Controlled Release of Curcumin via Folic Acid Conjugated Magnetic Drug Delivery System

Curcumin loaded β-cyclodextrin-magnetic graphene oxide nanoparticles decorated with folic acid receptors as a new theranostic agent to improve prostate cancer treatment

This article presents a novel approach to treating prostate cancer using a nanocarrier composed of folic acid (FA), β-cyclodextrin (β-CD), and magnetic graphene oxide (MGO) as a theranostic agent. The carrier is designed to improve the solubility and bioavailability of curcumin, a potential therapeutic substance against prostate cancer. Folic acid receptors overexpressed on the surface of solid tumors, including prostate cancer, may facilitate targeted drug delivery to tumor cells while avoiding nonspecific effects on healthy tissues. The anticancer efficacy of Folic acid-curcumin@β-CD-MGO in vitro was also examined on LNCaP (an androgen-dependent) and PC3 (an androgen-independent) prostate cancer cells. The relaxivity of nanoparticles in MRI images was also investigated as a diagnostic factor. The results showed a concentration-dependent inhibitory effect on cell proliferation, induction of oxidative damage, and apoptotic effects. Also, nanoparticle relaxometry shows that this agent can be used as a negative contrast agent in MRI images. Overall, this study represents a promising theranostic agent to improve the delivery and trace of curcumin and enhance its therapeutic potential in the treatment of prostate cancer.

The Concept of Folic Acid in Health and Disease

Folates have a pterine core structure and high metabolic activity due to their ability to accept electrons and react with O-, S-, N-, C-bounds. Folates play a role as cofactors in essential one-carbon pathways donating methyl-groups to choline phospholipids, creatine, epinephrine, DNA. Compounds similar to folates are ubiquitous and have been found in different animals, plants, and microorganisms. Folates enter the body from the diet and are also synthesized by intestinal bacteria with consequent adsorption from the colon. Three types of folate and antifolate cellular transporters have been found, differing in tissue localization, substrate affinity, type of transferring, and optimal pH for function. Laboratory criteria of folate deficiency are accepted by WHO. Severe folate deficiencies, manifesting in early life, are seen in hereditary folate malabsorption and cerebral folate deficiency. Acquired folate deficiency is quite common and is associated with poor diet and malabsorption, alcohol consumption, obesity, and kidney failure. Given the observational data that folates have a protective effect against neural tube defects, ischemic events, and cancer, food folic acid fortification was introduced in many countries. However, high physiological folate concentrations and folate overload may increase the risk of impaired brain development in embryogenesis and possess a growth advantage for precancerous altered cells.

An enzyme-mediated controlled release system for curcumin based on cyclodextrin/cyclodextrin degrading enzyme

In this study, an enzyme-triggered system based on β-cyclodextrin (β-CD) has been developed to achieve controlled release of hydrophobic drugs in the presence of maltogenic amylase (MAase). The inclusion complex formation of curcumin (CUR), as a model anticancer compound, with β-CD was characterized by fluorescence and Fourier transform infrared (FTIR) spectroscopy. CUR was loaded into β-CD with an encapsulation efficiency of approximately 30 %. The in vitro profiles of CUR release from β-CD showed that 100 % of the drug was released after one hour incubation in the presence of MAase with cyclodextrin degrading activity. Fluorescence microscopy images indicate a significantly greater cellular uptake of CUR using β-CD-CUR/MAase system compared to β-CD-CUR inclusion complex without MAase. The β-CD-CUR/MAase system exhibited lower IC₅₀ values and greater anti-proliferative effects in comparison with free CUR and β-CD-CUR in MCF-7 and Huh-7 cancer cells. The results from fluorescence microscopy and flow cytometric assay using the acridine orange/ethidium bromide and Annexin V-PE/7-AAD staining suggest that the β-CD-CUR/MAase system exhibited higher cytotoxic and apoptotic effects on cancer cells compared to other formulations. This triggered release of CUR in the presence of MAase is owing to the β-CD degradation by MAase resulting ring opening and chain scission in β-CD. We demonstrate that this enzyme-mediated controlled release system has a potential application for controlled release of poorly water-soluble drugs or hydrophobic compounds such as CUR.