Yifeng Jin

Pharmacological effects of berberine and its derivatives: a patent update

ABSTRACT Introduction: A number of plant-derived agents are used in many therapeutic areas. Berberine, an important protoberberine alkaloid, is present in a number of medicinal plants that have been widely used in traditional Chinese medicine for hundreds of years. Modern research has shown that berberine and its derivatives display several pharmacological effects through various mechanisms. Areas covered: This review discusses recent and mostly Chinese patents that report the synthesis of berberine, berberine derivatives and berberine salts, and methods of preparation for formulations (traditional Chinese medicine) containing herbal components rich in berberine, along with their applications. The review covers several therapeutic effects of berberine, its derivatives and pharmaceutical formulations against cancer, obesity, diabetes, inflammation, atherosclerosis, Alzheimer’s disease, rheumatoid arthritis and cardiovascular diseases. In addition, the mechanisms underlying the pharmacological effects are discussed. Expert opinion: Modification of the functional groups of berberine has a significant effect on the pharmacological activity. However, studies on altering the atoms and size of the berberine skeleton are rare. Thus, it may be beneficial to initiate a drug development program focused on inserting heterocyclic rings of different sizes into berberine. Furthermore, structural modification to improve the safety, efficacy and selectivity is necessary to promote the use of berberine-based drugs in clinical settings.

Design, synthesis and systematic evaluation of cytotoxic 3-heteroarylisoquinolinamines as topoisomerases inhibitors.

A series of 3-heteroarylisoquinolinamines were designed, synthesized and evaluated for cytotoxicity, topoisomerases (topos) inhibitory activities and cell cycle inhibition. Several of the 3-heteroarylisoquinolines exhibited selective cytotoxicity against human ductal breast epithelial tumor (T47D) cells over non-cancerous human breast epithelial (MCF-10A) and human prostate cancer (DU145) cells. Most of the derivatives showed greater cytotoxicity in human colorectal adenocarcinoma (HCT-15) cells than camptothecin (CPT), etoposide and doxorubicin (DOX). Generally, 3-heteroarylisoquinolinamines displayed greater affinity for topo I than topo II. 3-Heteroarylisoquinolinamines with greater topo I inhibitory effect exhibited potent cytotoxicity. Piperazine-substituted derivative, 5b, with potent topo I and moderate topo II activities intercalated between DNA bases and interacted with topos through H-bonds at the DNA cleavage site of a docking model. Moreover, flow cytometry indicated that cytotoxic 3-heteroarylisoquinolinamines led to accumulation of human cervical (HeLa) cancer cells in the different phases of the cell cycle before apoptosis. Taken together, 3-heteroarylisoquinolinamines possessed potent cytotoxicity with topos and cell cycle inhibitory activities.

Substituted 2-arylquinazolinones: Design, synthesis, and evaluation of cytotoxicity and inhibition of topoisomerases.

A series of 2-arylquinazolinones with structural homology to known 3-arylisoquinolines were designed and synthesized in order to develop safe, effective, and selective cytotoxic agents targeting topoisomerases (topos). 2-Arylquinzolinones with various substitutions on the aromatic rings were obtained by thermal cyclodehydration/dehydrogenation on reacting anthranilamides and benzaldehydes. The compounds had superior topo I-inhibitory activities but were generally inactive against topo IIα. Among the 6-methyl-, 6-amino-, and 7-methylquinazolinones, 6-amino-substituted derivatives displayed potent cytotoxicity at submicromolar to nanomolar concentrations against human colorectal adenocarcinoma cells (HCT-15), human ductal breast epithelial tumor cells (T47D), and cervical cancer cells (HeLa). There was a good correlation between topo I inhibition and the cytotoxic effects of 6-aminoquinazolinones. Docking models demonstrated that topo I inhibition by these compounds is owing to intercalation and H-bond interactions with the DNA bases and amino acid residues at the enzymatic site.

