Corresponding Author: Mohammad Arfan, Institute of Chemical Sciences, ... Abdur Rauf, Naveed Muhammad Syed Uzair Ali Shah, Ajmal Khan and Mumtaz Ali.
Academic Journal of Plant Sciences 6 (3): 113-116, 2013 ISSN 1995-8986 © IDOSI Publications, 2013 DOI: 10.5829/idosi.ajps.2013.6.3.1103
The Comparative Free Radical Scavenging Effect of Trigonella foenumgraecum, Solanum nigram and Spinacia oleracea Mohammad Arfan, 2Saira Gul, 1Rabia Usman, 1Arshad Khan, 1 Abdur Rauf, 2Naveed Muhammad 3Syed Uzair Ali Shah, 3Ajmal Khan and 4Mumtaz Ali 1
1
Institute of Chemical Sciences, University of Peshawar, Peshawar, KPK, Pakistan 2 Departments of Pharmacy, University of Peshawar, Peshawar, KPK, Pakistan 3 International Center for Chemical and Biological Sciences (ICCBS), University of Karachi, Karachi-75270, Pakistan 4
Department of Chemistry, University of Malakand, Chakdara, Pakistan
Abstract: In the current finding the crude ethanolic extract and various solvent isolated fractions of Trigonella foenum graecum, Solanum nigram and Spinacia oleracea was assessed for antioxidant potential. The crude extract and its fractions were subjected to antioxidant potential by DPPH free radical assay. Ethanolic fraction of S. nigram showed maximum radical scavenging effect (40.00) followed by chloroform extract 38.50 % at 100µg/ml. The ethyl acetate extract and methanolic extract of Trigonella foenum graecum showed 78 and 80% effect at the same concentration respectively. While the crude extract and various isolated fractions of Spinacia oleracea L remain almost least active among all fractions. The comparison of the antioxidant of crude extract of three plants exhibited that Trigonella foenum graecum has maximum antioxidant potential followed by Solanum nigram and Spinacia oleracea respectively. Key words: Trigonella foenum graecum
Solanum nigram
INTRODUCTION
Antioxidant activity
these plants could have antioxidant effects which need to be evaluated and compared for best antioxidant choice among the three plants. Trigonella foenum graecum is an annual herb that belongs to the family Leguminosae. The seeds of this plant are used in India and in oriental countries as flavoring agent and treatment of diabetes mellitus [4]. It is widely cultivated in Asia, Africa and Mediterranean countries [5] and in Chinese traditional medicine; the seeds of this plant is used as a tonic and also used for stomach disorders. The whole arial parts of this plant are used for the renal disorders [6]. Recently, three novel flavones has been isolated from the methanolic extract of its stem including kaempferol 3-O- -D-glucosyl(1 2) - -D-galactoside(lily), kaempferol 3-O- -D-glucosyl(1 2) - -D-glycoside 7-O- -D-glucoside, kaempferol 3-O- -Dglucosyl(1 2)-(6?-O-acetyl)- -D-glycoside 7-O- -Dglucoside. A new quercetin glycoside has also been isolated and its structure is quercetin 3-O- -D-glucosyl (1 2)- -D-glycoside 7-O- -D-glucoside [7]. Furthermore,
The reactive oxygen species (ROS) are the free radicals produced in the biological systems, involved in the various degenerative traumatic and inflammatory diseases [1, 2]. The ROS includes hydroxyl radical, hydrogen peroxide, superoxide radical and hypochlorous acid, nitric oxide, peroxynitrite. Several mechanisms are involved in the generation of free radicals which then exerts oxidative stress leading to tissue injury and damage of the cellular components like DNA, protein membrane lipids. An ultimate result of oxidative stress is cellular apoptosis [3]. The endogenous antioxidant system continuously deactivating the ROS but in the disease conditions the antioxidant system becomes insufficient to combat the ROS. In such a disease state the use of antioxidant remedies from natural products could be beneficial without producing severe side effects. The literature survey of Trigonella foenum graecum, Solanum nigram and Spinacia oleracea indicated that Corresponding Author:
Spinacia olerace
Mohammad Arfan, Institute of Chemical Sciences, University of Peshawar, Peshawar, KPK, Pakistan
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the aqueous methanol extract of its seeds was examined for radical scavenging properties and exhibited in vitro antioxidant activity. The antiradical activity is present and is correlated with polyphenolic components present in the extract [8]. Solanum nigram, one of the member of solanaceae family, very popular medicinal herb in china and it is believed to have various therapeutic effects, mainly against various cancer types [9]. Two novel oligosaccharides are isolated from the extract of the aerial parts of this plant. Oligosaccharides of 2-deoxy sugars have been reported to possess immunomodulating, anticomplementarry, antitumor and anticancer activities [10]. The activity of superoxide dismutase (SOD) in Solanum nigram leaves decreases with an increase of Cd (cadmium) concentration. The SOD is one of the stress-resistant enzymes and its activity is enhanced by increasing Cd in soil [11]. Spinacia oleracea L is one of the most important green leafy vegetables which contain large quantities of bioactive compounds and nutrients such as ascorbate, carotenoids, tocopherols, phenolics, folate and minerals [12]. Spinach leaves are consumed as vegetable in all over the world which contain many acylated flavonol glycosides possessing strong antioxidant activity [13]. Spinach contain large amount of p-coumaric acid derivatives responsible for its antioxidant activity [13]. Studies have shown that exogenous application of Ascophyllum nodosum extract on spinach increases its endogenous antioxidant activity [12]. The purpose of the present study is to evaluate and compare the antioxidant potential of the crude extract and fractions of Trigonella foenum graecum, Solanum nigram and Spinacia oleracea for best antioxidant choice among the three plants.
