The Effect of Griffonia Simplicifolia on Pain Intensity, Central and Peripheral Sensitization, Painmodulation in Healthy Volunteers

This planned study is based on a randomized, placebo-controlled cross-over design. Griffonia simplicifolia contains the serotonin-precursor 5-hydroxytryptophan (5-HTP), an endogenous amino acid. 5-HTP can cross the blood-brain barrier and is converted to serotonin. Low serotonin levels are associated with depression, anxiety disorders and sleep disorders, among others. Griffonia simplicifolia is marketed as a food supplement in accordance with EU Directive 2002/46/EC. Several clinical studies have examined the efficacy of 5-HTP in chronic pain conditions. The data suggest a clinical analgesic efficacy, without, however, allowing conclusions about the underlying mechanisms. These have not yet been investigated in a human experimental pain model. The aim of the study is to investigate the influence of 5-HTP in peripheral and central sensitization, as well as descending inhibitory pathways by Quantitative Sensory Testing (QST). These findings are of great relevance for a better understanding of clinical efficacy. For this purpose, "repetitive phasic heat application" is a validated method for achieving short-term peripheral and central sensitization. As a non-invasive human pain model, it is therefore well suited for investigating the analgesic and anti-hyperalgesic effects of drugs. Furthermore, the influence of Griffonia simplicifolia on mood (depression, anxiety), memory, sleep quality and psychological well-being will be investigated by using psychological questionnaires as secondary target variables.