Journal of Organic Chemistry: Synthesis and Process Development

Synthesis, cytotoxicity of Carnosine peptide analogues on mitochondria obtained from cancerous rats’ liver

MohammadrezaGholibeikiana, AmirrezaArvaneh

Cancer is a complex disease that is characterized by cell proliferation, cell transformation and disruption apoptotic process.1Cancer is a group of diseases marked by uncontrolled growth and spread of abnormal cells. If the tumor spread is not controlled, it can result in mortality. Cancer is caused by both external different factors (tobacco, chemicals, radiation, and infectious organisms) and internal different factors (inherited mutations, hormones, immune conditions, and mutations that occur from metabolism).2Cancer can start in the breast, lungs, colon, or even in the blood cells. Cancers are similar in some ways, but they are different in growth ways and sprea.3 Normal cells divide in a regular route. They die when they are damaged, and new cells take their place. Cancer is formed when the cells begin to grow out of control. The cancer cells keep on growing and new ones will replace the damaged cells.4When cancer cells spread in the body, it is called metastasis. Many new and effective therapies are currently being used to treat cancer. Among the new ways to improve cancer, chemotherapy based on peptides has attracted a great interest and considerable attention due to the unique advantages of peptides, such as a low molecular weight, the ability to specifically target tumor cells, and low toxicity in normal tissues. During the past decade, peptides have gained a wide range of applications in medicine, drug delivery and biotechnology.5Liver cancer represents one of the most common malignancy global. Hepatocellular carcinoma represents a major form of primary liver cancer in adults. The most important risk factors are hepatitis B and C infections.

The ideal anticancer candidates would have a tendency to kill cancer cells without affecting normal cells. Despite these efforts, anticancer drugs also have a side effects on normal cells.6 Possible functions of the dipeptide of Carnosine include buffer, anti-oxidant, antiglycator, aldehyde and carbonyl scavenger, chelator of metal ion, immuno-stimulant, wound healing agent and neurotransmitter. In 1986, it was reported that Carnosine can inhibit growth of tumor cells.7 In 2008, Carnosine was shown to inhibit growth of cultured glioblastoma cells,8 most probably via effects on glycolysis.9,10 Other results indicated that Carnosine can suppress tumor growth in animals.11,12 The number of biochemical markers have been identified in the induction of apoptotic cell death, including an increase of reactive oxygen species (ROS), collapse of mitochondrial membrane potential (MMP). In the intrinsic apoptotic cell death pathway, ROS are potent inducers of oxidative damage and have been suggested as main regulators of apoptotic cell death. Remarkably, intracellular ROS increase prior to cytochrome c release from mitochondria during the activation of apoptotic process.13 Cytochrome c release is an endpoint of destruction to mitochondria and a starting point of cell death signaling resulting in either apoptosis or necrosis in the exposed tissue depending on cellular ATP levels

Power from Sunshine: Solar Energy Harvesting In order to Solve the World Energy Crisis

Kavya Keremane

The growing need for energy by the human society and depletion of conventional energy sources demands a renewable, safe, infinite, low-cost and omnipresent energy sources. One of the most suitable ways to solve the foreseeable world’s energy crisis is to use the power of sun. Out of all renewable sources of energy, solar energy plays a vital role in the long-term energy supply security, global climate change and also offers a solution to fossil fuel emissions. Most of the commercial solar panels use silicon as light harvester, which makes the panels heavier, rigid and is very expensive. After extensive research scientists found alternative classes of materials with perovskite crystal structure, which received much attention due to their low-cost potential, light weight, ease of processing. These materials are not yet completely commercialized and are under extensive research. Current studies states that the production of high efficiency, stable, scalable photovoltaic solar cells may lie in the development of perovskite solar cell technology.

Simple phenylene-bridged D-A type photosensitizers for DSSC application: Synthesis, optical, electrochemical and theoretical studies

Kavya S. Keremanea, Airody Vasudeva Adhikari

Over the past three decades, the quest for low-cost energy production from renewable energy resources has gained much attention to address the problem of world energy crisis.1–4 The new third-generation photovoltaic device, especially dye-sensitized solar cells (DSSCs) have attained much interest as a new generation sustainable photovoltaic devices, mainly due to their ability to convert direct sunlight into electricity at low fabrication cost, and easy manufacturing process when compared to conventional p-n junction solar cells.5,6 Typically, DSSCs are composed of sandwich structure: dye-adsorbed wide bandgap metal-oxide-semiconductor electrode (TiO2), a platinum counter electrode, filled with an electrolyte containing I-/I3- redox couple. In general, the working principle of DSSCs involves the absorption of photons by the sensitizers (dyes) to get excited and consequently injection of electrons into the conduction band (CB) of the TiO2 followed by regeneration of the dye using the redox electrolyte.7 Among all the components of DSSCs, the photosensitizer (dye) plays a key rolein enhancing power-conversion efficiency (PCE) of the cell.

The sensitizers with appropriate HOMO-LUMO energy levels and light-harvesting ability may lead to satisfactory photoelectric conversion efficiency.8 During the last decades, much effort has been made on developing new sensitizers to enhance the overall performance of the devices. Till date, the metal-organic complexes (Ru-based) have been shown to achieve a high PCE above 14 % under AM 1.5 irradiation.9,10 Due to their high manufacturing cost, tedious synthetic methods, tricky purification steps, and environmental issues, metal-free organic dyes have been used as an alternative to replace them. These organic dyes overcome all the above-said drawbacks with their high molar extinction coefficient, better flexibility for structural control, environmental friendliness, and considerable efficiencies.11-13However, the PCE of these sensitizers is still low when compared to devices based on Ru-based dyes.