Bioactivity-guided identification of anti-AHPND (acute hepatopancreatic necrosis disease) metabolites of Ecklonia arborea

Abstract

Acute hepatopancreatic necrosis disease (AHPND) of shrimps is a disease caused by Vibrio parahaemolyticus which has caused a dramatic drop in shrimp production worldwide. Seaweeds of the genus Ecklonia have been reported as natural sources of antibacterial compounds. The present study aims to develop a bio-guided fractionation using the Fast-Centrifugal Partition Chromatography (FCPC) to isolate and identify bactericidal compounds against V. parahaemolyticus AHPND+ from Ecklonia arborea extract. The enriched-phlorotannins extract (EPE) showed a bactericidal activity 4.6-fold higher than crude extract of E. arborea and this activity was increased to 10-fold in pool 8 with a minimum bactericidal concentration (MBC) of 350 μg mL−1 after FCPC fractionation. Eckol and dieckol were the major compounds in pool 8 with 5.23 mg g−1 and 1.67 mg g−1, respectively. The isolated eckol showed weak antibacterial activity compared to pool 8, whereas a dieckol-rich extract showed bactericidal activity at 750 μg mL−1. Data suggested that the bactericidal activity of pool 8 could be attributed to the content of phlorotannins, mainly eckol, and dieckol. EPE and its purified fraction pool 8 from E. arborea collected from Mexico may be useful to develop antibiotic agents for medicated shrimp feed additive to combat AHPND infection.