Yearam Jung

Quantitative Relationships Between the Cytotoxicity of Flavonoids on the Human Breast Cancer Stem-Like Cells MCF7-SC and Their Structural Properties

As some breast cancer‐related deaths can be attributed to the metastasis of cancer stem cells, chemotherapeutic agents targeting breast cancer stem cells are of interest as a potential treatment. Flavonoids that exhibit cytotoxicity on breast cancer stem cells have rarely been observed. Thus, the objective of this study was to measure potential cytotoxic effects of 42 different flavonoids on the human breast cancer stem‐like cell line, MCF7‐SC. The relationship between flavonoid structural properties and cytotoxicity has not been reported previously; therefore, we determined quantitative structure–activity relationships using both comparative molecular field analysis and comparative molecular similarity analysis. Further biological experiments including Western blot analysis, flow cytometry, and immunofluorescence microscopy were also conducted on the most cytotoxic 8‐chloroflavanone.

1H and 13C NMR spectral assignments of novel flavonoids bearing benzothiazepine

Benzothiazepine is a heterocyclic compound containing nitrogen and sulfur. A variety of derivatives can be designed by modifying the positions of the double bond and benzene ring. 2,3-Dihydro1,5-benzothiazepine (also known as 2,3-dihydro[b][1,4]thiazepine) derivatives show diverse biological activities, including inhibitory effects on alpha-glucosidase, urease, cholinesterase, and butyrylcholinesterase, and agonistic activity toward the transient receptor potential ankyrin 1 (TRPA1) receptor (Fig. 1(A)). When two benzene rings are attached at the C-2 and C-4 positions, 2,4-diphenyl2,3-dihydro-1,5-benzothiazepine containing a C6-C3-C6 skeleton can be derived (Fig. 1(B)). Flavonoids are found in various plants as their secondary metabolites and are composed of C6-C3-C6 skeletons (Fig. 1(C)). Because methoxylation and naphthalenyl groups can increase cellular compartmentation and cell permeability, we designed and synthesized methoxylated 4-(1-hydroxy-naphthalen-2-yl)-2-phenyl-2,3-dihydro-1,5-benzothiazepine derivatives (Fig. 1(D)). However, flavonoids bearing a benzothiazepine skeleton have rarely been reported, even though their design and synthesis are of interest because of their biological diversity. Furthermore, because the 1H and 13C NMR, and high resolution mass spectrometric (HR/MS) data can be used as references for further study, herein, we report the NMR and MS data of 27 novel flavonoids bearing benzothiazepine skeletons.

1H and 13C NMR spectral assignments of naphthalenyl chalcone derivatives

Cellular homeostasis of reduction and oxidation is maintained by the elimination and generation of reactive oxygen species (ROS). In cancer cells, the amount of ROS produced by glycolysis is higher than that of normal cells. As a result, ROS generation is more lethal to cancer cells than normal cells. This phenomenon has been applied to the development of chemotherapeutic agents. Compounds generating ROS can be potent anticancer drugs and selectively kill cancer cells. ROS consist of hydroxy radicals, hydrogen peroxide, and superoxide. Many ROS-generating natural compounds are known, including curcumin, piperlongumine, chalcone, and cinnamaldehyde (Fig. 1A). All these compounds contain a Michael acceptor moieties, which are known to generate ROS. The ability to generate ROS depends upon the aromatic rings or substituents attached to the α,β-unsaturated carbonyl group, as shown in inset of Fig. 1A. We designed compounds containing α,β-unsaturated carbonyl groups with a 2-hydroxyphenyl substituent attached to the ketone carbon and a naphthalenyl group attached to the beta carbon (Fig. 1B) and synthesized 30 naphthalenyl chalcone derivatives. Their complete H and C Nuclear magnetic resonance (NMR) data and high-resolution mass spectrometric (HRMS) data are reported here as references for identifying newly synthesized derivatives or those isolated from natural sources in the future.

Colorectal anticancer activities of polymethoxylated 3-naphthyl-5-phenylpyrazoline-carbothioamides.

To develop potent chemotherapeutic agents for treating colorectal cancers, polymethoxylated 3-naphthyl-5-phenylpyrazoline-carbothioamide derivatives were designed. Twenty-two novel derivatives were synthesized and their cytotoxicities were measured using a clonogenic long-term survival assay. Of these derivatives, 3-(1-hydroxynaphthalen-2-yl)-N-(3-methoxyphenyl)-5-(4-methoxyphenyl)-pyrazoline-1-carbothioamide (NPC 15) exhibited the best half-maximal cell growth inhibitory concentrations (196.35nM). To explain its cytotoxicity, further biological experiments were performed. Treatment with NPC 15 inhibited cell cycle progression and triggered apoptosis through the caspase-mediated pathway. Its inhibitory effects on several kinases participating in the cell cycle were investigated using an in vitro kinase assay. Its half-maximal inhibitory concentrations for aurora kinases A and B were 105.03μM and 8.53μM, respectively. Further analysis showed that NPC 15 decreased phosphorylation of aurora kinases A, B, and C and phosphorylation of histone H3, a substrate of aurora kinases A and B. Its molecular binding mode for aurora kinase B was elucidated using in silico docking. In summary, polymethoxylated 3-naphthyl-5-phenylpyrazoline-carbothioamides could be potent chemotherapeutic agents.

