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 freeze‐dried 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.