κ-Carrageenan folate nanoencapsulation of fucoidan from Sargassum plagiophyllum and anticancer activity enhancement

Fucoidan (F) is an anticancer potential natural compound extracted from the brown seaweed Sargassum plagiophyllum. However, poor solubility and lack of targeted delivery are major drawbacks in its therapeutic application. The aim of this study is to enhance the delivery and efficacy of fucoidan by encapsulating it using κ-carrageenan (C) and Carrageenan folate (Cf) as carrier matrices. The particle size of the resulting fucoidan-loaded nanocapsules with κ-Carrageenan (F-CNPs) and κ-Carrageenan folate (F-CfNPs), were 84.2±12.1nm and 93.2±10.7nm, respectively. Encapsulation Efficiency (EE) was high, with 92.34±0.58% for F-CNPs and 95.41± 0.06% for F-CfNPs, while the Loading amount (LA) were 46.17±0.29% and 47.70±0.03%, respectively. Anticancer activities of the nanocapsules against HeLa and MCF-7 cell lines were performed. The IC₅₀ values in F-CfNPs were significantly lower compared with F-CNPs, representing increased efficacy due to the addition of the targeting folate group. In HeLa cells, the IC₅₀ values were 33.13±4.53μg ml^-1 for F-CNPs, 21.14±3.59 μg ml^-1 for F-CfNPs, and 3.16±3.56 μg ml^-1 for doxorubicin. While, in MCF-7 cells, the IC₅₀ values were 30,56±3.86 μg ml^-1 for F-CNPs, 24.92±3.83μg ml^-1 for F-CfNPs, and 15.79±2.84μg ml^-1 for doxorubicin. These results clearly indicated that the fucoidan nanocapsules acted as a potent therapeutic against HeLa and MCF.7 cell lines. However, F-CfNPs showed higher efficiency among the fabricated NPs due to higher cellular uptake. This study toward the 14^th Sustainable Development Goals (SDG) by utilizing brown seaweed to enhance its economic value and aligns with the 3rd SDG goal of ensuring good health well-being through improvements in cancer treatment.