Citrus wastewater as a source of value‐added products: Quali‐quantitative analysis and in vitro screening on breast cancer cell lines

Citrus wastewater from industries is a source of bioactive compounds whose recovery could be a useful approach to convert processing waste into potential resources to be exploited in food, pharmaceutical, and chemical companies. Citrus wastewater, obtained from the industrial processing of Citrus sinensis, was freezedried and qualitative/quantitative evaluated using HPLC/MS Q‐TOF analysis. Antiproliferative activity was investigated on MDA‐MB‐231 (triple‐negative breast cancer cell line), MCF‐7 (breast cancer cell line), and its multidrug‐resistant variant MCF‐7R. Fraction 8 emerged for its cytotoxicity toward MCF‐7R cells. Its main component, the polymethoxylated flavone nobiletin (80%), is likely involved in increasing the number of G1‐phase MCF‐7R cells without inducing cell death. Notably, fraction 8 sensitizes MCF7‐R cells to the antiproliferative effects of doxorubicin, thus contributing to overcoming MCF7‐R multidrug resistance. Our studies highlighted the possibility of applying a sustainable strategy for citrus wastewater recycling to recover functional compounds as useful adjuvants for the prevention and treatment of malignancies.