Regioselective syntheses and analyses of phlorofucofuroeckol‐A derivatives

Abstract

Phlorofucofuroeckol-A (PFF-A) is a phlorotannin extracted from various brown algae. PFF-A shows low toxicity when ingested and various biochemical effects, including antioxidant, anti-inflammatory, anti-cancer, and anti-allergy properties. In this study, various di-O-substituted PFF-A derivatives were synthesized by introducing alkyl or acyl groups at two specific hydroxyls out of the nine nearly equivalent phenolic OH groups present in PFF-A. The exact molecular structures of the synthesized derivatives were analyzed using two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy, which confirmed that the substituents were regioselectively introduced at the 1 OH and 6 OH positions. Small amounts of three mono-O-substituted derivatives were generated as by-products in this reaction, and their structures and regioselectivity were determined using 2D NMR spectroscopy. This study can provide insights into understanding the mechanism of action of eckol-based compounds and developing new drug candidates.

Recycling of Lithium‐Ion Batteries—Current State of the Art, Circular Economy, and Next Generation Recycling

“…[299] Similar approaches were also published elsewhere. [300,301] Another method based on hydrothermal relithiation was investigated by Sloop et al and Shi et al The cathode materials were treated in LiOH and Li 2 SO 4 solutions and then thermally annealed. [302,303] Electrochemical methods for relithiation were also investigated.…”

In-Depth Understanding of Ecklonia stolonifera Okamura: A Review of Its Bioactivities and Bioactive Compounds

“…Phlorofucofuroeckol-A is reported to be present in various brown algae and is a phlorotannin with various biological activities [ 48 ], including tyrosinase inhibition and antioxidant, anti-obesity, anti-diabetic, anti-inflammatory, anti-atherosclerotic, anti-hepatotoxic activities [ 16 , 17 , 21 , 22 , 24 , 31 , 34 , 35 , 40 , 44 , 49 ]. Phlorofucofuroeckol-A is a pentacyclic substructure that includes a dibenzo-p-dioxin skeleton ( Table 2 ).…”