In vivo immunomodulatory effect of Tilia x viridis extracts on normal lymphocyte proliferation: a direct and an indirect action

The flowers of Tilia species have been used in Europe for many years to treat colds, bronchitis, fever, inflammations and influenza. It is well known that lymphocytes play a role in acquired immunity related to pathogens and tumor cells attachment. The aim of this study was to determine the effect of an aqueous (AE) and a dichloromethane extract (DM) from Tilia x viridis which is widely used and distributed in Argentina, on normal murine lymphocyte proliferation after being administered to mice. Both extracts presented a stimulatory effect on normal murine lymphocyte proliferation. The effect exerted by DM was principally related to macrophage activation, meanwhile AE exerted an important direct effect on lymphocytes related to the rutin presence. The stimulating effect, exerted on normal lymphocytes was due to a protective effect of apoptosis and also to cell IL2 production.

"In vivo" murine macrophages activation by a dichloromethane extract of Tilia x viridis

Macrophages are involved in the host defense against infectious pathogens and tumors. Tilia species have been used in folk medicine for the treatment of infectious diseases, previously it was demonstrated that a dichloromethane (DM) extract possess antiproliferative action "in vitro" on a lymphoma cell line. The aim of this work was to study the "in vivo" effect of DM extract upon mice peritoneal macrophages. DM extract-activated macrophages phagocytosis through hydrogen peroxide (H(2)O(2)) and nitric oxide (NO) production (phagocytosis (%): basal 16.93 +/- 0.18, DM extract 25.93 +/- 2.8; H(2)O(2) (M): basal 0.0022 +/- 0.00016, DM extract 0.0036 +/- 0.0005; NO (mM): basal 0.0052 +/- 0.0007, DM extract 0.0099 +/- 0.0004). These actions were mediated by cell superoxide dismutase activation. On the other hand, DM extract decreased tumor necrosis factor alpha but increased interleukin-10 in serum. These results suggest that the modulation activity exerted by the extract on immune system cells could be an important mechanism to acquire resistance to tumors and infectious diseases.