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Cynara scolymus is a plant used both as food as well as medicinal plant worldwide. Cynarin is one of the main active principles of the plant, and it is also present in species such as Echinacea purpurae, which is known to have immunomodulatory activity. Thus, the objective of this study is to evaluate the immune effects of C. scolymus in rats. Rats were treated with 1.0-, 2.0-, or 4.0-g/kg body weight of C. scolymus extract for 28 days. Haemogram, serum biochemistry, lymphoid organs weight, and their cell phenotypes were evaluated. Macrophages and neutrophils oxidative burst, specific humoral immune response, and the delayed-type hypersensitivity (DTH) were studied. No changes in the haemogram, biochemical profile, antibody titers, lymphoid organs, and in their cellularities were observed. An increase in the basal activity of reactive oxygen species from male's macrophage was observed. There was a suppression of the DTH response in both gender when treated with the highest dose of C. scolymus. This study is the first in the literature that revealed an immunosuppressive effect of C. scolymus. We also verified that the doses of artichoke extract here employed did not cause general toxicity. [ABSTRACT FROM AUTHOR]

Pteridium aquilinum (bracken fern) is one of the most common plants. Epidemiological studies have revealed a higher risk of certain types of cancers (i.e., esophageal, gastric) in people who consume bracken fern directly (as crosiers or rhizomes) or indirectly through the consumption of milk from livestock that fed on the plant. In animals, evidence exists regarding the associations between chronic bracken fern intoxication, papilloma virus infection, and the development of carcinomas. While it is possible that some carcinogens in bracken fern could be responsible for these cancers in both humans and animals, it is equally plausible that the observed increases in cancers could be related to induction of an overall immunosuppression by the plant/its various constituents. Under the latter scenario, normal tumor surveillance responses against nascent (non-bracken-induced) cancers or responses against viral infections (specifically those linked to induction of cancers) might be adversely impacted by continuous dietary exposure to this plant. Therefore, the overall objective of this study was to evaluate the immunomodulatory effects of bracken fern following daily ingestion of its extract by a murine host over a period of 14 (or up to 30) days. In C57BL/6 mice administered (by gavage) the extract, histological analyses revealed a significant reduction in splenic white pulp area. Among a variety of immune response parameters/functions assessed in these hosts and isolated cells, both delayed-type hypersensitivity (DTH) analysis and evaluation of IFNγ production by NK cells during TH1 priming were also reduced. Lastly, the innate response in these hosts—assessed by analysis of NK cell cytotoxic functionality—was also diminished. The results here clearly showed the immunosuppressive effects of P. aquilinum and that many of the functions that were modulated could contribute to the increased risk of cancer formation in exposed hosts. [ABSTRACT FROM AUTHOR]