Antinociceptive, neurobehavioral and antioxidant effects of Eupatorium triplinerve Vahl on rats

Abstract

Ethnopharmacological relevanceEupatorium triplinerve Vahl belongs to the Asteraceae family, popularly known as Japana. It is a perennial shrub native to Amazon rainforests of South America. Its leaves are used through infusions, decoctions, baths, and tea. It is largely used in Brazilian folk medicine as sedative, febrifuge, stimulant, tonic and anti-inflammatory. Aim of the studyThe present study evaluated the putative effects of Eupatorium triplinerve on the central nervous system (CNS), including locomotor and anxiety activity, depression-like behavior, and antinociception and oxidative stress. Materials and methodsTwo-month-old male Wistar rats (n=7–10 rats/group) and Swiss male and female mice of the species Mus musculus (n=7–10 per group) were administered with 100mg/kg, 200mg/kg, 400mg/kg, 600mg/kg, and 800mg/kg of hydroalcoholic extracts of Eupatorium triplinerve (HEET). The behavioral assays included open-field (OF), elevated Plus-maze (EPM), and forced swimming tests (FS). The antinociceptive activity was verified using chemical (acetic acid and formalin) and thermal (hot plate) models of nociception. The oxidative stress levels were measured in rat blood samples after behavioral assays and Trolox equivalent antioxidant capacity (TEAC), nitric oxide and malondialdehyde (MDA) levels were measured in vivo. ResultsOral pretreatment with HEET reduced the locomotion in OF test (200–800mg/kg), increased central locomotion and open arms entries in the OF and EPM tests, respectively (600–800mg/kg), and decreased the immobility time in the FS (200–800mg/kg). It also reduced the writhing number evoked by acetic acid injection (200–800mg/kg) and licking time in the first phase of the formalin test (400–800mg/kg). In the oxidative stress assays, the extract decreased TEAC, Nitric Oxide and MDA levels in response to swimming stress induced in rats. ConclusionsThese results were indicative for the first time that Eupatorium triplinerve exerted mild sedative, anxiolytic and antidepressive effects on the CNS. Antinociceptive effects not related to opioid system and antioxidant activity were also observed. These results support the ethnopharmacological use of Eupatorium triplinerve in popular medicine.