Total Synthesis of Pulmonarin B and Design of Brominated Phenylacetic Acid/Tacrine Hybrids: Marine Pharmacophore Inspired Discovery of New ChE and Aβ Aggregation Inhibitors

A marine natural product, pulmonarin B (1), and a series of related tacrine hybrid analogues were synthesized and evaluated as cholinesterase (ChE) inhibitors. The in vitro ChE assay results revealed that 1 showed moderate dual acetylcholinesterase (AChE)/ butyrylcholinesterase (BChE) inhibitory activity, while the hybrid 12j proved to be the most potent dual inhibitor among the designed derivatives, being almost as active as tacrine. Molecular modeling studies together with kinetic analysis suggested that 12j interacted with both the catalytic active site and peripheral anionic site of AChE. Compounds 1 and 12j could also inhibit self-induced and AChE-induced Aβ aggregation. In addition, the cell-based assay against the human hepatoma cell line (HepG2) revealed that 1 and 12j did not show significant hepatotoxicity compared with tacrine and donepezil. Taken together, the present study confirmed that compound 1 was a potential anti-Alzheimer’s disease (AD) hit, and 12j could be highlighted as a multifunctional lead compound for anti-AD drug development

Design, Synthesis and Biological Evaluation of Novel Coumarin-Based Hydroxamate Derivatives as Histone Deacetylase (Hdac) Inhibitors with Antitumor Activities

A series of novel coumarin-based hydroxamate derivatives were designed and synthesized as histone deacetylase inhibitors (HDACis). Selective compounds showed a potent HDAC inhibition with nM IC50 values, with the best compound (10e) being nearly 90 times more active than vorinostat (SAHA) against HDAC1. Compounds 10e and 11d also increased the levels of acetylated histone H3 and H4, which is consistent with their strong HDAC inhibition. In addition, 10e and 11d displayed a higher potency toward human A549 and Hela cancer cell lines compared with SAHA. Moreover, 10e and 11d significantly arrested A549 cells at the G2/M phase and enhanced apoptosis. Molecular docking studies revealed the possible mode of interaction of compounds 10e and 12a with HDAC1. Our findings suggest that these novel coumarin-based HDAC inhibitors provide a promising scaffold for the development of new potential cancer chemotherapies

Discovery of New Selective Butyrylcholinesterase (BChE) Inhibitors with Anti-Aβ Aggregation Activity: Structure-Based Virtual Screening, Hit Optimization and Biological Evaluation

In this study, a series of selective butyrylcholinesterase (BChE) inhibitors was designed and synthesized from the structural optimization of hit 1, a 4-((3,4-dihydroisoquinolin-2(1H)-yl)methyl)benzoic acid derivative identified by virtual screening our compound library. The in vitro enzyme assay results showed that compounds 9 ((4-((3,4-dihydroisoquinolin-2(1H)-yl)methyl)phenyl)(pyrrolidin-1-yl)methanone) and 23 (N-(2-bromophenyl)-4-((3,4-dihydroisoquinolin-2(1H)-yl)methyl)benzamide) displayed improved BChE inhibitory activity and good selectivity towards BChE versus AChE. Their binding modes were probed by molecular docking and further validated by molecular dynamics simulation. Kinetic analysis together with molecular modeling studies suggested that these derivatives could target both the catalytic active site (CAS) and peripheral anionic site (PAS) of BChE. In addition, the selected compounds 9 and 23 displayed anti-Aβ1–42 aggregation activity in a dose-dependent manner, and they did not show obvious cytotoxicity towards SH-SY5Y neuroblastoma cells. Also, both compounds showed significantly protective activity against Aβ1-42-induced toxicity in a SH-SY5Y cell model. The present results provided a new valuable chemical template for the development of selective BChE inhibitors

Bioactive Pyridone Alkaloids from a Deep-Sea-Derived Fungus Arthrinium sp. UJNMF0008

