Composition and anti-inflammatory activity of extracts from three Paeonia species

Ethnopharmacological relevance: The roots of Paeonia species are widely used in Traditional Chinese Medicine for various diseases and, mainly, for their anti-inflammatory activity. Aim of the study: This research aimed to investigate the composition of extracts from three peonies, the herbaceous species, P.lactiflora, and the tree peonies of the section Moutan, P. rockii, and P. ostii,and their property to inhibit inflammation in bronchial epithelial and Human Embryonic Kidney (HEK 293/T) cells. Materials and methods: Paeonia apolar extracts were obtained by maceration from dried roots of three species using chloroform as extraction solvent. Composition and concentrations of the chemotaxonomic markers, benzoic acid and monoterpene derivatives, were established by a HPLC-DAD method. Total polyphenols content was determined by the Folin-Ciocalteau colorimetric assay. Anti-inflammatory activity was studied in bronchial epithelial cells affected by Cystic Fibrosis (CF), CuFi1, and the normal counterpart NuLi1. Cell proliferation and viability were evaluated by BrdU incorporation and MTT assays. The ability of the extracts to modulate cytokines (IL-6) and chemokines (IL-8 and RANTES) secretion was tested by ELISA specific immunoassays. Moreover, the anti-inflammatory activity was confirmed in HEK 293/T cells transfected with a NF- κB reporter plasmid determining NF- κB activity by luciferase assay. Results: The total polyphenol content, expressed as benzoic acid equivalents, ranged from 105.2-110.0 (P.rockii and P.ostii) to 347.0 (P. lactiflora) μg/mg. HPLC analysis indicated that the amount of benzoic acid and monoterpenes, paeoniflorigenone and benzoylpaeoniflorin, was almost superimposable (10.4%, 15.1%, and 6.5% w/w) in P. rockii and P. ostii, whereas P. lactiflora was characterized by a very high concentration of benzoic acid (34.5% w/w). All Paeonia extracts at sub-toxic concentrations strongly reduced RANTES production in unstimulated as well as TNFα-stimulated CuFi1 cells. Moreover, P. lactiflora also reduced IL- 8 secretion. In NuLi1 cells Paeonia extracts determined only a reduction of RANTES, even though with a lesser extent. This interesting effect on chemokine secretion seems to be correlated to a direct inhibition of NF- κB activity, as revealed in HEK 293/T cells. Conclusion: Among the three peonies, P. lactiflora, possess anti-inflammatory activity due to inhibition of chemokines (IL-8 and RANTES) release, particularly in CF cells. Results confirmed the traditional anti-inflammatory use of peony and suggested a relevantpotential application in the treatment of Cystic Fibrosis.