ABSTRACT
Objective:To explore effects of different extracts and monomers of <italic>Lepidium meyenii </italic>（Maca） on the proliferation of mouse splenic lymphocytes and induction of interleukin-2 （IL-2） and tumor necrosis factor-<italic>α</italic> （TNF-<italic>α</italic>） by observing their immunomodulatory effects. Method:An octadecylsilyl （ODS） column was used to enrich the methanol extract of <italic>L. meyenii</italic> in stages to obtain six fractions and three monomers. Different groups of extracts and monomers of <italic>L. meyenii </italic>at different doses were set up. Cell counting Kit-8 （CCK-8） was used to detect the effect on the proliferation of mitogen-free， concanavalin A （Con A）-induced， and lipopolysaccharides （LPS）-induced mouse splenic lymphocytes. Enzyme-linked immunosorbent assay （ELISA） was used to determine the levels of IL-2 and TNF-<italic>α</italic>. Result:<italic>L. meyenii </italic>extracts Fr<sub>3</sub> and Fr<sub>6</sub>， and monomers <italic>N</italic>-benzyl hexadecanamide and 1，2-dihydro-4-carboxaldehyde-3-benzyl-<italic>N</italic>-hydroxypyridine slightly promoted the proliferation of Con A-induced T lymphocytes and LPS-induced B lymphocytes （<italic>P</italic><0.01） as compared with the conditions in the model group. <italic>L. meyenii</italic> extracts and monomers significantly induced the secretion of IL-2 and TNF-<italic>α</italic> by splenic lymphocytes （<italic>P</italic><0.01）. Conclusion:<italic>L. meyenii</italic> extracts and monomers can achieve immunological enhancement by promoting the secretion of IL-2 and TNF-<italic>α</italic>， and facilitate the proliferation of splenic lymphocytes. The active components are presumedly macamides and pyridine alkaloids， and the specific mechanism still needs to be further explored.