Bull. Chem. Soc. Jpn. への投稿のすすめ

https://pubs.rsc.org/en/content/articlepdf/2014/cc/c3cc47081d

Aerobic oxidation catalysis with stable radicals

It has been a long time since C–H bond oxidations first attracted chemists’ attention. In the last several decades, C–H bond oxidation has been extensively investigated and applied in chemistry. Transition-metal catalyzed C–H bond oxidative transformations presents one of the state-of-arts at the frontiers of chemistry. Iron, as a cheap, readily accessible metal, has already shown its unique utility. This review attempts to focus on C–H bond cleavage in oxidative transformation via iron catalysis, as well as applications in synthetic chemistry.

Iron-catalyzed/mediated oxidative transformation of C–H bonds

A Pd-catalyzed aerobic oxidative C–H nitration and acylation of arenes with simple and readily available tert-butyl nitrite (TBN) and toluene as the radical precursors has been developed. Molecular oxygen is employed as the terminal oxidant and oxygen source to initiate the active radical reactants. Many different directing groups such as pyridine, pyrimidine, pyrazole, pyridol, pyridylketone, oxime, and azo groups can be employed in these novel transformations. The PdII/PdIV catalytic cycle through a radical process is the most likely pathway for these oxidative C–H nitration and acylation reactions.

Aerobic Oxidation of PdII to PdIV by Active Radical Reactants: Direct C–H Nitration and Acylation of Arenes via Oxygenation Process with Molecular Oxygen

Stereoselective Nitration of Olefins with tBuONO and TEMPO: Direct Access to Nitroolefins under Metal-free Conditions

Synthesis of (E)-nitroolefins via decarboxylative nitration using t-butylnitrite (t-BuONO) and TEMPO

This article examines the environmental factor-induced oxidative stress (OS) and their effects on male reproductive and sexual health. There are several factors that induce OS, i.e. radition, metal contamination, xenobiotic compounds, and cigarette smoke and lead to cause toxicity in the cells through metabolic or bioenergetic processes. These environmental factors may produce free radicals and enhance the reactive oxygen species (ROS). Free radicals are molecules that include oxygen and disbalance the amount of electrons that can create major chemical chains in the body and cause oxidation. Oxidative damage to cells may impair male fertility and lead to abnormal embryonic development. Moreover, it does not only cause a vast number of health issues such as ageing, cancer, atherosclerosis, insulin resistance, diabetes mellitus, cardiovascular diseases, ischemia-reperfusion injury, and neurodegenerative disorders but also decreases the motility of spermatozoa while increasing sperm DNA damage, impairing sperm mitochondrial membrane lipids and protein kinases. This chapter mainly focuses on the environmental stressors with further discussion on the mechanisms causing congenital impairments due to poor sexual health and transmitting altered signal transduction pathways in male gonadal tissues. 

Effect of Environmental Stressors, Xenobiotics, and Oxidative Stress on Male Reproductive and Sexual Health.

Breast adenocarcinoma is one of the leading causes of death among women regardless of development in the field of diagnosis, treatment and prevention. Synergistic approaches are emerging as a strategy to overcome monotherapy resistance in cancer treatment. Evaluation of the combinatory activity of β-carotene (BC) and lupeol (LUP) for anti-proliferative activity by median effect equation and combination index. Validation was performed by fixed dose combination against murine mammary adenocarcinoma namely Ehrlich ascites carcinoma (EAC). Cytotoxicity assay was performed using the MTT and Trypan blue methods. Isobologram and combination index analysis were used to analyze the type of interaction between β-carotene (BC) and lupeol (LUP). Based on the synergistic dose combination determination of in-vivo antitumor activity was performed using EAC cells inoculated in mice treated with BC, LUP and their combination (BC+LUP). Tumor volume, cell count, weight along with hematological, biochemical and antioxidant parameters were evaluated. The combination (BC+LUP) exhibited the highest inhibition (IC50=54.8 ± 1.84) compare to the standard inhibitor, wher eas BC and LUP showed moderate inhibition with an IC50 of 101.5 ± 2.66, and 84.08±3.56 respectively. The hematological, biochemical, and tissue antioxidant parameters were reverted to normal levels in the treated animal groups. BC and Lupeol reduced the volume, weight, and viable cell count of the tumor; increased the life span of EAC tumor-bearing mice. β-Carotene and lupeol were found to be more effective in combination for the anti-proliferative activity. Thus combination techniques must be employed to find out the synergistic activity of the molecules. 

Combination Synergy between β-Carotene and Lupeol against Breast Adenocarcinoma in vitro and in vivo using Combination Index

Comparing the reactivity of an oxoiron(IV) cation radical and its oxoiron(V) tautomer towards C-H bonds.

Objective: The research was design to conduct anti-diabetic activity of methanol extract of Aeschynanthus sikkimensis (Clarke) Stapf. in streptozotocin induce hyperglycemic rats. Material and method: Streptozotocin 35mg/kg body weight was injected intraperitoneal to produce hyperglycemia rats which were pretreated with a high fat diet.72 hours after introduction of STZ, the hyperglycemic rats received MEAS at dose 200 and 400 mg/kg body weight for 28 days. Reference drug used was Glibenclamide (0.5 mg/kg, orally). During the 28 days treatment fasting blood glucose level were determined on every 7th day. Serum and hepato renal biochemical parameters were estimated. Result: MEAS at the dose of 200 and 400mg/kg outstandingly (P <0.05) and dosage dependently reduce blood glucose levels towards normal as differentiate to STZ control group Serum and hepato renal biochemical parameter were altogether (P<0.05) restore towards the typical levels in MEAS sedated rats as differentiated to STZ control group. Conclusion: It may be concluded that the whole plant extract of Aeschynanthus sikkimensis (Clarke) Stapf which belong to the family Gesneriaceae showed encouraging hypoglycemic action in STZ induced diabetic rats.

Sandipan Jana

Papers

Synthesis of (E)-nitroolefins via decarboxylative nitration using t-butylnitrite (t-BuONO) and TEMPO

Effect of Environmental Stressors, Xenobiotics, and Oxidative Stress on Male Reproductive and Sexual Health.

Combination Synergy between β-Carotene and Lupeol against Breast Adenocarcinoma in vitro and in vivo using Combination Index

Comparing the reactivity of an oxoiron(IV) cation radical and its oxoiron(V) tautomer towards C-H bonds.

Anti - diabetic activity of aeschynanthus sikkimensis (clarke) stapf. extract in streptozotocin induced hyperglycemic rats