Bioactivity-guided isolation of benzocoumarin and quinonoid compounds from Rubia schumanniana and their anti-inflammatory activity in vitro.

The bioactivity-guided isolation was performed to explore bioactive components from 75% ethanol extract of Rubia schumanniana. The structures of ten compounds, including one new benzocoumarin type compound (1) and nine known quinonoids (2-10), were determined by means of analysis of comprehensive spectroscopic data. Anti-inflammatory activity evaluation revealed that compounds 1-10 could inhibit overproduction of NO induced by LPS, and compounds 2-4 and 6-7 exhibited the inhibitory ration more than 50% at 30 μM, especially compound 3 exhibited the strongest inhibitive efficiency with 80.6% inhibition rate. Our work revealed the potential of R. schumanniana as prospective natural source of anti-inflammatory compounds.