Chemical Composition and Antioxidant Activity of Cucumis Dipsaceus Ehrenb
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International Food Research Journal 21(4): 1465-1472 (2014) Journal homepage: http://www.ifrj.upm.edu.my Chemical composition and antioxidant activity of Cucumis dipsaceus Ehrenb. Ex Spach fruit Nivedhini, V., Chandran, R. and *Parimelazhagan, T. Department of Botany, Bioprospecting laboratory, Bharathiar University, Coimbatore, Tamil Nadu, India Article history Abstract Received: 26 May 2013 The study was undertaken to explore the nutritional and antioxidant property of Cucumis Received in revised form: dipsaceus. The results revealed significant amount starch (1.07 mg/g), proteins (85.9 mg/g), 3 February 2014 essential aminoacids and some most important minerals like calcium (14820 ppm) and nitrogen Accepted: 4 February 2014 (6300 ppm). The phenolic (3.04 g GAE/100 g extract) tannin (1.66 g GAE/100 g extract) and Keywords flavonoid content (11.26 g RE/100 g extract) was found to be high in ethyl acetate, chloroform and methanol extract of fruit. Response of Cucumis dipsaceus fractional extracts towards Proximate composition various antioxidant assays was appreciable especially in ABTS+, metal chelating, nitric oxide Minerals and DPPH assays. Methanol extract of Cucumis dipsaceus fruit showed the highest activity Amino acids (4907.22 µg TE/g) to stabilize ABTS radical. Metal chelating activity was efficiently exhibited Antioxidant by Cucumis dipsaceus fruit methanol extract (12.4 g EDTA equi/100g extract). DPPH (IC = Cucumis dipsaceus 50 10.37 µg/mL) assay also revealed higher free radical inhibition of fruit. This study has clearly pointed out the nutritional and antioxidant properties of Cucumis dipsaceus which could support its use as a nutraceutical supplement in health promoting diets. © All Rights Reserved Introduction thereby causing damage to proteins, cells and DNA (Shetti et al., 2009). However the presence of free Plants have always been a good source of food and radicals within the body can also have significant role medicine and the relevance of plant based products in the development and progression of many diseases has gained much interest because of their nutraceutical processes like congestive heart failure, hypertension, property with lesser side effects. The effects of cerebrovascular accidents and diabetic complications nutrients are dose-dependent and shortages are called (Chen et al., 2002). Degradation due to oxidative deficiencies (Audrey, 1994). Anti-nutrients are certain reactions can affect all biomolecules, but mostly natural or synthetic compounds that interfere with lipids, carbohydrates and proteins (Hinnerburg et the absorption of nutrients. One common example al., 2006). Due to suspected toxicity of synthetic is “phytate”, which forms insoluble complexes with anti-oxidants like BHA (Butylated hydroxyl anisole) calcium, zinc, iron, and copper (Sarkiyayi and Agar, and BHT (butylated hydroxyl toluene) (Madhavi 2010). Proteins can also be anti-nutrients, such as and Salunkhe, 1995) the interest is highly focussed the trypsin inhibitor and lectins found in legumes on searching plant based antioxidants because of (Giliani et al., 2005). Flavonoids are a form of anti- their therapeutic performance and low toxicity. nutritional factors. These compounds chelate metals Antioxidants protect the integrity of cellular structures such as iron and zinc, and reduce the absorption of and macromolecules from damage due to free these nutrients. They also inhibit digestive enzymes radicals. Carotenoids and phenolic compounds are and may precipitate proteins (Beecher, 2003). The dietary antioxidants (Shahidi and Chi-tang, 2007). investigations of such nutritional and anti-nutritional Cucumis dipsaceus Ehrenb. ex Spach is a factors enable us to know the nutritional and anti- species of flowering plant belonging to the family nutritional values and to avoid consumption of highly Cucurbitaceae. It has its origin in Ethiopia and is toxic plants. It will also provide knowledge on the known by several common names like teasel gourd, nutritional implication of feeding on staples of low Arabian cucumber, hedgehog, pepino-diablito, nutritive quality, which will help to ensure better concombre porc-epic etc. Usually Cucumis dipsaceus health condition of people in developing countries are consumed as a leafy vegetable (Verdcourt and (Sarikiyayi and Agar, 2010). But there are certain Trump, 1969), its fruit juice is topically applied to useful flavonoids in plants which acts as an important prevent hair loss (Rainer and Ashley, 2010). However, free radical scavengers. being a fruit growing in wild no attempt has been Free radicals are highly unstable and undergo taken to evaluate the parameters which could support chemical reactions either to grab