Free Radical Scavenging Activities of Zizyphus mauritiana

In the present study, antioxidant activities of the two varieties of fruits of Zizyphus mauritiana (Boroi) were investigated. Ethanolic extracts of fruits powder were characterized by the method described by Hatano et al. [1] in which stable 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical solution were used. In the present investigation, it is found that all of the fruit extracts have remarkable antioxidant activities. The IC ’s 50 (inhibition concentration 50) of the ethanolic extracts of Zizyphus mauritiana (Local) and Z. mauritiana (Narikeli kul) were 72 and 250 μg/ml respectively. Between these two varieties local variety showed higher antioxidant activities. Therefore, the research clearly indicates local variety of Zizyphus mauritiana is exceptionally advantageous for human health. Key word: Antioxidant activity Fruits Zizyphus mauritiana Ethanolic extracts and IC50. INTRODUCTION odd, unpaired electron [8]. But when weak bonds split, Antioxidant means "against oxidation." An and react quickly with other compounds, trying to capture antioxidant is any substance that retards or prevents the needed electron to gain stability. Generally, free deterioration, damage or destruction by oxidation [2]. It is radicals attack the nearest stable molecule, "stealing" its a classification of several organic substances, including electron. When the "attacked" molecule loses its electron, vitamins C and E, vitamin A (which is converted from it becomes a free radical itself, beginning a chain reaction beta-carotene), selenium and a group known as the and can be "thousand of events long" [9]. Once the carotenoids [2, 3]. process is started, it can cascade, finally resulting in the A free radical is a compound with one or more disruption of a living cell [4]. unpaired electrons in its outer orbital [4]. Such unpaired Free radicals are formed continuously as normal byelectrons make these species very unstable and products of oxygen metabolism during mitochondrial therefore quite reactive with other molecules due to the oxidative phosphorylation. Thus the mitochondrion is the presence of unpaired electron(s) [5] and they try to pair main source of free radicals [10, 11]. their electron(s) and generate a more stable compound. The role of free radicals in many disease conditions The most dangerous free radicals are the atomic and has been well established. Several biochemical reactions molecular varieties of oxygen which is known as Reactive in our body generate reactive oxygen species and these Oxygen Species (ROS). While ROS are not technically are capable of damaging crucial bio-molecules. If they are free radicals, they are highly reactive with the molecules not effectively scavenged by cellular constituents, they around them [6]. ROS is a collective term, which lead to disease conditions [12, 13] e.g. Cerebrovascular includes not only the oxygen radicals (Ö and OH) but Disease, Cancer, Arteriosclerosis, Atherosclerosis, Heart 2 . also some non-radical derivatives of oxygen, including Disease, Senility, Aging, Behcet's Disease, Crohn's hydrogen peroxide (H O ), hypochlorous acid (HOCl) Disease, Cataracts, Sunburn, Ulcers, Osteoporosis, 2 2 and ozone (O ) [7]. Rheumatoid Arthritis, Diabetes Mellitus, Emphysema, 3 The human body is composed of many different Stroke [6], Rheumatoid Arthritis, Hemorrhagic Shock, types of cells. Cells are composed of many different types Cardiovascular Disorders, Cystic Fibrosis, of molecules. Molecules consist of one or more atoms of Neurodegenerative Diseases (e.g. Parkinsonism, one or more elements joined by chemical bonds. Normally, Alzheimer’s disease), Gastrointestinal Ulcerogenesis, bonds don’t split in a way that leaves a molecule with an AIDS and even early Senescence [12, 13]. Free radicals free radicals are formed [5]. Free radicals are very unstable World J. Agric. Sci., 5 (3): 318-322, 2009 319 Table 1: The detailed data on extraction of fruits. Wt. of Wt. of bottles Wt. of the final Name Wt. during Wt. after % of water Wt. used for bottles used for with extract (g) extract (g) of fruit Type collection (gm) drying (g) in green fruits extraction (g) Alcohol used (ml) evaporation (g) after evaporation Z. mauritiana Mature 1250 110 91.2 50 125 46.4 52.4 6 (Local) Z. mauritiana Mature 1250 103 91.76 50 125 52.1 58.6 5.5 (Narikeli kul) also spoil foods and degrade materials such as rubber, % radical =(absorbance of blank-absorbance of gasoline and lubricating oils [14]. Antioxidants can take scavenging activity sample)/(absorbance of blank) x 100 the form of enzymes in the body, vitamin supplements, or industrial additives. They are routinely added to metals, From calibration curves, obtained from different oils, foodstuffs and other materials to prevent free radical concentrations of the extracts, the IC (Inhibitory damage. To neutralize these free radicals antioxidant plays concentration 50%) was determined. IC value denotes an important role [15]. the concentration of sample required to scavenge 50% of In recent years, one of the areas which attracted a the DPPH free radicals [18]. great deal of attention is the possible therapeutic potential of antioxidants in controlling degenerative diseases Procedure: associated with marked oxidative damage. Several plant extracts and different classes of phytochemicals have Table 1. showing detailed data on extraction of fruits. been found to have quite prominent antioxidant activity [15, 16, 17]. In the present study, we investigated the At first, 6 test tubes were taken to make aliquots of 6 antioxidant activity of the crude extracts of the two conc. (1,5, 10, 50, 100 and 500μg/ml) with the samples. varieties of Zizyphus mauritiana. Fruit extracts and ascorbic acid were weighed Objectives: required concentrations by dilution technique. Here 1. To investigate the antioxidant activity of the crude DPPH was weighed and dissolved in ethanol to make extracts of some local fruits of Bangladesh. 0.004% (w/v) solution. To dissolve homogeneously 2. To determine the intensity of antioxidative magnetic stirrer was used. compounds present in our local fruits. After making the desired concentrations 3ml of MATERIALS AND METHODS by pipette. Measurement of Antioxidant Activities: The antioxidant tubes for 30 mins in light to complete the reactions. activity of the ethanolic extracts was determined on the DPPH was also applied on the blank test tubes at the basis of their scavenging activity of the stable 1, 1same time where only ethanol was taken as blank. diphenyl-2-picryl hydrazyl (DPPH) free radical. DPPH is a After 30 minutes, the absorbances of each test tube stable free radical containing an odd electron in its were taken by a UV spectrophotometer. structure and usually utilized for detection of the radical IC ’s were measured from % Inhibition vs. Conc. scavenging activity in chemical analysis. 1ml of each graphs. solution of different concentrations (1-500μg/ml) of the extracts was added to 3 ml of 0.004% ethanolic DPPH free RESULTS radical solution. After 30 minutes the absorbance of the preparations were taken at 517 nm by a UV DPPH is one of the free radicals widely used for spectrophotometer which was compared with the testing preliminary radical scavenging activity of a corresponding absorbance of standard ascorbic acid compound or a plant extract. In the present study, concentrations (1-500 μg/ml).The method described by ethanolic extracts of the two varieties of the fruit of Hatano et al. [1] was used to measure the absorbance Zizyphus mauritiana (Boroi) showed potential free-radical with some modifications. Then the % inhibition was scavenging activity. The antioxidant activities of the calculated by the following equation: individual compounds, present in the extracts may depend 50