synthesis and output of fecal total steroids ..
In summary, a total synthesis of the natural product ..
Zaragozic acids and squalestatins were documented by Merck, Glaxo, and Tokyo Noko University/Mitsubishi Kasei Corporation as part of a program aimed at identifying novel inhibitors of squalene synthase, as well as farnesyl transferase. These natural products have attracted considerable attention from numerous synthetic chemists because of their therapeutic potential and novel architecture. This review highlights our total syntheses of zaragozic acid C by two convergent strategies. The key steps in our first-generation synthesis involve 1) simultaneous creation of the C4 and C5 quaternary stereocenters through the Sn(OTf)2-promoted aldol coupling reaction between the α-keto ester and silyl ketene thioacetal derived from - and -tartaric acids, respectively; and 2) construction of the bicyclic core structure acid-catalyzed internal ketalization under kinetically controlled conditions. The second-generation strategy relies on a tandem carbonyl ylide formation/1,3-dipolar cycloaddition approach and features elongation of the C1 alkyl side chain through an olefin cross-metathesis as well as high convergency and flexibility.
19/12/2017 · Total Synthesis of t ..
All substance in life, our bodies, our computer, humans and even the grass outside is made of atoms and molecules. Atoms are the smallest unit, while molecules are composed of two or more atoms. Humans and all other organisms maintain their basic structure and function by these molecules and undergo by metabolic reactions. In metabolic reactions, some bigger molecules are broken down into smaller molecules, and other smaller molecules organized into bigger molecules to extract energy for survival, growth and maintenance. Free radicals are produced constantly within and outside the cell, some as by-products of energy-releasing oxidation others by UV light, radioactivity, intake of drugs and chemicals. Inhalation of cigarette smoke, exposure to air pollution and mental stress is also accompanied by an increased production of free radicals, causing disease states such as cancer, atherosclerosis, arthritis, diabetes, dermatological system disorders, cataracts and other age-related diseases. This is where antioxidants is used. Antioxidants neutralizes the harmful free radicals and hence improves quality of life.
Free radicals are created by losing an electron, the antioxidant molecule steps in and supplies the free radical with another electron and hence neutralizes it. Due to its molecular structure, Squalene is an excellent antioxidant possessing great capacity to receive or donate electrons without suffering molecular disruption. Squalenes powerful free radical-quenching ability has been shown to be equal to that of BHT (butylated hydroxytoluene), one of the most powerful antioxidants known to science. This unique stability is the key to Squalene's ability to terminate the on-going or chain damage inside our bodies. (lipid peroxidation chain reaction. According to laboratory research, this happens specifically in the skins surface.
Squalene - Powerful immune stimulator
As we know human immune system is a miracle of nature, designed to protect us from the harmful effects of our environment and disease-producing virus, bacteria and other microbes. Without a well-developed and maintained immune system, we will suffer infections and serious life-threatening diseases. Hence optimal function of our immune system is important. Experimental studies have shown that squalene-supplemented diets lead to increased performance of the immune system and laboratory studies have confirmed that squalene enhances the function of macrophages. (macrophages are type of white blood cells that ingests (takes in) or kills bacteria and virus. Macrophages are key players in the immune system) Squalene show broad spectrum of anti-viral, anti-fungal and anti-bacterial properties. Hence to maintain good immune response, intake of squalene is very promising in a current stressful and polluted environment.
Squalene Prevents cancer
Various scientific data on diseases among people suggest, that squalene help prevent cancer and can also fight established tumors.
In Greece, women with high total fat intake, mainly olive oil, have a breast cancer rate of only about one-third that of women in the United States.
In Spain, a case-control study showed a reduced risk for breast cancer in women with the highest olive oil consumption.
In Greece, a large case-control study breast cancer risk was 25% lower in women consuming olive oil more than once a day.
In another case-control study in Spain, women with the highest consumption of monounsaturated fatty acid (MUFA)(largely from olive oil) had a greatly reduced risk of breast cancer.
Leading scientists on this field, Theresa J. Smith and Harold L. Newmark, suggest that this protecting effect can be related to the high concentration (0.2-0.7%) of squalene in olive oil.
Squalenes powerful antioxidant and cytoprotective effects (protecting cells from damage) are very significant. A research team from Torontos Hospital for Sick Children demonstrated that squalene has selective cytoprotection on individual cell (in-vitro) and on whole organism. (in-vivo)
Through extensive research, squalene has further been shown to: