Chinese Journal of Natural Medicines 2014, 12(9): 06720676
Chinese Journal of Natural Medicines
Amelioration of altered antioxidant enzyme activity by Satureja khuzistanica essential oil in alloxan-induced diabetic rats Hassan Ahmadvand1, 2 1
Razi Herbal Researches Center, Lorestan University of Medical Sciences, Khoram Abad, Iran;
2
Department of Biochemistry, Faculty of Medicine, Lorestan University of Medical Sciences, Khoram Abad, Iran Available online September 2014
[ABSTRACT] AIM: To examine the possible protective effect of Satureja khuzistanica essential oil (SKE) on antioxidant enzyme activity in alloxan-induced Type 1 diabetic rats. METHOD: Thirty Sprague-Dawley male rats were divided into three groups randomly; group one as control, group two diabetic, with no treatment, and group three treatment with SKE at 500 ppm in drinking water, respectively. Diabetes was induced in the second and third groups by alloxan injection subcutaneously. After eight weeks, animals were anaesthetized. Blood samples were also collected before killing to measure antioxidant enzymes activity. RESULTS: SKE significantly increased the serum level of glutathione and the serum activity of glutathione peroxidase, superoxide dismutase, and catalase in the treated group compared with the diabetic untreated group. CONCLUSION: The findings showed that SKE exerts beneficial effects on the antioxidant enzymes activity in alloxan-induced Type 1 diabetic rats. [KEY WORDS] Diabetes; Antioxidant enzyme activity; Satureja khuzistanica; Essential oil
[CLC Number] R965
[Document code] A
[Article ID] 2095-6975(2014)09-0672-05
Introduction Free radicals are generated continuously in the body due to both normal metabolism and disease [1]. Oxidative stress is the imbalance between oxidant and antioxidant systems in favor of the former. Antioxidant systems include antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX), in addition to low molecular agents and dietary antioxidants. Clinical and experimental studies have shown that disturbing the oxidant–antioxidant balance system is involved in the pathogenesis of chronic diseases such as cancer [2], coronary heart disease, and diabetes and many diabetic complications [2] . Hyperglycemia is confounded for the complications of diabetes because hyperglycemia directly causes glycation of [Received on] 04-May-2013 * [ Corresponding author] Hassan Ahmadvand: Tel: 98-913-226 7893, 98-661-6200133, Fax: 98-661-6200133, Email: hassan_a46 @yahoo.com This author has no conflict of interest to declare. Published by Elsevier B.V. All rights reserved
hyperglycemia directly causes glycation of proteins, lipids, and nucleic acids, then injures cells and induces lipid peroxidation [3]. Antioxidant and antioxidative enzyme activities are reduced due to glycation or an increase of lipid peroxidation products [4]. A number of natural antioxidants, such as vitamin E and phenolic compounds, are known to have hypoglycemic, hypolipidemic, or both activities [5].Synthetic drugs have many side effects; therefore, screening for new antidiabetic sources from natural antioxidants is still attractive because they may be safe and a good alternative for treatment of diabetes mellitus. A growing body of research indicates that antioxidant deficiencies, such as vitamin E and coenzyme Q10, contribute to the development of diabetes [5-6]. Recently, much attention has been focused on the central and key role of oxidative stress in the pathogenesis of different diabetic complications [6]. Several studies have shown that antioxidant treatment reduces diabetic complications [7]. Because of increasing demand of patients for the use of natural products and other plant-based drugs with anti-diabetic activity, the general trend now is to use natural products for medicinal purposes in their naturally available form [8] . Polyphenols, well-known antioxidants, have also been shown to function as antidiabetic
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Hassan Ahmadvand. / Chin J Nat Med, 2014, 12(9): 672676
dants, have also been shown to function as antidiabetic agents by reducing blood glucose levels [9]. Researchers are recently interested to investigate the extraction of natural antioxidants from medicinal plants to replace synthetic antioxidants [10]. Therefore, research into the determination of natural antioxidant sources is important to promote public health [2]. The essential oil of Satureja khuzistanica Jamzad (Lamiaceae), an endemic plant of Iran, decreases glucose and malondealdehyde in the serum of diabetic patients [10-11]. The components of this extract were analyzed with gas chromatography/mass spectrometry (GC-MS) in the Research Center of Lorestan University, as reported a previous paper [11]. Since the protective effects of SKE on antioxidant enzymes activity in alloxan-induced type 1 diabetic rats have not previously been reported, the objectives of the present study were to investigate amelioration of altered antioxidant enzyme activity by S. khuzistanica essential oil in alloxaninduced type 1 diabetic rats.
