The role of plant processing for the cancer preventive potential of Ethiopian kale ().

: Ethiopian kale () is a horticulturally important crop used as leafy vegetable in large parts of East and Southern Africa. The leaves are reported to contain high concentrations of health-promoting secondary plant metabolites. However, scientific knowledge on their health benefits is scarce. : This study aimed to determine the cancer preventive potential of using a human liver model focusing on processing effects on the pattern of secondary plant metabolites and bioactivity. : was cultivated under controlled conditions and differentially processed (raw, fermented, or cooked) after harvesting. Human liver cancer cells (HepG2) were treated with ethanolic extracts of raw or processed leaves and analyzed for their anti-genotoxic, anti-oxidant, and cytostatic potential. Chemical analyses were carried out on glucosinolates including breakdown products, phenolic compounds, carotenoids, and chlorophyll content. : Pre-treatment with extracts concentration dependently reduced aflatoxin-induced DNA damage in the Comet assay, reduced the production of reactive oxygen species as determined by electron paramagnetic resonance spectroscopy, and induced Nrf2-mediated gene expression. Increasing extract concentrations also promoted cytostasis. Processing had a significant effect on the content of secondary plant metabolites. However, different processing methodologies did not dramatically decrease bioactivity, but enhanced the protective effect in some of the endpoints studied. : Our findings highlight the cancer preventive potential of as indicated by the protection of human liver cells against aflatoxin . In general, consumption of should be encouraged as part of chemopreventive measures to combat prevalence of aflatoxin-induced diseases.