Antioxidant Properties of Popular Turmeric (Curcuma Longa) Varieties from Bangladesh
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Hindawi Journal of Food Quality Volume 2017, Article ID 8471785, 8 pages https://doi.org/10.1155/2017/8471785 Research Article Antioxidant Properties of Popular Turmeric (Curcuma longa) Varieties from Bangladesh E. M. Tanvir,1,2 Md. Sakib Hossen,1 Md. Fuad Hossain,3 Rizwana Afroz,1,4 Siew Hua Gan,5 Md. Ibrahim Khalil,1,5 and Nurul Karim1 1 Laboratory of Preventive and Integrative Biomedicine, Department of Biochemistry and Molecular Biology, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh 2Veterinary Drug Residue Analysis Division, Institute of Food & Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka 1349, Bangladesh 3Department of Agricultural Biology, Faculty of Agriculture, University of Ruhuna, Mapalana, Matara, Sri Lanka 4School of Pharmacy, Pharmacy Australia Centre of Excellence, The University of Queensland, Woolloongabba, QLD 4102, Australia 5Human Genome Centre, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia Correspondence should be addressed to Md. Ibrahim Khalil; [email protected] and Nurul Karim; [email protected] Received 19 February 2017; Revised 4 April 2017; Accepted 20 April 2017; Published 31 May 2017 Academic Editor: Ignacio Garc´ıa-Estevez´ Copyright © 2017 E. M. Tanvir et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We investigated the aqueous and ethanolic extracts of different forms (local names: mura and chora) of turmeric (Curcuma longa) from the Khulna and Chittagong divisions of Bangladesh for their antioxidant properties and polyphenol, flavonoid, tannin, and ascorbic acid contents. The antioxidant activity was determined using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical- scavenging activity and ferric reducing antioxidant power (FRAP) values. The ethanolic extract of Chittagong’s mura contained the highest concentrations of polyphenols (16.07%), flavonoids (9.66%), and ascorbic acid (0.09 mg/100 g) and chora resulted in high yields (17.39%). The ethanolic extract of Khulna’s mura showed a higher DPPH radical-scavenging activity with the lowest 50% inhibitory concentration (IC50) (1.08 g/mL), while Khulna’s chora had the highest FRAP value (4204.46 ± 74.48 M Fe [II] per 100 g). Overall, the ethanolic extract had higher antioxidant properties than those in the aqueous extract. However, the tannin concentration was lower in the ethanolic extract. We conclude that the turmeric varieties investigated in this study are useful sources of natural antioxidants, which confer significant protection against free radical damage. 1. Introduction Many people consume antioxidants as a defense against oxidative stress. Antioxidants in the form of commercial The complex biochemical reactions of the body and increased food additives have been manufactured synthetically and exposure to environmental toxicants and dietary xenobiotics may contain high amounts of preservatives [3]. Some syn- result in the generation of reactive oxygen species (ROS) and thetic antioxidants, such as butylated hydroxyanisole (BHA), reactive nitrogen species (RNS), leading to oxidative stress butylated hydroxytoluene (BHT), and tertiary butyl hydro- under different pathophysiological conditions [1]. Antioxi- quinone (TBHQ), have been reported to produce toxins or act dants prevent oxidative damage through one-electron reac- as carcinogens [2, 4]. Therefore, identifying potential natural ∙− tions with free radicals [superoxide radicals (O2 ), hydroxyl antioxidant sources can be a useful alternative to ensure ∙ ∙ radicals (OH ), singlet oxygen (O ), and hydrogen peroxide sound health [5]. Food is the source of essential nutrients for (H2O2)] that adversely alter cellular lipids, protein, DNA, growth and maintenance, but other bioactive compounds of and polysaccharides [1, 2]. Therefore, a balance between plant origin promote health by slowing the aging process and free radical and antioxidant concentrations is necessary to preventing disease [6]. As a result, antioxidant constituents maintain proper physiological functions [2]. in plant material have piqued the interest of scientists, food 2 Journal of Food Quality manufacturers, cultivators, and consumers for their roles in (Darmstadt, Germany). All of the chemicals and reagents the maintenance of human health [3]. used in this study were of analytical grade. Turmeric is a golden spice derived from the rhizome of the Curcuma longa plant, which belongs to the Zingiberaceae 2.2. Turmeric Collection. Two different turmeric varieties family [7]. Since ancient times, turmeric has been used as the (“mura” and “chora”) were collected from the Khulna district principal