title: A phlorotannin constituent of Ecklonia cava alleviates postprandial hyperglycemia in diabetic mice.
abstract: BACKGROUND
  2,7″-Phloroglucinol-6,6'-bieckol is a type of phlorotannin isolated from brown algae, Ecklonia cava Kjellman (Phaeophyceae; Laminareaceae). 2,7″-Phloroglucinol-6,6'-bieckol mediates antioxidant activities. However, there has been no research on improving postprandial hyperglycaemia using 2,7″-phloroglucinol-6,6'-bieckol.
  
  
  OBJECTIVE
  This study investigated the inhibitory effects of 2,7″-phloroglucinol-6,6'-bieckol on activities of α-glucosidase and α-amylase as well as its alleviating effect on postprandial hyperglycaemia in streptozotocin-induced diabetic mice.
  
  
  METHODS
  α-Glucosidase and α-amylase inhibitory assays were carried out. The effect of 2,7″-phloroglucinol-6,6'-bieckol on hyperglycaemia after a meal was measured by postprandial blood glucose in streptozotocin-induced diabetic and normal mice. The mice were treated orally with soluble starch (2 g/kg BW) alone (control) or with 2,7″-phloroglucinol-6,6'-bieckol (10 mg/kg bw) or acarbose (10 mg/kg BW) dissolved in 0.2 mL water. Blood samples were taken from tail veins at 0, 30, 60, and 120 min and blood glucose was measured by a glucometer.
  
  
  RESULTS
  2,7″-Phloroglucinol-6,6'-bieckol showed higher inhibitory activities than acarbose, a positive control against α-glucosidase and α-amylase. The IC50values of 2,7″-phloroglucinol-6,6'-bieckol against α-glucosidase and α-amylase were 23.35 and 6.94 μM, respectively, which was found more effective than observed with acarbose (α-glucosidase IC50of 130.04 μM; α-amylase IC50of 165.12 μM). In normal mice, 2,7″-phloroglucinol-6,6'-bieckol significantly suppressed the postprandial hyperglycaemia caused by starch. The 2,7″-phloroglucinol-6,6'-bieckol administration group (2349.3 mmol·min/L) had a lower area under the curve (AUC) glucose response than the control group (2690.83 mmol·min/L) in diabetic mice.
  
  
  CONCLUSIONS
  2,7″-Phloroglucinol-6,6'-bieckol might be used as an inhibitor of α-glucosidase and α-amylase as well as to delay absorption of dietary carbohydrates.
authors.affiliation: a Department of Food Science and Nutrition , Pusan National University , Busan , Republic of Korea.
authors.forename: Hyun-Ah
authors.initials: HA
authors.lastname: Lee
authors.affiliation: b Korea Mouse Metabolic Phenotyping Center , Jeju , Republic of Korea.
authors.forename: Ji-Hyeok
authors.initials: JH
authors.lastname: Lee
authors.affiliation: c Department of Food Science and Nutrition and Research , Pusan National University , Busan , Republic of Korea.|d Institute of Ecology for the Elderly , Pusan National University , Busan , Republic of Korea.
authors.forename: Ji-Sook
authors.initials: JS
authors.lastname: Han
mesh_terms: D041721:3T3-L1 Cells; D000818:Animals; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000187:drug effects* / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000139:chemically induced / Q000188:drug therapy*; D004146:Dioxanes / Q000302:isolation & purification / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D065089:Glycoside Hydrolase Inhibitors / Q000302:isolation & purification / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D000459:Phaeophyceae / Q000737:chemistry*; D010696:Phloroglucinol / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D019518:Postprandial Period; D013311:Streptozocin; D013997:Time Factors; D000516:alpha-Amylases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000520:alpha-Glucosidases / Q000378:metabolism
chemical_list: C000603848:2,7''-phloroglucinol-6,6'-bieckol; D015415:Biomarkers; D001786:Blood Glucose; D004146:Dioxanes; D065089:Glycoside Hydrolase Inhibitors; D013311:Streptozocin; D010696:Phloroglucinol; D000516:alpha-Amylases; D000520:alpha-Glucosidases
keywords: streptozotocin; α-Glucosidase; α-amylase