1H and 13C NMR spectral assignments of 18 novel polymethoxylated hydroxynaphthopyrazolylchalconoids

Among plant-derived polyphenols produced via phenylpropanoids pathway, chalcones are biosynthesized by a combination of 4-coumaroyl-CoA with malonyl-CoA. Chalcones are known as chalconoids (Figure 1A). They consist of two benzene rings connected via the α,β-unsaturated carbonyl group, which may close to form another ring, to give flavonoids with three rings. It was known that chalconoids act as potassium channel blockers and aromatase inhibitors. As reported previously, some chalconoids can be converted to flavonoids easily (Fig. 1B). Therefore, their stabilities remained to be solved to develop as biological active compounds. A substitution of α,β-unsaturated carbonyl group with pyrazoline group (pyrazolylchalconoids) can prevent the conversion of chalconoids to flavonoids (Fig. 1C). Methoxylation increases the cell permeability and stability of many plant-derived polyphenols. We designed hydroxynaphthopyrazolylchalconoids with hydroxynaphthyl A-ring and trimethoxylated B-ring (Fig. 1D), and synthesized 18 derivatives. Their NMR data and mass spectrometric (MS) data can help us to identify plant-derived polyphenols newly synthesized or isolated from natural sources in the future, thus, we report here the complete H and C NMR data and high-resolution MS data.

1) H and (13) C NMR spectral assignments of novel naphthalenylphenylpyrazolines.

Compounds containing pyrazolinyl-1-carbothioamide scaffolds (Fig. 1A) can act as anticancer agents, antimicrobial agents, and monoamine oxidase inhibitors. When ethyl 2-bromoacetate is added to pyrazolinyl-1-carbothioamide, 2-pyrazolin-1-ylthiazol4(5H)-one (Fig. 1B) is produced. Compounds containing thiazolone scaffolds show hepatitis C virus inhibitory effects, antitubercular, antibacterial, and antimicrobial activities. We designed naphthalenylphenylpyrazolinyl-1-carbothioamides (Fig. 1C) and naphthalenylphenyl-2-pyrazolin-1-ylthiazol-4(5H)-ones (Fig. 1D). Five thousand compounds containing pyrazolinyl-1-carbothioamide scaffolds and three thousand compounds containing 2-pyrazolin-1ylthiazol-4(5H)-one scaffolds have been reported. Similar to chalcones (Fig. 1E), naphthalenylphenylpyrazolinyl-1-carbothioamides and naphthalenylphenyl-2-pyrazolin-1-ylthiazol-4(5H)-ones contain a C6C3-C6 skeleton. Chalcones are a group of plant-derived polyphenols. Because of their diverse biological activities, chalcones are still being derivatized. Therefore, the NMR and mass spectrometric (MS) data of the compounds we have designed and synthesized could help us identify newly synthesized derivatives or derivatives isolated from natural sources in the future. We report herein the complete H and C NMR data and high resolution MS data of 13 novel naphthalenylphenylpyrazolinyl-1-carbothioamides and five novel naphthalenylphenylpyrazolinyl-1-thiazol-4(5H)-ones.

1) H and (13) C NMR spectral assignments of 19 novel polymethoxylated diphenylnaphthylpyrazolinylcarbothioamides.

Chalcones are secondary metabolites in plants produced via the phenylpropanoid pathway. Because 2-hydroxychalcones (Fig. 1A) are known to show various biological activities including anticancer and antioxidative effects, their derivatives have been investigated and reported. However, cyclization of 2hydroxychalcones results in the formation of flavanones. As such, the α,β-unsaturated carbonyl group was replaced with a pyrazoline group (Fig. 1B). Diphenylpyrazolines contain a C6-C3-C6 skeleton similar to chalcones, and they show more biological activities including tyrosinase inhibition, antimicrobial effects, and monoamine oxidase inhibition. Diphenylpyrazolinyl-1-carbothioamdes (Fig. 1C) show dual inhibitory effects on monoamine oxidase and cholinesterase. Therefore, we designed phenyl-N-phenyl-naphthalenylpyrazolinyl-1-carbothioamide (Fig. 1D) and synthesized 19 derivatives. Pyrazolinyl-1-carbothioamdes are important because of their diverse biological activities, and their NMR and mass spectrometric (MS) data can aid in the identification of newly synthesized or isolated derivatives in the future. Therefore, we report herein the complete H and C NMR and highresolution MS data of 19 novel polymethoxylated diphenylnaphthylpyrazolinyl-1-carbothioamides.

1H and 13C NMR spectral assignments of flavone derivatives

We prepared 2′,3′-naphthoflavones and 3′,4′-naphthoflavones with an additional benzene ring at the B-ring of flavone. Out of the 36 flavone derivatives prepared, 19 derivatives are novel. We obtained the complete H and C NMR as well as high-resolution mass (HRMS) spectral data of the 36 flavone derivatives to identify the newly synthesized derivatives or those isolated from natural sources in the future.

Flavones with inhibitory effects on glycogen synthase kinase 3β

Because glycogen synthase kinase-3 (GSK-3) activity is linked to various human diseases, it has been targeted in new drug development. Flavonoids, including luteolin, apigenin, and quercetin, inhibit GSK-3β; however, the relationships between their structural properties and inhibitory effects are unclear. We measured the inhibitory effects of 34 flavonoid derivatives on GSK-3β and calculated hologram quantitative structure–activity relationships to provide information on pharmacophores for designing novel compounds with better activities. The in vitro binding effect of flavonoids was confirmed using Western blotting for myricetin, which showed the best inhibitory activity, and the binding mode between myricetin and GSK-3β was elucidated using in silico docking.

Relationships Between the Structural Properties of Flavonoids and their Inhibitory Activities Against Matrix Metallopeptidase 9

Targeting of MMP-9 could be a useful approach for anticancer therapy. The inhibitory activities of 23 flavonoids on tumor necrosis factors alpha (TNF alpha)-induced matrix metalloproteinases 9 (MMP-9) gene expression were analyzed quantitatively. To elucidate the relationships between the structural...