Ishophloroglucin A, a Novel Phlorotannin for Standardizing the Anti-α-Glucosidase Activity of Ishige okamurae

Abstract

Nutraceutical use of algae requires understanding of the diversity and significance of their active compositions for intended activities. <i>Ishige okamurae</i> (<i>I. okamurae</i>) extract is well-known to possess α-glucosidase inhibitory activity; however, studies are needed to investigate its active composition in order to standardize its α-glucosidase inhibitory activity. In this study, we observed the intensity of the dominant compounds of each <i>I. okamurae</i> extract harvested between 2016 and 2017, and the different potency of each <i>I. okamurae</i> extract against α-glucosidase. By comparing the anti-α-glucosidase ability of the dominant compounds, a novel Ishophloroglucin A with highest α-glucosidase inhibitory activity was identified and suggested for standardization of anti-α-glucosidase activity in <i>I. okamurae</i> extract. Additionally, a validated analytical method for measurement of Ishophloroglucin A for future standardization of <i>I. okamurae</i> extract was established in this study. We suggest using Ishophloroglucin A to standardize anti-α-glucosidase potency of <i>I. okamurae</i> and propose the significance of standardization based on their composition for effective use of algae as marine-derived nutraceuticals.