The decreases in liver transaminases (ALT and AST), cholesterol, triglyceride, and weight in the case group showed the effectiveness of berberis vulgaris. In fact, the antioxidants, as well as anti-inflammatory effects of the phenolic compounds present in berberis vulgaris demonstrate its hepatoprotective role (
15-
19). Shulman states that the decrease in liver triglycerides leads to the progression of insulin sensitivity and protection against type II diabetes (14). A large number of studies have also shown that NAFLD can predict type II diabetes, as well as metabolic syndrome, and therefore, treating this disorder can be an effective way of preventing type II diabetes (
14).
The theory of insulin resistance, which is considered as the main mechanism in liver steatosis states that insulin resistance leads to lipid accumulation in hepatocytes through two mechanisms:
Increase in lipolysis, which results in an increase in free fatty acids;
Hyperinsulinemia, which increases beta oxidation in mitochondria through increasing the reabsorption of fatty acids by the hepatocytes and, consequently, leads to lipid accumulation in the hepatocytes (
20,
21).
In general, NAFLD has a close relationship with metabolic syndrome, diabetes, hypertension, and dyslipidemia. Therefore, all the medications used for treating the metabolic disorders can improve liver disorders and it seems that insulin sensitizing agents are efficient. However, this method might not be appropriate for non-diabetic or thin patients (
22).
Motalleb believes that alkaloid protoberin, which is one of the major components of berberis, has attracted much attention in the recent years and is one of the best reactive oxygen species (
23).
Wei et al. investigated the effect of berberine on type II diabetes accompanied by fatty liver. That study was conducted on 30 diabetic patients who were also suffering from fatty liver. The study subjects received 500 mg berberine pills three times a week, for 8 weeks, and the results revealed that the ALT, AST, glycated hemoglobin (HbA1C), FBG, body-mass index (BMI), LDL, triglycerides, total cholesterol, and gamma glutamyl transferase (GGT) markers had significantly decreased in comparison to the levels before the treatment (
24).
In the
in vitro study of Yang et al. treatment by berberine hydrochloride reduced triglycerides, LDL-C, liver transaminases and improved liver steatosis in the case group (
25). In the same line, Zhang et al. revealed that berberine considerably helped to improve dyslipidemia, as well as diabetes, and significantly corrected lipid and diabetes parameters. In comparison to the placebo group, ALT, AST, and GGT significantly decreased in the berberine group. Also, ALT, AST, and GGT had decreased from 30 ± 21 to 22 ± 14 IU/L (P < 0.001), 26 ± 12 to 22 ± 7 IU/L (P = 0.006) and 34 ± 20 to 30 ± 24 IU/L (P = 0.53), respectively (
26).
In another study, Taheri et al. investigated the effect of hydroalcoholic extract of berberis on liver enzymes activity in mice. The results showed that the hydroalcoholic extract of berberis had significantly decreased the serum ALT level, while no significant decrease was observed regarding AST (
27).
Furthermore, Murugesh et al. studied the antioxidant and hepatoprotective role of berberis. In that animal study, hepatotoxicity was created in one group of mice by administration of paracetamol, and one week after starting the administration of methanolic berberis extract, the increased levels of enzymes had dropped significantly. Besides, the serum levels of AST and ALT reached the normal level, which was interpreted as hepatocyte cytoplasmic membrane repair (
15). These findings are consistent with those of the present study
Motalleb et al. also came to the conclusion that berberis vulgaris extract reduced the activity of liver enzymes, while at the same time preventing the expression of alpha-fetoprotein in liver cancer (
28).
Moreover, Eidi et al. investigated the hepatoprotective effect of berberis extract on the toxicity resulting from carbon tetrachloride in mice. After intraperitoneal use of three different doses of berberis for 28 days, the rate of aminotransferases had significantly decreased almost down to the normal level (
29).
Ebrahimi et al. conducted a study on 57 patients with hyperlipidemia in Iran. After 8 weeks of intervention with berberis vulgaris processed in vinegar, no significant changes were observed in BMI, total cholesterol concentration and triglycerides. However, a significant decrease was found in HDL-C and LDL-C concentrations, and also in the total cholesterol to HDL-C ratio (
30). Similarly, in the study by Farhadi et al. which employed 200 mg capsules of aqeous extract of berberis three times a day for 2 weeks, significantly decreased blood cholesterol and triglycerides? of 5.13% and 17.2%, respectively (
31).
Another study was conducted by Yin et al. on the effectiveness and safety of berberine in the treatment of the patients with type II diabetes in China in 2008. The results revealed no significant changes regarding HDL-C and LDL-C in the berberine group during the 1st and 13th weeks. Nevertheless, a significant decrease was found in HbA1c, as well as FBG levels (
32).
The findings of the present study are in agreement with those of the previous investigation. However, despite the fact that most of the study patients were nondiabetic, no significant decrease was observed in FBG. Nonetheless, it should be noted that the diabetic patients with more than 1 year duration of the disease, or who were using antidiabetic medication, were excluded from the current study. Therefore, the changes in FBG in this study cannot be generalized, and this may be considered as one of the limitations of the present research. Finally, using aminotransferase level in the follow up of NAFLD represented the other limitation of the study, as histologic findings are presently the gold standard method.
The study findings revealed the effectiveness of berberis vulgaris extract in reducing liver transaminases (ALT and AST), cholesterol, triglyceride, LDL-C, and weight. In addition, these factors have a close relationship with NAFLD. Therefore, due to its low cost and low incidence and severity of complications, berberis extract can be used as a supplementary medication in treating NAFLD.