Aim of the study: To ascertain the effective constituents in Xiexin Decoction for anti-inflammation and the interactions of these constituents at the pharmacodynamic level.
Materials and methods: Rats were administered oral Xiexin Decoction 1h before intraperitoneal lipopolysaccharide. Nitric oxide production and Xiexin Decoction constituents in venous serum samples were quantified and the correlation between nitric oxide production and each constituent in serum was calculated. Raw264.7 cells were stimulated with lipopolysaccharide and one or more Xiexin Decoction constituents; cell viability and nitric oxide production was quantified.
Results: Xiexin Decoction significantly decreased nitric oxide production in vivo, which correlated well with rhein, baicalin, emodin and aloe-emodin. All the typical constituents of Xiexin Decoction, with the exception of physcione and chrysophanol, dose-dependently inhibited nitric oxide production in vitro. In an orthogonal designed in vitro study, rhein was the most powerful constituent, followed by baicalin then berberine and no synergy was found among these constituents.
Conclusions: Rhein was the most effective anti-inflammatory constituent in Xiexin Decoction followed by baicalin; no synergy was observed between rhein, baicalin and berberine at the pharmacodynamic level in vitro.