Immunostimulant activity of Uncaria Tomentosa and its tannins
Uncaria tomentosa (Ut), commonly known as Cat's claw or “uña de gato”, is a medicinal plant with immunostimulant, cytotoxic and antioxidant properties. The aim of this work is to investigate the immunostimulant activity of Ut bark decoction and its tannin-rich fraction (TF) on human macrophages. Ut decoction and TF were obtained as previously . The production of inflammatory-related cytokines, namely interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12 (p70), granulocyte-macrophage colony-stimulating factor (GM-CSF), chemokine (C-C motif) ligand (CCL) 2, CCL3, CCL4, and tumor necrosis factor (TNF)-α, in the culture medium of human macrophages treated with Ut decoction and TF, were determined by Bio-Plex suspension array system (Bio-Rad, Hercules, CA). We found that Ut decoction increases the expression of all the mentioned cytokines, revealing an immunostimulant action. Tannins partially contributed to this activity. In conclusion, our data supports the traditional use of Uncaria tomentosa as immunostimulant plant and points its tannins as immunomodulating compounds that could play a significant role in human disease prevention and treatment.
Acknowledgements: Research supported by FCT fellowships (SFRH/BD/46281/2008 and SFRH/BD/72918/2010), FTC project (PTDC/SAU-FCF/105429/2008) and FEDER/COMPETE (FCOMP-01–0124-FEDER-011096).  C. Gonçalves et al., Phytochemistry 2005; 66: 89–98.