PARP-1/-2 (IC50 = 30 nM/2 nM) inhibitor, demonstrated selective cytotoxic effect toward breast cancer gene 1 ( BRCA1)-deficient cells compared to isogenic BRCA1-proficient cells.

Quantum Reality in the Selective Reduction of a Benzofuran System

Two 2,3-disubstituted benzofurans (1 and 2), analogs of gamma-aminobutyric acid (GABA), were synthesized to obtain their 2,3-dihydro derivatives from the Pd/C-driven catalytic reduction of the double bond in the furanoid ring. The synthesis produced surprising by-products. Therefore, theoretical calculations of global and local reactivity were performed based on Pearson's hard and soft acids and bases (HSAB) principle to understand the regioselectivity that occurred in the reduction of the olefinic carbons of the compounds. Local electrophilicity (ω_k) was the most useful parameter for explaining the selectivity of the polar reactions. This local parameter was defined with the condensed Fukui function and redefined with the electrophilic (P_k⁺) Parr function. The similar patterns of both resulting sets of values helped to demonstrate the electrophilic behavior (soft acid) of the olefinic carbons in these compounds. The theoretical calculations, nuclear magnetic resonance, and resonance hybrids showed the moieties in each compound that are most susceptible to reduction.

Novel phthalide dimers from the aerial parts of Ligusticum sinense Oliv cv. Chaxiong

Five new phthalide dimers, chaxiongnolides C-G (1-5), the two enantiomers of riligustilide (6a and 6b) and tokinolide B (7) were isolated from the aerial parts of Ligusticum sinense Oliv cv. Chaxiong. The structures of 1-5 were elucidated through extensive spectroscopic analysis, and the relative configurations of compounds 2 and 3 were further confirmed by an X-ray diffraction experiment. The absolute configurations of 1-3 were assigned by comparing calculated and experimental ECD spectra. The ECD exciton chirality method was used to confirm the absolute configurations of compounds 4, 5, 6a and 6b. Compounds 1-3 are the first dimeric phthalides to be reported that are comprising a sedanolide unit. The compounds were evaluated in vitro for their cytotoxic activity against select human cell lines.

Phthalides serve as potent modulators to boost fetal hemoglobin induction therapy for β-hemoglobinopathies

Fetal hemoglobin (HbF) induction therapy has become the most promising strategy for treating β-hemoglobinopathies, including sickle-cell diseases and β-thalassemia. However, subtle but critical structural difference exists between HbF and normal adult hemoglobin (HbA), which inevitably leads to reduced binding of the endogenous modulator 2,3-bisphosphoglycerate (2,3-BPG) to HbF and thus increased oxygen affinity and decreased oxygen transport efficiency of HbF. We combined the oxygen equilibrium experiments, resonance Raman (RR) spectroscopy, and molecular docking modeling, and we discuss 2 phthalides, z-butylidenephthalide and z-ligustilide, that can effectively lower the oxygen affinity of HbF. They adjust it to a level closer to that of HbA and make it a more satisfactory oxygen carrier for adults. From the oxygen equilibrium curve measurements, we show that the 2 phthalides are more effective than 2,3-BPG for modulating HbF. The RR spectra show that phthalides allosterically stabilize the oxygenated HbF in the low oxygen affinity conformation, and the molecular docking modeling reveals that the 2 chosen phthalides interact with HbF via the cleft around the γ1/γ2 interface with a binding strength ∼1.6 times stronger than that of 2,3-BPG. We discuss the implications of z-butylidenephthalide and z-ligustilide in boosting the efficacy of HbF induction therapy to mitigate the clinical severities of β-hemoglobinopathies.

Semisynthetic aurones inhibit tubulin polymerization at the colchicine-binding site and repress PC-3 tumor xenografts in nude mice and myc-induced T-ALL in zebrafish

Structure-activity relationships (SAR) in the aurone pharmacophore identified heterocyclic variants of the (Z)-2-benzylidene-6-hydroxybenzofuran-3(2H)-one scaffold that possessed low nanomolar in vitro potency in cell proliferation assays using various cancer cell lines, in vivo potency in prostate cancer PC-3 xenograft and zebrafish models, selectivity for the colchicine-binding site on tubulin, and absence of appreciable toxicity. Among the leading, biologically active analogs were (Z)-2-((2-((1-ethyl-5-methoxy-1H-indol-3-yl)methylene)-3-oxo-2,3-dihydrobenzofuran-6-yl)oxy)acetonitrile (5a) and (Z)-6-((2,6-dichlorobenzyl)oxy)-2-(pyridin-4-ylmethylene)benzofuran-3(2H)-one (5b) that inhibited in vitro PC-3 prostate cancer cell proliferation with IC50 values below 100 nM. A xenograft study in nude mice using 10 mg/kg of 5a had no effect on mice weight, and aurone 5a did not inhibit, as desired, the human ether-à-go-go-related (hERG) potassium channel. Cell cycle arrest data, comparisons of the inhibition of cancer cell proliferation by aurones and known antineoplastic agents, and in vitro inhibition of tubulin polymerization indicated that aurone 5a disrupted tubulin dynamics. Based on molecular docking and confirmed by liquid chromatography-electrospray ionization-tandem mass spectrometry studies, aurone 5a targets the colchicine-binding site on tubulin. In addition to solid tumors, aurones 5a and 5b strongly inhibited in vitro a panel of human leukemia cancer cell lines and the in vivo myc-induced T cell acute lymphoblastic leukemia (T-ALL) in a zebrafish model.

