The role of plant processing for the cancer preventive potential of Ethiopian kale (Brassica carinata).
Background: Ethiopian kale (Brassica carinata) 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.Objective: This study aimed to determine the cancer preventive potential ofB. carinatausing a human liverin vitromodel focusing on processing effects on the pattern of secondary plant metabolites and bioactivity.Design:B. carinatawas 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 processedB. carinataleaves 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.Results: Pre-treatment withB. carinataextracts 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.Conclusion: Our findings highlight the cancer preventive potential ofB. carinataas indicated by the protection of human liver cells against aflatoxinin vitro. In general, consumption ofB. carinatashould be encouraged as part of chemopreventive measures to combat prevalence of aflatoxin-induced diseases.
Molecular Preventive Medicine, Institute for Prevention and Cancer Epidemiology, University of Freiburg - Medical Center , Freiburg im Breisgau , Germany.
Grace Akinyi
GA
Odongo
Molecular Preventive Medicine, Institute for Prevention and Cancer Epidemiology, University of Freiburg - Medical Center , Freiburg im Breisgau , Germany.
Nina
N
Schlotz
Molecular Preventive Medicine, Institute for Prevention and Cancer Epidemiology, University of Freiburg - Medical Center , Freiburg im Breisgau , Germany.
Corinna
C
Herz
Department of Plant Quality, Leibniz Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e. V ., Großbeeren , Germany.
Franziska S
FS
Hanschen
Department of Plant Quality, Leibniz Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e. V ., Großbeeren , Germany.
Susanne
S
Baldermann
Department of Plant Quality, Leibniz Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e. V ., Großbeeren , Germany.
Susanne
S
Neugart
Department of Safety and Quality of Fruits and Vegetables , Max Rubner-Institut , Karlsruhe , Germany.
Bernhard
B
Trierweiler
Department of Safety and Quality of Fruits and Vegetables , Max Rubner-Institut , Karlsruhe , Germany.
Lara
L
Frommherz
Department of Microbiology and Biotechnology, Max Rubner-Institut , Karlsruhe , Germany.
Charles M A P
CM
Franz
Department of Plant Quality, Leibniz Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e. V ., Großbeeren , Germany.
Benard
B
Ngwene
Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg , Hamburg , Germany.
Abraham Wahid
AW
Luvonga
Department of Plant Quality, Leibniz Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e. V ., Großbeeren , Germany.
Monika
M
Schreiner
Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg , Hamburg , Germany.
Sascha
S
Rohn
Molecular Preventive Medicine, Institute for Prevention and Cancer Epidemiology, University of Freiburg - Medical Center , Freiburg im Breisgau , Germany.
Evelyn
E
Lamy
Aflatoxin B1; African leafy vegetables; Brassicaceae; anti-genotoxicity; cancer chemoprevention; glucosinolates; polyphenols; secondary plant metabolites