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Year : 2018  |  Volume : 50  |  Issue : 4  |  Page : 177--184

The effect of Portulaca oleracea and α-linolenic acid on oxidant/antioxidant biomarkers of human peripheral blood mononuclear cells

Seydeh Negin Yahyazadeh Mashhadi1, Vahid Reza Askari2, Vahideh Ghorani3, Gholam Ali Jelodar1, Mohammad Hossein Boskabady4,  
1 Department of Basic Science, School of Veterinary, Shiraz University, Shiraz, Iran
2 Department of Pharmacology, Pharmacological Research Center of Medicinal Plants, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
3 Pharmaciutical Research Center; Department of Physiology, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
4 Department of Physiology, School of Medicine; Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran

Correspondence Address:
Dr. Gholam Ali Jelodar
Department of Basic Science, School of Veterinary, Shiraz University, Shiraz
Iran
prof. Mohammad Hossein Boskabady
Department of Physiology Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad 9177948564
Iran

Abstract

OBJECTIVES: Various pharmacological effects including antioxidant property of Portulaca oleracea L. were reported previously. In the present study, the effect of the extract of the plant and its constituent, α-linolenic acid (ALA), on oxidant and antioxidant markers of PHA/non-stimulated human mononuclear cells was evaluated. MATERIALS AND METHODS: The effect of 10, 40, and 160 μg/ml of P. oleracea and 5, 15, and 45 μg/ml of ALA or dexamethasone (0.1 mM) on nitric oxide (NO), malondialdehyde (MDA), total thiol (SH), superoxide dismutase (SOD), and catalase (CAT) in the supernatant of phytohemagglutinin-A (PHA)- and nonstimulated lymphocytes was examined (n = 6 for each group). RESULTS: In nonstimulated cells, dexamethasone, high concentration of the extract (160 μg/ml), and ALA (45 μg/ml) significantly increased thiol, CAT, and SOD values. Dexamethasone and high concentration of ALA significantly reduced MDA value (P < 0.01 to P < 0.001). However, the levels of NO and MDA due to dexamethasone and 160 μg/ml of the extract and 15 and 45 μg/ml of ALA treatment were also reduced in PHA-stimulated cells (P < 0.001 for all cases). Treatment of stimulated lymphocyte by dexamethasone and two higher concentrations of the extract and ALA also leads to increased levels of thiol, CAT, and SOD (P < 0.05 to P < 0.001). CONCLUSIONS: P. oleracea and ALA, as well as dexamethasone, decreased NO and MDA levels but increased antioxidant agents in human lymphocytes. These results suggest that P. oleracea and ALA may have therapeutic effect in diseases associated with enhancement of oxidation agents as an antioxidant agent.



How to cite this article:
Yahyazadeh Mashhadi SN, Askari VR, Ghorani V, Jelodar GA, Boskabady MH. The effect of Portulaca oleracea and α-linolenic acid on oxidant/antioxidant biomarkers of human peripheral blood mononuclear cells.Indian J Pharmacol 2018;50:177-184


How to cite this URL:
Yahyazadeh Mashhadi SN, Askari VR, Ghorani V, Jelodar GA, Boskabady MH. The effect of Portulaca oleracea and α-linolenic acid on oxidant/antioxidant biomarkers of human peripheral blood mononuclear cells. Indian J Pharmacol [serial online] 2018 [cited 2019 Jun 24 ];50:177-184
Available from: http://www.ijp-online.com/text.asp?2018/50/4/177/244724


Full Text



 Introduction



Oxidants are free radicals that produce naturally in the body, but their overproduction can oxidize nucleic acids, proteins, and lipids and lead to oxidative stress.[1] Oxidative stress is caused by enhanced oxidant markers such as reactive oxygen species (ROS) and reactive nitrogen species and/or reduction of antioxidant systems.[2] Moreover, the oxidants play an important role in the pathogenesis of some diseases such as inflammation, asthma, chronic obstructive pulmonary disease, rheumatoid arthritis, and other inflammatory disorders.[3]

Production of ROS by inflammatory cells plays an important role in the development of inflammatory disorders.[4] Antioxidants are substances that, at low concentration, have the ability of preventing oxidation process and scavenging free radicals.[5]

