Capsanthin-Loaded Micelles: Preparation, Characterization and in vitro Evaluation of Cytotoxicity Using MDA-MB-231 Breast Cancer Cell Line.

Research background: Breast cancer is one of the most common cancers and remains a major cause of morbidity and mortality among women worldwide. In developed countries, breast cancer as a multifactorial disease is a major health concern, and its incidence is constantly rising in low and middle-income countries. Numerous studies have demonstrated that phytochemicals such as carotenoids inhibit breast cancer growth and induce apoptosis. We recently enhanced the solubility of capsanthin in water by encapsulating it in diosgenin polyethylene glycol succinate, a novel non-ionic surfactant. Thus, this study aims to evaluate the cytotoxicity of water-soluble capsanthin-loaded micelles in MDA-MB-231 cells in vitro through tetrazolium dye MTT assay.

Experimental approach: In the current study, capsanthin, a hydrophobic carotenoid, is extracted from sweet red pepper (Capsicum annuum). Capsanthin-loaded diosgenin polyethylene glycol succinate 1000 (cap-DPGS-1000) micelles were prepared from capsanthin extract (cap) and diosgenin polyethylene glycol succinate 1000 (DPGS-1000) using the solid dispersion method. The capsanthin extract and cap-DPGS-1000 micelles were characterized by UV-visible spectroscopy, high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), particle size distribution, polydispersity, and scanning electron microscopy (SEM). The effects of capsanthin extract and cap-DPGS-1000 micelles on a human triple-negative breast cancer cell line (MDA-MB-231) were tested to check the cell viability, proliferation and cytotoxicity of the micelles.

Results and conclusions: The solubility of encapsulated cap-DPGS-1000 micelles in water is greatly enhanced and leads to an increased scope for localized drug delivery, a better delivery option for treating residual cancerous tumours. The encapsulated capsanthin showed a sustained release in simulated intestinal fluid (pH=6.8). Our research proposes a sustained drug delivery system that ensures effective and controlled release to the affected site. The characterization data revealed no change in the structure and functional groups in the encapsulated capsanthin. The IC₅₀ value of the cap-DPGS-1000 micelles against MDA-MB-231 breast cancer cells was (3.10±1.09) μg/mL, which is much lower than of capsanthin extract ((81.1±1.5) μg/mL). Capsanthin extract and capsanthin-loaded micelles are promising drug candidates to induce apoptosis and increase reactive oxygen species (ROS) in cancer cells.

Novelty and scientific contribution: The result shows the cytotoxic effect of capsanthin and capsanthin-loaded micelles on MDA-MB-231 cell line for the first time. Capsanthin from sweet red pepper (Capsicum annuum) showed remarkable cytotoxic effect on the triple-negative MDA-MB-231 cell line.