Writing in the Journal of Future Foods, scientists report that the Rhodiola extract could activate an enzymatic pathway call AMPK (or adenosine 5′-monophosphate-activated protein kinase), a key enzyme for controlling metabolic activity in the body.
The Rhodiola extract was also associated with increases in the activity of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px).
“These results taken together suggested that EAE may enhance insulin signaling and antioxidant capacity, promote nutrient absorption and metabolism, and ultimately improve the insulin resistance,” wrote scientists from Guangdong Ocean University and Fujian Agriculture and Forestry University.
R. rosea is a perennial herb that mostly grows at high altitudes in arctic areas of Europe and Asia. Demand for products formulated with Rhodiola rosea has been increasing, with forms of the herb in trade including dry extracts in solid dosage forms such as capsules and tablets, liquid extracts, cut, dried rhizome and root, and powdered rhizome and root.
This rising demand is straining global supply because of the (over)reliance on wild sources, leading some experts to call for more cultivation of the herb. Such efforts are already underway in North America, with notable cultivation in Alaska (Alaska Rhodiola Enterprises, LLC) and Canada (Alberta Rhodiola Rosea Growers Organization, ARRGO). Nektium and PLT Health Solutions have been working on cultivating the plant in the Altai region in Siberia.
The traditional primary health uses of the herb include stress, mental and physical fatigue, depression, and to boost energy. Active constituents in the herb include a glucoside referred to as salidroside, plus a family of cinnamyl mono- and diglycosides referred to as rosavin.
The new study used Caenorhabditis elegans or C. elegans, tiny transparent worms with a short lifespan. The worms are a simple organism with specific types of metabolic genes that are similar to mammals.
The worms were exposed to high glucose levels to establish a model of insulin resistance and then exposed to three different doses of the R. rosea extracts: 0, 100, and 200 micrograms per millilitre.
The results showed that the higher dose led an approximately 50% increase in insulin signal intensity, while the activities of SOD, CAT, and GSH-Px increased by 10.9, 14.2 and 27.9, respectively, compared to the control group.
The researchers also found that the herb was associated with beneficial changes in gene expression linked to lifespan, glucose uptake, energy homeostasis, lipid metabolism, and insulin resistance.
“The insulin signal of the nematodes was increased, the glucose level in the nematodes was decreased to close to the human fasting blood glucose, indicating that the potential hypoglycemic effect of [Rhodiola extracts],” wrote the researchers.
Source: Journal of Future Foods
December 2022, Volume 2, Issue 4, Pages 365-371, doi: 10.1016/j.jfutfo.2022.08.008
“Effects of Rhodiola rosea and its major compounds on insulin resistance in Caenorhabditis elegans”
Authors: Hui Teng et al.