In West African countries like Benin traditional medicines continue to play a key-role in addition to state health care. Piliostigma thonningii is commonly used in the northern region of Benin to treat inflammatory disorders and to promote wound healing processes (1, 2). However, knowledge about the phytochemical profile and underlying pharmacological mechanisms of actions is still scarce. Therefore, a combination of antioxidant and chromatographic screening methods using HPLC, LC-MS and DPPH-TLC was performed to study the phenolic profile of the ethanolic and aqueous leaf extracts. Furthermore, the anti-inflammatory effect of Piliostigma thonningii leaf extracts in immortalized human keratinocytes (HaCaT) was investigated. To mimic an inflammatory process on skin, the cells were stimulated with tumor necrosis factor alpha (TNF a ) to overproduce interleukins 8 and 6. Subsequently, cytokine levels in supernatants were measured by ELISA and the cell viability was investigated using the MTT assay. An aqueous leaf extract of Piliostigma thonningii concentration-dependently reduced the levels of IL-8 and IL-6 at nontoxic concentrations, resulting- in IC50 values of 74.4 µg/ml and 89 µg/ml, respectively. The phytochemical and antioxidant screenings could confirm quercitrin as the main phenolic compound for both extracts. The decrease of inflammatory mediators by Piliostigma thonningii aqueous leaf extract in TNF a -stimulated HaCaT-cells supports its ethnomedicinal usage for anti-inflammatory purposes. Pharmacokinetic studies are warranted to assess the absorption of the compounds during topical and oral application.
[1] Piliostigma thonningii (PROTA). (2015, July 5). PlantUse English, Retrieved 08:56, March 29, 2018 from https://uses.plantnet-project.org/e/index.php?title=Piliostigma_thonningii_(PROTA)&oldid=196867 .
[2] Vissiennon, Z., Ahyi, V., Koupkaki, E., & Nieber, K. (2011). Anti-inflammatory effects of novel gel-formulations with traditional used plants in Benin. Planta Medica, 77(12), PF67.