Caldomycin, a new guanidopolyamine produced by a novel agmatine homocoupling enzyme involved in homospermidine biosynthesis

An extreme thermophilic bacterium, Thermus thermophilus produces more than 20 unusual polyamines, but their biosynthetic pathways, including homospermidine, are not yet fully understood. Two types of homospermidine synthases have been identified in plants and bacteria, which use spermidine and putrescine or two molecules of putrescine as substrates. However, homospermidine synthases with such substrate specificity have not been identified in T. thermophilus. Here we identified a novel agmatine homocoupling enzyme that is involved in homospermidine biosynthesis in T. thermophilus. The reaction mechanism is different from that of a previously described homospermidine synthase, and involves conjugation of two molecules of agmatine, which produces a diamidino derivative of homospermidine (caldomycin) as an immediate precursor of homospermidine. We conclude that there is a homospermidine biosynthetic pathway from agmatine via caldomycin synthase followed by ureohydrolase in T. thermophilus. Furthermore, it is shown that caldomycin is a novel compound existing in nature.

Synthesis of 2,8-Dioxabicyclo[3.3.1]nonane Derivatives and Their Neuroprotective Activities

Twenty natural-product-like 2,8-dioxabicyclo[3.3.1]nonane derivatives were synthesized and their neuroprotective activities were tested using human monoamine oxidases (MAO) A and B and acetyl and butyryl cholinesterases (ChE). Compound 1s showed inhibitory activity for MAO-A, MAO-B and acetylcholinesterase (AChE) (IC50 values 34.0, 2.3 and 11.0 µM, respectively). The inhibition mode of (-)-1s for MAO-B was investigated. Chiral HPLC of (±)-1s separated the enantiomers and (-)-1s showed MAO-B inhibitory activity. Molecular docking simulation of (-)-1s and MAO-B revealed the binding mode.

Synthesis and Biological Evaluation of 2-Azolylmethylene-3-(2H)-benzofuranone Derivatives as Potent Monoamine Oxidases Inhibitors

A series of 2-azolylmethylene-3-(2H)-benzofuranone derivatives, 2-indolylmethylene-3-(2H)-benzofuranone and 2-pyrrolylmethylene-3-(2H)-benzofuranone derivatives, were synthesized, and their monoamine oxidase (MAO) A and B inhibitory activities were evaluated. Compounds 1b, 3b, 6b, 7b, and 10b showed strong inhibitory activity against MAO-A, and compound 3b showed the highest potency and selectivity, with an IC50 value of 21 nM and a MAO-A selectivity index of 48. Compounds 3c, 4c, 9a, 9c, 10c, 11a, and 11c showed strong inhibitory activity against MAO-B, and compound 4c showed the highest potency and selectivity, with an IC50 value of 16 nM and a MAO-B selectivity index of >1100. Further analysis of these compounds indicated that compound 3b for MAO-A and compound 4c for MAO-B were competitive inhibitors, with Ki values of 10 and 6.1 nM, respectively. Furthermore, computational analyses, such as quantitative structure-activity relationship (QSAR) analysis of the 2-azolylmethylene-3-(2H)-benzofuranone derivatives conducting their pIC50 values with the Molecular Operating Environment (MOE) and Mordred, and molecular docking analysis using MOE-Dock supported that the 2-azolylmethylene-3-(2H)-benzofuranone derivatives are a privileged scaffold for the design and development of novel MAO inhibitors.

A Tricyclic Aromatic Polyketide Isolated from the Marine-Derived Fungus Curvularia aeria

A novel tricyclic polyketide, curvulanone (1), was isolated from the marine-derived fungus Curvularia aeria. The structure of 1 was determined by NMR and single-crystal X-ray crystallography. 1 had a cyclopentabenzopyranone with 3-acetic acid structure that is rarely found in natural compounds. Monoamine oxidase and sirtuin 1 inhibitory test was exhibited and 1 showed their inhibitory activity.

Potentiation of Anticancer Activity of G2/M Blockers by Mild Hyperthermia

BACKGROUND/AIM

Hyperthermia (HT), combined with chemotherapy, has been used to treat various types of cancer. This study aimed to investigate the HT-sensitivity of malignant and non-malignant cells, and then evaluate the combination effect of docetaxel (DTX) and a newly synthesized chromone derivative (compound A) with HT.

MATERIALS AND METHODS

The number of viable cells was determined using the MTT method. Cell cycle distribution was analyzed using a cell sorter, and DNA fragmentation pattern was detected using agarose gel electrophoresis.

RESULTS

Among 12 cultured cells, oral squamous cell carcinoma (OSCC), especially Ca9-22 cells, and myelogenous leukemia cells showed higher sensitivity to HT than lung carcinoma and glioblastoma cell lines, while normal oral cells were the most resistant. Cytotoxicity of DTX on Ca9-22 cells was maximum at 41-42°C and 45~60 min exposure to HT. DXT, compound A, and HT induced G2/M arrest of Ca-22 cells. Mild HT enhanced the DTX- and compound A-induced subG1 arrest, in a synergistic fashion.

CONCLUSION

The combination G2/M blockers and mild-HT can potentially be used for the treatment of OSCC.

