In Vitro Screening of Sargassum spp. Ethanolic Extracts for Antioxidant Activity and Inhibition of Disease-Associated Enzymatic Targets Related to Diabetes, Alzheimer's Disease, and Parkinson's Disease.

Sargassum is a large and diversified genus of marine brown algae that is distributed widely in tropical and subtropical areas. They have been used for centuries in Asian countries, and have demonstrated a variety of health advantages, including anti-cardiovascular disease, anti-osteoarthritis, anti-cancer, anti-inflammatory, antioxidant, and hypopigmentation effects. However, the putative anti-diabetic, anti-Alzheimer's, and anti-Parkinson's diseases activities of various Sargassum spp. have not been investigated and compared thoroughly. Thus, the purpose of this study was to examine the anti-diabetic, anti-Alzheimer's, and anti-Parkinson's diseases' activities of ten Sargassum and one myagroides species collected off the Korean coast. In this study, we examined the inhibitory activity of 70% ethanolic extract of the Sargassum and myagroides species against protein tyrosine phosphatase 1B (PTP1B), α-glucosidase, peroxynitrite (ONOO-), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), BACE1, MAO-A, and MAO-B. Among the Sargassum and myagroides species tested, S. hemiphyllum, S. filicinum, and S. miyabei showed potent PTP1B inhibitory activity (IC50 values of 2.11, 1.87, and 6.49 μg/mL, respectively), α-glucosidase inhibitory activity (IC50 values of 3.67, 2.30, and 11.12 μg/mL, respectively), and ONOO- scavenging activity, with IC50 values of 2.07, 4.49, and 2.46 μg/mL, respectively. Moreover, S. miyabei exhibited the highest BACE1 and BChE inhibitory activity, with IC50 values of 3.38 and 39.76 μg/mL, respectively. The highest MAO-A inhibitory activity was seen in S. miyabei, S. serratifolium, and S. macrocarpum, with IC50 values of 16.91, 12.46, and 14.02 μg/mL, respectively. Therefore, our findings showed that Sargassum species have health benefits and may be useful in treating diabetes and neurological disorders.