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SLT00228 - PHENOLIC AND ANTIOXIDANT PROPERTIES OF CITRUS LEMON SEED EXTRACT


CHAPTER ONE

  • INTRODUCTION

In living system,oxidation is a basic part of normal metabolic process, in which reactive oxygen species (hydrogen peroxide and hypochlorous acid) and many free radicals (hydroxyl radical (OH) and superoxide anion) are generated (Halliewell, 2000;Pietta, 2000;Vijayabaskaranet al., 2010). Rapid production of free radicals may cause alteration in the structure and function of cell constituents and membranes and can in human neurologic and other disorders such as cancer,diabetes,inflammatory disease,asthma,cardiovascular,neurodegenerative diseases and premature ageing. Therefore, the prevention of the above conditions requires the presence of antioxidants or free radicals scavenging molecules in the body.

There are plenty of antioxidant substances present in plants (fruits, vegetables, medicinal herbs, etc.) and the free radical scavenging molecules present in them are in the form of phenolic compounds (e.g.phenolic acids,flavonoids,quinines, coumarins,lignans,tannins), nitrogen compounds (alkaloids, amines), vitamins, terpenoids (including carotenoids), and some other endogenous metabolites. So to maintain a healthy body, one should always increase the intake of foods rich in antioxidant compounds that lower the risk of chronic health problems associated with the above disease conditions (Halliwell, 1994; Klipsteinet al., 2000;Bimal et al., 2011). Naturally occurring antioxidants can be used in foods and also for prevention and treatment of free radical-related disorders which can also be replaced by commercially available,synthetic antioxidants such as butylatedhydroxyanisole (BHA) and butylatedhydroxytoluene (BHT), which are quite unsafe to use and is restricted due to their carcinogenic effects. Nitric oxide (NO) is a potent pleiotropic inhibitor of platelet aggregation and 16 regulation of cell mediated toxicity. It is a diffusible free radical that plays many roles as an effectors molecule in diverse biological systems including neuronal messenger, vasodilation and antimicrobial activities. The most commonly used methods for measuring antioxidant activity are those which involve the generation of free radicals which are then neutralized by antioxidant compounds. DPPH is a well-known radical and a trap (scavenger) for other radicals (Husain et al., 1987, Visioliet al., 2000;Parr et al., 2004;Solaiet al., 2010).

            Antioxidants in all leaves play important roles as health protecting factors due to the fact that they are unable to neutralize reactive oxygen species (ROS) and thus prevent a condition known as oxidative stress. Important nutraceutical agents are phenolic compounds which are crucial for their activity as antioxidants.The nutritive value of seed is not considered as its ability to supply the basic nutrients such as carbohydrates, protein and lipids, but also its ability to provide other health benefits (Oboh, 2006). These health benefits are contributed by the presence of certain bioactive phytochemicals in the leaves materials. In recent times, a lot of focus have been shifted to functional food research in order to identify and characterize the various nutraceutical agents in various types of food and for them to be applied for their various health benefits such as reduction of risk towards specific diseases, or maintenance and treatment for given health condition (Oboh, 2006).

            By definition, ´traditional´ use of herbal medicines implies substantial historical use, and this is certainly true for many products that are available as ´traditional herbal medicines´. Traditional herbal medicine is sometimes referred to as alternative medicine. It is the indigenous healing system based on the culture, traditional of the people with their beliefs about the causes or ill-health, According to the World Health Organisation (WHO) (1978), Traditional medicine is the sum total of all knowledge and practices whether explicable or not used in the diagnosis, prevention and elimination of physical, mental imbalance and relying exclusively on practical experience and observation down from generation whether verbally or in writing depending on the religious and socio-cultural beliefs. It is a practice derived from the values and perception of the members of the community.The pharmacological treatment of disease began long ago with the use of herbs (Schulz et al., 2001).