A Comparative Study of Tumor-Specificity and Neurotoxicity between 3-Styrylchromones and Anti-Cancer Drugs

Background. Many anti-cancer drugs used in clinical practice cause adverse events such as oral mucositis, neurotoxicity, and extravascular leakage. We have reported that two 3-styrylchromone derivatives, 7-methoxy-3-[(1E)-2-phenylethenyl]-4H-1-benzopyran-4-one (Compound A) and 3-[(1E)-2-(4-hydroxyphenyl)ethenyl]-7-methoxy-4H-1-benzopyran-4-one (Compound B), showed the highest tumor-specificity against human oral squamous cell carcinoma (OSCC) cell lines among 291 related compounds. After confirming their superiority by comparing their tumor specificity with newly synthesized 65 derivatives, we investigated the neurotoxicity of these compounds in comparison with four popular anti-cancer drugs. Methods: Tumor-specificity (TS_M, TS_E, TS_N) was evaluated as the ratio of mean CC₅₀ for human normal oral mesenchymal (gingival fibroblast, pulp cell), oral epithelial cells (gingival epithelial progenitor), and neuronal cells (PC-12, SH-SY5Y, LY-PPB6, differentiated PC-12) to OSCC cells (Ca9-22, HSC-2), respectively. Results: Compounds A and B showed one order of magnitude higher TS_M than newly synthesized derivatives, confirming its prominent tumor-specificity. Docetaxel showed one order of magnitude higher TS_M, but two orders of magnitude lower TS_E than Compounds A and B. Compounds A and B showed higher TS_M, TS_E, and TS_N values than doxorubicin, 5-FU, and cisplatin, damaging OSCC cells at concentrations that do not affect the viability of normal epithelial and neuronal cells. QSAR prediction based on the Tox21 database suggested that Compounds A and B may inhibit the signaling pathway of estrogen-related receptors.

Total Synthesis and Monoamine Oxidase Inhibitory Activities of (±)-Entonalactam A and Its Derivatives

The first total synthesis of isoindolinone (±)-entonalactam A (6), originally obtained from the fungus Entonaema sp., was achieved in 14 steps from commercially available 5-bromovanillin via benzophenone intermediates. Isoindolinone, phthalide, and benzophenone analogues of natural products were also synthesized. The monoamine oxidase (MAO) A and B inhibitory activities were tested. The isoindolinone derivative 30 exhibited inhibition of both MAO-A and -B (IC₅₀ = 17.8 and 15.8 μM, respectively).

Polyamines produced by an extreme thermophile are essential for cell growth at high temperature

An extreme thermophile, Thermus thermophilus grows at an optimum temperature of around 70 oC and produces 16 different polyamines including long-chain and branched-chain polyamines. We found that the composition of polyamines in the thermophile cells changes with culture temperature. Long-chain and branched-chain polyamines (unusual polyamines) were increased in the cells grown at high temperature such as 80 oC, but they were minor components in the cells grown at relatively lower temperature such as 60 oC. The effects of polyamines on cell growth were studied using T. thermophilus HB8 ΔspeA deficient in arginine decarboxylase. Cell growth of this mutant strain was significantly decreased at 70 oC. This mutant strain cannot produce polyamines and grows poorly at 75 oC. It was also determined whether polyamines are directly involved in protecting DNA from DNA double-strand breaks induced by heat. Polyamines protected DNA against double-strand breaks. Therefore, polyamines play essential roles in cell growth at extremely high temperature through maintaining a functional conformation of DNA against DNA double-strand breaks and depurination.

A Dual Anti-Inflammatory and Anti-Proliferative 3-Styrylchromone Derivative Synergistically Enhances the Anti-Cancer Effects of DNA-Damaging Agents on Colon Cancer Cells by Targeting HMGB1-RAGE-ERK1/2 Signaling

The current anti-cancer treatments are not enough to eradicate tumors, and therefore, new modalities and strategies are still needed. Most tumors generate an inflammatory tumor microenvironment (TME) and maintain the niche for their development. Because of the critical role of inflammation via high-mobility group box 1 (HMGB1)–receptor for advanced glycation end-products (RAGE) signaling pathway in the TME, a novel compound possessing both anti-cancer and anti-inflammatory activities by suppressing the HMGB1-RAGE axis provides an effective strategy for cancer treatment. A recent work of our group found that some anti-cancer 3-styrylchromones have weak anti-inflammatory activities via the suppression of this axis. In this direction, we searched such anti-cancer molecules possessing potent anti-inflammatory activities and discovered 7-methoxy-3-hydroxy-styrylchromone (C6) having dual suppressive activities. Mechanism-of-action studies revealed that C6 inhibited the increased phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) under the stimulation of HMGB1-RAGE signaling and thereby suppressed cytokine production in macrophage-like RAW264.7 cells. On the other hand, in colorectal cancer HCT116 cells, C6 inhibited the activation of ERK1/2, cyclin-dependent kinase 1, and AKT, down-regulated the protein level of XIAP, and up-regulated pro-apoptotic Bax and caspase-3/7 expression. These alterations are suggested to be involved in the C6-induced suppression of cell cycle/proliferation and initiation of apoptosis in the cancer cells. More importantly, in cancer cells, the treatment of C6 potentiates the anti-cancer effects of DNA-damaging agents. Thus, C6 may be a promising lead for the generation of a novel class of cancer therapeutics.

Epicardial adipose tissue is associated with exercise intolerance in patients with diabetes with asymptomatic left ventricular structural and functional abnormalities

Background

The volume of epicardial adipose tissue (EAT), which is an index of visceral fat, is high in patients with type 2 diabetes mellitus (T2DM) and may affect the myocardial performances. However, the association between EAT and left ventricular (LV) structure and function, and exercise capacity in patients with asymptomatic heart failure has not been studied.

