Herein, the development of visible light-mediated atom transfer radical addition (ATRA) of haloalkanes onto alkenes and alkynes using the reductive and oxidative quenching of [Ir{dF(CF3)ppy}2(dtbbpy)]PF6 and [Ru(bpy)3]Cl2 is presented. Initial investigations indicated that the oxidative quenching of photocatalysts could effectively be utilized for ATRA, and since that report, the protocol has been expanded by broadening the scope of the reaction in terms of the photocatalysts, substrates, and solvents. In addition, further modifications of the reaction conditions allowed for the efficient ATRA of perfluoroalkyl iodides onto alkenes and alkynes utilizing the reductive quenching cycle of [Ru(bpy)3]Cl2 with sodium ascorbate as the sacrificial electron donor. These results signify the complementary nature of the oxidative and reductive quenching pathways of photocatalysts and the ability to predictably direct reaction outcome through modification of the reaction conditions.

Visible light-mediated atom transfer radical addition via oxidative and reductive quenching of photocatalysts.

Ginger (Zingiber officinale Roscoe) is a common and widely used spice. It is rich in various chemical constituents, including phenolic compounds, terpenes, polysaccharides, lipids, organic acids, and raw fibers. The health benefits of ginger are mainly attributed to its phenolic compounds, such as gingerols and shogaols. Accumulated investigations have demonstrated that ginger possesses multiple biological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, neuroprotective, cardiovascular protective, respiratory protective, antiobesity, antidiabetic, antinausea, and antiemetic activities. In this review, we summarize current knowledge about the bioactive compounds and bioactivities of ginger, and the mechanisms of action are also discussed. We hope that this updated review paper will attract more attention to ginger and its further applications, including its potential to be developed into functional foods or nutraceuticals for the prevention and management of chronic diseases.

Bioactive compounds and bioactivities of ginger (zingiber officinale roscoe)

Background Syzygium cumini (L.) Skeels (jambolan) is commonly used in Indian traditional medicine to treat a variety of diseases such as obesity, diabetes etc. The cytotoxic potential of S. cumini (SC) against oral cancer cell line remains elusive. Therefore, in this study, we evaluated the cytotoxic effect of S. cumini in human oral squamous cell carcinoma (OSCC) cell line (SCC-25 cells). Material and methods Oral squamous cell carcinoma cells are treated with different concentrations (10, 20, and 40 μg/mL) of S. cumuni for 24 hours and cytotoxicity was analyzed by MTT assay. The intracellular reactive oxygen species (ROS) was measured using the indicator dye, 2',7'-dichlorofluorescin diacetate staining. Apoptosis-related morphological changes were evaluated by dual acridine orange/ethidium bromide (AO/EB) fluorescent staining and phosphatidylserine externalization was measured by annexin V assays. The protein and gene expression of cadherin-1 was evaluated by western blotting and PCR analysis. Results Syzygium cumini treatments caused cytotoxicity of OSCC cell line and induced intracellular ROS accumulation. This treatment also caused apoptosis-related morphological changes and externalization of phosphatidylserine in OSCC cells. Further, S. cumini treatments increased protein and gene expression of cadherin-1. Conclusion Syzygium cumini extract inhibits the proliferation of OSCC cells and induces apoptosis through ROS accumulation and therefore, it could be used for the prevention of OSCC.

Syzygium cumini extract induced reactive oxygen species-mediated apoptosis in human oral squamous carcinoma cells.

Hepatocellular carcinoma is the second most common cause of cancer death in the world and its incidence has dramatically increased worldwide in the past two decades. Syringic acid (SA) has been studied for its hepatoprotective, anti-inflammatory, immunomodulatory, free radical scavenging, and antioxidant activities. We aimed to evaluate the cytotoxic effect of SA against human hepatoma HepG2 cell line. Cytotoxicity was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. HepG2 cells were treated with SA at concentration ranges of 25, 50, and 100 µM for 24 h. Reactive oxygen species (ROS) expression was investigated by dichlorofluorescein staining assay. Morphological changes of SA-treated HepG2 cells were evaluated by acridine orange (AO) and ethidium bromide (EB) dual staining. Apoptotic marker gene expressions were evaluated by qPCR. SA treatment caused significant cytotoxicity and liberation of ROS in HepG2 cells. AO and EB staining showed membrane blebbing and distortion in SA-treated cells. Apoptotic markers such as caspases 3 and 9, cytochrome c, Apaf-1, Bax, and p53 gene expressions were significantly increased upon SA treatment indicating the possibility of apoptosis induction in HepG2 cells. This treatment also caused significant downregulation of Bcl-2 gene expression. SA has a cytotoxic effect on human HepG2 cell line, and this might be a promising agent in anticancer research.

Syringic acid triggers reactive oxygen species-mediated cytotoxicity in HepG2 cells.

Advances in selective conversions by heterogeneous photocatalysis.

