# The Effect of Soy Protein–Phycocyanin Concentrate Complex Treatment on Biomarkers of HDL Functional Properties in Male Wistar Rats

## TL;DR

This study shows that a soy protein-phycocyanin complex can improve the function of HDL particles in rats with high cholesterol diets.

## Contribution

The novel finding is that phycocyanin concentrate preserves HDL functionality by preventing protein depletion and enhancing paraoxonase-1 activity.

## Key findings

- Phycocyanin concentrate prevents protein depletion in HDL particles, a marker of dysfunction.
- Treatment with phycocyanin significantly increased paraoxonase-1 levels in HDL particles.
- Phycocyanin reduced triglyceride and malondialdehyde levels in HDL and serum.

## Abstract

Due to improper nutrition, high-density lipoproteins (HDLs) can be subjected to structural changes, acquiring a dysfunctional phenotype. Therefore, research efforts are currently focused on improving HDL functionality despite its blood level. The aim of this study was to evaluate the effect of phycocyanin concentrate (as part of a food matrix) on the functional properties of HDL. Male Wistar rats were fed a high-fat diet containing 2% cholesterol for 113 days. Experimental animals were treated with 30 and 300 mg/kg b.w. of phycocyanin concentrate mixed with soy protein isolate. Serum and hepatic cholesterol and triglyceride levels, and the content of protein, triglycerides, choline-containing phospholipids, malondialdehyde, sphingosine-1-phosphate, and paraoxonase-1 in HDL fractions were assessed. The decrease in protein in HDL particles is characteristic for dysfunctional phenotype of these particles. Phycocyanin concentrate diet prevented the depletion of protein in HDL particles, regardless of the dosage. The functionality of HDL is associated with paraoxonase-1 activity, which inhibits lipid peroxidation in lipoproteins. Our results have shown a significant increase in the level of paraoxonase-1 in HDL particles in groups treated with phycocyanin. HDL particles become more enriched with triglycerides with the development of hyperlipidemia. Triglycerides in HDL particles and in serum decreased by two times in animals receiving 30 mg/kg b.w. of phycocyanin. The MDA content in HDL particles decreased in all animals receiving a high-fat diet with the addition of 2% cholesterol. The introduction of 300 mg/kg of phycocyanin returned this indicator to the values of the Control group. Thus, biomarkers of dysfunctional changes in HDL in rodent hyperlipidemia models may be a useful tool for assessing lipid metabolism disorders. Also, the results confirm the potential ability to use phycocyanin concentrate as part of lipid-lowering products.