Effects of oral administration of Pfaffia paniculata (Brazilian ginseng) on incidence of spontaneous leukemia in AKR/J mice.

Pfaffia paniculata (Brazilian ginseng) administered subcutaneously and intraperitoneally inhibits growth of allogeneic cancer cells in mice. The goal of this study was to determine whether oral administration of P. paniculata inhibits development of spontaneous leukemia. Four-week-old female AKR/J mice were given oral doses of powdered roots from P. paniculata three times weekly for 8 weeks; controls received phosphate-buffered saline. Enlargement of thymic lymphoma in the mice treated with P. paniculata was significantly suppressed, as compared with controls (128 +/- 67.3 mg versus 219.9 +/- 84.2 mg, respectively; P < .01); proliferation of endogenous recombinant murine leukemia viruses (MuLV) in the thymus was markedly inhibited after the first oral treatment as compared with untreated controls (final age, 28 weeks; P < .05). In normal 3-week-old female AKR/J mice, mortality from thymic lymphoma was delayed markedly after injection into the thymus of cell-free extract of thymus from the experimental female 28-week-old AKR/J mice that received the oral P. paniculata preparation. These results suggest that the agent's suppressive effects on spontaneously occurring leukemia caused by endogenous recombinant MuLV in female AKR/J mice may depend on enhancement of nonspecific immune or cellular immune systems (or both) by the P. paniculata preparation.