Aims

To elucidate whether the volume of EAT deteriorates the exercise capacity in patients with T2DM.

Methods

EAT thickness and LV structural and functional abnormality components (e.g., global longitudinal strain, E/e', LV mass index, relative wall thickness) were measured with echocardiography in 176 patients with asymptomatic heart failure (Stage A and B) and 62 healthy controls (HC). To evaluate exercise capacity, peak oxygen uptake (peakVO2) was measured by using the cardiopulmonary exercise testing.

Results

Lipid metabolism, glucose metabolism, brain natriuretic peptide and estimated glomerular filtration rate at cystatin were worse in the heart failure (HF) group than in the HC. The EAT was significantly thicker and peakVO2 was lower in patients with LV structural and functional abnormalities than in individuals without these abnormalities (p<0.001). As the number of LV structural and functional abnormality components increased, the thickness of the EAT increased and peakVO2 decreased (p<0.001). The EAT thickness (β=−0.207) was negatively correlated with peakVO2, even after adjusting for multivariates (R2=0.724).

Conclusions

In patients with T2DM with asymptomatic heart failure, EAT is associated with LV structural and functional abnormalities. It also suggests that increase of visceral fat around myocardium contributes to exercise intolerance.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): National University Corporation Tsukuba University of Technology education and research Grant

A 3-styrylchromone converted from trimebutine 3D pharmacophore possesses dual suppressive effects on RAGE and TLR4 signaling pathways

Receptor for advanced glycation end-products (RAGE) and Toll-like receptors (TLRs) are potential therapeutic targets in the treatment of acute and chronic inflammatory diseases. We previously reported that trimebutine, a spasmolytic drug, suppresses RAGE pro-inflammatory signaling pathway in macrophages. The aim of this study was to convert trimebutine to a new small molecule using in silico 3D pharmacophore similarity search, and dissect the mechanistic anti-inflammatory basis. Of note, a unique 3-styrylchromone (3SC), 7-methoxy-3-trimethoxy-SC (7M3TMSC), converted from trimebutine 3D pharmacophore potently suppressed both high mobility group box 1-RAGE and lipopolysaccharide-TLR4 signaling pathways in macrophage-like RAW264.7 cells. More importantly, 7M3TMSC inhibited the phosphorylation of extracellular signaling-regulated kinase 1 and 2 (ERK1/2) and downregulated the production of cytokines, such as interleukin-6. Furthermore, 3D pharmacophore-activity relationship analyses revealed that the hydrogen bond acceptors of the trimethoxy groups in a 3-styryl moiety and the 7-methoxy-group in a chromone moiety in this compound are significant in the dual anti-inflammatory activity. Thus, 7M3TMSC may provide an important scaffold for the development of a new type of anti-inflammatory dual effective drugs targeting RAGE/TLR4-ERK1/2 signaling.

Synthesis and antifungal activity of polycyclic pyridone derivatives with anti-hyphal and biofilm formation activity against Candida albicans

Thirty-five pyridone derivatives were synthesized, with derivatization conducted on polycyclic pyridone scaffolds, including cis- or trans-oxydecalin and other cyclic structures, by domino-Knoevenagel-electrocyclic reactions. The anti-fungal activities of the synthesized compounds were tested against Candida albicans. Ten compounds inhibited hyphal formation without inhibiting growth. Pyridones with anti-hyphal formation activity (4c, 6d, 12a and 12c) were tested for their ability to inhibit biofilm formation. Compound 6d showed both anti-hyphal and biofilm inhibition activity.

Safety and feasibility of minimally invasive esophagectomy for elderly esophageal cancer patients

The number of elderly patients with esophageal cancer has increased in recent years. The use of thoracoscopic esophagectomy has also increased, and its minimal invasiveness is believed to contribute to postoperative outcomes. However, the short- and long-term outcomes in elderly patients remain unclear. This study aimed to elucidate the safety and feasibility of minimally invasive esophagectomy in elderly patients. This retrospective study included 207 patients who underwent radical thoracoscopic esophagectomy for thoracic esophageal squamous cell carcinoma at Kobe University Hospital between 2005 and 2014. Patients were divided into non-elderly (<75 years) and elderly (≥75 years) groups. A propensity score matching analysis was performed for sex and clinical T and N stage, with a total of 29 matched pairs. General preoperative data, surgical procedures, intraoperative data, postoperative complications, in-hospital death, cancer-specific survival, and overall survival were compared between groups. The elderly group was characterized by lower preoperative serum albumin levels and higher American Society of Anesthesiologists grade. Intraoperative data and postoperative complications did not differ between the groups. The in-hospital death rate was 4% in the elderly group, which did not significantly differ from the non-elderly group. Cancer-specific survival was similar between the two groups. Although overall survival tended to be poor in the elderly group, it was not significantly worse than that of the non-elderly group. In conclusion, the short- and long-term outcomes of minimally invasive esophagectomy in elderly versus non-elderly patients were acceptable. Minimally invasive esophagectomy is a safe and feasible modality for elderly patients with appropriate indications.