The extract of ginger (Zingiber officinale Roscoe) and its major pungent components, [6]-shogaol and [6]-gingerol, have been shown to have an anti-proliferative effect on several tumor cell lines. However, the anticancer activity of the ginger extract in pancreatic cancer is poorly understood. Here, we demonstrate that the ethanol-extracted materials of ginger suppressed cell cycle progression and consequently induced the death of human pancreatic cancer cell lines, including Panc-1 cells. The underlying mechanism entailed autosis, a recently characterized form of cell death, but not apoptosis or necroptosis. The extract markedly increased the LC3-II/LC3-I ratio, decreased SQSTM1/p62 protein, and enhanced vacuolization of the cytoplasm in Panc-1 cells. It activated AMPK, a positive regulator of autophagy, and inhibited mTOR, a negative autophagic regulator. The autophagy inhibitors 3-methyladenine and chloroquine partially prevented cell death. Morphologically, however, focal membrane rupture, nuclear shrinkage, focal swelling of the perinuclear space and electron dense mitochondria, which are unique morphological features of autosis, were observed. The extract enhanced reactive oxygen species (ROS) generation, and the antioxidant N-acetylcystein attenuated cell death. Our study revealed that daily intraperitoneal administration of the extract significantly prolonged survival (P = 0.0069) in a peritoneal dissemination model and suppressed tumor growth in an orthotopic model of pancreatic cancer (P < 0.01) without serious adverse effects. Although [6]-shogaol but not [6]-gingerol showed similar effects, chromatographic analyses suggested the presence of other constituent(s) as active substances. Together, these results show that ginger extract has potent anticancer activity against pancreatic cancer cells by inducing ROS-mediated autosis and warrants further investigation in order to develop an efficacious candidate drug.

/pdf/anticancer-effect-of-ginger-extract-against-pancreatic-6alfxahngc.pdf

Anticancer Effect of Ginger Extract against Pancreatic Cancer Cells Mainly through Reactive Oxygen Species-Mediated Autotic Cell Death.

Redox system for perfluoroalkylation of arenes and α-methylstyrene derivatives using titanium oxide as photocatalyst

Colloidal stable fluoroalkyl end-capped 2-(methacryloyloxy)ethanesulfonic acid oligomer [RF-(MES)n-RF]/polyaniline[PAn]/TiO2 nanocomposites and RF-(MES)n-RF/An-dimer (An-dimer: N,N′-diphenyl-1,4-phenylenediamine)/TiO2 nanocomposites were prepared by the interactions of TiO2 nanoparticles with RF-(MES)n-RF/PAn nanocomposites or RF-(MES)n-RF/An-dimer nanocomposites, which were prepared by the composite reaction of RF-(MES)n-RF oligomer with PAn or An-dimer. These two types of fluorinated TiO2 nanocomposites can exhibit quite different photochromic behaviors: RF-(MES)n-RF/PAn/TiO2 nanocomposites can exhibit a reversible wavelength change for polaron absorptions around 760–820 nm by alternation of UV irradiation and storage in the dark; in contrast, RF-(MES)n-RF/An-dimer/TiO2 nanocomposites can exhibit a reversible color change from blue to colorless (a reversible absorbance change) by the similar treatment.

Controlling photochromism between fluoroalkyl end-capped oligomer/polyaniline and N,N'-diphenyl-1,4-phenylenediamine nanocomposites induced by UV-light-responsive titanium oxide nanoparticles.

A redox system for fluoroalkylation with perfluoroalkyl iodide using TiO2 as a photocatalyst was developed. Photoirradiation of perfluoroalkyl iodide and α-methylstyrene in CH3CN in the presence of...

Perfluoroalkylation of α-Methylstyrene Using Titanium Oxide as a Photocatalyst.

Fluoroalkyl end-capped acrylic acid oligomer [RF-(ACA)n-RF]/, 2-(methacryloyloxy)ethanesulfonic acid oligomer [RF-(MES)n-RF]/, 2-acrylamido-2-methylpropanesulfonic acid oligomer [RF-(AMPS)n-RF]/polyaniline [PAn] nanocomposites were prepared by the polymerization of aniline initiated by ammonium persulfate in the presence of the corresponding oligomers, respectively. These fluorinated oligomers were also applied to the preparation of the corresponding fluorinated oligomers/phenyl-capped aniline dimer (An-dimer: N,N′-diphenyl-1,4-phenylenediamine) nanocomposites by the interaction of the fluorinated oligomers with An-dimer. These fluorinated composites thus obtained were found to afford nanometer size-controlled fine particles possessing a good dispersibility and stability in water and traditional organic media such as methanol. UV–vis spectra of RF-(MES)n-RF/PAn nanocomposites and RF-(AMPS)n-RF/PAn nanocomposites showed the similar absorption peaks around 350, 430, and 780 nm to those of the usual Bronsted acid-doped PAn; however, interestingly, RF-(ACA)n-RF/PAn nanocomposites were found to exhibit only an absorption peak around 430 nm based on the polaron transition.

Mari Iizuka

Papers

Anticancer Effect of Ginger Extract against Pancreatic Cancer Cells Mainly through Reactive Oxygen Species-Mediated Autotic Cell Death.

Redox system for perfluoroalkylation of arenes and α-methylstyrene derivatives using titanium oxide as photocatalyst

Controlling photochromism between fluoroalkyl end-capped oligomer/polyaniline and N,N'-diphenyl-1,4-phenylenediamine nanocomposites induced by UV-light-responsive titanium oxide nanoparticles.

Perfluoroalkylation of α-Methylstyrene Using Titanium Oxide as a Photocatalyst.

Preparation of novel fluoroalkyl end-capped oligomers/polyaniline and/ N,N′ -diphenyl-1,4-phenylenediamine nanocomposites