Bioactivity evaluation of underutilized marine raw materials for the management of metabolic syndrome

Abstract

Metabolic syndrome (MetS) is the medical term for a cluster of risk factors including obesity, high blood pressure, and high blood sugar, which increases the risk of developing stroke, heart disease, and type 2 diabetes. Marine raw materials have been described to exert various bioactive properties beneficial to human health, including anti-inflammatory, antioxidant, and antidiabetic abilities. In this study, marine protein hydrolysates of shrimp shell, cod head, sprat (Sprattus sprattus), and blue whiting (Micromestistius poutassou), biomass of the microalgae Nannochloropsis salina and Tetraselmis chui, and flash-fractions of 24 marine invertebrate extracts, were evaluated for anti-inflammatory, antioxidant, and antidiabetic bioactivities using a panel of bioassays. The refined shrimp peptide concentrate (RSPC) was characterized as active at the lowest concentration tested (0.5 mg/mL) in the antidiabetic DPP-IV inhibitory assay, and showed the higher antioxidative effect of the samples tested in the FRAP antioxidant assay. The rat insulinoma palmitate stress assay was developed to approach the apoptotic conditions of pancreatic beta cells in patients of type 2 diabetes, but could not determine whether samples exerted protective effects as standard test concentrations of palmitate and glucose could not be established. This study has given a thorough basis in the technical challenges met in investigating the bioactivity in complex marine samples, especially in disturbances in absorbance readouts due to strong color of the highly concentrated samples. Nevertheless, this study could be useful in guiding a better selection of which bioassays to be used and the adjustments needed in further evaluation of bioactivity in complex marine samples.

Metabolic syndrome; diabetes; inflammation; oxidative stress; in vitro bioactivity study; underutilized marine raw materials; protein hydrolysates; microalgae; marine invertebrates