Development of Newly Synthesized Chromone Derivatives with High Tumor Specificity against Human Oral Squamous Cell Carcinoma

Since many anticancer drugs show severe adverse effects such as mucositis, peripheral neurotoxicity, and extravasation, it was crucial to explore new compounds with much reduced adverse effects. Comprehensive investigation with human malignant and nonmalignant cells demonstrated that derivatives of chromone, back-bone structure of flavonoid, showed much higher tumor specificity as compared with three major polyphenols in the natural kingdom, such as lignin-carbohydrate complex, tannin, and flavonoid. A total 291 newly synthesized compounds of 17 groups (consisting of 12 chromones, 2 esters, and 3 amides) gave a wide range of the intensity of tumor specificity, possibly reflecting the fitness for the optimal 3D structure and electric state. Among them, 7-methoxy-3-[(1E)-2-phenylethenyl]-4H-1-benzopyran-4-one (compound 22), which belongs to 3-styrylchromones, showed the highest tumor specificity. 22 induced subG1 and G2 + M cell population in human oral squamous cell carcinoma cell line, with much less keratinocyte toxicity as compared with doxorubicin and 5-FU. However, 12 active compounds selected did not necessarily induce apoptosis and mitotic arrest. This compound can be used as a lead compound to manufacture more active compound.

Switching of band inversion and topological surface states by charge density wave

Topologically nontrivial materials host protected edge states associated with the bulk band inversion through the bulk-edge correspondence. Manipulating such edge states is highly desired for developing new functions and devices practically using their dissipation-less nature and spin-momentum locking. Here we introduce a transition-metal dichalcogenide VTe2, that hosts a charge density wave (CDW) coupled with the band inversion involving V3d and Te5p orbitals. Spin- and angle-resolved photoemission spectroscopy with first-principles calculations reveal the huge anisotropic modification of the bulk electronic structure by the CDW formation, accompanying the selective disappearance of Dirac-type spin-polarized topological surface states that exist in the normal state. Thorough three dimensional investigation of bulk states indicates that the corresponding band inversion at the Brillouin zone boundary dissolves upon the CDW formation, by transforming into anomalous flat bands. Our finding provides a new insight to the topological manipulation of matters by utilizing CDWs' flexible characters to external stimuli.

Syntheses and crystal structures of two piperine derivatives

The title compounds, 5-(2H-1,3-benzodioxol-5-yl)-N-cyclo-hexyl-penta-2,4-dienamide, C18H21NO3 (I), and 5-(2H-1,3-benzodioxol-5-yl)-1-(pyrrolidin-1-yl)penta-2,4-dien-1-one C16H17NO3 (II), are derivatives of piperine, which is known as a pungent component of pepper. Their geometrical parameters are similar to those of the three polymorphs of piperine, which indicate conjugation of electrons over the length of the mol-ecules. The extended structure of (I) features N-H⋯O amide hydrogen bonds, which generate C(4) [010] chains. The crystal of (II) features aromatic π-π stacking, as for two of three known piperine polymorphs.

Further Quantitative Structure-Cytotoxicity Relationship Analysis of 3-Styrylchromones

BACKGROUND/AIM

Very few studies are available about the biological activity of 3-styrylchromones. Our previous study demonstrated the importance of methoxy group at 6-position of the chromone ring and hydroxyl group at 4'-position of phenyl group in styryl moiety. As a sequel of this study, we synthesized fourteen compounds that include eight 3-styrylchromones where methoxy group was introduced at 7-position of chromone rings, and then evaluated their tumor-specificity.

MATERIALS AND METHODS

Tumor-specificity (TS) was calculated by relative cytotoxicity against human oral squamous cell carcinoma cell lines versus human normal oral cells. Apoptosis induction and growth arrest were monitored by cell-cycle analysis. Quantitative structure-activity relationship analysis of TS was performed with 3,167 chemical descriptors.

RESULTS AND DISCUSSION

Two compounds, 7-methoxy-3-[(1E)-2-phenylethenyl]-4H-1-benzopyran-4-one [7] and 3-[(1E)-2-(4-hydroxyphenyl)ethenyl]-7-methoxy-4H-1-benzopyran-4-one [14] showed higher tumor-specificity than doxorubicin and 5-FU, suggesting the importance of methoxy group in 7-position of the chromone ring. These compounds induced the apoptosis and mitotic arrest in HSC-2 cells. The tumor-specificity of 3-styrylchromone derivatives were most correlated with descriptors for molecule shape and electronic charge. The present study suggested that modification by introducing methoxy group at 7-position, instead at 6-position, further increased the tumor-specificity of 3-styrylchromone.

Quantitative Structure-Cytotoxicity Relationship of 2-Arylazolylchromones and 2-Triazolylchromones

BACKGROUND/AIM

4H-1-Benzopyran-4-one (chromone), present in various flavonoids as a backbone structure, has been used for the synthesis of anticancer drugs. The study aimed at investigating the cytotoxicity of eight 2-arylazolylchromones and twelve 2-triazolylchromones against four human oral squamous cell carcinoma (OSCC) cell lines and three human normal mesenchymal oral cells, and then performed a quantitative structure-activity relationship (QSAR) analysis.

MATERIALS AND METHODS

Cell viability was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The distribution of cells to various phases of cell cycle was determined by cell cycle analysis. A total of 3,218 physicochemical, structural and quantum chemical features were calculated for QSAR analysis from the most stabilized structure optimized using CORINA.

RESULTS

2-[4-(4-fluorophenyl)-1H-imidazol-1-yl]-4H-1-benzopyran-4-one [6] had the highest tumor-specificity (TS), comparable with that of 5-flurouracil (5-FU) and doxorubicin, inducing cytostatic growth inhibition, accumulation of G₂+M phase cells with no cells in the G₁ phase. All eight 2-triazolylchromones showed much lower tumor-specificity, confirming our previous finding. Tumor-specificity was also correlated with 3D shape, topological shape, size, ionization potential, and the presence of more than two aromatic rings in the molecule and imidazole ring in the nitrogen-containing heterocyclic ring.

