Assessing medicinal plants from South-Eastern Spain for potential anti-inflammatory effects targeting nuclear...

Identification of plants with anti-inflammatory activity can be successfully based on information gained through knowledge on their traditional use. This is particularly true for biodiversity-rich regions of the world such as the Mediterranean. While such approaches are often single target based, here we used a multitarget, cell-based approach focusing on the pro-inflammatory signaling cascade and especially the NF-kappaB (NF-kappaB) pathway.

The plants from South-Eastern Spain were chosen on the basis that they were recorded as having a traditional use against an indication related to inflammation. The primary target was the transcription factor NF-kappaB (using a luciferase-based assay in HeLa cells). In addition extracts were tested in vitro for effects on cytokines (IL-6, IL-8, TNF-alpha) or PGE(2) in monocytes and for potential cytotoxic/pro-apoptotic action as well as for their influence on the cell cycle.

Overall, 64 medicinal plant drugs from 61 species were assessed as potential inhibitors of inflammatory mediators to levels of 100-10 microg/ml. Three plants showed the highest level of activity (50 microg/ml) in inhibiting the activation of NF-kappaB in 5.1 cells: Helichrysum stoechas (Asteraceae), Dorycnium pentaphyllum (Fabaceae, s.l.) and Phlomis almeriensis (Lamiaceae). In the tests against the cytokines it was particularly striking to find that a number of species, Bupleurum fruticosum, Chamaespartium tridentatum, Genista ramosissima, Helichrysum stoechas, Mercurialis tomentosa, Ononis ramosissima, Peganum harmala, Picnomon acarna, Retama sphaerocarpa and Santolina viscosa showed extracts that were active at inhibiting TNF-alpha (10 microg/ml).

Overall, this project has identified a series of species with an activity profile which merits further phytochemical-pharmacological investigation.