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A series of new indole-3-acetic acid (IAA)-tacrine hybrids as dual acetylcholinesterase (AChE)/butyrylcholinesterase (BChE) inhibitors were designed and prepared based on the molecular docking mode of AChE with an IAA derivative (1a), a moderate AChE inhibitor identified by screening our compound library for anti-Alzheimer's disease (AD) drug leads. The enzyme assay results revealed that some hybrids, e.g. 5d and 5e, displayed potent dual in vitro inhibitory activities against AChE/BChE with IC50 values in low nanomolar range. Molecular modeling studies in tandem with kinetic analysis suggest that these hybrids target both catalytic active site and peripheral anionic site of cholinesterase (ChE). Molecular dynamic simulations and Molecular Mechanics/Poisson-Boltzmann Surface Area (MM-PBSA) calculations indicate that 5e has more potent binding affinity than hit 1a, which may explain the stronger inhibitory effect of 5e on AChE. Furthermore, their predicted pharmacokinetic properties and in vitro influences on mouse brain neural network electrical activity were discussed. Taken together, compound 5e can be highlighted as a lead compound worthy of further optimization for designing new anti-AD drugs.

Protein arginine methyltransferase 5 (PRMT5) is an epigenetics related enzyme that has been validated as an important therapeutic target for glioblastoma and mantel cell lymphoma. In the present study, 11 novel PRMT5 inhibitors with 5-benzylidene-2-phenylthiazolone scaffold were identified by molecular docking-based virtual screening and structural optimization. Their IC50 values against PRMT5 at enzymatic level were ranging from 0.77 to 23 μM. As expected, the top two active hits (5 and 19) showed potent anti-proliferative activity against MV4-11 cells with EC50 values lower than 10 μM and reduced the cellular symmetric arginine dimethylation levels of SmD3 protein. Besides, 5 and 19 demonstrated the mechanism of cell killing in cell cycle arrest and apoptotic effect. The probable binding modes of the two compounds were explored and further verified by molecular dynamics simulation. The structure-activity relationship (SAR) of this class of structures was also discussed and further demonstrated by molecular docking simulation.

Protein arginine methyltransferase 5 (PRMT5) is an epigenetics related enzyme that has been validated as a promising therapeutic target for human cancer. Up to now, two small molecule PRMT5 inhibitors has been put into phase I clinical trial. In the present study, a series of candidate molecules were designed by combining key pharmacophores of formerly reported PRMT5 inhibitors. The in vitro PRMT5 inhibitory testing of compound 4b14 revealed an IC50 of 2.71 μM, exhibiting high selectivity over PRMT1 and PRMT4 (>70-fold selective). As expected, 4b14 exhibited potent anti-proliferative activity against a panel of leukemia and lymphoma cells, including MV4-11, Pfeiffer, SU-DHL-4 and KARPAS-422. Besides, 4b14 showed significant cell cycle arrest and apoptosis-inducing effects, as well as reduced the cellular symmetric arginine dimethylation level of SmD3 protein. Finally, affinity profiling analysis indicated that hydrophobic interactions, π-π stacking and cation-π actions made the major contributions to the overall binding affinity. This scaffold provides a new chemical template for further development of better lead compounds targeting PRMT5.

In this study, a series of compounds with 1,2,4-oxadiazole core was designed and synthesized for the optimization of JC01, an anti-inflammatory hit identified from our in-house compound library using NF-κB pathway luciferase assay and NO production assay. All the synthetic compounds 1-29 have been screened for their anti-inflammatory effects by evaluating their inhibition against LPS-induced NO release, and compound 17 exhibited the highest activity. Western blotting and immunofluorescence analysis revealed that 17 prominently inhibited LPS-induced activation of NF-κB in RAW264.7 cells and blocked the phosphorylation of p65. Consistent with these results, it was found that 17 prevented the nuclear translocation of NF-κB induced by LPS. These data highlighted 17 as a promising anti-inflammatory agent by inhibiting NF-κB activity.

Two new quinolone alkaloids, superbusines A (1) and B (2), were obtained from the whole plants of a Chinese medicinal plant, Dianthus superbus var. superbus. Their structures, featuring a glucosyl moiety linked with a rare 2-(hydroxymethyl)-5-(2-hydroxypropan-2-yl)phenol fragment, were determined on the basis of detailed spectroscopic analyses, and the absolute configurations were assigned by time-dependent density functional theory (TD-DFT)-based electronic circular dichroism (ECD) calculations. The two alkaloids were evaluated in a series of bioassays without showing antimicrobial, anti-inflammatory, antioxidant, cytotoxic and α-glucosidase inhibitory properties, while they exhibited slight protection against amyloid-β(Aβ)-induced injury on neuron SH-SY5Y cells.

Twenty-five novel pregnenolone/2-cyanoacryloyl conjugates (6-30) were designed and prepared, with the aim of developing novel anticancer drugs with dual NF-κB inhibitory and anti-proliferative activities. Compounds 22 and 27-30 showed inhibition against TNF-α-induced NF-κB activation in luciferase assay, which was confirmed by Western blotting. Among them, compound 30 showed potent NF-κB inhibitory activity (IC50=2.5μM) and anti-proliferative against MCF-7, A549, H157, and HL-60 cell lines (IC50=6.5-36.2μM). The present study indicated that pregnenolone/2-cyanoacryloyl conjugate I can server asa novel scaffold for developing NF-κB inhibitors and anti-proliferative agents in cancer chemotherapy.

A series of new cinnamic acid-pregenolone hybrids (5a-5o) was designed, synthesized and evaluated for their in vitro antiproliferative activity. Some of them showed potential antiproliferative activity and selectivity towards a panel of cancer cell lines, including A549, H157, HepG2, MCF-7, and HL-60. Among these analogs, compound 5f showed the most promising activity with IC50 values ranging from 3.2 to 6.8 μM, and it was taken as a model compound in the following antiproliferative mechanism study. In Hoechst 33258 staining assay, 5f-treated A549 cells displayed significant apoptosis characteristics. Flow cytometry analysis revealed that 5f showed the antiproliferative activity against A549 via G1 cell cycle arrest and inducing apoptosis. Western blotting analysis demonstrated that 5f enhanced apoptosis of A549 cells by down-regulating Bcl-2 and up-regulating Bax protein expression. The present study highlighted this series of cinnamic acid-pregenolone hybrids as a new antiproliferative lead prototype.

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.

Although the mechanism of Alzheimer’s disease (AD) is still not fully understood, the development of multifunctional AChE inhibitors remains a research focus for AD treatment. In this study, 48 AChE candidate inhibitors were picked out from SPECS database through a pharmacophore- and molecular docking-based virtual screening. The biological evaluation results indicated that four compounds 7, 29, 41 and 48 with different scaffolds exhibited potent and selective AChE inhibitory activity, with the best IC50 value of 1.62 ± 0.11 μM obtained for 48. Then their mechanism of action, the inhibition on Aβ aggregation, neurotoxicity, and neuroprotective activity against Aβ-induced nerve cell injury were well studied. The binding mode of 48 with AChE was also proposed. The present bioassay results indicated that these multifunctional AChE inhibitors were worth for further structural derivatization to make them the anti-AD lead compounds.

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 A&beta, 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&rsquo, s disease (AD) hit, and 12j could be highlighted as a multifunctional lead compound for anti-AD drug development.