*3.1. Preparation of FX*

FX was isolated from the dried *Hincksia mitchellae* (Harvey) P. C. Silva brown algae. The brown algae, *Hincksia mitchellae* (Harvey) P. C. Silva, was originally collected from the Taiwan coast and characterized. The material used in this study was obtained by cultivation in enriched seawater medium (SWM-III) in the lab. The dried powder was extracted with acetone in a brown bottle for 24 h, filtered (No. 2, Whatman filter paper, Maidstone, Kent, UK) and the solvent removed, with a temperature lower than 35 °C. The crude extracts were separated by using a silica gel flash column chromatography (Geduran® Si 60, 0.040–0.063 mm, Merck, Darmstadt, Germany), eluted with ethyl acetate/ *n*-hexane (4.5:5.5, v/v). The redorange color fraction was collected and passed through a second silica gel column eluted with ethanol/acetone/ *n*-hexane (1:19:80, v/v). After removing the solvent, the residue was re-dissolved in acetone/ *n*-hexane (45:55, v/v). An equal volume of Millipore-Q water was added, and the mixture was standing at ƺ20 °C for 4 h until a red precipitate was produced. The precipitate was filtered and dried in a freeze drier. The obtained solid was confirmed as FX by H-NMR and the purity checked by HPLC (PU-980 pump and UV-visible absorbance detector, Jasco, Japan and LiChrospher® 100 RP-18 column, 5 ΐm, Merck, Darmstadt, Germany). The mobile phase used was methanol/H2O (90:10, v/v) with a flow rate of 1 mL/min. The FX was detected at 450 nm and quantified from the peak area by using a standard curve with previous purified and identified FX (95%). The purity of FX prepared was >95% by this HPLC analysis.
