7-prenyloxi-6-methoxycoumarin from Polygala sabulosa A.W. Bennett Regulates p38 MAPK and NF-kB Pathways Inhibiting the Inflammation Induced by Carrageenan in the Mouse Model of Pleurisy

Context: Polygala sabulosa, popularly known as “timutu-pinheirinho,” has been used in Brazilian folk medicine for the treatment of bowel and kidney disorders and as an expectorant. Objective: Evaluate the anti-inflammatory effects of the crude extract (CE), acetonic fraction (Ac), and the main compound, 7-prenyloxi-6-methoxycoumarin (PC) on a mouse model of carrageenan-induced pleurisy. Materials and Methods: A mouse model of carrageenan-induced pleurisy was used to investigate the effects of P. sabulosa CE, Ac and PC on leukocyte migration, exudate formation, activities of myeloperoxidase (MPO), and adenosine-deaminase (ADA), levels of tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β) and nitric oxide (NO). In addition, the effect of the plant material on lung histology was also evaluated. The effects of PC on the TNF-α, IL-1β and NO synthase 2 (NOS2) mRNA expression, were also investigated. Finally, the effect of PC on the nuclear factor-kappa B (NF-ΚB) and p38 mitogen-activated protein kinase (p38 MAPK) was also evaluated. Results: CE, Ac and PC reduced inflammation in the pleural cavity and lungs. This effect was evidenced by reduction on all inflammatory parameters evaluated; the exception being the inability of the CE to inhibit exudate formation. In isolation, PC showed reduction on mRNA levels of TNF-α, IL-1β and NOS2, and on activation of the NF-ΚB and p38 MAPK pathways. Conclusion: The presented results show that P. sabulosa has significant anti-inflammatory activity, as does its main compound, PC. Moreover, the results suggest that PC exerts its effects mainly by inhibited the NF-ΚB and p38 MAPK pathways.