Methanol extract of Xanthium strumarium L. possesses anti-inflammatory and anti-nociceptive activities

Abstract

As an attempt to identify bioactive natural products with anti-inflammatory activity, we evaluated the effects of the methanol extract of the semen of Xanthium strumarium L. (MEXS) on lipopolysaccharide (LPS)-induced nitric oxide (NO), prostaglandin E2 (PGE2) and tumor necrosis factor-α (TNF-α) production in RAW 264.7 cells. Our data indicate that MEXS is a potent inhibitor of NO, PGE2 and TNF-α production. Consistent with these findings, the expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein and iNOS, COX-2 and TNF-α mRNA were down-regulated in a concentration-dependent manner. Furthermore, MEXS inhibited nuclear factor kappa B (NF-κB) DNA binding activity and the translocation of NF-κB to the nucleus by blocking the degradation of inhibitor of kappa B-α (IκB-α). We further evaluated the anti-inflammatory and anti-nociceptive activities of MEXS in vivo. MEXS (100, 200 mg/kg/d, p.o.) reduced acute paw edema induced by carrageenin in rats, and showed analgesic activities in an acetic acid-induced abdominal constriction test and a hot plate test in mice. Thus, our study suggests that the inhibitions of iNOS, COX-2 expression, and TNF-α release by the methanol extract of the semen of Xanthium strumarium L. are achieved by blocking NF-κB activation, and that this is also responsible for its anti-inflammatory effects. © 2005 Pharmaceutical Society of Japan.