Edible Brown Alga E cklonia cava Derived Phlorotannin-Induced Anti-Adipogenic Activity in Vitro

Abstract

The present study performed the bioactivity-monitored isolation of anti-adipogenic phlorotannins from Ecklonia cava as a part of the ongoing research to develop antiobesity nutraceuticals from natural origin. Extracts were partitioned into n-hexane, 85% aqueous MeOH, n-BuOH and water fractions. Their adipogenic activities were examined by measuring glycerol release level and adipogenic-related gene expression in differentiating 3T3-L1 preadipocytes. Among them, n-BuOH fractions significantly increased glycerol secretion and reduced the regulation of adipogenic transcription factors, peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), as well as tumor necrosis factor α (TNFα). Further separation from n-BuOH fraction led to the isolation of phlorotannins, triphlorethol-A, eckol and dieckol. Phlorotannins increased the glycerol secretion and reduced the glucose consumption levels of 3T3-L1 adipocytes. Moreover, the phlorotannins reduced the expression levels of PPARγ, C/EBPα and differentiation-dependent factor 1/sterol regulatory element-binding protein 1c, as well as downstream genes such as fatty acid binding protein-4, fatty acid transport protein-1, fatty acid synthase, Leptin and acyl-CoA synthetase 1. In addition, phlorotannins increased the mRNA expression of hormone-sensitive lipase while suppressing perilipin and TNFα expressions. Practical Applications Brown alga, Ecklonia cava, is one of the most common edible algae in East Asian countries and widely consumed throughout Korea and Japan because of its nutritional importance along with its medicinal value. Constituents of E. cava, especially phenolic compounds, are considered to possess several bioactivities against various complications and diseases. In this regard, this study provides valuable insights concerning the antiobesity potential of E. cava and effective ingredients. Results indicate that the isolated phlorotannins act as antiobesity agents and suggest possible mechanisms of action. Following this study, a better utilization of E. cava via proper extraction of antiobesity constituents will pave the way for future nutraceuticals with antiobesity value.