Materials and Methods Isolation of the essential oil from Satureja khuzistanica Satureja khuzistanica essential oil was prepared from cultivated S. khuzistanica in Khoram Abad (Lorestan Province, western Iran). The plant material was identified by the Department of Botany of the Research Institute of Forests and Rangelands (TARI) in Tehran, Iran. A voucher specimen (No. 58416) has been deposited at the TARI Herbarium [10]. The aerial parts of the plants were collected during the flowering stage and were air-dried at ambient temperature in the shade. The aerial parts were hydro-distilled using a Clevenger apparatus for 4 h, giving a yellow oil in 0.9%, W/W yield. The oil was dried over anhydrous sodium sulfate and stored at 4 ºC. The components of Satureja khozestanica essential oil were analyzed by GC-MS in the Research Center of Lorestan University as reported previously [10]. Animals Thirty male mature Sprague–Dawley rats (180–200 g) were obtained from the Pasteur Institute of Tehran and were allowed to adapt in their new location for one week. This study was approved by the Animal Ethics Committee of the Medical University of Lorestan in accordance to the National Health and Medical Research Council Guidelines. The rats were divided into three groups (10 per each). The studied groups were as follows: group 1 served as the control, group 2 as diabetic without treatment, and group 3 as the diabetic group treated with SKE. Diabetes induction Diabetes was induced after overnight fasting in the second and third groups by injection of alloxan monohydrate (120 mg·kg–1) subcutaneously [10]. Beta cell degradation by alloxan leads to release of more insulin. Because of acute hypoglycemia, the rats received 10% sucrose solution for 48 h instead of drinking water. Five days after induction of diabetes, blood samples were gathered from the end part of their
tails. Blood glucose was measured by glucometer and the rats with blood glucose level of ≥300 mg·dL–1 (16.7 mmol·L–1) were considered as diabetic [10]. During the first five days after diabetes induction, 1–3 rats per group died because of alloxan toxicity. The rats were kept at 12/12 dark-light period at a (21 ± 3)°C temperature. All animals were allowed access to food and water ad libitum during the experiment. The third group was treated with SKE by 500 ppm in drinking water [10]. The treatment was begun at the first day of diabetes induction. After eight weeks of treatment, animals were anesthetized (Nesdonal 50 mg·kg–1, i.p.), blood samples were obtained from hearts and allowed to clot for 20 min in laboratory temperature and then centrifuged at 3 000 r·min–1 for 10 min for serum separation [10]. Levels of glutathione (GSH) The serum level of GSH was assayed spectrophotometrically at 412 nm, according to the method of Ellman [12] using a Shimadzu (Tokyo, Japan) spectrophotometer. The contents of GSH were expressed as mmol/mg-pr. Activity of CAT CAT activity was estimated following the method of Sinha [13]. The reaction was started by the addition of sample (20 μL) in 30 mmol·L–1 hydrogen peroxide (H2O2) (2 mL) in 50 mmol·L–1 potassium phosphate buffer (pH 7.0). Enzyme units are expressed as mmol·L–1 of consumed H2O2 per mg-pr. Activity of SOD The SOD activity in the serum was determined using a SOD assay kit (Randox Life Sciences, Crumlin, UK) according to the manufacturer's protocol. Activity of GPX The GPX activity in the serum was determined using a GPX assay kit (Randox Life Sciences, Crumlin, UK) to the manufacturer's protocol. Statistical analysis All values are expressed as mean ± SD. The data were compared between groups by the Mann-Whitney U test. Statistical analyses were performed using the SPSS 13 for Windows software. P < 0.05 was considered statistically significant.
