# Enhanced bioavailability of a krill oil-based milk thistle extract formulation: in vitro and human studies

## TL;DR

A new krill oil-based formulation improves the absorption of milk thistle extract, boosting its bioavailability and effectiveness.

## Contribution

A krill oil formulation significantly enhances silymarin bioavailability in vitro and in human trials.

## Key findings

- The krill oil formulation increased silybin's apparent transport coefficient by 28% compared to silymarin powder.
- The formulation showed an 8.59-fold higher AUC0-8h and 15.08-fold greater Cmax of silybin in human trials.
- Phospholipid-based systems improve uptake kinetics of lipophilic compounds like silymarin.

## Abstract

The milk thistle plant (Silybum marianum) is known for its hepatoprotective properties. However, the poor water solubility of silymarin limits its dissolution in the intestinal tract and restricts its bioavailability following oral administration.

To improve bioavailability, special formulations, in particular micellar solubilization, are explored. In this study, we examined the transport rate of silymarin in a krill oil-based formulation across a Caco-2 epithelial barrier after upstream digestion simulation in vitro. Furthermore, in a randomized cross-over design study the bioavailability of the krill oil-based formulation was investigated after single dose intake in fasting conditions in healthy participants.

We could demonstrate that the apparent transport coefficient of silybin, measured as lead substance of milk thistle extract, across the epithelium is efficiently boosted by a krill oil formulation, resulting in a 28% increase compared to silymarin powder. Consistent with these findings, a significant enhancement of bioavailability (P < 0.0001) was demonstrated for the krill oil-based formulation in comparison to the milk thistle extract resulting in an 8.59-fold higher AUC0-8h and a 15.08-fold greater Cmax of silybin and faster uptake kinetic after single dose intake.

These findings suggest that phospholipid-based delivery systems offer a promising strategy for improving the efficacy of lipophilic bioactives. Furthermore, the combination of krill oil with milk thistle extracts efficiently provides silybin, PUFAs, and choline, which are important nutrients contributing to liver and heart health.