ingredient of dishes originating from Bangladesh of Khulna division and the Khagrachari district of Chittagong andIndiaforitscolor,flavor,andtaste.Itisalsousedinsocial division in Bangladesh in July 2013. Following collection, and religious ceremonies in Ayurvedic and folk medicines the turmeric samples were packed into sterile polybags against various ailments, including gastric, hepatic, gyneco- before transportation to the Laboratory of Preventive and logical, and infectious diseases [7, 8]. Integrative Biomedicine in the Biochemistry and Molecular Dry turmeric contains 69.43% carbohydrates, 6.3% pro- Biology Department, Jahangirnagar University, Savar, Dhaka, teins, 5.1% oils, 3.5% minerals, and other elements [9]. Bangladesh. The bioactive chemical constituents in turmeric have been extensively investigated. To date, approximately 235 com- 2.3. Extract Preparation and Yield Determination. Turmeric pounds, primarily phenolics and terpenoids, have been iden- samples were cleaned and air-dried in the shade for two tified from various species of turmeric, including twenty- days before being ground to a fine powder in a blender two diarylheptanoids and diarylpentanoids, eight phenyl- (CM/L7360065, Jaipan, Mumbai, India). The fine powder propenes as well as other phenolics, sixty-eight monoter- was used to prepare both ethanolic and aqueous extracts penes, 109 sesquiterpenes, five diterpenes, three triter- basedonKang’smethod[13]withslightmodification.Briefly, penoids, four sterols, two alkaloids, and fourteen other com- 20% ethanolic extract was prepared by adding turmeric pounds [10]. Curcuminoids (mostly curcumin) and essential powder (20 g) in 70% ethanol solution to make a 100 mL oils (primarily monoterpenes) are the major bioactive con- solution. Similarly, for 20% aqueous extract preparation, 20 g stituents showing different bioactivities. Calebin-A, vanillic of turmeric powder was dissolved in water to make a 100 mL acid, vanillin, quercetin, and other phenolic compounds have solution. Both ethanol and aqueous extract solutions were also previously been identified from turmeric [7, 11]. placed in the dark to avoid reactions that may occur in the The herbaceous perennial is extensively cultivated in presence of light and were shaken in a shaker for 72 h at the tropical areas of South Asia, including Bangladesh, room temperature. Then, the solutions were filtered through India, and China, while India is the primary exporter of Whatman No. 1 filter paper and concentrated in a rotary turmeric [7]. To meet increased demands in both national evaporator (Buchi, Tokyo, Japan) under reduced pressure ∘ ∘ and international markets, Bangladesh has developed many (100 psi) at 40 C(forethanol)and55C(forwater).The ∘ promising and sustainable spice companies including Square, dried extracts were collected and preserved at −20 Cfor BDfoods,Archu,Pran,ACI,andDekko,maximizingits subsequent analysis. The percentage of yield of the extracts conducive geographical location for turmeric cultivation, was determined according to the following formula: % especially in hilly areas of the greater Chittagong division. yield = [weight of sample extract/initial weight of sample] The turmeric yield was 5.16 metric tons per hectare in the × 100. Eight different turmeric extracts were prepared for 2007-2008 production period and increased daily due to the antioxidant analysis (Table 1). development and dissemination of improved varieties [8]. Popular turmeric rhizome shapes include oblong with short 2.4. Phytochemical Analysis branches, which is locally named “chora,” as well as ovate, which is locally named “mura” (Figure 1). However, in the 2.4.1. Estimation of Total Polyphenol Content. The total poly- Khulna district, these local turmeric varieties are popularly phenol content (TPC) of the turmeric extracts was estimated known as “kopil moni chora” and “kopil moni mura.” spectrometrically according to the Folin-Ciocalteu method The medicinal values and antioxidant properties of some [14] and adopted by Afroz et al. [15]. Briefly, 0.4 mL of turmeric varieties have already been reported [6, 12]. How- the extract (0.25 mg/mL) was mixed with 1.6 mL of 7.5% ever,therearelittleknowledgeandscientificdataonthe sodium carbonate solution. Then, 2 mL of 10-fold diluted antioxidant compositions and activities of turmeric produced Folin-Ciocalteu reagent was added, and the final reaction in Bangladesh. Thus, the present study aimed to investigate mixturewasincubatedfor1hinthedark.Theintensityofthe the antioxidant properties of turmeric varieties from Kha- blue-colored complex was measured at 765 nm using a PD- grachari and Khulna districts, Bangladesh, using different 303S spectrophotometer (APEL, Japan).