Pterostilbene Attenuates High Fat Diet-induced Obesity and Hepatic Dysfunction in Rats: A Functional Evaluation Based on Taiwan's Health Food Assessment Criteria

Abstract

Background/aim: Obesity represents a significant global health challenge and is closely linked to the prevalence of metabolic syndromes and liver disorders. In Taiwan, the Ministry of Health and Welfare has instituted specific evaluation protocols for functional foods to mitigate body fat accumulation, underscoring mechanisms beyond caloric restriction. The present study sought to assess the anti-adipogenic and metabolic effects of pterostilbene (PTS) using a rat model of high fat diet (HFD)-induced obesity, in compliance with Taiwan's regulatory standards for health claims about "difficult-to-form body fat".

Materials and methods: Male Sprague-Dawley (SD) rats were fed a HFD for six months to induce obesity. Subsequently, the SD rats were administered PTS orally at dosages of 30 or 50 mg/kg/day for 45 days. This study evaluated various parameters, including body weight, food intake, feed efficiency, body fat percentage, liver weight, and serum biochemical markers.

Results: Forty-five day 30 and 50 mg/kg PTS oral treatment significantly reduced body weight gain, food intake, and feed efficiency (all p<0.05). Remarkably, over 70% of the rats exhibited reduction in body fat exceeding 0.02%, meeting the established regulatory efficacy standards. Furthermore, notable improvements were observed in the aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglycerides (TG), total cholesterol (TC), and glucose (GLU) levels (all p<0.05).

Conclusion: PTS is a promising natural compound for the formulation of health foods aimed at enhancing fat metabolism and providing liver protection. The observed effects are consistent with physiological expectations and aligned with the regulatory efficacy criteria established in Taiwan.

Keywords: Pterostilbene (PTS); high fat diet (HFD); liver protection; obesity.

Figure 1

Experimental design and effects of pterostilbene (PTS) on obese rats. (A) Schematic representation of experimental procedure. Male SD rats were fed a HFD for six months to induce obesity, which was defined as body weight exceeding 20% of those fed a basic diet. Subsequently, the rats were divided into three groups and subjected to a 45-day treatment regimen with control vehicle (corn oil), 30 mg/kg/day PTS (administered orally), or 50 mg/kg/day PTS (administered orally). After the treatment period, all rats were euthanized for subsequent analysis. (B) Representative images of rats from the control group and high-dose (50 mg/kg/day) PTS group.

Figure 2

Effects of pterostilbene (PTS) on body weight in obese rats. (A) Body weight during the 45-day treatment period in control and PTS-treated groups. SD rats in the control group (black circles) exhibit a continuous increase in body weight, whereas those treated with PTS at 30 mg/kg/day (light gray circles) and 50 mg/kg/day (dark gray circles) show significantly reduced weight gain. Statistical significance: *p<0.05, ***p<0.001 vs. control group. (B) Body weight change during the treatment period. The control group shows a steady increase in body weight, whereas the PTS 30 and 50 mg/kg/day groups exhibit weight stabilization and reduction, respectively. Statistical significance: ***p<0.001 vs. control group. Data are presented as mean±SEM.

Figure 3

Effects of pterostilbene (PTS) on food intake and feed efficiency in obese rats. (A) Food intake during the 45-day treatment period in control and PTS-treated groups. The control group (black circles) maintains a relatively stable food intake, whereas rats treated with PTS at 30 mg/kg/day (light gray circles) and 50 mg/kg/day (dark gray circles) show a significant reduction in food intake over time. Statistical significance: ***p<0.001 vs. control group. (B) Feed efficiency (%) during the treatment period. Statistical significance: ***p<0.001 vs. control group. Data are presented as mean±SEM.

Figure 4

Effects of pterostilbene (PTS) on body fat percentage and liver/body weight ratio in obese rats. (A) Body fat percentage in control and PTS-treated groups. The control group exhibits the highest body fat percentage, whereas PTS treatment at 30 and 50 mg/kg/day show significantly reduced body fat accumulation. Statistical significance: ***p<0.001 vs. control group. (B) Liver/body weight ratio (%) in control and PTS-treated groups. Statistical significance: ***p<0.001 vs. the control group. Data are presented as mean±SEM.

Figure 5

Effects of pterostilbene (PTS) on serum biochemical parameters in obese rats. Serum biochemical test values for aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC), triglycerides (TG), and glucose (GLU) in the control and PTS-treated groups. Statistical significance: ***p<0.001 vs. the control group. Data are presented as mean±SEM.