Portulaca oleracea from Portulacaceae may reach 40 cm in height[6] and contain omega-3 fatty acids, α-linolenic acid (ALA), gamma-linoleic acid, α-tocopherol, ascorbic acid, β-carotene, and glutathione.[7]

Pharmacological effects including anti-inflammatory,[8] antioxidant[9] chemopreventive, genoprotective,[10] and antiendothelial inflammation effects[11] have been reported for P. oleracea. The relaxant effect of the P. oleracea extract on tracheal smooth muscle[12] and its possible mechanisms including effect on muscarinic[13] and ß-adrenergic receptors[14] were shown previously. The extract of the plant also showed bronchodilatory effect in asthmatic patients.[15]

ALA is an essential fatty acid with several pharmacological properties.[16] The therapeutic potential of ALA on cardiovascular diseases, arthritis, asthma, cancer, nervous system, bone, inflammation, and oxidative stress was also reported.[17] ALA showed anti-inflammatory properties by suppressing tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6).[18] Effects of ALA on oxidative stress including reducing lipid peroxidation, suppressing ROS generation, and enhancing superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) levels were shown.[19]

Antioxidant effects of the extract of P. oleracea and ALA as the plant constituent were evaluated in the supernatant of phytohemagglutinin-A (PHA)-stimulated and nonstimulated human lymphocytes in this study.

 Materials and Methods



Plant extract and α-linolenic acid

The plant was prepared from Sabzevar, Khorasan Razavi Province, Iran. A sample was deposited in the herbarium of the School of Pharmacy, Mashhad University of Medical Sciences (Herbarium No: 240-1615-12).

The hydroethanolic extract of P. oleracea was prepared using macerated method as previously described.[20] The extract was then dissolved in complete RPMI-1640 (10% fetal bovine serum + 1% penicillin/streptomycin).

Human mononuclear cells (lymphocytes) isolation

Human mononuclear cells (lymphocyte) were isolated from six healthy male volunteers (mean age ± standard deviation, 24.4 ± 5.6 years; mean height, 178.5 ± 12.4 cm) exactly according to our previous studies.[20],[21] The volunteers who have no history of inflammatory, autoimmune, and infection diseases and respiratory complaints were enrolled for this study. The study was approved by the Ethical Committee of the Mashhad University of Medical Sciences (EC-MUMs Code: 920296), and all volunteers gave their informed consent.

Experimental groups

Oxidant and antioxidant biomarkers examined in various groups are shown in [Table 1].{Table 1}

Measurement of oxidant and antioxidant markers

The levels of oxidant markers including nitric oxide (NO) and malondialdehyde (MDA) as well as antioxidant markers including thiol, SOD, and CAT were measured in the supernatant of cultured lymphocytes as described previously.[22]

Statistical analysis

Data were presented by their means ± standard error of the mean. Comparison of the results between untreated (control) and treated groups as well as between treated groups with the extract and ALA was performed using one-way analysis of variance with Tukey–Kramer post hoc test. P < 0.05 was considered as statistical significance level.

 Results



Effect of lymphocyte stimulation with phytohemagglutinin-A on various parameters

Lymphocyte stimulation with PHA led to a significant increase in NO and MDA levels compared to nonstimulated lymphocytes. However, values of thiol, CAT, and SOD were significantly reduced in lymphocytes after incubation with PHA in comparison with nonstimulated cells (P < 0.001 for all cases) [Table 2].{Table 2}

Effects of dexamethasone, the extract, and α-linolenic acid on oxidant markers

There was no significant difference in NO and MDA values between groups treated with dexamethasone, the extract concentrations, and 5 and 15 μg/ml of ALA in nonstimulated lymphocyte media [Figure 1] and [Figure 2]. Only MDA level was significantly decreased after treatment with dexamethasone and high concentration of ALA (45 μg/ml, P < 0.001) [Figure 2]a. However, in PHA-stimulated cells, NO and MDA level was concentration-dependently decreased in the extract- and ALA-treated cells. NO level was significantly decreased due to cells treated with 160 μg/ml of the extract as well as 15 and 45 μg/ml of ALA but MDA level showed significant decrease in treated cells with two last concentrations of the extract and ALA (P < 0.01 to P < 0.001). Dexamethasone treatment also significantly reduced NO and MDA levels compared to control group (P < 0.001 for both cases) [Figure 1] and [Figure 2].{Figure 1}{Figure 2}

The change of MDA level due to medium concentration of ALA was lower, but its change due to high ALA concentration was higher than the effects of the corresponding extract concentrations in nonstimulated cells (P < 0.01 to P < 0.001) [Table 2].

