Anti-inflammatory effects of the willow bark extract STW 33-I (Proaktiv®) in LPS-activated human monocytes and differentiated macrophages

Anatomy and Cell Biology, Department of Medical Cell Biology, University of Marburg, Robert-Koch-Str. 8, 35032 Marburg, Germany.
Phytomedicine: international journal of phytotherapy and phytopharmacology (Impact Factor: 3.13). 12/2010; 17(14):1106-13. DOI: 10.1016/j.phymed.2010.03.022
Source: PubMed


Willow bark extract is frequently used in the treatment of painful rheumatological diseases, such as arthritis and back pain. Its effect has been attributed to its main component salicin, but pharmacological studies have shown that the clinical efficacy of the willow bark extract cannot be explained by its salicin content alone. Therefore different modes of action have been suggested for the anti-inflammatory effect of willow bark extract. Here, we report in vitro data revelling the effect and mode of action of the aqueous willow bark extract STW 33-I as well as a water-soluble fraction (fraction E [Fr E]) in comparison with well-known non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin (ASA) and diclofenac (Diclo) on pro-inflammatorily activated human monocytes and differentiated macrophages.
STW 33-I and the water-soluble Fr E showed concentration-dependent and significant anti-inflammatory effects in lipopolysaccharide-activated monocytes. Both inhibited the intracellular protein expression of tumour necrosis factor-alpha (TNFα) as well as the mRNA expression of TNFα and cyclooxygenase 2 (COX-2), and the release of nitric oxide (NO). In addition, apoptosis of pro-inflammatorily activated monocytes was induced. Furthermore, treatment of activated macrophages with STW 33-I inhibited the nuclear translocation of the p65 subunit of the nuclear transcription factor-kappa B (NF-κB p65).
The present in vitro investigations suggest a significant anti-inflammatory activity of willow bark water extract STW 33-1 and of its water-soluble fraction by inhibiting pro-inflammatory cytokines (TNFα), COX-2 and nuclear translocation of the transcription factor NF-κB in pro-inflammatorily activated monocytes. Our results provide further evidence for the therapeutic use of STW 33-I in inflammation-related disorders.

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    • "DHA has been reported to significantly reduce the expression of p65 and its nuclear binding [39]. Bonaterra et al. [40] explained similar effects on NF-κB translocation using willow bark extract, aspirin and diclofenac. The studies with various pharmaceutical medicines have indicated that therapeutics blocking NF-κB translocation might be an effective treatment for inflammatory disease [41]. "
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    • "Therefore, COX-inhibition was first regarded the main mechanism of the anti-inflammatory activity of WB. In the meanwhile it was shown that WB can also modulate relevant pro-and anti-inflammatory cytokines like TNF-␣, IL-6, IL-1, IL-10, and IL-8 (Bonaterra et al. 2009; Fiebich et al. 2005; Fiebich and Chrubasik 2004) and that not only salicyl alcohol derivatives, but also the polyphenols of WB contribute to this modulation (Khayyal et al. 2005; Nahrstedt et al. 2007). In addition, polyphenols are known to possess antioxidant and neuroprotective effects which can also interfere with inflammatory events (Kannappan et al. 2011). "
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    ABSTRACT: Inflammatory processes are increasingly recognised to contribute to neurological and neuropsychatric disorders such as depression. Thus we investigated whether a standardized willow bark preparation (WB) which contains among other constituents salicin, the forerunner of non-steroidal antiphlogistic drugs, would have an effect in a standard model of depression, the forced swimming test (FST), compared to the antidepressant imipramine. Studies were accompanied by gene expression analyses. In order to allocate potential effects to the different constituents of WB, fractions of the extract with different compositions of salicyl alcohol derivative and polyphenols were also investigated.
    Phytomedicine: international journal of phytotherapy and phytopharmacology 06/2012; 19(10):930-9. DOI:10.1016/j.phymed.2012.05.004 · 3.13 Impact Factor
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    • "Due to the low achievable salicylic acid plasma concentration, which is equivalent to only ∼100 mg of acetylsalicylic acid after oral application of 240 mg Willow bark extract (Schmid et al. 2001), recent work concentrated on the additional contribution of polyphenolic compounds on the anti-inflammatory and analgesic effect. Standardised extracts rich in polyphenols showed significant clinical effects (for review Vlachojannis et al. 2009) and extracts as well as fractions containing polyphenols also showed inhibitory activity in vitro on several molecular targets like transcription factors, proinflammatory cytokines (Bonaterra et al. 2010), cyclooxygenases and radical production (Khayyal et al. 2005). Consequently, the overall effect of Willow bark extracts can be most likely explained by different effects of various phenolic compounds on distinct targets (Nahrstedt et al. 2007). "
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