Cyperus articulatus: Anti-inflammatory and antinociceptive activity of a medicinal plant from the Amazon

Abstract

Ethnopharmacological relevance: Cyperus articulatus L., popularly known as priprioca, is a plant used in the Amazon for perfumed baths and homemade perfumes. In traditional medicine, its rhizomes are used to treat diseases related to inflammatory processes.

Aim of the study: Due to its promising bioactive properties, this study sought to investigate its phytochemistry and the anti-inflammatory and antinociceptive activity of the essential oil obtained from C. articulatus (CAEO) in in vitro and in vivo tests.

Material and methods: The essential oil was obtained from the rhizomes of C. articulatus and extraction was carried out via hydrodistillation. Then, the oil was analyzed by GC-MS analyses. Initially, culture of RAW 264.7 macrophages stimulated by lipopolysaccharide (LPS) was used to evaluate cytotoxicity and interference in the production of mediators of the inflammatory process (nitrite, IL-1β, TNF-α and PGE₂) after exposure to CAEO. The acute toxicity of CAEO was evaluated and the results were used to define doses of 10, 100 and 400 mg kg^-1 for evaluation of CAEO in in vivo tests using mice. The carrageenan-induced air pouch models and the Evans test were used to evaluate the anti-inflammatory activity by measuring the number of total leukocytes and vascular permeability. Antinociceptive activity was evaluated via tests of contortions induced by acetic acid, hot plate, and formalin.

Results: Treatment with CAEO reduced the levels of nitrite IL-1β, TNF-α and PGE₂ in the macrophage culture, revealing its anti-inflammatory potential. CAEO decreased carrageenan-induced leukocyte migration and vascular permeability, which are important events related to the acute inflammatory response. Nociceptive activity was significantly inhibited by CAEO in the acetic acid-induced contortions model, hot plate, and in both phases of the formalin test. The treatment with naloxane reversed the antinociceptive effect observed in the formalin test, suggesting the participation of opioid receptors in the mechanism of action of CAEO.

Conclusion: The observed results reveal the anti-inflammatory and antinocipeptive activity of C. articulatus essential oil in vivo and support the traditional use of this plant in the treatment of different diseases involving inflammation and pain.

Keywords: Essential oil; Inflammation; Medicinal plant; Pain; Preclinical.