Ameliorative Effects of Flavonoids from Platycodon grandiflorus Aerial Parts on Alloxan-Induced Pancreatic Islet Damage in Zebrafish.

Platycodon grandiflorus (balloon flower), used as a food reserve as well as in traditional herbal medicine, is known for its multiple beneficial effects. In particular, this plant is widely used as a vegetable in Republic of Korea. We examined the ameliorative effects of P. grandiflorus on alloxan-induced pancreatic islet damage in zebrafish. The aerial part treatment led to a significant recovery in pancreatic islet size and glucose uptake. The efficacy of the aerial part was more potent than that of the root. Eight flavonoids (1-8) were isolated from the aerial part. Structures of two new flavone glycosides, designated dorajiside I (1) and II (2), were elucidated to be luteolin 7-O-α-L-rhamno-pyranosyl (1 → 2)-(6-O-acetyl)-ß-D-glucopyranoside and apigenin 7-O-α-L-rhamnopyranosyl (1 → 2)-(6-O-acetyl)-ß-D-glucopyranoside, respectively, by spectroscopic analysis. Compounds 1, 3, 4 and 6-8 yielded the recovery of injured pancreatic islets in zebrafish. Among them, compound 7 blocked KATP channels in pancreatic ß-cells. Furthermore, compounds 3, 4, 6 and 7 showed significant changes with respect to the mRNA expression of GCK, GCKR, GLIS3 and CDKN2B compared to alloxan-induced zebrafish. In conclusion, the aerial part of P. grandiflorus and its constituents conferred a regenerative effect on injured pancreatic islets.

Anticancer effects of the HDAC inhibitor, 3ß,6ß­dihydroxyurs­12­en­27­oic acid, in MCF­7 breast cancer cells via the inhibition of Akt/mTOR pathways.

Astilbe chinensis (A. chinensis) is a perennial herb that is used to treat chronic bronchitis and pain. The anticancer activity of 3ß,6ß­dihydroxyurs­12­en­27­oic acid (ACT­3), a major component isolated from A. chinensis, has not yet been investigated in detail. The purpose of the present study was to investigate the histone deacetylase (HDAC) inhibitory and anticancer activities of ACT­3 compared with suberoylanilide hydroxamic acid (SAHA) in MCF­7 human breast cancer cells. The purity of ACT­3 was determined using high­performance liquid chromatography. In the present study, the effects of ACT­3 on anticancer effects of MCF­7 cells were determined by measuring the level of apoptotic cell death and cell cycle regulator using flow cytometry analysis and western blot analysis, respectively. The effects of ACT­3 on HDAC enzyme activity were measured using assay kits. ACT­3 and SAHA increased the levels of acetylated histone H3 and reduced the levels of HDAC1 and HDAC3 in MCF­7 cells. ACT­3 significantly decreased the cell viability in a concentration­dependent manner and induced different morphological changes at high concentrations. ACT­3 and SAHA significantly inhibited the colony formation in MCF­7 cells. ACT­3 inhibited total HDAC activity in a dose­dependent manner. ACT­3 significantly reduced the expression levels of cyclin D1 and cyclin­dependent kinase 4, and upregulated the expression levels of p21WAF1 and p53. A significant increase in the G1 phase cell population was observed in MCF­7 cells and ACT­3 induced apoptosis by reducing the ratio of B­cell lymphoma­2 (Bcl­2)/Bcl­2­associated X (Bax) and releasing cleaved caspase 9. Additionally, ACT­3 significantly increased autophagic cell death by inhibiting the serine­threonine kinase/mammalian target of the rapamycin pathway. Autophagy induction was confirmed via acridine orange staining. ACT­3 significantly increased the pERK1/2 and p21 in MCF­7 cells. Thus, the activated ERK pathway played an important role in cell cycle arrest and apoptosis via ERK­dependent induction of p21 in MCF­7 cells. These data indicated that ACT­3 can be used as a promising anticancer agent to overcome the limitations and reduce the side effects of conventional anticancer drugs.

ß-Peltoboykinolic Acid from Astilbe rubra Attenuates TGF-ß1-Induced Epithelial-to-Mesenchymal Transitions in Lung Alveolar Epithelial Cells.

Epithelial-to-mesenchymal transition (EMT) is increasingly recognized as contributing to the pathogenesis of idiopathic pulmonary fibrosis. Therefore, novel plant-based natural, active compounds have been sought for the treatment of fibrotic EMT. The aim of the present study was to investigate the inhibitory effects of Astilbe rubra on TGF-ß1-induced EMT in lung alveolar epithelial cells (A549). A. rubra was subjected to extraction using 70% ethanol (ARE), and ethanol extracts of the aerial part and that of the rhizome were further partitioned using various solvents. Protein expression and cell motility were investigated to evaluate the inhibitory effects of ARE on EMT. EMT occurred in A549 cells treated with TGF-ß1, but was prevented by co-treatment with ARE. The dichloromethane fractions showed the strongest inhibitory effect on TGF-ß1-induced EMT. ß-Peltoboykinolic acid was isolated from the dichloromethane fractions of A. rubra by activity-oriented isolation. ß-Peltoboykinolic acid not only attenuated TGF-ß1-induced EMT, but also the overproduction of extracellular matrix components including type I collagen and fibronectin. The Smad pathway activated by TGF-ß1 was inhibited by co-treatment with ß-peltoboykinolic acid. Taken together, these results indicate that ß-peltoboykinolic acid from A. rubra and dichloromethane fractions shows potential as an antifibrotic agent in A549 cells treated with TGF-ß1.

