Saururus chinensis (Lour.) Baill. is a perennial herb and grows in Korea, China, and Japan. Interestingly, (7S,8S)-Δ8'-3,4-methylenedioxy-3',5,5'-trimethoxy-7-monoacetate-8.O.4'-neolignan (MTMN), one of the active neolignans, was first isolated from the roots of Saururus chinensis. The compound was screened for anti-inflammatory activity using a RAW264.7 murine macrophage cell line. The dried roots of S. chinensis (9.7 kg) were extracted with 70% methanol and then solvent fractionation. From the ethyl acetate fraction, MTMN was purified through silica gel column and reverse-phase column chromatography and its structure was identified by spectroscopic analysis with nuclear magnetic resonance, circular dichroism, and mass spectrometry. RAW264.7 cells were induced using lipopolysaccharide (LPS) and treated with or without MTMN. Production of nitric oxide (NO) and prostaglandin E2 (PGE2) levels were measured and protein expressions of nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were analyzed by immunoblotting. The isolated neolignan was (7S,8S)-Δ8'-3,4-methylenedioxy-3',5,5'-trimethoxy-7-monoacetate-8.O.4'-neolignan. This compound suppressed the LPS-induced iNOS and COX-2 protein expressions, which led to a decrease in the production of NO and PGE2 levels. Further studies, including in animal models, will be required to establish the precise pharmacological effect of MTMN.
Keywords: Saururus chinensis; inflammation; neolignan.