Results Effect of SKE on serum GSH of diabetic rats The levels of GSH in serum are shown in Fig. 1. The level of GSH in the untreated diabetic rats was significantly (1.2-fold) lower than that of control animals. The level of GSH in the serum of diabetic rats treated with SKE was higher than the level found in the control animals. The treatment of diabetic animals with SKE could significantly (47%) inhibit the decrease of GSH in comparison with the untreated diabetic animals. Effect of SKE on serum SOD activity of diabetic rats The activity of SOD in the untreated diabetic rats was significantly (1.3-fold) lower than that of control animals. The activity of SOD in the serum of diabetic rats treated with SKE
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nificantly (1.43-fold) lower than that of control animals. The activity of CAT in the serum of diabetic rats treated with SKE was very low, similar to the level found in the control animals. The treatment of diabetic animals with SKE could significantly (39.34%) inhibit the decrease of CAT activity in comparison with the untreated diabetic animals (Fig. 4).
Fig. 1 The effect of SKE on serum GSH in alloxan-induced diabetic rats. *P < 0.05 vs control group; #P < 0.05 vs diabetic without treatment group
was similar to the level found in the control animals. The treatment of diabetic animals with SKE could significantly (19.92%) inhibit the decrease of SOD activity in comparison with the untreated diabetic animals (Fig. 2). Effect of SKE on serum GPX activity of diabetic rats The activity of GPX in the untreated diabetic rats was significantly (1.25-fold) lower than that of control animals. The activity of GPX in the serum of diabetic rats treated with SKE was very low, similar to the level found in the control animals. The treatment of diabetic animals with SKE could inhibit (21.15%) the decrease of GPX activity in comparison with the untreated diabetic animals (Fig. 3).
Fig. 2 The effect of SKE on serum SOD in alloxan-induced diabetic rats. *P < 0.05 vs control group; #P < 0.05 vs diabetic without treatment group.
Fig. 3 The effect of SKE on serum GPX in alloxan-induced diabetic rats. *P < 0.05 vs control group
Effect of SKE on serum CAT activity of diabetic rats The activity of CAT in the untreated diabetic rats was sig-
Fig. 4 The effect of SKE on serum CAT in alloxan induced diabetic rats. *P < 0.05 vs control group; #P < 0.05 vs diabetic without treatment group
Discussion This study showed that SKE has beneficial effects in increasing the reduced serum antioxidant enzymes and GSH in alloxan-induced diabetic rats. There is much evidence that free radicals such as superoxide can induce cell and tissue injuries throughout lipid peroxidation and increase carcinogenesis, inflammation, early aging, cardiovascular diseases and tissue damage in diabetes [14]. Plant extracts such as those of Artemisia afra and Aframomum melegueta, and Aloe vera gel [15], and antioxidants, such as vitamin E and coenzyme Q10, and antioxidant enzymes, such as SOD, GPX, and CAT, protect the cells against oxidative stress-mediated cellular injuries by converting the toxic free radicals to non-toxic products [16]. Therefore, the use of antioxidants as complementary therapy may be useful for diseases that are related to oxidative stress. Serum SOD, GPX, and CAT activity and the GSH level, as markers of antioxidant enzymes status, were significantly decreased in the untreated diabetic animals in comparison with the control group. Treatment by SKE could maintain serum SOD, GPX, and CAT activity and the GSH level of the treated animal at the same or even higher level as that of the control group. SOD, GPX and CAT activity and GSH level are considered to be antioxidant enzymes for assessing antioxidant status [17]. There are reports that natural antioxidants, such as vitamin E, vitamin C, melatonin, zinc, flavonoids, taurine, N-acetylcysteine, L-arginine, and natural phenolic compounds could increase antioxidant enzymes and antioxidant status in diabetes [18-19]. Many studies indicated that various plant extracts increase antioxidant enzymes and antioxidant status and have protective effects on lipid peroxidation in different disease. For example, grape seed (Vitis zvinifera) extract and Helicteres isora bark extract ameliorate the oxidative stress in animal models [20]. Karaoz et al.
