Protein Tyrosine Phosphatase 1B and α-Glucosidase Inhibitory Phlorotannins from Edible Brown Algae, Ecklonia stolonifera and Eisenia bicyclis

• Published in: Bioscience, biotechnology, and biochemistry Vol. 75; no. 8; pp. 1472 - 1480
• Main Authors: MOON, Hye Eun, ISLAM, Md. Nurul, AHN, Bo Ra, CHOWDHURY, Sabiha Sultana, SOHN, Hee Sook, JUNG, Hyun Ah, CHOI, Jae Sue
• Format: Journal Article
• Language: English
• Published: Tokyo Japan Society for Bioscience, Biotechnology, and Agrochemistry 2011; Japan Society for Bioscience Biotechnology and Agrochemistry
• Subjects: alpha-Glucosidases - metabolism; Benzofurans - chemistry; Benzofurans - pharmacology; Biological and medical sciences; Blood Glucose - analysis; Complex Mixtures - chemistry; Complex Mixtures - pharmacology; Diabetes Mellitus - drug therapy; Diabetes Mellitus - enzymology; Diabetes Mellitus - physiopathology; Dioxins - chemistry; Dioxins - pharmacology; Ecklonia stolonifera; Eisenia bicyclis; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - pharmacology; Fundamental and applied biological sciences. Psychology; Glycoside Hydrolase Inhibitors; Humans; Hyperglycemia - drug therapy; Hyperglycemia - enzymology; Hyperglycemia - physiopathology; Hypoglycemic Agents - chemistry; Hypoglycemic Agents - pharmacology; Kinetics; Magnetic Resonance Spectroscopy; Phaeophyceae - chemistry; Phloroglucinol - chemistry; Phloroglucinol - pharmacology; phlorotannin; protein tyrosine phosphatase 1B; Protein Tyrosine Phosphatase, Non-Receptor Type 1 - antagonists & inhibitors; Protein Tyrosine Phosphatase, Non-Receptor Type 1 - metabolism; Solutions; Spectrophotometry; Tannins - chemistry; Tannins - pharmacology; Yeasts; α-glucosidase; Enzyme; Algae; Phosphoric monoester hydrolases; Esterases; Eisenia hicyclis; Annelida; Oligochaeta; Eisenia; Glycosylases; Heterokontophyta; α-Glucosidase; phlorotannin; Glycosidases; Hydrolases; Inhibition; protein tyrosine phosphatase IB; Invertebrata; Ecklonia stolonifera; Phaeophyceae; Protein-tyrosine-phosphatase
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.110137

The present work investigates protein tyrosine phosphatase 1B (PTP1B) and the α-glucosidase inhibitory activities of two edible brown algae, Ecklonia stolonifera and Eisenia bicyclis, as well as in their isolated phlorotannins. Since the individual extracts and fractions showed significant inhibitory activities, column chromatography was performed to isolate six phlorotannins, phloroglucinol (1), dioxinodehydroeckol (2), eckol (3), phlorofurofucoeckol-A (4), dieckol (5), and 7-phloroeckol (6). Phlorotannins 3-6 were potent and noncompetitive PTP1B inhibitors with IC 50 values ranging from 0.56 to 2.64 μM; 4-6 exhibited the most potent α-glucosidase inhibition with IC 50 values ranging from 1.37 to 6.13 μM. Interestingly, 4 and 6 were noncompetitive, while 5 exhibited competitive inhibition in an α-glucosidase assay. E. stolonifera and E. bicyclis as well as their isolated phlorotannins therefore possessed marked PTP1B and α-glucosidase inhibitory activities; this could lead to opportunities in the development of therapeutic agents to control the postprandial blood glucose level and thereby prevent diabetic complications.