Antiedema and antinociceptive potential of the essential oil of Pectis elongata Kunt (Asteraceae) from the Brazilian Amazon

Abstract

Ethnopharmacological relevance: Pectis elongata, a herbaceous species that is known in northern Brazil as "cominho" or "limãozinho", is traditionally used in the region for the treatment of fevers, colds, hypotension, genitourinary and gastric disorders, and pain.

Aim of the study: Determine the chemical composition and acute oral toxicity and evaluate whether Pectis elongata essential oil (PeEO) has antiedema and antinociceptive activity.

Materials and methods: The chemical composition was determined using gas chromatography coupled to mass spectrometry (GC/MS) and the degree of toxicity determined by the LD₅₀. The antiedema and antinociceptive potential was evaluated via the λ-carrageenan-induced paw edema test and formalin test, respectively.

Results: Citral (geranial and neral) was characterized as a major component of the PeEO, representing 89% of the total identified compounds. According to OECD criteria (2002), the EO was considered non-toxic since it presented LD₅₀ values over 2000 mg kg^-1. Its antiedema potential was observed at doses of 200 and 400 mg kg^-1 (p ≤ 0.05). At a dose of 400 mg kg^-1, PeEO also showed antinociceptive potential (p ≤ 0.05), both in the neurogenic phase and in the inflammatory phase.

Conclusions: PeEO, which is rich in citral, did not induce any characteristic signs of acute oral toxicity and was also efficient in reducing carrageenan-induced paw edema, in addition to presenting antinociceptive potential and acting on both central and peripheral pain. It is thus a promising candidate for the development of a new herbal medicine with anti-inflammatory and analgesic action.

Keywords: Antinociceptive; Citral; Essential oil; Inflammation; Pain; Toxicity.