Plumbagin from a tropical pitcher plant (Nepenthes alata Blanco) induces apoptotic cell death via a p53-dependent pathway in MCF-7 human breast cancer cells.

Plumbagin (5-hydroxy-2-methyl-1,4-naphthaquinone) has displayed antitumor activity in vitro and in animal models; however, the underlying molecular mechanisms have not been fully explored. The aim of this study was to investigate the anticancer effects of plumbagin isolated from Nepenthes alata against MCF-7 breast cancer cells. We examined the cytotoxicity, cell cycle regulation, apoptotic cell death, and generation of intracellular reactive oxygen species (ROS) in MCF-7 cells. Plumbagin exhibited potent cytotoxicity in MCF-7 cells (wild-type p53) compared to that in SK-OV-3 (null-type) human epithelial ovarian cancer cells. Specifically, plumbagin upregulated the expression of p21CIP1/WAF1 in MCF-7 cells, causing cell cycle arrest in the G2/M phase through inhibition of cyclin B1 levels. Plumbagin also significantly increased the ratio of Bax/Bcl-2 and release of cytochrome c, resulting in apoptotic cell death in MCF-7 cells. Furthermore, plumbagin dramatically increased the intracellular ROS level, whereas pretreatment with the ROS scavenger N-acetyl cysteine protected against plumbagin-induced cytotoxicity, suggesting that ROS formation plays a pivotal role in antitumor activity in MCF-7 cells. In mice bearing MCF-7 cell xenografts, plumbagin significantly reduced tumor growth and weight without apparent side effects. We therefore concluded that plumbagin exerts anticancer activity against MCF-7 cells through the generation of intracellular ROS, resulting in the induction of apoptosis via a p53-dependent pathway. This study thus identifies a new anticancer mechanism of plumbagin against p53-dependent breast cancer cells and suggests a novel strategy for overcoming of breast cancer therapy.

Chemiluminescent Probe for the In†Vitro and In†Vivo Imaging of Cancers Over-Expressing NQO1.

Activatable (turn-on) probes that permit the rapid, sensitive, selective, and accurate identification of cancer-associated biomarkers can help drive advances in cancer research. Herein, a NAD(P)H:quinone oxidoreductase-1 (NQO1)-specific chemiluminescent probe 1 is reported that allows the differentiation between cancer subtypes. Probe 1 incorporates an NQO1-specific trimethyl-locked quinone trigger moiety covalently tethered to a phenoxy-dioxetane moiety through a para-aminobenzyl alcohol linker. Bio-reduction of the quinone to the corresponding hydroquinone results in a chemiluminescent signal. As inferred from a combination of in vitro cell culture analyses and in vivo mice studies, the probe is safe, cell permeable, and capable of producing a "turn-on" luminescence response in an NQO1-positive A549 lung cancer model. On this basis, probe 1 can be used to identify cancerous cells and tissues characterized by elevated NQO1 levels.

Afrocyclamin A, a triterpene saponin, induces apoptosis and autophagic cell death via the PI3K/Akt/mTOR pathway in human prostate cancer cells.

BACKGROUND: Afrocyclamin A, an oleanane-type triterpene saponin, was isolated from Androsace umbellata which used as a traditional herbal medicine. PURPOSE: This study aimed to explore the anticancer activity of afrocyclamin A on human prostate cancer cells in vitro as well as in vivo. METHODS: Cytotoxicity, cell cycle distribution, apoptosis, and autophagic cell death were measured following exposure to afrocyclamin A. In vivo antitumor activity of afrocyclamin A was assessed in a xenograft model. The protein levels of p-Akt, p-mTOR, Bax, Bcl-2, caspase-3, and caspase-9 were quantified using western blot analysis. RESULTS: In DU145 cells, afrocyclamin A increased cytotoxicity, caused changes in cell morphology, and induced sub-G0/G1 phase indicating increased apoptosis. Afrocyclamin A robustly induced autophagic cell death as demonstrated by the conversion of LC3B-I to LC3B-II, and the formation of autophagic vacuoles as revealed by western blot analysis and fluorescence staining, respectively. Afrocyclamin A also inhibited the phosphorylation of PI3K, Akt, and mTOR, suggesting their role in afrocyclamin A induced cell death. In addition, afrocyclamin A inhibited cell migration and invasion in concentration and time-dependent manners. In an in vivo xenograft model, afrocyclamin A inhibited the growth of DU145 cells. CONCLUSION: Afrocyclamin A has anticancer activity via the PI3K/Akt/mTOR pathway, which leads to cell death.