or donate electrons, its use as vegetable. Therefore, the present study has *Corresponding author. Email: [email protected] Tel: +04222428305; Fax: +04222425706 1466 Nivedhini et al./IFRJ 21(4): 1465-1472 been undertaken to evaluate the nutritional, anti- Estimation of amino acids nutritional and antioxidant properties of fruit Amino acids in leaves were determined according to the procedure of Ishida et al. (1981). Extracted Materials and Methods samples (1 mg/ml) were filtered through a 0.45 µm membrane filter and 20 µL of the filtrate was injected Collection of plant materials in to a HPLC (model LC 10 AS, Shimadzu, Mount The fruits were collected during the month of holly, New Jersey) equipped with a cation exchange November 2011. The collected plant material was column packed with a strongly acidic cation identified and their authenticity was confirmed by exchange resin, i.e., styrene divinyl benzene co- comparing the voucher specimen at the herbarium polymer with sulphonic group. The temperature was of Botanical survey of India (BSI), Southern circle maintained at 40ºC and the run time was 15 min. The Coimbatore, Tamil Nadu (No. BSI/SRC/5/23/2011- amino acid analysis was with the non-switching flow 12/Tech-1466). The Plant was certified by Dr. P. method and fluorescence detection after post-column Satyanarayana, Scientist ‘D’, BSI, Coimbatore. derivatization with o-phthaldehyde. Identification was Freshly collected fruits were cleaned to remove based on the comparison between the retention time adhering dust and then dried under shade. The dried of the standards of the amino acids and those in fruit sample was powdered and used for further studies. and was confirmed and quantified by a fortification technique (spiking). Successive solvent extraction Fresh (1 kg) fruits were taken and air died under Mineral quantification room temperature. The air dried, powdered fruit (100 For the sample digestion, 0.5 g of dried sample g) was extracted in Soxhlet extractor successively was mixed with 5 ml digestion mixture and kept in with petroleum ether and methanol. Finally, the digestion unit at 300°C. The process was allowed to material was macerated using hot water (80ºC) with continue till the mixture turns colourless. Desired occasional stirring for 24 hr and the water extract was volume of distilled water is added to the digested filtered. The methanol extract alone was subjected and cooled samples. Solution was filtered and mixed to fractional extraction using chloroform, ethyl well till all sediments got dissolved. Subsequently acetate and methanol (Raaman, 2006). The period of minerals were determined as follows: nitrogen (N) extraction may range from 24 to 48 hr for each solvent through micro Kjeldahl method; phosphorus (P) depending on the extractability of the solvents. Each by treating the digested samples with ammonium time before extracting with the next solvent, the molybdate and freshly prepared ascorbic acid and material was dried in hot air oven below 40oC. The analyzed by spectrophotometer (Hitachi U-2001 different solvent extracts were concentrated by rotary Japan); potassium (K), sodium (Na), and calcium vacuum evaporator and then air dried. The extracts (Ca) were determined by Flame Photometer by the were freeze dried (1-12 g) and stored in desiccators method of Allen (1989). The microelements (Fe, CO, until further analysis. Cu, Mg, and Zn) were determined through Atomic Absorption Spectrophotometer. Nutritional analysis Analysis of anti-nutritional factors Proximate composition Trypsin inhibition ability was evaluated in The moisture content of the fruit was estimated powdered fruit samples on a synthetic substrate by taking plant samples and the weight was taken BAPNA. The degree of inhibition is expressed in before and after incubation in a hot-air-oven at 50oC TIU/mg protein by the method of Sadasivam and for 24 h, followed by cooling in a desiccator. The Manikam (1992). recommended methods of Association of Official Analytical Chemists (1990) were used for the In vitro antioxidant studies determination of ash. Ash content was determined by incineration of 2 g of sample in a muffle furnace Quantification of total phenolics, tannins and kept at 600oC for 6 h. The protein was estimated flavonoids as described by Lowry et al. (1990). The starch The total phenol content was determined content was estimated as described by Sadasivam according to the method described by Siddhuraju and Manickam (1992) using glucose as a standard. and Becker (2003). Using the same extract the The samples were analyzed in aliquots and the results tannins were estimated after treatment with polyvinyl expressed on dry weight basis. polypyrrolidone (PVPP) Sidduraju and Manian, Nivedhini et al./IFRJ 21(4): 1465-1472 1467 (2007). The tannin content of the sample was were employed