Introduction: Recent studies have shown that systemic responses of increased circulating lymphocytes and elevated proinflammatory cytokines and subtle inflammation may accompany the onset and persistence of symptoms of functional gastrointestinal diseases like functional dyspepsia (FD) and irritable bowel syndrome (IBS). The complexity of these diseases indicates that there are different pathophysiological mechanisms involved. We hypothesised that STW 5, a phytomedicinal product used in FD and IBS patients has anti-inflammatory effects like NSAIDs, but without GI side effects.
Methods: Data from in vitro studies were revealed and analysed for elucidating possible mechanisms of action underlying the anti-inflammatory effects of STW 5.
Results: STW 5 activated COX-1, but had no effect on COX-2 mRNA expression in contrast to the control substances, like ASS and diclofenac, which inhibited COX-1 and COX-2 mRNA expression [1]. STW 5 inhibited the increased gene expression and reduced significantly the release of TNF-alpha by activation of adenosine A2A receptors in LPS (100 ng/ml)-stimulated human monocytes, while having no effect in untreated cells [2]. Radioligand binding assays confirmed the affinity of STW 5 to adenosine A2A receptors.
Conclusion: The mechanism of action of STW 5 as an anti-inflammatory medication without involving COX-1 or COX-2 inhibitory properties may be an important reason for the very good tolerability of this medicinal product in patients with FD and IBS, as indicated by clinical trials and therapeutic use.
References: 1. Michael, S., et al. 2012. Inflammatory Bowel Disease 3: 41; 2. Bonaterra, G. A., et al. 2008. Z. Phytotherapie 29: S22