CONCLUSION

[6] can be a lead compound for designing anticancer drugs.

Synthesis of natural product-like polyprenylated phenols and quinones: Evaluation of their neuroprotective activities

Twenty-seven natural product-like polyprenylated phenols and quinones were synthesized and their neuroprotective activity was tested using human monoamine oxidase B (MAO-B) and SH-SY5Y cells. Eight compounds inhibited MAO-B (IC₅₀ values < 25 μM) and the inhibition mode and molecular docking of two (8c and 16c) were investigated. Compounds inhibiting MAO-B activity were additionally tested for their ability to protect SH-SY5Y cells from peroxide injury. Three derivatives (3c, 8c and 16c) exhibited both MAO-B inhibitory and neuroprotective activity. A structure activity-relationship study showed that a phenolic hydroxyl group and a longer side chain are important for both activities.

P629Voluntary exercise associated with myokine production ameliorates cardiac remodeling and inflammation in a myocardial infarction mouse model

Background

Left ventricular (LV) remodeling, through excessive inflammation, leads to heart failure. Exercise (Ex) training is associated with a risk reduction in heart failure through direct and indirect mechanisms by which Ex contributes an anti-inflammatory effect. During Ex, contracting muscle fibers release myokines, including interleukins (ILs), tumor necrosis factor α (TNF-α), follistatin-like protein 1 (FSTL-1), and fibroblast growth factor 21 (FGF-21), into the bloodstream. These myokines may have beneficial effects on other damaged organs, such as an infarcted myocardium, through anti-inflammatory effects. However, the exact mechanisms of the anti-inflammatory effects of voluntary Ex in myocardial infarction (MI) are poorly understood. Therefore, we investigated the effect of voluntary Ex on cardiac remodeling and inflammation, the relationship between cardiac remodeling and skeletal muscle (SKM) response, and circulating myokine levels in a mouse model of MI.

Methods

Twelve-week-old male C57BL/6J mice were used and divided into the following 4 groups: sham operation (Sham), MI, Sham+Ex, and MI+Ex. MI was induced by ligation of the left anterior descending coronary artery. Ex groups began voluntary wheel running for 4 weeks after the operation. An echocardiography was performed at baseline and 4 weeks after the operation. The mRNA levels in the LV infarcted area and SKM were measured with RT-PCR and western blot analysis. Plasma levels of myokines were also measured with immunoassays.

Results

Four weeks after MI induction, echocardiographic evaluation showed that the MI mice had a larger LV end-diastolic diameter (LVEDD) and end-systolic diameter (LVESD) than the Sham mice. The MI mice also showed higher mRNA levels of TNF-α, IL-1β, IL-6, and IL-10 in the LV tissue when compared to the Sham mice. These changes were significantly ameliorated in the MI+Ex mice. Interestingly, in the MI+Ex mice, mRNA levels of IL-6, IL-1β, FSTL-1, and FGF-21 in the SKM were significantly higher than in the MI mice, while there were no significant differences in TNF-α and IL-10 levels in all groups. Similarly, protein expression levels of peroxisome proliferator-activated receptor gamma coactivator 1-alpha, sirtuin-1, and mitochondrial transcriptional factor A of mitochondrial function markers in SKM were also significantly higher in the MI+Ex mice than in the MI mice. Furthermore, there were significant correlations between plasma levels of IL-1β, but not other myokines, and LVEDD, and LVESD. In addition, there was also a significant correlation between the SKM IL-1β level and LVESD in the Sham+Ex mice (all, P<0.05).

Conclusions

Amelioration of cardiac remodeling and inflammation by voluntary Ex is associated with increased myokines, especially IL-1β, in a MI mouse model. These results suggest that increased myokine levels, through voluntary exercise, may play an important role in the prevention of cardiac remodeling after MI.

2-Styrylchromone derivatives as potent and selective monoamine oxidase B inhibitors

A series of eighteen 2-styrylchromone derivatives (see Chart 1) were synthesized and evaluated for their monoamine oxidase (MAO) A and B inhibitory activities. Many of the derivatives inhibited MAO-B comparable to pargyline (a positive control), and most of them inhibited MAO-B selectively. Of the eighteen derivatives, compound 9 having methoxy group at R¹ and chlorine at R⁴ showed both the best MAO-B inhibitory activity (IC₅₀ = 17 ± 2.4 nM) and the best MAO-B selectivity (IC₅₀ for MAO-A/IC₅₀ for MAO-B = 1500). The mode of inhibition of compound 9 against MAO-B was competitive and reversible. Quantitative structure-activity relationship (QSAR) analyses of the 2-styrylchromone derivatives were conducted using their pIC₅₀ values with the use of Molecular Operating Environment (MOE) and Dragon, demonstrating that the descriptors of MAO-B inhibitory activity and MAO-B selectivity were 1734 and 121, respectively, that showed significant correlations (P < 0.05). We then examined the 2-styrylchromone structures as useful scaffolds through three-dimensional-QSAR studies using AutoGPA, which is based on the molecular field analysis algorithm using MOE. The model using pIC₅₀ value indexes for MAO-B exhibited a determination coefficient (R²) of 0.873 as well as a Leave-One-Out cross-validated determination coefficient (Q²) of 0.675. These data suggested that the 2-styrylchromone structure might be a useful scaffold for the design and development of novel MAO-B inhibitors.

