Viburnum stellato-tomentosum Extract Suppresses Obesity and Hyperglycemia through Regulation of Lipid Metabolism in High-Fat Diet-Fed Mice.

The potential biological activities of Viburnum stellato-tomentosum (VS), a plant mainly found in Costa Rica, have yet to be reported. Supplementation of VS extract for 17 weeks significantly decreased body weight gain, fat weight, fasting glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), and triglyceride levels in high-fat diet (HFD)-fed C57BL/6J mice. The molecular mechanisms underlying the anti-obesity and glucose-lowering effects of VS extract were investigated. VS extract suppressed adipocyte hypertrophy by regulating lipogenesis-related CCAAT/enhancer-binding protein α (C/EBPα) and insulin sensitivity-related peroxisome proliferator-activated receptor γ (Pparg) expression in adipose tissue (AT) and hepatic steatosis by inhibiting C/EBPα and lipid transport-related fatty acid binding protein 4 (FABP4) expression. VS extract enhanced muscular fatty acid ß-oxidation-related AMP-activated protein kinase (AMPK) and PPARα expression with increasing Pparg levels. Furthermore, VS extract contained a much higher content of amentoflavone (AMF) (29.4 mg/g extract) compared to that in other Viburnum species. AMF administration decreased Cebpa and Fabp4 levels in the AT and liver, as well as improved insulin signaling-related insulin receptor substrate 1 (Irs1) and glucose transporter 1 (Glut1) levels in the muscle of HFD-fed mice. This study elucidated the in vivo molecular mechanisms of AMF for the first time. Therefore, VS extract effectively diminished obesity and hyperglycemia by suppressing C/EBPα-mediated lipogenesis in the AT and liver, enhancing PPARα-mediated fatty acid ß-oxidation in muscle, and PPARγ-mediated insulin sensitivity in AT and muscle.

Amentoflavone-Enriched Selaginella rossii Warb. Suppresses Body Weight and Hyperglycemia by Inhibiting Intestinal Lipid Absorption in Mice Fed a High-Fat Diet.

Many Selaginellaceae species are used as traditional medicines in Asia. This study is the first to investigate the anti-obesity and anti-diabetic effects of Selaginella rossii (SR) in high-fat diet (HFD)-fed C57BL/6J mice. Seven-day oral administration of ethanol extract (100 mg/kg/day) or ethyl acetate (EtOAc) extract (50 mg/kg/day) from SR improved oral fat tolerance by inhibiting intestinal lipid absorption; 10-week long-term administration of the EtOAc extract markedly reduced HFD-induced body weight gain and hyperglycemia by reducing adipocyte hypertrophy, glucose levels, HbA1c, and plasma insulin levels. Treatment with SR extracts reduced the expression of intestinal lipid absorption-related genes, including Cd36, fatty acid-binding protein 6, ATP-binding cassette subfamily G member 8, NPC1 like intracellular cholesterol transporter 1, and ATP-binding cassette subfamily A member 1. In addition, the EtOAc extract increased the expression of protein absorption-related solute carrier family genes, including Slc15a1, Slc8a2, and Slc6a9. SR extracts reduced HFD-induced hepatic steatosis by suppressing fatty acid transport to hepatocytes and hepatic lipid accumulation. Furthermore, amentoflavone (AMF), the primary compound in SR extracts, reduced intestinal lipid absorption by inhibiting fatty acid transport in HFD-fed mice. AMF-enriched SR extracts effectively protected against HFD-induced body weight gain and hyperglycemia by inhibiting intestinal lipid absorption.

Combination Treatment of Arazyme and Soy Leaf Extract Attenuates Hyperglycemia and Hepatic Steatosis in High-Fat Diet-Fed C57BL/6J Mice.

Arazyme and extracts of soy leaves (ESLs) are used as ingredients for functional foods; however, their combined administration has not been studied. This study assessed the combined effect of Arazyme and ESLs in high-fat-diet (HFD)-induced obese C57BL/6J mice fed 2 mg/kg Arazyme, 50 mg/kg ESLs, or a combination of 2 mg/kg Arazyme and 50 mg/kg ESLs by oral gavage for 13 weeks. Individually, Arazyme and ESLs had no effect on the HFD-induced phenotypes. The combination of Arazyme and ESLs significantly suppressed body weight gain, improved glucose and insulin tolerance, and suppressed hepatic steatosis by reducing lipid synthesis and enhancing lipid utilization gene expression. Furthermore, the combination significantly reduced HFD-induced plasma bile acid reabsorption by suppressing bile acid transporter expression, including the ATP biding cassette subfamily B member 11 (Abcb11), solute carrier family 10 member 1 (Slc10a1), Slc10a2, Slc51a, and Slc51b in the liver and gut. Moreover, the combination of Arazyme and ESLs significantly prevented HFD-induced islet compensation in the pancreas. These results suggest that the incorporation of Arazyme combined with ESLs reduces HFD-induced body weight, hyperglycemia, and hepatic steatosis by regulating liver-gut bile acid circulation in HFD-fed mice. This combination can markedly reduce treatment doses and enhance their therapeutic effects, thereby reducing therapeutic healthcare costs.