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showed that a combination of vitamin E and vitamin C could reduce lipid peroxidatiion and increase the antioxidants GSH, SOD, and GPX. Also these researchers reported that melatonin has similar results to a combination of vitamin E and vitamin C [21]. A previous study from this laboratory showed that coenzyme Q10 increases GSH, SOD, CAT, and GPX, and decreases lipid peroxidation, glomerular hypertrophy, glomerulosclerosis, and loss of glomerular number in untreated diabetic nephropathy in rats [22]. The Results of this study are in accordance with other studies and showed that SKE, similar to other natural antioxidants, could increase the GSH level and SOD, GPX, and CAT activity. Therefore, natural antioxidants and plant extracts with beneficial effects on antioxidant enzymes could prevent or be helpful in reducing the complications of different tissue damage seen in diabetes patients [23]. Carvacrol is a good antioxidant-scavenger of peroxyl radicals and has anti-inflammatory properties [10, 24]. Also researchers have reported the role of oxidative stress as a central factor in the onset and progression of diabetic complications, such as vascular defects and nephropathy [5]. At this time the detailed molecular protective mechanisms of SKE can not be fully explained by these results. In summary, this study showed that SKE has beneficial effects in increasing the reduced serum antioxidant enzymes and glutathione in alloxan-induced diabetic rats. Hence, an acceleration of antioxidant enzymes may decrease diabetic complications such as nephropathy in diabetic patients.
tions [J]. Circ Res, 2010, 107 (9): 1058-1070. [7] [8]
dian J Physiol Pharmacol, 2006, 50 (3): 297-302. [9]
antioxidant effects of phenolic extracts and purified hydroxytyrosol from olive mill waste in vitro and in rats. ChemicoBiol Interact, 2009, 180 (3): 421-432. [10] Ahmadvand H, Tavafi M, Khalatbary AR. Hepatoprotective and hypolipidemic effects of Satureja khozestanica essential oil in alloxan-induced Type 1 diabetic rats [J]. Iran J Pharmaceut Res, 2012, 11 (4): 1219-1226. [11] Abdollahi M, Salehnia A, Mortazavi SH, et al. Antioxidant, antidiabetic, antihyperlipidemic, reproduction stimulatory properties and safety of essential oil of Satureja khuzestanica in rat in vivo: a oxicopharmacological study [J]. Med Sci Monit, 2003, 9 (9): 331-335. [12] Ellman GL. Tissue sulfahydryl groups [J]. Arch Biochem Biophys, 1959, 82: 70-77. [13] Sinha AK. Colorimetric assay of catalase [J]. Anal Biochem, 1972, 47: 389-394. [14] Ahmadvand H, Tavafi M, Khosrowbeygi A. Amelioration of altered antioxidant enzymes activity and glomerulosclerosis by coenzyme Q10 in alloxan-induced diabetic rats [J]. J Diabetes Complicat, 2012, 26 (6): 476-482. [15] Rajasekaran S, Sivagnanam K, Subramanian S. Modulatory treated with streptozotocin [J]. J Pharm Pharmacol, 2005, 57 (2), 241-246. [16] McMahon M, Skaggs BJ, Sahakian L, et al. High plasma leptin levels confer increased risk of atherosclerosis in women with
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Cite this article as: Hassan Ahmadvand. Amelioration of altered antioxidant enzyme activity by Satureja khuzistanica essential oil in alloxan-induced diabetic rats [J]. Chinese Journal of Natural Medicines, 2014, 12(9): 672-676
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Chinese Journal of Natural Medicines
Amelioration of altered antioxidant enzyme activity by Satureja khuzistanica essential oil in alloxan-induced diabetic rats Hassan Ahmadvand1, 2 1
Razi Herbal Researches Center, Lorestan University of Medical Sciences, Khoram Abad, Iran;
2
Department of Biochemistry, Faculty of Medicine, Lorestan University of Medical Sciences, Khoram Abad, Iran Available online September 2014