Recent Progress of Basic Studies of Natural Products and Their Dental Application

The present article reviews the research progress of three major polyphenols (tannins, flavonoids and lignin carbohydrate complexes), chromone (backbone structure of flavonoids) and herbal extracts. Chemical modified chromone derivatives showed highly specific toxicity against human oral squamous cell carcinoma cell lines, with much lower toxicity against human oral keratinocytes, as compared with various anticancer drugs. QSAR analysis suggests the possible correlation between their tumor-specificity and three-dimensional molecular shape. Condensed tannins in the tea extracts inactivated the glucosyltransferase enzymes, involved in the biofilm formation. Lignin-carbohydrate complexes (prepared by alkaline extraction and acid-precipitation) and crude alkaline extract of the leaves of Sasa species (SE, available as an over-the-counter drug) showed much higher anti-HIV activity, than tannins, flavonoids and Japanese traditional medicine (Kampo). Long-term treatment with SE and several Kampo medicines showed an anti-inflammatory and anti-oxidant effects in small size of clinical trials. Although the anti-periodontitis activity of synthetic angiotensin II blockers has been suggested in many papers, natural angiotensin II blockers has not yet been tested for their possible anti-periodontitis activity. There should be still many unknown substances that are useful for treating the oral diseases in the natural kingdom.

Protective Effects of Brain Infarction by N-Acetylcysteine Derivatives

BACKGROUND AND PURPOSE

We recently found that acrolein (CH₂=CH-CHO) is more strongly involved in brain infarction compared with reactive oxygen species. In this study, we looked for acrolein scavengers with less side effects.

METHODS

Photochemically induced thrombosis model mice were prepared by injection of Rose Bengal. Effects of N-acetylcysteine (NAC) derivatives on brain infarction were evaluated using the public domain National Institutes of Health image program.

RESULTS

NAC, NAC ethyl ester, and NAC benzyl ester (150 mg/kg) were administered intraperitoneally at the time of induction of ischemia, or these NAC derivatives (50 mg/kg) were administered 3× at 24-h intervals before induction of ischemia and 1 more administration at the time of induction of ischemia. The size of brain infarction decreased in the order NAC benzyl ester>NAC ethyl ester>NAC in both experimental conditions. Detoxification of acrolein occurred through conjugation of acrolein with glutathione, which was catalyzed by glutathione S-transferases, rather than direct conjugation between acrolein and NAC derivatives. The level of glutathione S-transferases at the locus of brain infarction was in the order of administration of NAC benzyl ester>NAC ethyl ester>NAC>no NAC derivatives, suggesting that NAC derivatives stabilize glutathione S-transferases.

CONCLUSIONS

The results indicate that detoxification of acrolein by NAC derivatives is caused through glutathione conjugation with acrolein catalyzed by glutathione S-transferases, which can be stabilized by NAC derivatives. This is a new concept of acrolein detoxification by NAC derivatives.

N1-Nonyl-1,4-diaminobutane ameliorates brain infarction size in photochemically induced thrombosis model mice

Inhibitors for polyamine oxidizing enzymes, spermine oxidase (SMOX) and N1-acetylpolyamine oxidase (PAOX), were designed and evaluated for their effectiveness in a photochemically induced thrombosis (PIT) mouse model. N1-Nonyl-1,4-diaminobutane (C9-4) and N1-tridecyl-1,4-diaminobutane (C13-4) competitively inhibited the activity of PAOX and SMOX in a manner comparable to N1,N4-bis(2,3-butadienyl)-1,4-butanediamine (MDL72527), an irreversible inhibitor of both enzymes. The two compounds were then tested for their effects in the PIT model. Both intraperitoneal (i.p.) and intracerebroventricular (i.c.v.) administration of C9-4 decreased infarct volumes significantly. By contrast, C13-4 reduced the volume of brain infarction by i.c.v. administration, but no reduction was observed after i.p. administration. C9-4 administered by i.p. injection reduced the volume of brain infarction significantly at doses of more than 3 mg/kg, and the dosage of 5 mg/kg or 10 mg/kg demonstrated the most potent effect and were more effective than equivalent doses of the other inhibitors such as MDL72527 and N-benzylhydroxylamine. I.P. injection of 5 mg/kg of C9-4 provided a therapeutic time window of longer than 12 h. This report demonstrates that C9-4 is a potent inhibitor of the polyamine oxidizing enzymes and is useful lead compound for candidate drugs with a long therapeutic time window, to be used in the treatment of ischemic stroke.

Quantitative Structure-Cytotoxicity Relationship of Cinnamic Acid Phenetyl Esters

BACKGROUND/AIM

Many phenolic acid phenethyl esters possess diverse biological effects including antioxidant, cytoprotective, anti-inflammation and anti-tumor activities. However, most previous antitumor studies have not considered the cytotoxicity against normal cells. Ten cinnamic acid phenetyl esters were subjected to quantitative structure-activity relationship (QSAR) analysis, based on their cytotoxicity and tumor-specificity, in order to find their new biological activities.

MATERIALS AND METHODS

Cytotoxicity against four human oral squamous cell carcinoma cell lines and three oral normal mesenchymal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor specificity (TS) was evaluated by the ratio of the mean 50% cytotoxic concentration (CC₅₀) against normal oral cells to that against human oral squamous cell carcinoma cell lines. Potency-selectivity expression (PSE) value was calculated by dividing the TS value by CC₅₀ against tumor cells. Apoptosis markers were detected by western blot analysis. Physicochemical, structural and quantum-chemical parameters were calculated based on the conformations optimized by force-field minimization.

