Extracts from the leaves of Campomanesia velutina inhibits production of LPS/INF-γ induced inflammatory mediators in J774A.1 cells and exerts anti-inflammatory and antinociceptive effects in vivo

Campomanesia velutina (Cambess) O. Berg, Myrtaceae, popularly known as "gabiroba" or "guavira", is used in traditional Brazilian medicine to treat several diseases, including inflammation and rheumatism. Extraction and isolation from leaves of the plant afforded the active compound myricetin 3-O-rhamnoside, also known as myricitrin. The ethanolic extract of leaves of C. velutina and its ethyl acetate and methanolic fractions were evaluated in inflammation (carrageenan-induced paw oedema) and analgesic models (acetic acid-induced abdominal writhing and hot plate test). Moreover, the ethanolic extract, its fractions and the isolated compound were also in vitro evaluated for their ability to modulate NO, TNF-α and IL-10 production from J774A.1 macrophages stimulated by LPS/IFN-γ. In vivo assays showed remarkable anti-inflammatory activity of ethanolic extract, ethyl acetate and methanolic fractions. The antinociceptive activity of ethanolic extract and A was demonstrated in acetic acid-induced abdominal writhing test. In vitro assays demonstrated that ethyl acetate and methanolic fractions fraction and myricitrin inhibited NO production from macrophages J774A.1. Also Myricitrin induced production of IL-10 anti-inflammatory cytokine. None of the samples was able to inhibited TNF-α production. The results demonstrated for the first time the anti-inflammatory and antinociceptive activity of C. velutina. .

Antigenic extracts of Leishmania braziliensis and Leishmania amazonensis associated with saponin partially protects BALB/c mice against Leishmania chagasi infection by suppressing IL-10 and IL-4 production

This study evaluated two vaccine candidates for their effectiveness in protecting BALB/c mice against Leishmania chagasiinfection. These immunogenic preparations were composed of Leishmania amazonensisor Leishmania braziliensisantigenic extracts in association with saponin adjuvant. Mice were given three subcutaneous doses of one of these vaccine candidates weekly for three weeks and four weeks later challenged with promastigotes of L. chagasiby intravenous injection. We observed that both vaccine candidates induced a significant reduction in the parasite load of the liver, while the L. amazonensisantigenic extract also stimulated a reduction in spleen parasite load. This protection was associated with a suppression of both interleukin (IL)-10 and IL-4 cytokines by spleen cells in response to L. chagasiantigen. No change was detected in the production of IFN-γ. Our data show that these immunogenic preparations reduce the type 2 immune response leading to the control of parasite replication.

Role of immune complexes from patients with different clinical forms of Schistosomiasis in the modulation of in vitro granuloma reaction

Schistosomiasis is a disease whose pathology is strongly related to the granulomatous reaction formed around parasite eggs trapped in host tissues. Studies have shown that the chronic intestinal form (INT) of the infection is associated with a variety of immunoregulatory mechanisms which lead to a diminished granulomatous reaction. Using an in vitro model of granuloma reaction, we show that immune complexes (IC) isolated from sera of INT patients are able to reduce granulomatous reaction developed by peripheral blood mononuclear cells (PBMC) from acute (AC), INT and hepatosplenic (HE) patients to soluble egg antigen (SEA)-conjugated polyacrylamide beads (PB-SEA). This inhibitory activity is also observed in cell proliferation assay of PBMC from INT and HE patients stimulated with SEA and adult worm antigen (SWAP). Furthermore, IC isolated from sera of patients with different clinical forms of the disease are also able to suppress INT patients PBMC reactivity. Therefore, our results show that circulating IC present in sera of patients with different clinical forms of schistosomiasis may down-regulate PBMC reactivity to parasite antigens resulting in a diminished granuloma reaction to parasite eggs.