Designing nanostructured lipid carriers modified with folate-conjugated chitosan for targeted delivery of osthole to HT-29 colon cancer cells: investigation of anticancer, antioxidant, and antibacterial activities

The present study proposed to design nanostructured lipid carriers (NLC) coated with chitosan (CS) conjugated folate (FA) for the targeted delivery of Osthole (OST) to the HT-29 colon cancer cell line and improve its anticancer capability. To assess the physicochemical characteristics of OST-loaded NLC decorated with CS-conjugated FA (OST-NCF-NPS), several techniques, including DLS, SEM, and FTIR, were applied. After determining the encapsulation efficiency of OST in CSFA-modified NLC-NPs, an MTT test was conducted to evaluate the cytotoxic effects of this nano platform on the HT-29 cancer cell line in comparison to normal HFF cells. Possible mechanisms of apoptosis in cancer cells treated with OST-NCF-NPs were examined using qPCR, flow cytometry, and AO/PI fluorescent staining methods. Moreover, the antioxidant capacity of these biosynthesized nanocarriers was determined using ABTS and DPPH methods, and their antibacterial potential was measured through disk diffusion, MIC, and MBC assays. According to the findings, OST-NCF-NPS had the ideal average size of 179.19 nm, low polydispersity (PI = 0.23), acceptable physical stability (ζ-potential = + 18.99 mV), and high entrapment efficiency (83.5%). The MTT data demonstrated the selective cytotoxicity of NPs toward cancerous cells compared to normal cells. Cell cycle and Annexin V/Propidium Iodide (AnV/PI) analysis indicated that OST-NCF-NPs increased the sub-G1 population and AnV/PI-positive cells. The occurrence of programmed cell death in the treated cells was also verified by altered expression of proapoptotic (BAX and caspase-3) and antiapoptotic (Bcl-2) genes. Furthermore, the NPs exhibited strong antibacterial activity, particularly against gram-negative bacteria, and high antioxidant effects in reducing ABTS and DPPH-free radicals.