Planta Med 2013; 79 - PF11
DOI: 10.1055/s-0033-1352068

Anti-inflammatory and anti-tumour effects of two species of Cat's Claw (Uncaria)

I Urdanibia 1, O Estrada 1, C Ibarra 1, F Michelangeli 1, B Milano 1, P Taylor 1
  • 1Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela.

South America has two predominant species of Cat's Claw (Uña de Gato), Uncaria tomentosa and U. guianensis, which are used in traditional medicine to treat inflammation. In this study, a commercial preparation of U. tomentosa (Samento) and a hydroethanolic preparation of U. guianensis were evaluated to determine their potential anti-inflammatory and anti-tumour activities. An ethyl acetate-soluble fraction, containing flavonoids and alkaloids, was further fractionated (Sephadex LH20 and HPLC). Two preparations showed promising activity, the compound SamA1 (U. tomentosa) and the subfraction UgAIV (U. guianensis). UgAIV inhibited nitric oxide (NO) production by LPS-activated RAW 264.7 macrophages in vitro (85% at 30 mg/ml) and in mice 1h after challenge with LPS (79% at 5 mg/Kg). UgAIV also inhibited the TNF-a, IL-6 and prostaglandin E2 responses in the same in vitro and in vivo models, as well as inhibiting NF-kB activation (70% at 30 mg/ml). Cox-2 expression was inhibited by UgAIV (36%) and iNOS by SamA1 (50%), both at 30 mg/ml. In RAW 264.7 macrophages, IkB degradation was 100% inhibited with SamA1 (30 mg/ml), with total inhibition of NF-kB translocation. The preparations reduced 4T1 mammary tumour growth at day 15 by 62% (SamA1) and 49% (UgAIV), reaching a maximum of 67% (SamA1) on day 20 and 91% (UgAIV) on day 33 post-inoculation. Tumour-bearing mice treated with the preparations showed serum NO, IL-6 and TNF-a at less than 50% of the controls. UgAIV decreased the number of tumour-infiltrating T lymphocytes, macrophages and neutrophils by more than 50%. UgAIV and SamA1 decreased the number of cell positive for COX-2, iNOS, IL-6, TNF-a and P65 in the infiltrate by more than 45%. The anti-inflammatory effect of UgAIV and SamA1 is possibly due to inhibition of NF-kB and the anti-tumour effect may be due to a reduction in pro-tumoural inflammatory processes in the tumour microenvironment. Identification of the active compound(s) is under way.