Mate has central nervous system-stimulant properties that are attributed to its methylxanthine alkaloids, such as caffeine [22
], and it is known to contain compounds with antioxidant properties, such as phenolic acids and caffeoylquinic acid derivatives, which are the most abundant compounds in the leaves [23
]. Other reported effects, including hepatoprotective, choleretic, diuretic, hypocholesterolemic, anti-rheumatic, antithrombotic, anti-inflammatory, anti-obesity, and cardioprotective effects, may partially be explained its popularity [23
]. Yerba Mate may have benefits over other weight-loss herbal medicines and supplements, the use of which has been clinically linked to adverse events [26
Because type 2 diabetes is a chronic and progressive disorder, pharmacotherapy will need to address drug-related side effects over longer time periods. Obesity is a well-recognized risk factor for type 2 diabetes, when combined with other known risk factors. It has been an important therapeutic goal to reduce the risk of type 2 diabetes through weight management. To this end, by using in vivo animal models of dietary-induced obesity, we have made the interesting observations that Yerba Mate has the ability to decrease the differentiation of preadipocytes and reduce accumulation of lipids in adipocytes, both of which contribute to lessened growth of adipose tissue, lower body weight gain, and decreased obesity. Our data from in vivo studies revealed that Yerba Mate treatment affects food intake and results in higher energy expenditure, likely from a higher basal metabolism in Yerba Mate-treated mice. Furthermore, in vivo effects of Yerba Mate on lipid metabolism included a significant reduction in serum cholesterol and reduced trends in serum triglyceride and glucose concentrations in mice fed HFD. These factors are the major players in metabolic syndrome and associated disorders.
Yerba Mate has been reported to have various biological activities, which are mainly attributed to its high polyphenol content [24
]. Chlorogenic acid, the main polyphenol in Yerba Mate, is thought to modulate the activity of glucose-6-phosphatase, which is involved in glucose metabolism [27
], and to reduce the risk of cardiovascular disease by decreasing the oxidation of LDL and cholesterol [28
]. In this sense, our results are in accordance with previous studies that have shown that Ilex paraguariensis
treatment improves glucose tolerance in obese animals [14
]. In addition to chlorogenic acid, methylxanthines are also thought to account for some of the pharmacological effects of Yerba Mate [30
]. Saponins, another important class of compounds found in Yerba Mate, have been reported to interfere with cholesterol metabolism [31
]. Thus, the effects of Yerba Mate on cholesterol levels could be partially attributed to its saponin content. The data presented in this study suggest that Yerba Mate extract may act synergistically to suppress body weight gain and visceral fat accumulation and to decrease the serum levels of cholesterol, triglycerides, and glucose. Adipose tissue is an endocrine organ, which has a fundamental role in metabolism and homeostasis regulation. The production and secretion of an excess or insufficient amount of adipokines greatly influence insulin sensitivity, glucose metabolism, inflammation, and atherosclerosis and may provide a molecular link between increased adiposity and the development of diabetes mellitus, metabolic syndromes, and cardiovascular diseases [32
]. In the present study, the level of leptin in serum was directly affected by a high-fat diet. Additionally, treatment with Yerba Mate extract recovered the concentration of leptin.
In conclusion, this study found that Yerba Mate extract has potent anti-obesity activity in vivo. Additionally, we observed that Yerba Mate treatment has a modulatory effect on glucose levels related to obesity.