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Recent Innovations in Chemical Engineering, 2014, 7, 106-112
Antioxidant Activities and Total Phenolics Contents from Extracts of Terminalia catappa, Carrisa carandas, and Opuntia ficus indica Fruits Shagufta Ishtiaque1*, Shahina Naz2, Rahmanullah Siddiqi2, Syed Umer Abdullah2, Kehkashan Khan3, Jawwad Ahmed4 and Muhammad Badaruddin4 1
Department of Chemical Engineering, University of Karachi, Karachi 75270, Pakistan; 2Department of Food Science & Technology, University of Karachi, Karachi 75270, Pakistan; 3Department of Chemistry, University of Karachi, Karachi 75270, Pakistan; 4Department of Food Engineering, NED University of Engineering & Technology, Karachi Received: February 14, 2015
Revised: March 10, 2015
Accepted: March 11, 2015
Abstract: To investigate potential sources of the natural antioxidants from fruits, Terminalia catappa, Carissa carandas, and Opuntia ficus indica, have been selected for this study. Their total phenolic content (TPC) and antioxidant activity (AOA) were determined by using DPPH (2,2-diphenyl-1picrylhydrazyl), ferric reducing power (FRP) and chelating effect methods. Data obtained show that among these species, the highest polyphenolic contents were found in T. catappa (1005 mg/100g GAE) with the highest AOA (49 to 79%), whereas, the least TPC was found in O. ficus indica (200 mg/100g GAE) having AOA (18 to 52%) . However, C. carandas fruit showed moderate polyphenolic content (410 mg/100g GAE) with a significant antioxidant activity (22-64%). On the basis of these results, it has been concluded that antioxidant activity is concentration dependent and TPC of fruits is directly proportional to the antioxidant activities determined by different methods.
Keywords: Antioxidant activity, total phenolic content, DPPH, FRP, chelating effect. 1. INTRODUCTION To perform biological activities, all living organisms need oxygen. However, using extra reactive oxygen species and oxygen free radicals causes severe health issues like diabetes, cancer, aging, heart attack, mental issues, etc. [1]. This oxidative stress not only causes health problems but also deteriorates the quality of food items. Oxidative destruction of lipids, which is termed as lipid peroxidation, is a very complex process, in which oxygen free radicals capture electrons from the lipids in cell membrane and hence resulted in destroying the whole cell. Due to this process, food items lose their color, taste, smell and appearance, and make these foods unacceptable. *Address correspondence to this author at the Department of Chemical Engineering, University of Karachi, Karachi 75270, Pakistan; Tel: 092-21-9926-1300; Fax: 092-21-9926-3402; E-mail:
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Various types of antioxidants can prevent oxidation of food items by different mechanisms such as free radical scavenging, mechanism involving peroxideas a reducing agent, etc. [2]. Therefore, oxidative damages may be minimized by using food or medicine containing antioxidants [1]. Both synthetic and natural antioxidants are used commonly. Since the beginning of the last century, some common types of synthetic antioxidants like butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were extensively used in oil based formulations, but due to their carcinogenic characteristics, they have now been replaced by natural antioxidants [3]. Since scientists are in a continuous search of highly effective non-toxic natural antioxidants, phenolic compounds from plant origin have also been evaluated for their antioxidant potential. Most of the edible plants have been analyzed for their antioxidant properties, © 2014 Bentham Science Publishers
Antioxidant Activities of Extracts from Fruits
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since they have been used by human beings in their daily life and were found nontoxic [4]. Antioxidants from most of the fruits and vegetables decrease the occurrence of diseases like cancer, cardiovascular diseases, neurological problems, etc. The antioxidant activity and total phenolic content have been extensively studied by many scientists. In a study conducted by [5], it was found that the total phenolics from the methanol extract of 21 fruit species of Thailand were found in the range of 0.05-0.96g/100g (GAE) of dried fruit. Similarly, 17 fruit species of different plants also contained total phenolic contents in the range of 26-2167 of GAE/100g and antioxidant activity in the range of 43-88% by DPPH method in their extracts [6]. However, due to the fact that these plants are of high economic importance and have a very high cost, scientists are still in the search of underutilized fruit plants with low cost. The main objective of this study is to explore more underutilized and economical sources for the extraction of phenolic contents for food and packaging industries. Antioxidants from the T. catappa have already been studied by various researchers [7]. Leaves and fruits of T. catappa are rich in polyphenolic content and antioxidant activity [8]. Similarly, C. carandas has extensively been studied for its total polyphenolic content and antioxidant activity [9]. Reported an IC50 value of C. carandas of about 27.45 µg/ml, however, in comparison with F. hirta fruit (12.6%), C. carandas has the highest yield (67.20%) [10]. Although O. ficusindica fruit has not been much explored by scientists, this fruit requires further studies based on its nutritional and pharmacological importance [11]. A comparative study has been conducted between peels, juicy pulp and seed of O. ficus fruits and the highest total phenolic content was found in peels (1507 mg AGE/100g) and lesser phenolic contents were found in juicy pulp and seed of the fruits (245.09 and 74.6 mg AGE/100g, respectively). Hence, the aim of the present study is to determine the potent and economical sources of phenolic compounds by comparing the total phenolic content and antioxidant activity (AOA) of the fruits of T. catappa, C. carandas, and O. ficus indica, by DPPH (2,2-diphenyl-1-picrylhydrazyl), ferric reducing and chelating effect methods.