There was no significant difference in NO level between groups treated with the extract and ALA compared to treated group with dexamethasone in nonstimulated cells [Figure 1]a, but the effects of all extract concentrations and 5 and 15 μg/ml of ALA on MAD level were significantly lower than the effect of dexamethasone (P < 0.001 for all cases) [Figure 2]a. In stimulated cells, the effects of 10 and 40 μg/ml of the extract and 5 μg/ml of ALA on NO level as well as all concentrations of extract and ALA on MDA level were significantly lower than dexamethasone effect (P < 0.05 for all cases) [Figure 1]b.

Effects of dexamethasone, the extract, and α-linolenic acid on antioxidant markers

In nonstimulated cells, only treatment with 160 μg/ml of the extract and 45 μg/ml of ALA as well as dexamethasone caused significant increase in thiol [Figure 3]a, CAT [Figure 4]a, and SOD [Figure 5]a levels compared to control group (P < 0.01 to P < 0.001 for all cases).{Figure 3}{Figure 4}{Figure 5}

In stimulated lymphocyte, concentration-dependent increase in thiol, CAT, and SOD levels was observed in treated groups with extract and ALA [Figure 3]b, [Figure 4]b, and [Figure 5]b. Thiol and SOD levels in groups treated with the extract concentrations and CAT level in groups treated with its two higher concentrations were statistically increased (P < 0.001 for all cases). Thiol level in only treated group with high concentration of ALA but CAT and SOD levels in groups treated with its 15 and 45 μg/ml were statistically increased (P < 0.05 to P < 0.001). Dexamethasone treatment also caused significant increase in thiol, CAT, and SOD levels (P < 0.001 for all cased) [Figure 3]b, [Figure 4]b, and [Figure 5]b.

The effect of 45 μg/ml of ALA on thiol value was significantly lower than the effect of 160 μg/ml of the extract in nonstimulated cells (P < 0.01). In stimulated lymphocytes, the effects of 15 and 45 μg/ml of ALA on thiol level were significantly less than the effects of corresponding extract concentrations (P < 0.001 and P < 0.01, respectively). Increased level of SOD due to treatment with ALA concentrations was significantly higher as compared to extract concentrations (P < 0.05 to P < 0.001) [Table 2].

The effects of all concentrations of the extract on SOD level and its two lower concentrations on thiol and CAT values were significantly lower than dexamethasone in nonstimulated cells (P < 0.001 for all cases). The effect of 5 and 15 μg/ml of ALA on thiol and CAT levels and its all concentrations on SOD level was also significantly lower compared to dexamethasone effect in nonstimulated cells (P < 0.001 for all cases) [Figure 3]a, [Figure 4]a, and [Figure 5]a.

The effects of two lower concentrations of ALA on thiol and SOD levels as well as the effects of two lower concentrations of extract and ALA on CAT level were significantly lower compared to dexamethasone in stimulated cells (P < 0.001 for all cases) [Figure 3]b, [Figure 4]b, and [Figure 5]b. Only the effects of high extract and ALA concentration on CAT were significantly greater compared to dexamethasone in stimulated cells (P < 0.01 to P < 0.001) [Figure 4]b.

Comparison between the effects of Portulaca oleracea extract and α-linolenic acid

In nonstimulated lymphocytes, the effect of 160 μg/ml of extract was significantly higher than its 10 and 40 μg/ml concentrations on thiol, CAT, and SOD levels (P < 0.05 to P < 0.001). The effect of the medium extract concentration on MDA value was also higher than its low concentration (10 μg/ml) (P < 0.05). Significant differences between medium and high concentrations of extract were seen only in thiol and SOD levels (P < 0.001 for both cases) [Table 2]. Significant difference was observed between the highest concentrations of ALA and its two lower concentrations in all measured parameters, except NO level (P < 0.001 for all cases).

