The Search for Anticarcinogenic Organoselenium Compounds from Natural Sources

ABSTRACT: Consumption of Se-enriched plants or yeast-based nutritional supplements is reported to reduce the risk of cancer. Separation and identification of natural organoselenium compounds in these plants is essential to understand the basis for their biological activity. Earlier work suggests that plants convert inorganic selenium in the soil or growth medium into organoselenium compounds, such as selenoamino acids, following a route similar to the sulfur assimilatory pathway. To separate and detect selenoamino acids in plant extracts, we employ ion pair LC with an inductively coupled plasma mass spectrometer (ICP-MS) detector and capillary GC with an atomic emission detector (AED), for underivatized and derivatized compounds, respectively. Volatile selenium compounds, such as those found in human garlic breath, have been analyzed using GC-AED. Results involving Se-enriched garlic and yeast-based nutritional supplements are presented.