Extraction and separation scheme of RPR-EA-S1 from RPR. RPR powder was extracted by Milli Q water under reflux and the extract was precipitated with EtOH. The resulting supernatant was concentrated and partitioned sequentially with n-C6H14, EtOAc and n-BuOH. The extracts were tested for their inhibitory effects on IL-10 production in primary human blood macrophages stimulated by BCG. The bioactive RPR-EA was further separated by silica gel column chromatography. RPR-EA-S1 fraction was selected by bioactivity assay and analyzed by HPLC and GC-MS.