RESULTS

Western blot analysis demonstrated that [9] stimulated the cleavage of caspase-3, suggesting the induction of apoptosis. QSAR analysis demonstrated that TS values were correlated with shape, size and ionization potential.

CONCLUSION

Chemical modification of the lead compound may be a potential choice for designing a new type of anticancer drugs.

Characterization of the Dissolution Behavior of Piperine/Cyclodextrins Inclusion Complexes

In this study, the physicochemical properties and solubility of inclusion complexes of ground mixtures (GMs) of piperine (PP), a pungent ingredient of pepper, with α- and γ-cyclodextrin (CD) were studied. From the solubility results, the PP/αCD inclusion molar ratio was determined to be 1/2, while that of PP/γCD was 1/1, according to the A_P-type phase diagram of PP/αCD and the B_S-type one of PP/γCD. The powder X-ray diffraction and differential scanning calorimetry analyses confirmed the formation of GM complexes with molar ratios of PP/αCD = 1/2 and PP/γCD = 1/1. The Raman analysis revealed the disappearance of the bands corresponding to the C=C, O-CH₂-O, -CH, and aliphatic C=C moieties of the methylene dioxyphenyl fragment of PP in the spectra of the inclusion complexes. In the dissolution tests, GM (PP/αCD = 1/2) and GM (PP/γCD = 1/1) showed higher solubility than free PP and the analogous physical mixtures. Furthermore, after 60 min, GM (PP/αCD = 1/2) exhibited higher solubility than GM (PP/γCD = 1/1). In the ¹H-¹H nuclear Overhauser effect spectroscopy measurements, GM (PP/αCD = 1/2) was found to present a head-to-head inclusion structure via the aliphatic C=C and methylene dioxyphenyl groups of PP and the two αCD molecules. In contrast, it was confirmed that γCD interacts with the O-CH₂-O functionality of the methylene dioxyphenyl group of PP in a molar ratio of 1/1. It was thus concluded that the differences in the PP/CD structures influence the solubility of the inclusion complexes.

Quantitative Structure-Cytotoxicity Relationship of 2-Azolylchromones

BACKGROUND/AIM

Twenty-four 2-azolylchromones were subjected to quantitative structure-activity relationship (QSAR) analysis based on their cytotoxicity and tumor specificity, in order to find their new biological activities.

MATERIALS AND METHODS

Cytotoxicity against two human oral squamous cell carcinoma cell lines and two human normal oral mesenchymal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Tumor specificity (TS) was evaluated by the ratio of the mean 50% cytotoxic concentration (CC₅₀) against oral cells to that against oral squamous cell carcinoma cell lines. Potency-selectivity expression (PSE) value was calculated by dividing the TS value by CC₅₀ against tumor cells. Apoptosis markers were detected by western blot analysis. Physicochemical, structural and quantum-chemical parameters were calculated based on the conformations optimized by force-field minimization.

RESULTS

Three sets of 4H-1-benzopyran-4-ones with indole ring showed much higher TS values than those with pyrrole, pyrazole, imidazole, 1,2,4-triazole, 1,2,3-triazole, indazole and benzimidazole rings. Among those with an indole ring, the compound having a 6-methoxy group, that exhibited the highest cytotoxicity, yielded one to three-order higher PSE values to compared with other groups of compounds. Western blot analysis demonstrated that this compound stimulated the cleavage of caspase-3, suggesting the induction of apoptosis. QSAR analysis demonstrated that TS values were correlated with 3D shape, polarizability, ionization potential and lipophilicity.

CONCLUSION

Chemical modification of the lead compound may be a potential choice for designing a new type of anticancer drug.

Pentamine as a Substrate for Measuring Spermine Oxidase Activity

A method for determining spermine oxidase activity is described using the pentamine 1,16-diamino-4,8,13-triazahexadecane (3343) as the substrate, coupled with o-phthalaldehyde-post-label ion-exchange HPLC. The synthesis of 3343 is also described.

Synthesis of Amide and Ester Derivatives of Cinnamic Acid and Its Analogs: Evaluation of Their Free Radical Scavenging and Monoamine Oxidase and Cholinesterase Inhibitory Activities

A series of cinnamic acid derivatives, amides (1-12) and esters (13-22), were synthesized, and structure-activity relationships for antioxidant activity, and monoamine oxidases (MAO) A and B, acetylcholinesterase, and butyrylcholinesterase (BChE) inhibitory activities were analyzed. Among the synthesized compounds, compounds 1-10, 12-18, and rosmarinic acid (23), which contained catechol, o-methoxyphenol or 5-hydroxyindole moieties, showed potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. Compounds 9-11, 15, 17-22 showed potent and selective MAO-B inhibitory activity. Compound 20 was the most potent inhibitor of MAO-B. Compounds 18 and 21 showed moderate BChE inhibitory activity. In addition, compound 18 showed potent antioxidant activity and MAO-B inhibitory activity. In a comparison of the cinnamic acid amides and esters, the amides exhibited more potent DPPH free radical scavenging activity, while the esters showed stronger inhibitory activities against MAO-B and BChE. These results suggested that cinnamic acid derivatives such as compound 18, p-coumaric acid 3,4-dihydroxyphenethyl ester, and compound 20, p-coumaric acid phenethyl ester, may serve as lead compounds for the development of novel MAO-B inhibitors and candidate lead compounds for the prevention or treatment of Alzheimer's disease.