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2. MATERIALS AND METHODS 2.1. Sampling About 9 kg of T.catappa and C.corundas fruits and O. ficus indica were purchased from the local market of Karachi, in July 2011. Since sample fruits were delicate and perishable in nature, these were washed, packed and stored at 5°C for the experimental purpose. 2.2. Chemicals Reagents and chemicals used (analytical grades) were purchased from BDH and Merck. 2.3. Extraction and Estimation of Phenolics Content in Fruits Procedure adopted for polyphenols extraction from crude methanol extract was reported earlier by a group of co-workers [12]. Similarly, a protocol for the estimation of total phenolic content followed was also taken from the earlier citation [13]. The size of fruits’ samples was slightly varied with each other with an average weight of 250gm. All samples were soaked in 80% methanol and then extracted and concentrated by using rotary vacuumevaporator (BUCHI, R-20, Switzerland). 2.4. Atioxidant Activity of the Fruit Extracts DPPH assay, reducing power assay, and Fe (II) chelating activity procedures were used to evaluate antioxidant potential of polyphenolic fruit extracts. 2.5. Radical Scavenging Activity by DPPH Assay DPPH activities of all fruits’ extracts were measured by using the method followed by Negi et al. [14]. Samples of different concentrations were prepared in methanol (50-250 µg/100 µL) with 1.4 mL, 0.2 mM and 1.5 mL of DPPH methanolic solution. After complete mixing, these extracts were kept in dark for the duration of 30 minutes. Spectrophotometer was used to measure the decreased absorbance of samples against blank at 515 nm. 2.6. Ferric Reducing Power (FRP) The Ferric reducing ability of fruits’ species was evaluated by the method developed by Jayaprakasha et al. [13]. Extracts were prepared in methanol solution (50-250 µg/mL). To these crude extracts, 2.5 mL of 1% potassium ferricyanide
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and 0.2 M (pH 6.6) phosphate buffer were added. Next step involved the incubation of these extracts at 50oC for 20 minutes. After incubation, 10% of 2.5 mL trichloroacetic acid was added. These mixtures were then centrifuged at 5000 rpm for the time period of 10 minutes. 0.1% FeCl3 (0.5 mL) was added and the absorbance of the samples was measured at 560 nm. Increased absorbance observed indicated samples’ reducing power. The results were expressed in %. 2.7. Chelating Effect The metal chelating effect (Fe2+) was determined by the method developed by Re et al. [15] with 2,2-Biphridyl assay. To the extracts’ of fruits prepared inmethanol (50-250 µg/mL), 1 mM FeSO4 solution (0.25 mL), 7.4 pH tris-HCl buffer (1mL), 0.1% in 0.2M HCl of 2,2′-bipyridyl solution (1mL) and methanol (2.5. mL) were added. The chelating activity of all extractswas evaluated using Na2EDTA as a standard. The absorbance of the samples was taken at 522 nm by using Spectrophotometer. 2.8. Statistical Analysis Samples were used in triplicates for statistical analysis and mean ± standard deviation was used to express data. The correlation between total phenolic content and antioxidant activity was calculated using Pearson correlation test. With the help of computer software SPSS (version 20), analysis of variance as two factorial (ANOVA) and Turkeys’ tests, were calculated among the mean values at p
