can allium chemical chest be a source of anticancer compounds?

Allium plants, mainly represented by allium sativum (garlic) and allium cepa (onion), have been consumed by humans since prehistoric times. they were believed to heal various diseases. for this reason, many allium species have been investigated for their bioactivity, including anticancer effect. up to date, numerous volatile sulfur compounds, saponins, phenolic compounds and a few alkaloids have been discovered from several allium species; many of these compounds have been investigated in terms of their anticancer potential. despite of high number of investigations, only relatively small number of allium species, out of at least 750 species, could be targets of research activities. besides sulfur compounds, saponins represent a high portion of allium secondary metabolites. due to relatively high number of saponins, in order to facilitate the future research, they have been classified based on the subgenera of their owner species, thus pointing out which species in the given subgenera have not been evaluated yet. the classification also involves saponins found widely in the genus or specific to certain subgenus or species. anticancer studies carried out on allium species are rather diverse. besides in vitro investigations, epidemiological studies were the first ones providing hints of anticancer activities of garlic and onion. modern studies are focused on the understanding of mechanisms of actions.