Eight new 4-hydroxy-2-pyridone alkaloids arthpyrones D–K (1–8), along with two known analogues apiosporamide (9) and arthpyrone B (10), were isolated from a deep-sea-derived fungus Arthrinium sp. UJNMF0008. The structures of the isolated compounds were elucidated on the basis of spectroscopic methods with that of 1 being established by chemical transformation and X-ray diffraction analysis. Compounds 1 and 2 bore an ester functionality linking the pyridone and decalin moieties first reported in this class of metabolites, while 3 and 4 incorporated a rare natural hexa- or tetrahydrobenzofuro[3,2-c]pyridin-3(2H)-one motif. Compounds 3–6 and 9 exhibited moderate to significant antibacterial activity against Mycobacterium smegmatis and Staphylococcus aureus with IC50 values ranging from 1.66–42.8 μM, while 9 displayed cytotoxicity against two human osteosarcoma cell lines (U2OS and MG63) with IC50 values of 19.3 and 11.7 μM, respectively

New Octadecanoid Enantiomers from the Whole Plants of Plantago depressa

In this study, 19 octadecanoid derivatives—four pairs of enantiomers (1–8), two racemic/scalemic mixtures (9–10), and nine biosynthetically related analogues—were obtained from the ethanolic extract of a Chinese medicinal plant, Plantago depressa Willd. Their structures were elucidated on the basis of detailed spectroscopic analyses, with the absolute configurations of the new compounds assigned by time-dependent density functional theory (TD-DFT)-based electronic circular dichroism (ECD) calculations. Six of them (1, 3–6, and 9) were reported for the first time, while 2, 7, and 8 have been previously described as derivatives and are currently obtained as natural products. Our bioassays have established that selective compounds show in vitro anti-inflammatory activity by inhibiting lipopolysaccharide-induced nitric oxide (NO) production in mouse macrophage RAW 264.7 cells

Identification of a novel small-molecule Keap1–Nrf2 PPI inhibitor with cytoprotective effects on LPS-induced cardiomyopathy

A new Keap1–Nrf2 protein–protein interaction (PPI) inhibitor ZJ01 was identified from our compound library by fluorescence polarization assay, surface plasmon resonance, molecular docking and molecular dynamics simulation. ZJ01 could in vitro trigger Nrf2 nuclear translocation, subsequently resulting in increased mRNA levels of Nrf2 target genes HO-1 and NQO1. Meanwhile, ZJ01 suppressed LPS-induced production of ROS and the mRNA levels of pro-inflammatory cytokines TNF-α, IL-1β and IL-6 in H9c2 cardiac cells. Moreover, in an in vivo mouse model of septic cardiomyopathy induced by intraperitoneal injection of lipopolysaccharide, ZJ01 demonstrated a cytoprotective effect, upregulated Nrf2 protein nuclear accumulation, and remarkably suppressed the abovementioned cytokine levels in cardiomyocytes. The results presented herein provided a novel chemotype for the development of direct Keap1–Nrf2 PPI inhibitors and suggested that compound ZJ01 is a promising drug lead for septic cardiomyopathy treatment. ZJ01 was identified as a new Keap1–Nrf2 PPI inhibitor and drug lead for septic cardiomyopathy treatment by in vitro and in vivo experiments

Quantum Chemistry Calculation-Aided Structural Optimization of Combretastatin A‑4-like Tubulin Polymerization Inhibitors: Improved Stability and Biological Activity

A potent combretastatin A-4 (CA-4) like tubulin polymerization inhibitor <b>22b</b> was found with strong antitumor activity previously. However, it easily undergoes <i>cis–trans</i> isomerization under natural light, and the resulting decrease in activity limits its further applications. In this study, we used quantum chemistry calculations to explore the molecular basis of its instability. Aided by the calculations, two rounds of structural optimization of <b>22b</b> were conducted. Accelerated quantitative light stability testing confirmed that the stability of these designed compounds was significantly improved as predicted. Among them, compounds <b>1</b> and <b>3b</b> displayed more potent inhibitory activity on tumor cell growth than <b>22b</b>. In addition, the potent <i>in vivo</i> antitumor activity of compound <b>1</b> was confirmed. Quantum chemistry calculations were used in the optimization of stilbene-like molecules, providing new insight into stilbenoid optimization and important implications for the future development of novel CA-4-like tubulin polymerization inhibitors