Sargassumin C, a Novel Butenolide from Sargassum micracanthum

Abstract

Objective: In our ongoing effort to search for the novel secondary metabolites from the marine algae, chemical investigation of a methanolic extract of Sargassum micracanthum led to the isolation of a novel butenolide (1) and a known compound (2). Methods: The methanolic extract of S. micracanthum was partitioned and subjected to medium pressure column chromatography and preparative-HPLC to yield two compounds (1 and 2). Their structures were established based on comprehensive spectroscopic data (1D NMR, 2D NMR, and HRESIMS). These compounds (1 and 2) were evaluated for the production of the NO in lipopolysaccharide (LPS)-induced RAW264.7 cells and pro-inflammatory cytokines such as IL-6, IL-1 β, TNF- α, and IL-10. Results: A new compound (1) was determined to be a new butenolide derivative, and a known compound (2) were identified as 2-hydroxy-(5 E,9 E)-6,10,14-trimethylpentadeca-5,9-dien-12-one. Compounds 1 and 2 showed inhibitory activities in a dose-dependent manner on LPS-induced NO production in RAW264.7 cells and pro-inflammatory cytokines. Conclusion: A new butenolide, sargassumin C (1), and 2-hydroxy-(5 E,9 E)-6,10,14-trimethylpentadeca-5,9-dien-12-one (2) were isolated from the brown alga, S. micracanthum. Compound 2 was more effective than 1 on NO production and pro-inflammatory cytokines.