Assessment of the anti-inflammatory effects of a hydroethanolic leaves extract emulsion from Schinus terebinthifolius Raddi in zymosan-induced arthritis

INTRODUCTION: Schinus terebinthifolius Raddi is a specie from the Anacardiaceae family, popularly known Aroeira. This species is widely used due to its astringent, antimicrobial, healing and anti-inflammatory action. Results published by our research group showed that the hydroethanolic extract from S. terebinthifolius (ST-70) is capable of inhibiting cell migration and the production of cytokines and chemokines in inflammatory models induced by zymosan. In this work, we aimed to evaluate the effect of ST-70 and ST-70 emulsion (F1) on the inflammatory response induced by zymosan.

METHODOLOGY: S. terebinthifolius leaves were macerated with 70% ethanol to obtain ST-70. The formulation (F1) was developed from Schinus extract using an emulsion system consisting of a non-ionic hydrophilic surfactant (Polaxamer 407), associated with polyethylene glycol 400 and oleic acid. C57BL/6 mice, males previously treated orally (p.o.) with ST-70 or with F1, followed by intra-articular (i.a.) injection of zymosan. Subsequently, joint edema was assessed by caliper 24 hours after induction. Synovial lavage was collected to assess total and differential leukocyte migration and cytokines by sandwich enzyme-linked immunosorbent assay (ELISA).

RESULTS: ST-70 and F1 reduced joint edema 24 hours after zymosan-induced arthritis. Besides, ST-70 inhibited total leukocyte (42.37%) and neutrophil counts in the synovial lavage (from 11.08 x105 to 5.75 x105 cells/cavity). Moreover, ST-70 and F1 were able to reduce the production of inflammatory mediators as MIP-1α and MCP-1.

CONCLUSION: The results suggest that ST-70 and F1 have an anti-inflammatory effect on zymosan-induced arthritis and may be a promising therapy for the disease.

CEUA: LW-15/2023