Cytokine profile and natural killer cell activity in Listeria monocytogenes infected mice treated orally with Petiveria alliacea extract.

In this work, we investigated the effects of Petiveria alliacea extract on the production of Th1-type and Th2-type cytokines and on NK cells activity in normal and Listeria monocytogenes infected mice. Our results demonstrated that in normal/non-infected mice P. alliacea administration led to increased levels of Interleukin-2 (IL-2). The infection alone enhanced INF-gamma levels and NK cell activity at 48 and 72 hours of infection. The treatment with five consecutive doses of 1000 mg/kg/day of P. alliacea extract, given previously to infection, led to further increases in IL-2 levels, in relation to normal/non-infected/P. alliacea treated controls, and in INF-gamma levels at 72 h of infection, compared to infected mice. On the other hand, the production of IL-4 and IL-10 were not altered either by the infection or by the treatment with P. alliacea extract. NK cells activity increased at 48 h and 72 h following the inoculation of the bacteria. When mice were treated with P. alliacea previously to infection, NK activity was higher than that observed at 48 h, 72 h and 120 h of infection in the infected animal. Based on these findings we suggest that P. alliacea up-regulates anti-bacterial immune response by enhancing both Th1 function and the activity of NK cells.

Petiveria alliacea L. extract protects mice against Listeria monocytogenes infection--effects on bone marrow progenitor cells.

In this study we have investigated the effects of Petiveria alliacea on the hematopoietic response of mice infected with Listeria monocytogenes. Our results demonstrate a protective effect of the crude extract of P. alliacea since the survival of the treated/infected was higher than that in the infected group. Moreover, the number of granulocyte/macrophage colonies (CFU-GM) and the serum colony stimulating activity levels were increased in the treated/infected mice in relation to the infected group. These results suggest an immunomodulation of Petiveria alliacea extract on hematopoiesis, which may be responsible, at least in part, for the increased resistance of mice to Listeria monocytogenes infection.