In vitro evaluation of the anticancer activity of Citrus unshiu markovich extract and its nanoparticles in HeLa cells

Introduction Citrus unshiu Markovich (CUM) is a Korean traditional medicine with proven therapeutic activities for various diseases. However, the major constraint associated with it is its poor solubility and bioavailability, thus requiring high dosages for cancer treatment. This study aimed to evaluate the anticancer activities of CUM peel extract. Methods An extract of CUM fruit skin peel was prepared and then subjected to analysis for total phenolic and flavonoid compounds and antioxidant activity. In silico bioactivity prediction analysis was performed using various bioinformatic tools. The CUM nanoparticles (NPs) was synthesized, and their anticancer activity against HeLa cancer cells was evaluated. The regulatory pathway investigation and protein-protein network associations were also carried out. Results The total phenolic and flavonoid contents were found to be 53.93 mg/g eq. of GAE and 7.96 μg/g, respectively. Citrus unshiu Markovich (CUM) peel extract exhibited the highest radical scavenging activities; with 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ABTS were found to be 99.96% and 98.60%, respectively. The ferric reducing antioxidant power (FRAP) assay yielded a value of 335.08 + 4.88 µmol FeSO 4 /L. Field-emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) revealed the CUM NPs were well dispersed and uniform, with an average diameter of 40–60 nm. Additionally, the Fourier-transform infrared spectroscopy Fourier transform infrared (FTIR) spectrum of CUM NPs showed strong peaks at 3,545, 2,938, 2,917, and 3,283 cm −1 attributed to different phenolic compounds. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay demonstrated that CUM NPs induced cytotoxicity against HeLa cells at an effective concentration of 30 μg/mL. Fluorescence-activated cell sorting (FACS) analysis revealed an apoptotic cell death of 54.4% in CUM NPs treated cells, compared with 16.5% in cells treated with free CUM. Furthermore, quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis of candidate gene expression demonstrated significant (p < 0.05) downregulation of interleukin-6 (IL-6), B-cell lymphoma 2 (Bcl-2), and matrix metalloproteinase-9 (MMP-9), and the genes Caspase-9, Bcl-2- associated X protein (Bax), and tumor protein p53 revealed significant (p < 0.05) upregulation in CUM NPs treated cells as compared to control groups. Discussion Phytochemical and antioxidant properties of CUM peel extract and its nano-formulated particles were demonstrating promising in-vitro anticancer activity against HeLa cervical cancer cells. These findings highlight the potential of CUM NPs as a promising nanotechnology-based approach for further exploration in cancer research and provide a foundation for further investigate their therapeutic applications.