In PHA-stimulated cells, MDA, CAT, and SOD values in treated cells with 40 and 160 μg/ml extract concentrations were significantly higher than its 10 μg/ml concentration (P < 0.05 to P < 0.001). Significant differences were seen between the effect of medium and high extract concentrations on MDA, CAT, and SOD values (P < 0.05 to P < 0.001) [Table 2]. The effect of highest concentrations of ALA on MDA and thiol values was significantly higher compared to its other concentrations (P < 0.01 to P < 0.001). CAT and SOD levels were also significantly different between two higher concentrations of ALA and its low concentration (P < 0.01 to P < 0.001) [Table 2].

 Discussion



P. oleracea contains several constituents and previous studies reported the antiulcerogenic, antibacterial, anti-inflammatory, and antioxidant effects for the plant.

Antioxidant effects of the extract of P. oleracea (hydroethanolic) and ALA (the major constituent of the plant) were evaluated in the present study by the measurement of NO, MDA, CAT, SOD, and thiol levels in the cellular media of PHA-stimulated and nonstimulated human lymphocytes.

PHA is a lymphocyte mitogen with high affinity for lymphocyte surface receptors which cause an inflammatory condition due to stimulation of these cells.[23] The results of the current study showed that NO and MDA levels significantly increased in PHA-stimulated lymphocytes. Other studies have shown that NO level enhanced in the supernatant of PHA- or lipopolysaccharide (LPS)/interferon gamma-stimulated lymphocytes or macrophages (RAW 264.7), which confirm the results of the present study.[22]

Treatment of only PHA-stimulated lymphocytes with the extract and ALA leads to significant and concentration-dependent reduction in the antioxidant agents such as NO and MDA. In PHA-stimulated cells, only 160 μg/ml of the extract (its higher concentrations) and two higher concentrations of ALA (15 and 45 μg/ml) inhibited NO production in a concentration-dependent manner. The results also indicated that MDA level was significantly decreased after treatment with high concentration of ALA (45 μg/ml) in nonstimulated cells. In PHA-stimulated lymphocytes, treated groups with 40 and 160 μg/ml of the extract and 15 and 45 μg/ml of ALA resulted to significant reduction in MDA level.

It was shown that stimulated RAW264.7, murine macrophage cell line by LPS, treated with methanolic extract of P. oleracea caused reduction of NO level, concentration dependently.[24] Previous studies also indicated that P. oleracea was able to inhibit oxidative stress response by the reduction of MDA and NO levels in colitis induced by dextran sulfate sodium in mice.[25] Significant decrease in NO and MDA level in the testis, kidney, and liver of treated rats with aqueous extract of P. oleracea for 12 days was also observed.[26] In addition, inhibitory effect of phenolic alkaloids isolated from P. oleracea on the formation of MDA and hydrogen peroxide-induced lipid peroxidation was shown in hydrogen peroxide-induced lipid peroxidation in rat brain homogenates.[27] The effect of the plant on NO and MDA production is supported by the results of previous studies.

Significant increase in antioxidant agents such as thiol group, CAT, and SOD in PHA-stimulated lymphocytes treated by both P. oleracea and its constituent ALA was also observed in the present study.

It has been demonstrated that MDA content significantly reduced and antioxidant enzyme activities such as CAT increased after treatment with purslane in aging mice.[28] Treatment of N-methyl-N-nitro-N-nitrosoguanidine (MNNG)-induced gastric cancer rats with purslane polysaccharides also indicated protection against MNNG-induced oxidative stress dose-dependently. Protection effect of purslane polysaccharides on the oxidative injury seems to be due to increase in SOD, CAT, and GPx activities.[29] These results also support the findings of the present study showing increased antioxidant agents due to P. oleracea and its constituent ALA treatment.