[ABSTRACT] AIM: To examine the possible protective effect of Satureja khuzistanica essential oil (SKE) on antioxidant enzyme activity in alloxan-induced Type 1 diabetic rats. METHOD: Thirty Sprague-Dawley male rats were divided into three groups randomly; group one as control, group two diabetic, with no treatment, and group three treatment with SKE at 500 ppm in drinking water, respectively. Diabetes was induced in the second and third groups by alloxan injection subcutaneously. After eight weeks, animals were anaesthetized. Blood samples were also collected before killing to measure antioxidant enzymes activity. RESULTS: SKE significantly increased the serum level of glutathione and the serum activity of glutathione peroxidase, superoxide dismutase, and catalase in the treated group compared with the diabetic untreated group. CONCLUSION: The findings showed that SKE exerts beneficial effects on the antioxidant enzymes activity in alloxan-induced Type 1 diabetic rats. [KEY WORDS] Diabetes; Antioxidant enzyme activity; Satureja khuzistanica; Essential oil
[CLC Number] R965
[Document code] A
[Article ID] 2095-6975(2014)09-0672-05
Introduction Free radicals are generated continuously in the body due to both normal metabolism and disease [1]. Oxidative stress is the imbalance between oxidant and antioxidant systems in favor of the former. Antioxidant systems include antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX), in addition to low molecular agents and dietary antioxidants. Clinical and experimental studies have shown that disturbing the oxidant–antioxidant balance system is involved in the pathogenesis of chronic diseases such as cancer [2], coronary heart disease, and diabetes and many diabetic complications [2] . Hyperglycemia is confounded for the complications of diabetes because hyperglycemia directly causes glycation of [Received on] 04-May-2013 * [ Corresponding author] Hassan Ahmadvand: Tel: 98-913-226 7893, 98-661-6200133, Fax: 98-661-6200133, Email: hassan_a46 @yahoo.com This author has no conflict of interest to declare. Published by Elsevier B.V. All rights reserved
hyperglycemia directly causes glycation of proteins, lipids, and nucleic acids, then injures cells and induces lipid peroxidation [3]. Antioxidant and antioxidative enzyme activities are reduced due to glycation or an increase of lipid peroxidation products [4]. A number of natural antioxidants, such as vitamin E and phenolic compounds, are known to have hypoglycemic, hypolipidemic, or both activities [5].Synthetic drugs have many side effects; therefore, screening for new antidiabetic sources from natural antioxidants is still attractive because they may be safe and a good alternative for treatment of diabetes mellitus. A growing body of research indicates that antioxidant deficiencies, such as vitamin E and coenzyme Q10, contribute to the development of diabetes [5-6]. Recently, much attention has been focused on the central and key role of oxidative stress in the pathogenesis of different diabetic complications [6]. Several studies have shown that antioxidant treatment reduces diabetic complications [7]. Because of increasing demand of patients for the use of natural products and other plant-based drugs with anti-diabetic activity, the general trend now is to use natural products for medicinal purposes in their naturally available form [8] . Polyphenols, well-known antioxidants, have also been shown to function as antidiabetic
– 672 –
Hassan Ahmadvand. / Chin J Nat Med, 2014, 12(9): 672676
dants, have also been shown to function as antidiabetic agents by reducing blood glucose levels [9]. Researchers are recently interested to investigate the extraction of natural antioxidants from medicinal plants to replace synthetic antioxidants [10]. Therefore, research into the determination of natural antioxidant sources is important to promote public health [2]. The essential oil of Satureja khuzistanica Jamzad (Lamiaceae), an endemic plant of Iran, decreases glucose and malondealdehyde in the serum of diabetic patients [10-11]. The components of this extract were analyzed with gas chromatography/mass spectrometry (GC-MS) in the Research Center of Lorestan University, as reported a previous paper [11]. Since the protective effects of SKE on antioxidant enzymes activity in alloxan-induced type 1 diabetic rats have not previously been reported, the objectives of the present study were to investigate amelioration of altered antioxidant enzyme activity by S. khuzistanica essential oil in alloxaninduced type 1 diabetic rats.
