A study on the nitric oxide production-suppressing activity of sanguisorbae radix components.

The active components of an aqueous extract of Sanguisorbae Radix, which possesses nitric oxide (NO) production-suppressing activity, were determined using macrophages that were activated by the addition of lipopolysaccharide. Significant inhibitory activity against the formation of both NO and inducible NO synthase, and NADPH-diaphorase activity, which is involved in NO generation, was shown by Sanguisorbae Radix fractions T-B and T-C. On further fractionation, the subfractions of T-B and T-C all showed high anti-NO activity. Sanguiin H-6, sanguiin H-11, 1,2,3,4,6-penta-O-galloyl-beta-D-glucose, eugeniin and polymeric proanthocyanidin were isolated from TB-3 and TC-4, and all were identified as exhibiting strong anti-NO activity. We have confirmed that sanguiin H-6 is the most active component of Sanguisorbae Radix with respect to the suppression of NO production. It is suggested that tannin makes a prominent contribution to the biological activity of Sanguisorbae Radix.