Protective effect of ethanol extract of P. oleracea on the lung of mice exposed to hypoxia was demonstrated by enhanced SOD level, decreased oxidative stress, and attenuated lung inflammation.[30]

Preventive effect of purslane on oxidative stress biomarkers such as SOD, CAT, GP, GSH, and MDA,[31] its effect on increased activities of CAT, SOD, and GPx,[32] reduction of lipid peroxidation levels, and increase in antioxidant enzyme activities[9] were reported which support the findings of the present study.

Comparison of the effect of P. oleracea with ALA (the plant constituent) showed that the effect of medium and high concentration of the extract on MDA as an oxidant marker was lower than the corresponding concentrations of ALA in nonstimulated cells. However, the effect of high extract concentration on thiol level in nonstimulated cells and the effect of its low and medium concentrations on thiol and SOD levels in stimulated lymphocytes were significantly higher than the effect of corresponding concentrations of ALA. In fact, the antioxidant and inflammatory properties of ALA were reported as suppressing effect on TNF-α and IL-6/IL-8, reducing lipid peroxidation, and suppressing ROS generation and enhanced SOD, GPx, and CAT,[19] which support the findings of the present study. The concentration of ALA in the essential oil of P. oleracea is 30%[33] which should be lower in the extract of the plant. Therefore, the studied concentrations of ALA were half (for low concentration) to one-fourth (for high concentration) of the extract concentrations. The effect of the extract on oxidant and antioxidant markers was comparable, especially for their high concentration. Comparable effect of ALA on antioxidant and specially oxidant markers indicates that the effect of the extract of P. oleracea on oxidant and antioxidant markers is due to its constituent ALA. The effects of both the extract and ALA on antioxidant and oxidant markers were concentration dependent which is a further confirmation of their antioxidant property.

Dexamethasone as a positive control at the concentration of 0.1 mM showed no significant decreasing effect on NO level in nonstimulated lymphocytes while caused significant decrease in stimulated cells. It also showed significant inhibitory effect on MDA level in both nonstimulated and stimulated lymphocytes. In contrast, dexamethasone significantly increased antioxidant agents including thiol, CAT, and SOD levels in both nonstimulated and PHA-stimulated lymphocytes.

The results indicated that reduction effect of dexamethasone on NO and MDA levels and its increasing effect on thiol, CAT, and SOD levels in PHA-stimulated lymphocytes were more than most concentrations of extract and ALA, except in the case of CAT level which the effect of dexamethasone was lower than highest concentrations of extract and ALA. The effect of dexamethasone on antioxidant enzymes seen in the present study is also supported by previous studies. José et al. have reported that the activity of antioxidant enzymes such as CAT, GPx, and SOD increased after administering dexamethasone in adult rat lung.[34] Similarly, Asayama et al. showed that dexamethasone enhanced SOD and CAT in the lungs and kidneys of fetal rat.[35] Comparable effect of the extract of P. oleracea and ALA (its constituent) on oxidant and antioxidant markers also supports the antioxidant effect of the plant and ALA.

 Conclusion



The present study indicated that P. oleracea has antioxidant effects on human lymphocytes. Results demonstrate that P. oleracea and its constituent ALA decreased NO and MDA levels and increased antioxidant agents such as thiol, CAT, and SOD levels in human PHA-stimulated lymphocytes comparable to the effects of dexamethasone. The similar effect of the plant and its constituent ALA suggests that the antioxidant effect of P. oleracea is mainly due to its constituent ALA. The results suggest that this plant could be used for the treatment of various diseases associated with enhancement oxidation agents including asthma, allergic disease, and cancers as an antioxidant drug.

Acknowledgments

Not applicable.

Financial support and sponsorship

This study financially supported by the Research Council of Mashhad University of Medical Sciences. The results present in this paper are from MSc thesis of first author.

Conflicts of interest

There are no conflicts of interest.