thick syrup and fractionated into n-hexane, chloroform, ethyl acetate and methanol fractions according to standard protocol [14,15] Dpph Radical Scavenging Assay: In this assay free radical scavenging ability of the test extracts and isolated fractions was determined by measuring the change in absorbance of DPPH (1, 1-Diphenyl-2-picrylhydrazyl radical). DPPH radical scavenging assay was carried out according to the standard protocol [16-18] with a minor modification. Concisely, a 1 mM stock solution of DPPH radical was prepared in MeOH. 1 ml of DPPH solution was mixed with 3 ml of sample solutions in ethanol (10-100 µg) and control (without sample). The resultant mixture was shaken and kept in dark for 30 min. Absorbance was measured spectrophotometrically at 517 nm. Decreasing of the DPPH solution absorbance indicates an increase of the DPPH radical-scavenging activity. Radical scavenging activity was expressed as the inhibition percentage and calculated by using the following equation, DPPH % = [(A-B)/A)] × 100 where, A = Absorbance of the control solution B = Absorbance of the test solution. Statistical Analysis: To analyze the data, the Graph Pad Prism (SPSS) software was used for measurement of percent inhibition. The percent values were presented in the tables and figure. RESULTS AND DISCUSSION The antioxidant activity of Trigonella foenum graecum, Solanum nigram and Spinacia oleracea are listed in Table 1, 2 and 3 respectively. The antioxidant activity n-hexane, chloroform, ethyl acetate and methanol fraction of these plants were listed in table 1-3 and compared in Figure 1. The concentration dependent antioxidant effect was observed with various solvent fractions of Trigonella foenum graecum as presented in Table 1. The maximum antioxidant effect was observed in highest dose (100 µg/ml) of all tested samples. The highest percent scavenging effect was 80.88% against chloroform fraction followed by ethyl acetate (78.55%). The lowest antioxidant effect was demonstrated with n-hexane fraction. These differences in antioxidant potential of
MATERIALS AND METHODS Plant Collection: The plants were collected in 2013, form malakand and identified by Dr Abdur Rashid Departemt of Botany University of Peshawar, Peshawar. Place of Study: The study was conducted in the organic and medicinal chemistry lab of University of Peshawar, KPK, Pakistan. Extract Preparation: Shade dried Trigonella foenum graecum, Solanum nigram and Spinacia oleracea was successively extracted with ethanol (x5). The combined ethanolic extracts was concentrated under vacuum into 114
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graecum is used for the management of diabetes mellitus and this antidiabetic effect of this plant might be attributed to its antioxidant potential [4]. Table 2 demonstrated the percent antioxidant potential of various solvent fractions of Solanum nigram. A low to moderate effect was demonstrated at dose dependent manner. The maximum effect was exhibited with chloroform (38.51%) followed by methanol (18.8%) and ethyl acetate fractions (16.54%). However, the n-hexane fraction demonstrated the lowest antioxidant potential (3.18%) compared to the rest of the fractions. The enhanced superoxide dismutase activity has been reported in the previous studies which is strong endogenous antioxidant responsible for conversion of superoxide anions to peroxide [11]. The antioxidant activity of Spinacia oleracea is shown in table 3. The S. Oleraceae has shown lowest dose-dependent antioxidant potential compared to the other two plants. The maximum antioxidant effect was observed in the ethanol fraction (11.55%) followed by ethyl acetate fraction (10.51%). The n-hexane fraction exhibited lowest (4.12%) anti-oxidant activity compared to other fractions. The antioxidant activities of the crude extract of the three test plants was determined and compared in the figure 1. The statistical analysis exhibited that the percent inhibition of Trigonella foenum graecum was found to be 80% followed by Solanum nigram with 40% inhibition. The percent inhibition of Spinacia oleracea was found to be below 20%.
Fig. 1: Comparative antioxidant study of three medicinal plants Table 1: DPPH radical scavenging activities of crude extract and various extracts of Trigonella foenum graecum Conc. (µg/ml) 10 20 40 60 80 100
%DPPH ------------------------------------------------------------------------------n-hexane Chloroform Ethyl acetate Methanol Ethanol 6.33 10.12 18.12 24.44 27.33 30.12
15.44 20.12 25.22 30.55 40.22 58.55
20.55 38.22 50. 55 60.01 72.33 78.55
12.2 35.43 46.40 61.0 70.54 80.88
12.22 20.00 40.05 48.55 50.31 60.55
Table 2: DPPH radical scavenging activities of crude extract and various extracts of Solanum nigram Conc. (µg/ml) 10 20 40 60 80 100
%DPPH ------------------------------------------------------------------------------n-hexane Chloroform Ethyl acetate methanol Ethanol 1.00 1.12 1.99 2.44 2.33 3.12
2.44 3.13 5.21 10.55 20.21 38.51
2.52 3.12 4. 51 6.00 9.331 16.54
1.21 3.73 4.23 7.00 9.54 18.80
4.22 8.00 13.12 21.51 30.32 40.00
CONCLUSION We concluded that crude extract and methanolic fraction of Trigonella foenum graecum possesses maximum antioxidant potential followed by crude extract and chloroform fraction of Solanum nigram. Among the three plants, Spinacia oleracea possesses least antioxidant activity (< 20% inhibition).
Table 3: DPPH radical scavenging activities of crude extract and various extracts of Spinacia oleracea L Conc. (µg/ml) 10 20 40 60 80 100
%DPPH --------------------------------------------------------------------------------n-hexane Chloroform Ethyl acetate methanol Ethanol 1.31 1.99 2.11 2.41 3.33 4.12
1.41 2.11 4.21 3.51 4.20 5.51
2.23 3.83 5. 44 6.00 7.12 10.51
2.20 3.40 4.41 6.01 7.51 8.80
1.01 2.01 4.01 6.51 10.00 11.55
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