The effect of Huang Lian Jie Du Tang and its single herbal components on NO production in RAW 264.7 macrophages, cell viability and proliferation

The Chinese herbal mixture Huang Lian Jie Du Tang is used in traditional Chinese medicine to clear heat and relieve toxicity. According to Western medical terminology it is used against eczema and skin diseases, chronic inflammatory intestinal diseases such as Morbus Crohn or Colitis ulcerosa, as well as against psychiatric disorders like schizophrenia and depression. Recent studies on the mixture showed that it is influencing LTB4 formation and NO production [1]. The aim of this study was to determine the inhibitory activity of the decoctions of the mixture and of the single herbs on NO production in RAW 264.7 macrophages as well as their influence on cell viability and proliferation using an XTT assay. The results of the mixture were compared with the activity of the single herbs. In addition, the decoctions were fractionated using liquid-liquid extraction with n-heptane, dichloromethane, ethyl acetate and n-butanol, and the gained fractions were also tested. The study showed that only the dichloromethane fraction of the decoction of Radix Scutellariae was able to inhibit NO production (Fig.1). The XTT assay (performed with CCRF-CEM leukemia cells) demonstrated no or only little influence of the decoctions and fractions on cell proliferation and cell viability. Further investigations are in progress to prove whether the inhibition of NO production is due to baicalein which is a major compound of Radix Scutellariae, or whether also other constituents contribute to the effect.

Fig.1: Inhibition of NO production in RAW 264.7 macrophages

Acknowledgements: The investigations were financially supported by the Austrian Federal Ministries of Health and of Science and Research within the research project „TCM and Age Related Diseases“.

References: 1. Zheng, H. (2009)J. Pharm. Pharmacol. 61:1699–1707.