References

1Amidi S, Mojab F, Bayandori Moghaddam A, Tabib K, Kobarfard F. A simple electrochemical method for the rapid estimation of antioxidant potentials of some selected medicinal plants. Iran J Pharm Res 2012;11:117-21.
2Boskabady MH, Farkhondeh T. Antiinflammatory, antioxidant, and immunomodulatory effects of Crocus sativus L. and its main constituents. Phytother Res 2016;30:1072-94.
3Geronikaki AA, Gavalas AM. Antioxidants and inflammatory disease: Synthetic and natural antioxidants with anti-inflammatory activity. Comb Chem High Throughput Screen 2006;9:425-42.
4Morikawa K, Watabe H, Araake M, Morikawa S. Modulatory effect of antibiotics on cytokine production by human monocytes in vitro. Antimicrob Agents Chemother 1996;40:1366-70.
5Saei-Dehkordi SS, Tajik H, Moradi M, Khalighi-Sigaroodi F. Chemical composition of essential oils in Zataria multiflora boiss. From different parts of Iran and their radical scavenging and antimicrobial activity. Food Chem Toxicol 2010;48:1562-7.
6Choudhary C, Meruva A, Ranjith N, Elumalai K. A review of phytochemical and pharmacological profile of Portulaca oleracea linn. Int J Res Ayurveda Pharm 2013;4:34-7.
7Uddin MK, Juraimi AS, Hossain MS, Nahar MA, Ali ME, Rahman MM. Purslane weed (Portulaca oleracea): A prospective plant source of nutrition, omega-3 fatty acid, and antioxidant attributes. ScientificWorldJournal 2014;2014:951019.
8Chan K, Islam MW, Kamil M, Radhakrishnan R, Zakaria MN, Habibullah M, et al. The analgesic and anti-inflammatory effects of Portulaca olerace a L. Subsp. Sativa (Haw.) celak. J Ethnopharmacol 2000;73:445-51.
9Chen B, Zhou H, Zhao W, Zhou W, Yuan Q, Yang G. Effects of aqueous extract of Portulaca oleracea L. On oxidative stress and liver, spleen leptin, PARα and FAS mRNA expression in high-fat diet induced mice. Mol Biol Rep 2012;39:7981-8.
10Behravan J, Mosafa F, Soudmand N, Taghiabadi E, Razavi BM, Karimi G. Protective effects of aqueous and ethanolic extracts of Portulaca oleracea L. Aerial parts on H2O2-induced DNA damage in lymphocytes by comet assay. J Acupunct Meridian Stud 2011;4:193-7.
11Lee AS, Lee YJ, Lee SM, Yoon JJ, Kim JS, Kang DG, et al. Portulaca oleracea ameliorates diabetic vascular inflammation and endothelial dysfunction in db/db mice. Evid Based Complement Alternat Med 2012;2012:741824.
12Boskabady MH, Boroushaki M, Aslani MR. Relaxant effect of Portulaca oleraceae on guinea pig tracheal chains and its possible mechanism (s) of action. Med Hypotheses Res 2004;1:139-47.
13Hashemzehi M, Khazdair MR, Kiyanmehr M, Askari VR, Boskabady MH. Portulaca olerace affects muscarinic receptors of guinea-pig tracheal smooth muscle. Iran J Pharma Sci 2016;78:388-94.
14Boskabady MH, Hashemzehi M, Khazdair MR, Askari VR. Hydro-ethanolic extract of Portulaca oleracea affects beta-adrenoceptors of guinea pig tracheal smooth muscle. Iran J Pharm Res 2016;15:867-74.
15Malek F, Boskabady MH, Borushaki MT, Tohidi M. Bronchodilatory effect of Portulaca oleracea in airways of asthmatic patients. J Ethnopharmacol 2004;93:57-62.
16Connor WE. Importance of n-3 fatty acids in health and disease. Am J Clin Nutr 2000;71:171S-5S.
17Kim KB, Nam YA, Kim HS, Hayes AW, Lee BM. A-linolenic acid: Nutraceutical, pharmacological and toxicological evaluation. Food Chem Toxicol 2014;70:163-78.
18Xie N, Zhang W, Li J, Liang H, Zhou H, Duan W, et al. A-linolenic acid intake attenuates myocardial ischemia/reperfusion injury through anti-inflammatory and anti-oxidative stress effects in diabetic but not normal rats. Arch Med Res 2011;42:171-81.
