Document Type : Research article
Departamento de Farmacia, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional (ENCB-IPN), Mexico City, 07738, México.
Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, 07360, Mexico.
Eysenhardtia polystachya is widely used in folk medicine as an anti-rheumatic and analgesic
agent, but no systematic study of its effects on several markers associated with rheumatoid
arthritis and its ethnomedical use as analgesic agent has been performed. We evaluated the
anti-arthritic and antinociceptive properties of an ethanolic extract of E. polystachya (EE) bark
and its rich-flavonoids fractions in murine models. The EE was administered orally at doses of
25, 50, 100, and 200 mg/kg/day, and its fractions at 25 mg/kg/day in all animal models. Antiarthritic
activity was evaluated using a complete Freund´s adjuvant (CFA)-induced rheumatoid
arthritis model in rats. The severity of arthritis was evaluated by changes in paw oedema,
body weight, arthritic index, radiological scores, histological assessment of synovial joints,
erythrocyte sedimentation rate, haematocrit, haemoglobin, serum rheumatoid factor, serum
C-reactive protein and serum levels of the pro-inflammatory cytokines IL-1β, IL-6, TNF-α,
IL-18, IFN-γ, GM-CSF, and anti-inflammatory cytokines IL-4, IL-10, IL-13. Antinociceptive
activity was evaluated using an acetic acid-induced abdominal contraction test and a hot-plate
test in mice. EE and its rich-flavonoids fractions inhibited secondary inflammatory reactions,
diminished the specific histopathological alterations in the joint capsule and reduced the serum
concentrations of the pro-inflammatory cytokines IL-6, TNF-α, and GM-CSF in arthritic rats.
EE also reduced the number of writhes produced by acetic acid and increased the response time
on the hot plate for mice. Our findings support the use of Eysenhardtia polystachya bark for the
treatment of rheumatoid arthritis and pain management.