Modification of 3-arylisoquinolines into 3,4-diarylisoquinolines and assessment of their cytotoxicity and topoisomerase inhibition

Inspired by the initial success of the monoarylisoquinolines and the quest to identify more potent and selective anticancer agents with topoisomerase (topo) inhibitory activity, series of diarylisoquinolines (3,4-diarylisoquinolones and 3,4-diarylisoquinolinamines) were designed and synthesized. Synthesis of these compounds primarily involved lithiated toluamide-benzonitrile cycloaddition, Suzuki coupling, and nucleophilic aromatic substitution reactions. Eight of the derivatives were selectively toxic against human ductal breast epithelial tumor cells (T47D), human prostate cancer cells (DU145), and human colorectal adenocarcinoma cells (HCT-15), but had no effect on normal human breast epithelial cells (MCF10A). The topo inhibitory activities of the diarylisoquinoline compounds were relatively dependent upon their chemical structure. 3,4-Diarylisoquinolones generally did not inhibit topo I and only showed moderate inhibition of topo II. In contrast, several 3,4-diarylisoquinolinamines showed superior topo I inhibitory activity. Isoquinolinamine derivatives had greater affinity for topo I than for topo II. Topo inhibition by 3,4-diarylisoquinolines was further supported by docking models showing intercalative and/or H-bond interactions between these compounds and the DNA/topo(s). An analysis of the correlation between the cytotoxicity and topo inhibition of these compounds indicated that the primary biological target of derivatives with potent cytotoxicity was topo, which in turn establishes diaryl-substituted isoquinolines as a novel class of potential anticancer drugs.

Structure-Based Discovery of Novel Cyclophilin A Inhibitors for the Treatment of Hepatitis C Virus Infections

Hepatitis C virus (HCV) is a major cause of end-stage liver disease. Direct-acting antivirals (DAAs), including inhibitors of nonstructural proteins (NS3/4A protease, NS5A, and NS5B polymerase), represent key components of anti-HCV treatment, but these are associated with increased drug resistance and toxicity. Thus, the development of host-targeted antiviral agents, such as cyclophilin A inhibitors, is an alternative approach for more effective, selective, and safer treatment. Starting with the discovery of a bis-amide derivative 5 through virtual screening, the lead compound 25 was developed using molecular modeling-based design and systematic exploration of the structure-activity relationship. The lead 25 lacked cytotoxicity, had potent anti-HCV activity, and showed selective and high binding affinity for CypA. Unlike cyclosporin A, 25 lacked immunosuppressive effects, successfully inhibited the HCV replication, restored host immune responses without acute toxicity in vitro and in vivo, and exhibited a high synergistic effect in combination with other drugs. These findings suggest that the bis-amides have significant potential to extend the arsenal of HCV therapeutics.

Computer-aided discovery of aminopyridines as novel JAK2 inhibitors.

The Janus kinase 2 (JAK2)-mediated signaling pathway plays an important role in controlling cell survival, proliferation, and differentiation. In recent years, genetic, biological, and physiological evidence has established JAK2 inhibitors as effective chemotherapeutic agents for the treatment of many different cancers. For this reason, we sought to identify novel small molecule inhibitors of JAK2. Using Surflex-Dock software, we tested 3010 compounds with known chemical structures in silico for their ability to interact with the JAK2 ATP-binding pocket. We selected the 10 highest-scoring compounds and tested their abilities to inhibit JAK2 activity in vitro. Compound 1a (ethyl 1-(5-((3-methoxyphenyl)carbamoyl)-3-nitropyridin-2-yl)piperidine-4-carboxylate) was identified. Optimization of 1a using docking studies led to the discovery of compounds 1b and 1d, potent JAK2 inhibitors. Furthermore, as V-shaped kinase inhibitors can curve around the protein backbone and access deep into the pocket, we developed a new series of compounds with a non-linear sulfonamide bond. Nine compounds were prepared and evaluated for JAK2 inhibitory effects. Compounds 7e (IC50=6.9μM) and 7h (IC50=12.2μM) showed better JAK2 inhibition, validating our design approach. This study successfully applied virtual screening for hit discovery, and a docking study for hit optimization. In addition, a novel approach to drug discovery, combining structure- and shape-based drug design, facilitated the design of more potent JAK2 inhibitors. The methods provide a guide for future development of inhibitors targeting JAK2 and other kinases.

