Naringin from Citrus maxima peel: a potential therapeutic agent for breast cancer via PKM2 inhibition

Abstract Introduction An extensive array of medicinal plants has undergone investigation, underscoring the imperative for the continued screening of natural inhibitors with the potential to target cancer metabolism. The current research endeavor was directed toward evaluating the chemotherapeutic efficacy of peel extracts of Citrus maxima and its constituent flavonoid, Naringin (NA), in the context of breast cancer, specifically targeting the pyruvate kinase isozyme M2 (PKM2). Materials and methods Extracts from the peel of Citrus maxima were prepared and analyzed using liquid chromatography–mass spectrometry (LC–MS) to detect the presence of the bioactive compound, NA. The potential anti-proliferative effects of these peel extracts of Citrus maxima and NA were examined against human breast cancer cell lines utilizing an MTT assay. To investigate the distribution of the cell cycle, cell cycle analysis was conducted. The induction of apoptosis was ascertained using Annexin V-FITC through flow cytometry. The protein expression of PKM2 was analyzed using Western blotting. Molecular docking and dynamics simulations analysis were employed. Results Liquid chromatography–mass spectrometry (LC–MS) analysis confirmed the existence of NA within the extracts of Citrus maxima. Both the crude extracts and NA demonstrated a dose-dependent inhibition of breast cancer cell proliferation. Our findings indicate that these crude extracts and NA instigate both early and late apoptosis, in addition to causing cell cycle arrest in the G2/M phase. Immunoblotting studies further revealed that the expression of PKM2 protein was suppressed by both the crude extracts and NA. Computational analysis demonstrated stable binding affinity with Ser77, His78, and Lys207 of PKM2. Conclusion This investigation unveils the presence of NA within Citrus maxima extracts, exhibiting robust affinity for PKM2 via molecular docking and dynamics simulations. Extracts and NA dose-dependently inhibit breast cancer cell proliferation. Notably, PKM2 regulates cancer cell glycolysis, promising intricate therapeutic prospects for breast cancer.