‘Overcoming the low bioavailability hurdle of quercetin’: Indena study supports phytosome use to boost absorption

By Stephen Daniells

- Last updated on GMT

© Getty Images / Zerbor
© Getty Images / Zerbor
A delivery system based on food-grade lecithin may boost the bioavailability of quercetin, a flavonoid linked to numerous health benefits but known to have poor low water solubility, low stability, and low bioavailability.

Scientists from Indena’s R&D department report that a delivery system based on food-grade lecithin – Quercetin Phytosome – was able to boost both in vitro​ solubility and oral absorption in healthy volunteers, compared to unformulated quercetin.

“The application of this new quercetin formulation overcomes the low bioavailability hurdle of quercetin,”​ they wrote in the European Journal of Drug Metabolism and Pharmacokinetics​.

The compound

Quercetin is a flavonoid found in fruits and vegetables. The compound has been linked to a range of potential health benefits, include lowering of inflammatory markers, cholesterol reduction, and improving blood pressure. However, many of these potential benefits are the result of observational, in vitro​ or animal studies, and data from human intervention studies are limited.

One such human study by researchers from the University of Utah did indicate that a daily 730 milligram supplement of quercetin led to significant reductions in blood pressure. The study, said to be the first to report the blood pressure-lowering activity of this compound, was published in the Journal of Nutrition​ (Nov. 2007, Vol. 137, pp. 2405-2411).

A study published in Nutrition Research​ earlier this year (Feb. 2018, Vol. 50, pp. 73-81) indicated that quercetin supplementation was associated with a better response to the oxidative environment produced by eccentric exercise, compared with placebo.

Despite the potential benefits, bioavailability of quercetin is low with estimations that only 20% of the administered dose reaches the blood.

This is where Indena’s use of a delivery system based on food-grade lecithin offers a solution: According to data published in European Journal of Drug Metabolism and Pharmacokinetics​the Quercetin Phytosome (Quercefit) proved to be up to 20-fold more bioavailable.

“The solubility of quercetin in that formulation was shown to be considerably higher than that of unformulated quercetin, leading to a significant improvement in quercetin bioavailability when the new formulation was administered to human volunteers in a clinical study,” ​wrote the researchers.  

“Dose linearity was also demonstrated for the new quercetin formulation, based on the two doses administered. It is noteworthy that the Quercetin Phytosome treatment was well tolerated and that no notable side effects were reported​.”

Study details

The new human study included 12 healthy men and women aged between 18 and 50 who were given one 500 mg dose of quercetin and two different doses of Quercetin Phytosome (250 mg or 500 mg) as film-coated tablets. Twelve pharmacokinetic samples were collected over the course of 24 hours.

“In the present work, a new formulation of quercetin based on a phytosome delivery system created, developed, and industrialized by Indena was studied,”​ wrote the researchers. “A phytosome is a solid dispersion of natural substances including lecithin.

“Therefore, phytosomes can be used to naturally promote the solubilities of poorly bioavailable active natural ingredients and their abilities to cross biological barriers, leading to significant improvements in bioavailability and thus biological activity.

“Water-soluble phytoconstituents such as quercetin are incorporated into the phospholipids in a phytosome, in contrast to a liposome, which is an aggregate of phospholipid molecules, including unbound active molecules. The hydrophilic quercetin is released from the phytosome into the lipid environment of an enterocyte membrane, allowing it to penetrate into the bloodstream.

“Data in the present work showed that incorporation into phytosomes led to increased quercetin solubility, and consequently to a significant improvement in its bioavailability in humans.”

Sports potential

As reported yesterday​, Indena will be showcasing its new Quercefit ingredient at SupplySide West in Las Vegas next week. The company has positioned the ingredient for sports nutrition applications.

Source: European Journal of Drug Metabolism and Pharmacokinetics
Published online ahead of print, doi: 10.1007/s13318-018-0517-3
“Improved Oral Absorption of Quercetin from Quercetin Phytosome®, a New Delivery System Based on Food Grade Lecithin”
Authors: A. Riva et al.

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