ASCORBIC ACID (VITAMIN C) CONTENT OF CUCUMBER. ; CHM

INTRODUCTION The cucumber is a creeping vine that roots in the ground and grows up trellises or other supporting frames, wrapping around supports with thin, spiraling tendrils. The plant has large leaves that form a canopy over the fruit. The fruit of the cucumber is roughly cylindrical, elongated with tapered ends, and may be as large as 60 centimeters (24 in) long and 10 centimeters (3.9 in) in diameter. Having an enclosed seed and developing from a flower, botanically speaking, cucumbers are classified as pepoes, a type of botanical berry. Much like tomatoes and squash they are often also perceived, prepared and eaten as vegetables. Cucumbers are usually more than 90% water. A vitamin is an organic compound required by an organism as a vital nutrient in limited amount [1]. An organic chemical compound is called a vitamin when it cannot be synthesized by an organism and must be obtained from diet. Thus, the term is conditional both on the circumstances and on the particular organism. For example, ascorbic acid is a vitamin for humans, but not for most other animals. Supplementation is important for the treatment of certain health problems [2].   Vitamin C, also known as ascorbic acid or ascorbate is essential for human health. It is a water soluble vitamin having the structure of monosaccharides. As a reducing agent, ascorbic acid readily loses two hydrogen atoms to become L-dehydroascorbic acid, which also has vitamin C activity [3]. Vitamin C cannot be synthesized by human and must be obtained from dietary source, primarily vegetables and fresh fruits. In human beings deprived of vitamin C, the life threatening nutritional deficiency disease scurvy develops [4]. The early story of ascorbic acid is associated with aetiology, treatment and preventions of the disease. Before the association of scurvy with diet was recognized, it was believed to be a veneral disease and was treated as such with disastrous result. Today incidents of scurvy surface in ascorbic acid deficiency [5].   Nevertheless, the main biochemical role that ascorbic acid plays is undoubtedly related to its function as a good reducing agent [6-7]. It is involved in several enzymatic reactions. Ascorbic acid plays some roles in collagen synthesis. Collagen is the principal component of skin and connective tissue, the organic substance of bones and teeth and the ground substance between cells. Deficiency of ascorbic acid causes impaired collagen synthesis. Thus, synthesis involves the enzymatic hydroxylation of protein to form a stable extracellular matrix and of lysine for glycosylation and formation of cross links in the fibers. However, ascorbic acid reduces the Fe” [8].   Ascorbic acid functions as a chelating agent. It interacts with some metal ions resulting in their enhanced absorption from the diet and their mobilization and distribution throughout the body. Ascorbic deficiency interferes with iron mobilization from the spleen but not from the liver. Supplementary ascorbic acid increases its mobilization from the body stores during the treatment of iron over load. This property is important in the treatment of anaemia [9].   An important biological function of ascorbic acid is the destruction of free radicals derived from oxygen (02) such as hydroxyl, Singlet oxygen and superoxide [10]. These free radical scavenging reactions are important in the eyes in the extracellular fluid of the lungs where they provide protection against other oxidizing agents such as ozone. The metabolism of L- tyrosine involves mixed function oxidase that is dependent on the presence of L- ascorbic acid [11].   Ascorbic acid plays very important role in the of the body system, hence it is imperative to analyze the ascorbic acid levels of some maintenance common fruits and vegetables to compare their various concentrations.  



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