The aqueous willow bark extract STW 33-I has anti-cancer and anti-inflammatory properties comparable to Aspirin and diclofenac

While NSAIDs are well known by their anti-inflammatory effects, where inhibition of NFκ-B is a central antiinflammatory mechanism, and by their anticancer effects via cyclooxygenases (COXs), these effects have not been yet proven for the polyphenol- and salicin-rich willow bark extract STW 33-I (Proaktiv®, water extract, 16–23:1), which is successfully used in the treatment of painful and inflammatory diseases [1]. The aim of this study was to determine anticancer and anti-inflammatory effects of STW 33-I and its polyphenols containing fraction E (Fr. E) compared to well characterized NSAIDs such as Aspirin (ASS) and diclofenac.

The anti-proliferative effect of STW 33-I on undifferentiated HT-29 colon carcinoma cells was determined by quantification of lactate dehydrogenase (LDH) release and by sulforhodamine B (SRB) measurement. Apoptosis was identified and quantified by YO-PRO-1 staining. Intracellular translocation of the NFκ-B p65 subunit was analyzed in THP-1 cells after differentiation by PMA, pre-treatment with the compounds, and afterward activation with LPS. Treatment with diclofenac (0.1–0.2 mM) and ASS (2.5–5 mM) for 5 hours was found to induce apoptosis in HT-29 colon carcinoma cells significantly. Treatment with STW 33-I had a comparable antiproliferative effect. The pro-apoptotic effect was confirmed by the SRB method and by LDH release. Our results also indicate that treatment of THP-1 cells for 4h with STW 33-I (50µg/ml) was effective to inhibit the translocation of the subunit p65 into the cell nucleus. The inhibition of p65 translocation by STW 33–1 was similar to diclofenac and ASS.

According to these results STW 33-I (Proaktiv®), which is used in back pain and rheumatic complaints, has antiproliferative and antiinflammatory properties similar to those of ASS and diclofenac.

Reference: 1. Nahrstedt, A. et al. (2007) Wien Med Wochenschr 157:348–351