Materials and Methods Isolation of the essential oil from Satureja khuzistanica Satureja khuzistanica essential oil was prepared from cultivated S. khuzistanica in Khoram Abad (Lorestan Province, western Iran). The plant material was identified by the Department of Botany of the Research Institute of Forests and Rangelands (TARI) in Tehran, Iran. A voucher specimen (No. 58416) has been deposited at the TARI Herbarium [10]. The aerial parts of the plants were collected during the flowering stage and were air-dried at ambient temperature in the shade. The aerial parts were hydro-distilled using a Clevenger apparatus for 4 h, giving a yellow oil in 0.9%, W/W yield. The oil was dried over anhydrous sodium sulfate and stored at 4 ºC. The components of Satureja khozestanica essential oil were analyzed by GC-MS in the Research Center of Lorestan University as reported previously [10]. Animals Thirty male mature Sprague–Dawley rats (180–200 g) were obtained from the Pasteur Institute of Tehran and were allowed to adapt in their new location for one week. This study was approved by the Animal Ethics Committee of the Medical University of Lorestan in accordance to the National Health and Medical Research Council Guidelines. The rats were divided into three groups (10 per each). The studied groups were as follows: group 1 served as the control, group 2 as diabetic without treatment, and group 3 as the diabetic group treated with SKE. Diabetes induction Diabetes was induced after overnight fasting in the second and third groups by injection of alloxan monohydrate (120 mg·kg–1) subcutaneously [10]. Beta cell degradation by alloxan leads to release of more insulin. Because of acute hypoglycemia, the rats received 10% sucrose solution for 48 h instead of drinking water. Five days after induction of diabetes, blood samples were gathered from the end part of their
tails. Blood glucose was measured by glucometer and the rats with blood glucose level of ≥300 mg·dL–1 (16.7 mmol·L–1) were considered as diabetic [10]. During the first five days after diabetes induction, 1–3 rats per group died because of alloxan toxicity. The rats were kept at 12/12 dark-light period at a (21 ± 3)°C temperature. All animals were allowed access to food and water ad libitum during the experiment. The third group was treated with SKE by 500 ppm in drinking water [10]. The treatment was begun at the first day of diabetes induction. After eight weeks of treatment, animals were anesthetized (Nesdonal 50 mg·kg–1, i.p.), blood samples were obtained from hearts and allowed to clot for 20 min in laboratory temperature and then centrifuged at 3 000 r·min–1 for 10 min for serum separation [10]. Levels of glutathione (GSH) The serum level of GSH was assayed spectrophotometrically at 412 nm, according to the method of Ellman [12] using a Shimadzu (Tokyo, Japan) spectrophotometer. The contents of GSH were expressed as mmol/mg-pr. Activity of CAT CAT activity was estimated following the method of Sinha [13]. The reaction was started by the addition of sample (20 μL) in 30 mmol·L–1 hydrogen peroxide (H2O2) (2 mL) in 50 mmol·L–1 potassium phosphate buffer (pH 7.0). Enzyme units are expressed as mmol·L–1 of consumed H2O2 per mg-pr. Activity of SOD The SOD activity in the serum was determined using a SOD assay kit (Randox Life Sciences, Crumlin, UK) according to the manufacturer's protocol. Activity of GPX The GPX activity in the serum was determined using a GPX assay kit (Randox Life Sciences, Crumlin, UK) to the manufacturer's protocol. Statistical analysis All values are expressed as mean ± SD. The data were compared between groups by the Mann-Whitney U test. Statistical analyses were performed using the SPSS 13 for Windows software. P < 0.05 was considered statistically significant.
Results Effect of SKE on serum GSH of diabetic rats The levels of GSH in serum are shown in Fig. 1. The level of GSH in the untreated diabetic rats was significantly (1.2-fold) lower than that of control animals. The level of GSH in the serum of diabetic rats treated with SKE was higher than the level found in the control animals. The treatment of diabetic animals with SKE could significantly (47%) inhibit the decrease of GSH in comparison with the untreated diabetic animals. Effect of SKE on serum SOD activity of diabetic rats The activity of SOD in the untreated diabetic rats was significantly (1.3-fold) lower than that of control animals. The activity of SOD in the serum of diabetic rats treated with SKE
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nificantly (1.43-fold) lower than that of control animals. The activity of CAT in the serum of diabetic rats treated with SKE was very low, similar to the level found in the control animals. The treatment of diabetic animals with SKE could significantly (39.34%) inhibit the decrease of CAT activity in comparison with the untreated diabetic animals (Fig. 4).
Fig. 1 The effect of SKE on serum GSH in alloxan-induced diabetic rats. *P < 0.05 vs control group; #P < 0.05 vs diabetic without treatment group
was similar to the level found in the control animals. The treatment of diabetic animals with SKE could significantly (19.92%) inhibit the decrease of SOD activity in comparison with the untreated diabetic animals (Fig. 2). Effect of SKE on serum GPX activity of diabetic rats The activity of GPX in the untreated diabetic rats was significantly (1.25-fold) lower than that of control animals. The activity of GPX in the serum of diabetic rats treated with SKE was very low, similar to the level found in the control animals. The treatment of diabetic animals with SKE could inhibit (21.15%) the decrease of GPX activity in comparison with the untreated diabetic animals (Fig. 3).
