Alkaloid fraction of Duguetia furfuracea demonstrated anti-inflammatory and antinociceptive effects through decrease of tumour necrosis factor alpha in mice models.

Duguetia furfuracea, popularly known as "araticum-seco," is traditionally used in folk medicine for the treatment of pain and inflammatory disorders. This study aimed to analyze the chemical composition and investigate the anti-inflammatory and antinociceptive activities of the alkaloid fraction obtained from the leaves of D. furfuracea (DfFAlk). The chemical composition of DfFAlk was characterized using ultra-fast liquid chromatography (UFLC) coupled with mass spectrometry (UFLC/ESI). In vivo anti-inflammatory activity was assessed using the carrageenan-induced paw oedema model. The effects of DfFAlk on polymorphonuclear leukocyte recruitment and tumor necrosis factor alpha (TNF-α) levels were also evaluated in mouse footpads. In addition, the antinociceptive effect was investigated using the abdominal writhing test, formalin test, and thermal hyperalgesia models, and motor and balance performance were assessed using the rota-rod test. Thirty-four alkaloids were annotated belonging to the aporphine, tetrahydroprotoberberine, benzyltetrahydroisoquinoline, tetrahydroisoquinoline, (bis)benzyltetrahydroisoquinoline, and proaporphine classes. Oral treatment with DfFAlk (100 and 300 mg/kg) significantly inhibited paw oedema, from 2 to 6 h post inflammatory stimulus. The alkaloid fraction (300 mg/kg) attenuated the tissue inflammatory infiltrate 4 and 6 h after carrageenan injection, and decreased TNF-α production, 4 h post carrageenan. The fraction (300 mg/kg) also significantly attenuated the acetic acid-induced writhing response and the formalin-induced licking in both phases. Furthermore, in the hot-plate model, the DfFAlk (300 mg/kg) increased the latency to response from 1 to 3 h after oral treatment. Additionally, DfFAlk-treated mice did not show any alteration of motor and balance performances. The data indicate that DfFAlk has anti-inflammatory and antinociceptive activities.