Effects of lutein from marigold extract on immunity and growth of mammary tumors in mice.

The effects of dietary lutein from marigold extract on the development and growth of a transplantable murine mammary tumor and on lymphocyte function were investigated. Mice were fed a diet containing 0.1% or 0.4% of lutein. In experiment 1, mice were fed the diets for 3 weeks and infused with mammary tumor cells into the mammary gland. Dietary lutein increased tumor latency and inhibited mammary tumor growth in a dose-dependent manner. The incidence of palpable tumors on day 28 post-infusion and final tumor weight were lower in mice fed lutein. In experiment 2, dietary lutein enhanced phytohemagglutinin-induced lymphocyte proliferation but had no effect on interleukin-2 production or lymphocyte cytotoxicity. Therefore dietary lutein increased tumor latency, suppressed mammary tumor growth and enhanced lymphocyte proliferation.