Fig. 2 The effect of SKE on serum SOD in alloxan-induced diabetic rats. *P < 0.05 vs control group; #P < 0.05 vs diabetic without treatment group.
Fig. 3 The effect of SKE on serum GPX in alloxan-induced diabetic rats. *P < 0.05 vs control group
Effect of SKE on serum CAT activity of diabetic rats The activity of CAT in the untreated diabetic rats was sig-
Fig. 4 The effect of SKE on serum CAT in alloxan induced diabetic rats. *P < 0.05 vs control group; #P < 0.05 vs diabetic without treatment group
Discussion This study showed that SKE has beneficial effects in increasing the reduced serum antioxidant enzymes and GSH in alloxan-induced diabetic rats. There is much evidence that free radicals such as superoxide can induce cell and tissue injuries throughout lipid peroxidation and increase carcinogenesis, inflammation, early aging, cardiovascular diseases and tissue damage in diabetes [14]. Plant extracts such as those of Artemisia afra and Aframomum melegueta, and Aloe vera gel [15], and antioxidants, such as vitamin E and coenzyme Q10, and antioxidant enzymes, such as SOD, GPX, and CAT, protect the cells against oxidative stress-mediated cellular injuries by converting the toxic free radicals to non-toxic products [16]. Therefore, the use of antioxidants as complementary therapy may be useful for diseases that are related to oxidative stress. Serum SOD, GPX, and CAT activity and the GSH level, as markers of antioxidant enzymes status, were significantly decreased in the untreated diabetic animals in comparison with the control group. Treatment by SKE could maintain serum SOD, GPX, and CAT activity and the GSH level of the treated animal at the same or even higher level as that of the control group. SOD, GPX and CAT activity and GSH level are considered to be antioxidant enzymes for assessing antioxidant status [17]. There are reports that natural antioxidants, such as vitamin E, vitamin C, melatonin, zinc, flavonoids, taurine, N-acetylcysteine, L-arginine, and natural phenolic compounds could increase antioxidant enzymes and antioxidant status in diabetes [18-19]. Many studies indicated that various plant extracts increase antioxidant enzymes and antioxidant status and have protective effects on lipid peroxidation in different disease. For example, grape seed (Vitis zvinifera) extract and Helicteres isora bark extract ameliorate the oxidative stress in animal models [20]. Karaoz et al.
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Hassan Ahmadvand. / Chin J Nat Med, 2014, 12(9): 672676
showed that a combination of vitamin E and vitamin C could reduce lipid peroxidatiion and increase the antioxidants GSH, SOD, and GPX. Also these researchers reported that melatonin has similar results to a combination of vitamin E and vitamin C [21]. A previous study from this laboratory showed that coenzyme Q10 increases GSH, SOD, CAT, and GPX, and decreases lipid peroxidation, glomerular hypertrophy, glomerulosclerosis, and loss of glomerular number in untreated diabetic nephropathy in rats [22]. The Results of this study are in accordance with other studies and showed that SKE, similar to other natural antioxidants, could increase the GSH level and SOD, GPX, and CAT activity. Therefore, natural antioxidants and plant extracts with beneficial effects on antioxidant enzymes could prevent or be helpful in reducing the complications of different tissue damage seen in diabetes patients [23]. Carvacrol is a good antioxidant-scavenger of peroxyl radicals and has anti-inflammatory properties [10, 24]. Also researchers have reported the role of oxidative stress as a central factor in the onset and progression of diabetic complications, such as vascular defects and nephropathy [5]. At this time the detailed molecular protective mechanisms of SKE can not be fully explained by these results. In summary, this study showed that SKE has beneficial effects in increasing the reduced serum antioxidant enzymes and glutathione in alloxan-induced diabetic rats. Hence, an acceleration of antioxidant enzymes may decrease diabetic complications such as nephropathy in diabetic patients.
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Cite this article as: Hassan Ahmadvand. Amelioration of altered antioxidant enzyme activity by Satureja khuzistanica essential oil in alloxan-induced diabetic rats [J]. Chinese Journal of Natural Medicines, 2014, 12(9): 672-676
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