A new animal study shows that low doses of two different Viola mandshurica extracts possess anti-obesity activity. The mouse model constructed by Korean researchers demonstrated that both extracts suppress the metabolic formation of fat as well as activate the metabolism-regulating AMPK enzyme in liver and adipose tissues.

This study was supported by the Korea Institute of Oriental Medicine. The results were published in the scientific journal BMC Complementary and Alternative.

• Ethanol extract and aqueous extract were prepared from V. mandshurica samples. Dosages of 50, 100, or 200 milligrams per kilogram (mg/kg) of either extract were administered to a high-fat diet (HFD)-induced obese mice.
• Both extracts reduced the body weight gain, the mass of liver and adipose tissue, the size of the adipocytes, and serum lipid concentration. They raised the adiponectin serum levels and increased mRNA expression in epididymal adipose tissue.
• The ethanol and aqueous extracts decreased the HFD-induced mRNA expression of lipogenic genes in adipose tissue. Conversely, they boosted mRNA expression of uncoupling protein 2 and adenosine monophosphate-activated protein kinase (AMPK), increasing the levels of these latter two enzymes.
• The V. mandshurica extracts reduced the number of accumulated lipids in the liver by increasing the phosphorylation of AMPK as well as acetyl-CoA carboxylase. The former enzyme regulates cellular metabolism while the latter facilitates the creation and degradation of fatty acids.
• The HPLC analysis identified the presence of the coumarin derivative esculetin and the flavonoid schaftoside in both extracts. Neither extract caused toxicity or mortality during the toxicity study.

The full text is available.

Based on their findings, the researchers surmise that V. mandshurica extracts could serve as safe and effective methods for treating obesity.

Journal reference

Sung Y-Y, Kim D-S, Kim S-H, Kim HK. ANTI-OBESITY ACTIVITY, ACUTE TOXICITY, AND CHEMICAL CONSTITUENTS OF AQUEOUS AND ETHANOL VIOLA MANDSHURICA EXTRACTS. BMC Complementary and Alternative Medicine. 2017;17(1). DOI: 10.1186/s12906-017-1810-4.