Efficient approach to purification of octaphlorethol A from brown seaweed, Ishige foliacea by centrifugal partition chromatography

The brown seaweed, Ishige foliacea is distributed along the coast of Jeju Island. The main compound that this seaweed produces, octaphlorethol A (OPA), has been recently reported to exhibit strong antidiabetic and whitening activities. However, obtaining pure OPA requires repetitive complex processes and its antioxidant effect in vivo has not been demonstrated. Therefore, we devised a method to efficiently detect and isolate OPA from I. foliacea using 2.2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+) on-line HPLC and centrifu-gal partition chromatography (CPC), respectively. And we evaluated its antioxidative properties using zebrafish as an in vivo model system. OPA among compounds from I. foliacea ethyl acetate (EtOAc) fraction had the lowest absorbance in ABTS+ on-line HPLC. A total of 11.2 mg OPA was rapidly isolated from the EtOAc fraction (500 mg) of I. foliacea extract by using CPC with a two-phase solvent system. In particular, OPA strongly inhibited reactive oxygen species and lipid peroxidation in 2.2′-azobis (2-amidinopropane) dihydro-chloride-induced zebrafish embryos.