Avaliação farmacológica das atividades antioxidante, antinociceptiva e anti-inflamatória de extratos de Caryocar villosum em ensaios in vitro e in vivo

Abstract

Pain and inflammation are organism protection signs in situations of danger and tissue damage. However, in an exacerbated way, molecular and cellular mechanisms lead to a persistent inflammatory pain resulting from the intense nociceptors sensitization, compromising the life quality of many people. Due to the adverse effects, chemical dependence and tolerance related to the current medicines, the search for new alternatives is necessary. In this context, the important Amazonian biodiversity provides sources of new therapeutic products, since many plants are used by the local population to treat their diseases, but few were scientifically studied. One of these species is Caryocar villosum, known as piquiá, which fruit oil is traditionally applied for the treatment of muscular pain and rheumatism. Scarce works report the pharmacological activities of piquiá oil in pain and inflammation, effects related to phenolic compounds. Therefore, the aim of this study was to evaluate the antioxidant, antinociceptive and anti-inflammatory activities of extracts obtained from other parts of piquiá. The scavenging activity of ABTS•+ and DPPH• radicals were evaluated in vitro. For the antinociceptive and anti-inflammatory activities in vivo, the tests of acetic acid-induced writhing, carrageenaninduced mechanical hyperalgesia, formalin and carrageenan-induced paw edema were performed. The locomotor activity was assessed by rota-rod test. The experiments carried out were approved by protocol of approval of the Ethics Committee nº 042/2016. The ethanolic extract of the Caryocar villosum fruit peels, EECv (peels), presented the lowest IC50 (5,33 µg/µL) against the DPPH• radical among all extracts. In addition, EECv (peels), given orally at dose of 300 mg/Kg, significantly inhibited the number of abdominal contortions, the paw licking time in the second phase of the formalin test and the mechanical hyperalgesia, when compared to the untreated group. The biological effect was reversed by prior administration of naloxone. EECv (peels) also significantly reduced the edema volume formed in the late phase, when compared to the untreated group. These pharmacological effects were attributed to the presence of phenolic compounds and flavonoids in the extract, as gallic and p-coumaroylquinic acids being the major substances. Therefore, it is suggested that EECv (peels) has antiinflammatory activity, by inhibition of prostaglandins synthesis, and peripheral antinociceptive activity with opioid pathway modulation. This attests the medicinal use of the Caryocar villosum fruit peels for the treatment of pain and inflammation, besides its oil, as well as the technological possibility to obtain a new phytomedicine.