Findings from an animal study revealed that consumption of the flavonoid rutin, found in the fruit rinds of oranges and grapefruit, cranberries as well as mulberries, can activate brown adipose tissue (BAT) which regulates energy metabolism.
Led by Drs Wan-Zhu Jin and Zengqiang Yuan — researchers from the Chinese Academy of Sciences in Beijing, China — the results identify rutin as a novel small molecule that may provide a natural approach to the treatment of metabolic syndrome.
The syndrome is thought to be caused by an underlying malfunction in energy utilisation and storage. As well as obesity, this term can also refer to a handful of medical conditions such as raised blood pressure, high glucose and cholesterol levels.
Rutin has already shown promise in interfering in the formation of blood clots in animal models and has proved popular as a dietary supplement.
However, rutin has been unable to back up its efficacy with a health claim as a European Food Safety Authority (EFSA) panel decided in 2010 there was insufficient evidence to support the compound’s antioxidant properties and benefits on vascular health and the circulatory system.
Jin led colleagues to use animal models that consisted of genetically obese mice and mice with diet-induced obesity.
They were fed a regular diet that was supplemented with 1 milligram per millilitre (mg/ml) of rutin.
The team found that the addition of rutin in both groups of mice significantly reduced body weight, and increased energy expenditure.
In particular the team noticed rutin played a role in rebalancing the levels of insulin and glucagon to maintain glucose levels.
In discussing their findings, the researchers identified rutin as a ‘cold mimetic’ activating a series of signalling pathways that increased the number of ‘energy producing’ mitochondria in the BAT.
More importantly rutin appeared to increase the activity of UCP1 – a protein that generates heat by non-shivering thermogenesis. UCP-1 also plays a central role in counteracting heat loss in new born babies.
"The beneficial effects of rutin on BAT-mediated metabolic improvement have evoked a substantial interest in the potential treatment for obesity and its related diseases, such as diabetes," said Jin,
"In line with this idea, discovery of more safe and effective BAT activators is desired to deal with obesity and its related diseases."
Rutin have shown notable capability of producing beneficial effects on several metabolic disorders albeit in animal models.
Previous studies have shown that rutin protects rats from the metabolic and cardiovascular changes caused by a high-fat and high-carbohydrate diet.
Additionally, rutin has been shown to improve the metabolic status of diabetic rats.
Source: Federation of American Societies for Experimental Biology
Published online ahead of print, doi:10.1096/fj.201600459RR
“Rutin ameliorates obesity through brown fat activation.”
Authors: Zengqiang Yuan and Wanzhu Jin