A new steroid glycoside, capelloside A (1), was isolated from the ethanolic extract of the startish Ugmaster capella along with the previously known coscinasteroside B (2). The structures of 1 was elucidated by extensive NMR and ESI-MS techniques as (24S)-24-O-(3-O-methyl-β-D-xylopyranosyl)-5a- cholestane-3β,6β,8,15α,24-pentoI 15-O-sulfate (1). Compounds 1 and 2 decreased intracellular ROS (reactive oxygen species) levels in murine macrophages of the RAW 264.7 cell line at induction by endotoxic lipopolysaccharide (LPS) from E. coli by 60% and 41%, correspondingly.