Anti-inflammatory activity of plant extracts: an effective in vitro model of study based on primary culture of porcine endothelial cells

Inflammation is a protective response exerted by the organism to eliminate an injurious stimulus. Endothelial cells play a fundamental role in different physiological processes since, changing their phenotype, modulate the complement and coagulation cascades, inflammation and innate and adaptive immunity. Medicinal plants have been the main remedy to treat different ailments and their study has permitted the development of many drugs. The aim of the present research was to study the phytochemical composition and the anti-inflammatory activity of four medicinal plants (Cucumis sativus L, Boswellia serrata Roxb. Colebr, Salvia sagittata Ruiz & Pav and Clinopodium tomentosum Kunth), traditionally used to treat different diseases, on primary culture of porcine aortic endothelial cells (pAECs) stimulated with Lipopolysaccharide (LPS). This approach is relevant in terms of screening possible positive activities of medicinal plants in relation to the Replacement and Reduction principles in agreement with the European Directive 2010/63/EU on the protection of animals used for scientific purposes and its implementation in Italy through “Decreto Legislativo“ n. 26/2014. Different extraction processes and techniques have been employed to verify their phytochemical and biological effects (HPLC, RT-PCR, Western blot). The phytochemical analysis revealed the presence of different bioactive compounds (11-keto-β-boswellic acid and β-boswellic acid in Boswellia serrata extracts, different phenolic acids and flavonoids with rosmarinic acid as the most abundant component in Salvia sagittata and Clinopodium tomentosum extracts). In the biological analysis, Cucumis sativus, Boswellia serrata, Salvia sagittata and Clinopodium tomentosum reduced the LPS-induced cytotoxicity with the decrement of different inflammatory cytokines and increment of protective molecules and anti-inflammatory cytokines. In conclusion, our results have clearly demonstrated that the medicinal plants studied have attenuated lipopolysaccharide induced inflammatory response in endothelial cells. Moreover the studies confirm the relevance of primary culture of pAECs as an interesting screening model to explore the huge variety of Ecuadorian medicinal plants.