1. Introduction
One of the most important diseases that is more strongly associated with obesity is Non-Alcoholic Fatty Liver Disease (NAFLD) [2 ,1]. Elevated plasma levels of enzymes secreted from the liver into the blood are associated with fatty liver. Regular physical activity and the use of portulaca oleracea supplementat may be effective in treating liver disease. This study aimed to examine the interactive effect of combined exercise and portulaca oleracea supplementation on liver enzymes in obese postmenopausal women with NAFLD.
2. Materials and Methods
40 obese women with NAFLD were randomly divided into four groups of supplementation (n=10), combined exercise (n=10), placebo (n=10), and supplementation + exercise (n=10) after signing an informed consent form. Portulaca oleracea supplementation was taken as a 500 mg capsule daily before lunch and dinner. Combined exercises included aerobic exercise with a intensity of 60-80% of maximum heart rate [3, 12] and resistance training with a intensity of 40-60 percent of one repetition maximum, in 3 sets of 8-12 repetition, and a 3-min rest interval [13], performed for 12 weeks, 3 session per week, each for 90 min. Liver enzymes were measured before and after the intervention. The subjects’ diets were also monitored under the supervision of a nutritionist by a oral reminder form one week before exercise until the end of the study. For statistical analysis, paired t-test and ANCOVA were used with a significance level set at P< 0.05.
3. Results
The Shapiro-Wilk test was used to check the normality of the data. Test results showed that the data were normal. Therefore, parametric tests of paired t-tests and ANVOVA were used. The results of the paired t-test showed that after 12 weeks of intervention, serum level of alanine aminotransferase (ALT) in the exercise + supplement group (P=0.00), exercise group (P=0.00), and supplement group (P=0.00) was significantly reduced as well as the serum level of aspartate aminotransferase (AST) in the exercise + supplement group (P=0.00), exercise group (P=0.000), and supplement group (P=0.001); and the serum level of Alkaline Phosphatase (ALP) in the exercise + supplement group (P=0.01), exercise group (P=0.002), and supplement group (P=0.001). The results of the ANCOVA showed that, with 95% confidence level, the combined exercise and supplementation with portulaca oleracea had a significant effect on the level of liver enzymes ALT and AST, but its effect on the ALP level was not significant after intervention (P=0.21) (Table 1).
4. Discussion
The type of used sports activities has different effects on the secretion and metabolic systems. Long-term endurance training whose energy production is more aerobic affect the activity of AST and ALT enzymes, because to continue this type of activity, there is a greater need for energy production through the aerobic system. Resistant training increases lipid oxidation, insulin sensitivity, and basal metabolic rate. Therefore, it may be possible to reduce the level of ALT enzyme (longer half-life and its maximum in liver tissue) and decrease the level of AST enzyme (shorter half-life) by increasing basal metabolic rate and lipid oxidation [16]. 
5. Conclusion
Portulaca oleracea inhibits lipid peroxidation by having many antioxidant properties and omega-3 and omega-6 fatty acids. This property is applied by breaking the existing oxidizing structure by cytochromes p450 and neutralizing free radicals (they damage hepatocytes and increase the activity of Cytosolic enzymes which Indicates the extent and type of liver damage) [8]. Therefore, due to the antioxidant properties of portulaca oleracea, the decrease in liver enzyme activity is predictable.

Ethical Considerations
Compliance with ethical guidelines
This study obtained its ethical approval from the Research Ethics Committee of Islamic Azad University of Rasht Branch (Code: IR.IAU.RASHT.REC.1397.034) and is a clinical trial registered by Iranian Registry of Clinical Trials (Code: IRCT.20190309042987.N1).
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Authors' contributions
All authors met the writing standards based on the recommendations of the International Committee of Medical Journal Editors (ICMJE).
Conflicts of interest
The authors declare no conflict of interest.