Anti-inflammatory, antinociceptive and antioxidant properties of Schinopsis brasiliensis bark

Abstract

Ethnopharmacological relevance: Schinopsis brasiliensis is a native plant from Brazil, popularly used in folk medicine to relieve pain and treat inflammation. This study evaluated the antinociceptive and anti-inflammatory activities and antioxidant properties of the hydroethanol extract (HEE) and ethyl acetate fraction (EAF) obtained from S. brasiliensis bark.

Materials and methods: The HEE and EAF of S. brasiliensis bark (10, 30 and 100mg/kg, p.o.) were evaluated using models of analgaesia (formalin-induced licking and hot-plate models) or inflammation (licking response by formalin-induced and carrageenan-induced cell migration into the subcutaneous air pouch). The antioxidant activities of HEE and EAF (50, 100 and 200µg/ml) were evaluated using the lipoperoxidation method induced in egg yolk by 2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and FeSO₄.

Results: HEE and EAF presented a central antinociceptive effect (at 100mg/kg dose), increasing the baseline and area under the curve in the hot plate model. EAF (100mg/kg) significantly reduced (p< 0.005) the pain response in the first (45%) and second (35%) phases of the formalin-induced licking model, while HEE (100mg/kg) reduced (38%) only the pain response in the second phase. Regarding anti-inflammatory activity, EAF (100mg/kg) also inhibited the inflammatory process induced by subcutaneous carrageenan injection in the SAP model, reducing the amount of the cytokine TNF-α produced.

Conclusion: HEE and EAF from S. brasiliensis bark show pharmacological interest because they were able to inhibit the peripheral and central transmission of pain. Our data also suggest that the anti-inflammatory activity caused by EAF exposure occurs through the inhibition of the pro-inflammatory cytokine TNF-α, also reducing the spreading of the inflammatory processes by neutralizing reactive oxygen species, which are by-products in the biosynthesis of pain mediators.

Keywords: Anti-inflammatory activity; Antinociceptive effect; Schinopsis brasiliensis.