Novel therapeutic roles of MC-4 in combination with everolimus against advanced renal cell carcinoma by dual targeting of Akt/pyruvate kinase muscle isozyme M2 and mechanistic target of rapamycin complex 1 pathways.

Current clinical trials of new anticancer therapies against metastatic renal cell carcinoma (RCC), including molecular-targeted therapies, have not shown promise. The purpose of this study was to preclinically assess the antitumor effects of MC-4, a partially purified material of Artemisia annua L., as a monotherapy or in combination with the known mechanistic target of rapamycin complex 1 (mTORC1) inhibitor, everolimus, against Caki-1 (Von Hippel-Lindau (VHL)+/+) and 786-O (VHL-/-) human RCC cells. MC-4 monotherapy significantly increased tumor growth inhibition and autophagic cell death in RCC cells in vitro and in vivo. Everolimus led to compensatory Akt activation by inhibiting only mTORC1 signaling pathway. In contrast to everolimus, MC-4 enhanced phosphatase and tensin homolog expression and reduced its downstream effector, Akt/pyruvate kinase muscle isozyme M2 (PKM2), leading to decreased expression of glucose transporter 1, which is associated with cancer cell metabolism. The synergistic antitumor and anti-metastatic effects induced by co-administration of MC-4 and everolimus involve cell growth inhibition and autophagic cell death via dual targeting of phosphatidylinositol 3-kinase (PI3K)/Akt/PKM2 and mTORC1. These findings suggest that MC-4 is a novel Akt/PKM2 inhibitor that can overcome the limitation of existing mTOR inhibitors and can be considered a novel strategy to treat patients with rapidly progressing advanced RCC.

Platycodon grandiflorus Root Extract Improves Learning and Memory by Enhancing Synaptogenesis in Mice Hippocampus.

Platycodon grandiflorus (Jacq.) A.DC. (PG) has long been used as an ingredient of foods and is known to have beneficial effects on cognitive functions as well. The present study examined the effect of each PG extract (PGE) from root, aerial part, and seeds on cognitive functions in mice. Changes in spatial learning and memory using a Y-maze test, and markers of adult hippocampal neurogenesis and synaptogenesis were examined. Moreover, changes in neuritogenesis and activation of the ERK1/2 pathway were investigated. Results indicated that mice administered PGE (root) showed increased spontaneous alternation in the Y-maze test and synaptogenesis in the hippocampus. In addition, PGE (root) and platycodin D, the major bioactive compound from the PG root, significantly stimulated neuritic outgrowth by phosphorylation of the ERK1/2 signaling pathway in vitro. These results indicate that the PGE (root), containing platycodin D, enhances cognitive function through synaptogenesis via activation of the ERK1/2 signaling pathway.

Direct acylation of N-benzyltriflamides from the alcohol oxidation level via palladium-catalyzed C-H bond activation.

A palladium-catalyzed ortho-acylation of N-benzyltriflamides from the alcohol oxidation level via C-H bond activation is described. These transformations have been applied to a wide range of substrates, and typically proceed with excellent levels of chemoselectivity and with high functional group tolerance.

Carboxymethylated cyclosophoraose as a novel chiral additive for the stereoisomeric separation of some flavonoids by capillary electrophoresis.

A carboxymethylated cyclosophoraose (CM-Cys) was synthesized by the chemical modification of neutral Cys, which was isolated from Rhizobium trifolii TA-1. CM-Cys was successfully applied as a novel chiral selector for the separation of some flavonoids including catechin, 3,5,7,3',4'-pentahydroxyflavanone, hesperidin, hesperetin, isosakuranetin, naringenin, naringin, and eriodictyol. The effects of pH, chiral additive concentration, and temperature on resolution and migration time were also studied.

Novel succinylated and large-sized osmoregulated periplasmic glucans of Pseudomonas syringae pv. syringae.

Osmoregulated periplasmic glucans (OPGs) are intrinsic components of the Gram-negative bacterial envelope and are important for bacterial-host interactions. The OPGs of Pseudomonas syringae pv. syringae have been known to be highly branched linear glucans ranging from 6 to 13 glucose residues devoid of any substituents, while having backbone structure similar to those of Escherichia coli and Erwinia chrysanthemi. Here, we report for the first time succinylated and large-sized OPGs from P. syringae pv. syringae. The glucans were isolated with trichloroacetic acid treatment and various chromatographic techniques. These were further characterized by thin-layer chromatography, matrix-assisted laser desorption/ionization time of flight mass spectrometer, and 1D (1)H nuclear magnetic resonance spectroscopy. The results demonstrate that novel anionic glucans with one succinyl residue at the C-6 position of the glucose unit as well as neutral glucans including large-sized glucans with up to 28 degrees of polymerization are produced in P. syringae pv. syringae. Furthermore, the succinylated and large-sized OPGs of P. syringae pv. syringae are necessary for hypoosmotic adaptation.