Berberine bioisostere Q8 compound stimulates osteoblast differentiation and function in vitro

Graphical abstract Figure. No Caption available. ABSTRACT The Q8 compound is a unique derivative of berberine. The present study investigated the functional role of Q8 to evaluate its potential for use in bone regeneration, especially in osteoblast differentiation. The safe concentration of Q8 increased BMP4‐induced alkaline phosphatase (ALP) activity, and induced RNA expression of ALP, bone sialoprotein (BSP), and osteocalcin (OC). The activities of ALP‐, BSP‐ and OC‐luciferase reporters were also increased by Q8. During osteoblast differentiation, Q8 stabilized the Runx2 and Osterix protein abundance by blocking the ubiquitin‐proteasome pathway, which in turn promoted Runx2 and Osterix induced transcriptional activity and subsequently increased the osteoblast differentiation. Meanwhile, depletion of Runx2 and Osterix markedly abolished the bone anabolic effect of Q8 on osteoblast differentiation. To evaluate the signal transduction pathway involved in the Q8‐mediated regulation of Runx2 and Osterix, we examined the reporter assay using various kinase inhibitors. Treatment with a protein kinase A (PKA) inhibitor, H89 inhibited the Q8‐mediated regulation of Runx2 and Osterix. Based on these findings, this study demonstrates that Q8 promotes the osteoblast differentiation by stabilization of Runx2/Osterix through the increased activation of PKA signaling. The enhancement of osteoblast function by Q8 may contribute to the prevention for osteoporosis.

Discovery of Isoquinolinoquinazolinones as a Novel Class of Potent PPARγ Antagonists with Anti-adipogenic Effects.

Conformational change in helix 12 can alter ligand-induced PPARγ activity; based on this reason, isoquinolinoquinazolinones, structural homologs of berberine, were designed and synthesized as PPARγ antagonists. Computational docking and mutational study indicated that isoquinolinoquinazolinones form hydrogen bonds with the Cys285 and Arg288 residues of PPARγ. Furthermore, SPR results demonstrated strong binding affinity of isoquinolinoquinazolinones towards PPARγ. Additionally, biological assays showed that this new series of PPARγ antagonists more strongly inhibit adipocyte differentiation and PPARγ2-induced transcriptional activity than GW9662.

Design and synthesis of novel androgen receptor antagonists via molecular modeling

Several androgen receptor (AR) antagonists are clinically prescribed to treat prostate cancer. Unfortunately, many patients become resistant to the existing AR antagonists. To overcome this, a novel AR antagonist candidate called DIMN was discovered by our research group in 2013. In order to develop compounds with improved potency, we designed novel DIMN derivatives based on a docking study and substituted carbons with heteroatom moieties. Encouraging in vitro results for compounds 1b, 1c, 1e, 3c, and 4c proved that the new design was successful. Among the newly synthesized compounds, 1e exhibited the strongest inhibitory effect on LNCaP cell growth (IC50=0.35μM) and also acted as a competitive AR antagonist with selectivity over the estrogen receptor (ER) and the glucocorticoid receptor (GR). A docking study of compound 1e fully supported these biological results. Compound 1e is considered to be a novel, potent and AR-specific antagonist for treating prostate cancer. Thus, our study successfully applied molecular modeling and bioisosteric replacement for hit optimization. The methods here provide a guide for future development of drug candidates through structure-based drug discovery and chemical modifications.