Quantitative Structure-Cytotoxicity Relationship of Newly Synthesized Piperic Acid Esters

BACKGROUND/AIM

Eleven piperic acid esters were subjected to quantitative structure-activity relationship (QSAR) analysis based on their cytotoxicity and tumor-specificity, in order to find their new biological activities.

MATERIALS AND METHODS

Cytotoxicity against four human oral squamous cell carcinoma cell lines and three oral normal mesenchymal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor specificity (TS) was evaluated by the ratio of the mean 50% cytotoxic concentration (CC₅₀) against normal cells to that against tumor cell lines. Potency-selectivity expression (PSE) value was calculated by dividing the TS value by CC₅₀ against tumor cells. Apoptosis markers were detected by western blot analysis. Physicochemical, structural and quantum-chemical parameters were calculated based on the conformations optimized by force-field minimization.

RESULTS

One phenylmethyl ester and five phenylethyl esters showed relatively higher cytotoxicity and tumor specificity, that were significantly modified by introduction of hydroxyl and methoxy groups. On the other hand, phenylpropyl ester, phenylbutyl ester and decyl ester were essentially inactive. (2E,4E)-5-(3,4-methylenedioxyphenyl)-2,4-pentadienoic acid 2-(3,4-dihydroxyphenyl)ethyl ester [4] had the highest TS and PSE values. This compound also stimulated the cleavage of caspase-3, suggesting the induction of apoptosis. TS values were correlated with molecular size, ionization potential, molecular shape, ionization potential and electronegativity. None of the compounds had any anti-HIV activity.

CONCLUSION

Chemical modification of the lead compound may be a potential choice for designing a new type of anticancer drugs.

Search for New Type of Anticancer Drugs with High Tumor Specificity and Less Keratinocyte Toxicity

Most current anticancer drugs have shown excellent therapeutic effects on human oral squamous cell carcinoma (OSCC), but they also produce potent cytotoxicity in normal oral keratinocytes. This review article summarizes our extensive research of tumor specificity and keratinocyte toxicity of nine groups of compounds synthesized in our laboratory. Among a total of 133 compounds, (E)-3-[2-(4-hydroxyphenyl)ethenyl]-6-methoxy-4H-1-benzopyran-4-one [3] (classified as 3-styrylchromones), (E)-3-[2-(4-chlorophenyl)ethenyl]-7-methoxy-2H-1-benzopyran [4] (classified as 3-styryl-2H-chromenes) showed the highest tumor specificity with the least keratinocyte toxicity. Compound [3] induced apoptotic cell death in a human OSCC cell line, possibly by down-regulating the glycerophospholipid pathway. Quantitative structure-activity relationship analysis demonstrated that the tumor specificities of [3] and [4] were well correlated with chemical descriptors related to their molecular size and lipophilicity. Chemical modification of these lead compounds by introduction of appropriate functional groups is a crucial step towards manufacturing new types of anticancer drugs with reduced keratinocyte toxicity.

Quantitative Structure-Cytotoxicity Relationship of Aurones

BACKGROUND/AIM

Seventeen aurones were subjected to quantitative structure-activity relationship (QSAR) analysis based on their cytotoxicity and tumor-specificity, in order to find their new biological activities.

MATERIALS AND METHODS

Cytotoxicity against three human oral squamous cell carcinoma cell lines and three oral mesenchymal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor specificity (TS) was evaluated by the ratio of the mean 50% cytotoxic concentration (CC₅₀) against normal cells to that against tumor cell lines. Potency-selectivity expression (PSE) value was calculated by dividing TS by CC₅₀ against tumor cells. Physicochemical, structural and quantum-chemical parameters were calculated based on the conformations optimized by force-field minimization.

RESULTS

Sixteen out of seventeen aurones showed relatively higher cytotoxicity and tumor specificity. Among them, (2Z)-2-[(4-hydroxyphenyl)methylene]-3(2H)-benzofuranone [7] showed the highest TS value and PSE values, comparable with those of doxorubicin and higher than 5-FU, respectively. TS values were correlated with molecular shape, size and polarizability rather than the types of substituted groups.

CONCLUSION

Chemical modification of the lead compound may be a potential choice for designing a new type of anticancer drugs.

Synthesis and Biological Evaluation of 3-Benzylidene-4-chromanone Derivatives as Free Radical Scavengers and α-Glucosidase Inhibitors

A series of 3-benzylidene-4-chromanone derivatives (3-20) were synthesized and the structure-activity relationships for antioxidant and α-glucosidase inhibitory activities were evaluated. Among synthesized compounds, compounds 5, 13, 18, which contain catechol moiety, showed the potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity (5: EC50 13 µM; 13: EC50 14 µM; 18: EC50 13 µM). The compounds 12, 14, 18 showed higher α-glucosidase inhibitory activity (12: IC50 15 µM; 14: IC50 25 µM; 18: IC50 28 µM). The compound 18 showed both of potent DPPH radical scavenging and α-glucosidase inhibitory activities. These data suggest that 3-benzylidene-4-chromanone derivatives, such as compound 18, may serve as the lead compound for the development of novel α-glucosidase inhibitors with antioxidant activity.

Photoexcitation dynamics of p-nitroaniline and N,N-dimethyl-p-nitroaniline in 1-alkyl-3-methylimidazolium-cation based ionic liquids with different alkyl-chain lengths

Back electron transfer and vibrational energy relaxation of p-nitroaniline and N,N-dimethyl-p-nitroaniline in ionic liquids were investigated using transient absorption spectroscopy.