19Shen J, Shen S, Das UN, Xu G. Effect of essential fatty acids on glucose-induced cytotoxicity to retinal vascular endothelial cells. Lipids Health Dis 2012;11:90.
20Askari VR, Rezaei A, Boskabady MH, Sadeghnia H, Abnus K, Iranshahi M. The influence of hydro-ethanolic extract of Portulaca oleracea on Th1/Th2 balance in isolated human lymphocytes. J Ethnopharmacol 2016;194:1112-21.
21Boskabady MH, Seyedhosseini Tamijani SM, Rafatpanah H, Rezaei A, Alavinejad A. The effect of crocus sativus extract on human lymphocytes' cytokines and T helper 2/T helper 1 balance. J Med Food 2011;14:1538-45.
22Shakeri F, Soukhtanloo M, Boskabady MH. The effect of hydro-ethanolic extract of Curcuma longa rhizome and curcumin on total and differential WBC and serum oxidant, antioxidant biomarkers in rat model of asthma. Iran J Basic Med Sci 2017;20:155-65.
23Boskabady MH, Mehrjardi SS, Rezaee A, Rafatpanah H, Jalali S. The impact of zataria multiflora boiss extract on in vitro and in vivo th1/Th2 cytokine (IFN-γ/IL4) balance. J Ethnopharmacol 2013;150:1024-31.
24Hong CH, Hur SK, Oh OJ, Kim SS, Nam KA, Lee SK. Evaluation of natural products on inhibition of inducible cyclooxygenase (COX-2) and nitric oxide synthase (iNOS) in cultured mouse macrophage cells. J Ethnopharmacol 2002;83:153-9.
25Yang X, Yan Y, Li J, Tang Z, Sun J, Zhang H, et al. Protective effects of ethanol extract from Portulaca oleracea L on dextran sulphate sodium-induced mice ulcerative colitis involving anti-inflammatory and antioxidant. Am J Transl Res 2016;8:2138-48.
26Dkhil MA, Moniem AE, Al-Quraishy S, Saleh RA. Antioxidant effect of purslane (Portulaca oleracea) and its mechanism of action. J Med Plants Res 2011;5:1589-93.
27Yang Z, Liu C, Xiang L, Zheng Y. Phenolic alkaloids as a new class of antioxidants in Portulaca oleracea. Phytother Res 2009;23:1032-5.
28Ahangarpour A, Lamoochi Z, Fathi Moghaddam H, Mansouri SM. Effects of Portulaca oleracea ethanolic extract on reproductive system of aging female mice. Int J Reprod Biomed (Yazd) 2016;14:205-12.
29Li Y, Hu Y, Shi S, Jiang L. Evaluation of antioxidant and immuno-enhancing activities of purslane polysaccharides in gastric cancer rats. Int J Biol Macromol 2014;68:113-6.
30Yue T, Xiaosa W, Ruirui Q, Wencai S, Hailiang X, Min L, et al. The effects of Portulaca oleracea on hypoxia-induced pulmonary edema in mice. High Alt Med Biol 2015;16:43-51.
31Ali SI, Said MM, Hassan EK. Prophylactic and curative effects of purslane on bile duct ligation-induced hepatic fibrosis in albino rats. Ann Hepatol 2011;10:340-6.
32Sumathi T, Christinal J. Neuroprotective effect of Portulaca oleraceae ethanolic extract ameliorates methylmercury induced cognitive dysfunction and oxidative stress in cerebellum and cortex of rat brain. Biol Trace Elem Res 2016;172:155-65.
33Petropoulos S, Karkanis A, Martins N, Ferreira IC. Phytochemical composition and bioactive compounds of common purslane (Portulaca oleracea L.) as affected by crop management practices. Trends Food Sci Technol 2016;55:1-10.
34José HJ, Berenice SG, Cecilia VR. Induction of antioxidant enzymes by dexamethasone in the adult rat lung. Life Sci 1997;60:2059-67.
35Asayama K, Hayashibe H, Dobashi K, Uchida N, Kato K. Effect of dexamethasone on antioxidant enzymes in fetal rat lungs and kidneys. Biol Neonate 1992;62:136-44.