Immunomodulatory effects of sucupira (Pterodon pubescens) seed infusion on collagen-induced arthritis

To evaluate the clinical and immunomodulatory efficacy of seed extracts from sucupira branca (Pterodon pubescens Benth.), a Brazilian anti-inflammatory folk medicine, against collagen II (CII)-induced arthritis (CIA) in mice.

Mice were divided into 3 groups: 1) normal control mice received a vehicle (ethanol 15% in water); 2) mice with CIA received the vehicle; and 3) mice with CIA received extract from 1 mg sucupira seeds/day. The daily oral treatments started 21 days after the first collagen immunization, ending 4 weeks later. We analyzed the arthritic index, the histopathology of the joints, the serum anti-CII IgG antibody level, and the absolute counts of the CD4+, CD8+, CD4+CD69+ and CD8+CD69+ subsets of inguinal lymph nodes (LN).

Sucupira treatment strongly reduced the severity of arthritis (p < 0.001). Vehicle-treated CIA mice exhibited invasive synovial pannus and significant articular leukocyte infiltration, features that were reduced or absent in sucupira-treated mice. Mice with CIA exhibited twice the number of CD4+ and CD8+ LN cells found in control mice. Suctupira-treated mice exhibited these subsets in numbers comparable to the latter. A two-thirds decrease in the level of serum anti-CII IgG antibody and a normalization of the CD4+CD69+ LN cell number in treated mice hallmark a negative regulatory effect of sucupira on B- and CD4 T-cell activation, respectively. The CD8+CD69+ cell number remained roughly the same in the 3 groups.

The clinical and immunomodulatory effects of sucupira on CIA provides a further experimental basis for the popular use of sucupira in chronic inflammatory diseases.