Sargassum horneri, a type of brown seaweed, has become popular in Korea over the past few years due to its massive influx from China. The present study is implemented towards developing methods for sustainable use of S. horneri biomass. Methanol extracts of S. horneri China (MSC) strain were investigated in order to isolate their bioactive natural products. Extracts were fractionated by solvent partitioning, high-performance centrifugal partition chromatography (HPCPC), and preparative high-performance liquid chromatography (prep-HPLC). Three norisoprenoids ((-)-loliolide, 3-hydroxy-5,6-epoxy-β-ionone (HEBI), and apo-9′-fucoxanthinone) were isolated from chloroform fractions of MSC, and their structures were elucidated by nuclear magnetic resonance (NMR) spectroscopy. Solvent conditions for the HPCPC separation were optimized as hexane, ethyl acetate, methanol, and water in a ratio of 5:5:5:5. The isolated compounds displayed potential anti-inflammatory properties in lipopolysaccharide (LPS)-induced RAW 264.7 macrophages. For the first time, the three compounds reported herein were isolated from S. horneri. With further studies, S. horneri-derived extracts and natural products could be developed as cosmetics and/or functional food materials. Display omitted •Sargassum horneri is an edible brown seaweed with bioactive properties.•Centrifugal partition chromatography (HPCPC) is an effective approach to isolate norisoprenoids compounds from S. horneri.•Norisoprenoids compounds showed good anti-inflammatory activity in Raw 264.7 macrophage cells.•Norisprenoids compounds are beneficial materials for functional foods and pharmaceuticals.