Oguz Merhan

By Oguz Merhan

Carotenoids are one of the most widespread pigment groups distributed in nature, and more than 700 natural carotenoids have been described so far, and new carotenoids are introduced each year. Carotenoids are derived from 4 terpenes, including totally 40 carbon atoms. Carotenoids are naturally synthesized by cyanobacteria, algae, plants, some fungi, and some bacteria, but not made by mammals. Lately, the beneficial properties of α-carotene, β-carotene, γ-carotene, lycopene, phytoene, phytofluene, lutein, zeaxanthin, β-cryptoxanthin, astaxanthin, and fucoxanthin carotenoids in prevention of various diseases, such as tumor formation, cardiovascular, and vision, have been documented due to their roles as antioxidants, activation in certain gene expression associated with cell-to-cell communication, provitamin A activity, modulation of lipoxygenase activity, and immune response. In this chapter, in addition to biochemical properties of carotenoids, how the structure of these molecules influences the oxidative stress in health and reducing the risk of formation of various diseases will be described.

Part of the book: Carotenoids

By Emine Atakisi and Oguz Merhan

Nitric oxide (NO) is known to have a very short half‐life, and it is oxidized to nitrate (NO3−) and nitrite (NO2−). The activity and/or expression of nitric oxide synthases (NOSs) can change in response to toxins or therapeutic medications. For example, in recent studies in our laboratory and others, it has been reported that the amount of NO was increased in the serum of N‐nitroso compounds‐treated animals. N‐nitroso compounds, which are found in different types of foodstuffs, including meat, salted fish, alcoholic beverages, agricultural drugs, insecticides, cigarettes, and several vegetables, are known to have carcinogenic effects. In addition, it is experimentally used to induce liver carcinoma to study the mechanisms of liver cytotoxic injury. Uncontrolled, prolonged, and/or massive production of NO by inducible NOS may cause liver damage, inflammation, and even tumor development during N‐nitroso compound toxicity. In this chapter, we explain the roles of NOS and NO in various toxicity conditions, such as toxicity in environment pollutant or food additive, and present the evaluation of the toxicity and the importance of NOSs in human health.

Part of the book: Nitric Oxide Synthase

By Dincer Erdag, Oguz Merhan and Baris Yildiz

Biogenic amines are low molecular weight organic nitrogen compounds. They are formed by the decarboxylation of amino acids or by amination and transamination of aldehydes and ketones during normal metabolic processes in living cells and therefore are ubiquitous in animals, plants, microorganisms, and humans. In food and beverages, they are formed by the enzymes of raw materials or are generated by microbial decarboxylation of amino acids. The structure of a biogenic amine can be aromatic and heterocyclic amines (histamine, tryptamine, tyramine, phenylethylamine, and serotonin); aliphatic di-, tri-, and polyamines (putrescine, cadaverine, spermine, spermidine, and agmatine); and aliphatic volatile amines (ethylamine, methylamine, isopentylamine, and ethanolamine). Many of them possess a strong pharmacologic effect, and others are important as precursors of hormones and components of coenzymes. The biogenic amine intoxication leads to toxicological risks and health hazards that trigger psychoactive, vasoactive, and hypertensive effects resulting from consumption of high amounts of biogenic amines in foods. The toxicological effects of biogenic amines increase when the mono- and diaminoxidase enzymes are deficient or drugs that inhibit these enzymes (pain reliever, stress, and depression drugs) are used. In this chapter, biosynthesis of biogenic amines, their toxic effects as well as their physiological functions, and their effect on health will be described.

Part of the book: Biogenic Amines

By Oguz Merhan

Melatonin (N-acetyl-5-methoxy-tryptamine) is a hormone taking place in many biological and physiological processes, such as reproduction, sleep, antioxidant effect, and circadian rhythm (biological clock), and is a multifunctional indolamine compound synthesized mainly from the metabolism of tryptophan via serotonin in the pineal gland. Melatonin, which is a hormone synthesized from the essential amino acid tryptophan, is substantially secreted from the pineal gland between the cerebral hemispheres found in the mammalian brain. In addition to this, it is also produced in the cells and tissues, such as the gastrointestinal system, gall, epithelial hair follicles, skin, retina, spleen, testis, salivary glands, bone marrow, leukocytes, placenta, and thrombocytes. It plays a role in many physiological events, such as synchronizing circadian rhythms, reproduction, fattening, molting, hibernation, and change of pigment granules, preserving the integrity of the gastrointestinal system with an anti-ulcerative effect in tissues and organs from which it is produced. Melatonin is also a powerful antioxidant and anti-apoptotic agent that prevents oxidative and nitrosative damage to all macromolecules due to its ability to form in metabolic activities, directly excrete toxic oxygen derivatives, and reduce the formation of reactive oxygen and nitrogen species. In this book chapter, we will explain the structure, synthesis, metabolism, and antioxidant effects of the melatonin hormone.

Part of the book: Melatonin

By Kadir Bozukluhan and Oguz Merhan

Acute phase proteins are proteins synthesized by the liver in response to the acute phase response. While these proteins are insignificant in healthy animals, their concentrations increase rapidly during infection, inflammation, or tissue damage and are used as an indicator of inflammation. Since the blood concentrations and importance levels of these clinically important proteins differ according to the animal species, they are evaluated separately for each animal species. Most of the acute phase proteins have been studied in detail in the field of human medicine and are routinely used in the diagnosis and prognosis of diseases. In the field of veterinary medicine, it has not been used sufficiently. In this book chapter, we will provide up-to-date information about acute phase proteins that are important for cattle, as well as explain that acute phase proteins can be used in the early diagnosis of diseases, in the differentiation of viral and bacterial infections, in guiding the treatment of sick animals and in determining their prognosis.

Part of the book: Cattle Diseases