Loliolide, a Carotenoid Metabolite, Is a Potential Endogenous Inducer of Herbivore Resistance

Jasmonic acid (JA) plays an important role in the induction of herbivore resistance in many plants. However, JA-independent herbivore resistance has been suggested. An herbivore-resistance-inducing substance was isolated from Tobacco mosaic virus-infected tobacco (Nicotiana tabacum) leaves in which a hypersensitive response (HR) was induced and identified as loliolide, which has been identified as a β-carotene metabolite. When applied to tomato (Solanum lycopersicum) leaves, loliolide decreased the survival rate of the two-spotted spider mite, Tetranychus urticae, egg deposition by the same pest, and the survival rate of larvae of the common cutworm Spodoptera litura without exhibiting toxicity against these herbivores. Endogenous loliolide levels increased not only with an infestation by S litura larvae, but also with the exogenous application of their oral secretions in tomato. A microarray analysis identified cell-wall-associated defense genes as loliolide-responsive tomato genes, and exogenous JA application did not induce the expression of these genes. Suppressor of zeaxanthin-less (szl), an Arabidopsis (Arabidopsis thaliana) mutant with a point mutation in a key gene of the β-carotene metabolic pathway, exhibited the decreased accumulation of endogenous loliolide and increased susceptibility to infestation by the western flower thrip (Frankliniella occidentalis). A pretreatment with loliolide decreased susceptibility to thrips in the JA-insensitive Arabidopsis mutant coronatine-insensitive1 Exogenous loliolide did not restore reduced electrolyte leakage in szl in response to a HR-inducing bacterial strain. These results suggest that loliolide functions as an endogenous signal that mediates defense responses to herbivores, possibly independently of JA, at least in tomato and Arabidopsis plants.

Preparation of Salvianolic Acid B Disodium Salt Considering the Water Extract Quality Standard

A preparation process of salvianolic acid B (SAB) disodium salt from Salvia miltiorrhiza Bunge (Danshen) is provided in this work. A water extract quality standard was also developed to estimate the influences of Danshen quality on SAB disodium salt quality at an early stage of the preparation process. Crude SAB solution was obtained after water extraction, concentration, acidification, 1-butanol extraction, water washing, basification, and water back extraction. Extraction temperature, extraction pH, and back-extraction pH were identified to be key parameters for the preparation of crude SAB solution. These parameters were optimized with Box⁻Behnken designed experiments. Crude SAB solution was further purified with a chromatography process. AMBERCHROW CG161M resin was selected as the best adsorbent. SAB disodium salt could be obtained by drying the eluate. Considering the quality of Danshen may affect the purity and yield of SAB disodium salt, different batches of Danshen were used to prepare SAB disodium salt with the optimized parameters. Water extract indices of phenolic compound purity and phenolic compound yield were measured. By developing models between SAB disodium salt purity and yield with water extract indices, the quality standard of Danshen water extract was obtained. The application of water extract quality standards can improve the quality consistency of SAB disodium salt. The effects of different batches of Danshen raw materials on the final product could be evaluated at the beginning of production stages. The present method could prepare about five grams of high-purity SAB disodium salt (>95%) in one preparation cycle. The method reported in this work can also be used to develop process intermediate quality standards for other natural products.

Dual BACE1 and Cholinesterase Inhibitory Effects of Phlorotannins from Ecklonia cava-An In Vitro and in Silico Study

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases with a multifactorial nature. β-Secretase (BACE1) and acetylcholinesterase (AChE), which are required for the production of neurotoxic β-amyloid (Aβ) and the promotion of Aβ fibril formation, respectively, are considered as prime therapeutic targets for AD. In our efforts towards the development of potent multi-target, directed agents for AD treatment, major phlorotannins such as eckol, dieckol, and 8,8'-bieckol from Ecklonia cava (E. cava) were evaluated. Based on the in vitro study, all tested compounds showed potent inhibitory effects on BACE1 and AChE. In particular, 8,8'-bieckol demonstrated the best inhibitory effect against BACE1 and AChE, with IC50 values of 1.62 ± 0.14 and 4.59 ± 0.32 µM, respectively. Overall, kinetic studies demonstrated that all the tested compounds acted as dual BACE1 and AChE inhibitors in a non-competitive or competitive fashion, respectively. In silico docking analysis exhibited that the lowest binding energies of all compounds were negative, and specifically different residues of each target enzyme interacted with hydroxyl groups of phlorotannins. The present study suggested that major phlorotannins derived from E. cava possess significant potential as drug candidates for therapeutic agents against AD.

Novel aryloxyphenoxypropionate derivates containing benzofuran moiety: Design, synthesis, herbicidal activity, docking study and theoretical calculation

A series of novel aryloxyphenoxypropionate (APP) herbicides containing benzofuran moiety were designed, synthesized and tested for herbicidal activity. The bioassay results indicated that most of target compounds possessed moderate to good herbicidal activity against monocotyledonous weeds. Compounds 5a-5d and 6a-6d showed 100% control efficiency against crabgrass (Digitaria sanguinalis) and barnyard grass (Echinochloa crus-galli) in both pre-emergence and post-emergence treatments at the dosage of 1500 g a.i. ha^-1. Compound 6c was the most promising, with herbicidal activity better than clodinafop-propargyl. Molecular docking for compound 6c and its hydrolysis acid 1c were performed. ACCase activities of some compounds were also tested. Theoretical calculations for corresponding hydrolysis products 1a-1ewere carried out. Based on the results of molecular docking, enzyme activity test and theoretical calculation, the potential mechanism for herbicidal activity of these compounds was evaluated.