Optimization, characterization, and biological activities of chitosan-tripolyphosphate microcapsules for the...

Polyphenol-rich extracts such as those from Lansium domesticum leaves possess antioxidant and cytotoxic properties but suffer from low stability and bioavailability, limiting their therapeutic potential. This study aimed to develop and optimize microcapsules using chitosan-sodium tripolyphosphate (CS-TPP) to enhance the stability and biological efficacy of L. domesticum leaf extract. A Box-Behnken design was employed to determine optimal concentrations of chitosan, TPP, and extract, resulting in an encapsulation efficiency of 81.45 %. Characterization using FTIR and DSC confirmed molecular interactions and improved thermal stability, while SEM analysis revealed spherical particles averaging 0.65 μm. In vitro release studies in simulated gastric and intestinal fluids showed sustained phenolic release, and storage at 4 °C preserved phenolic content more effectively than at 25 °C. The microcapsules exhibited strong antioxidant activity (DPPH, ABTS) and cytotoxic effects on MCF-7, T47D, and 4 T1 cells by inducing apoptosis at IC₅₀ levels. Acute oral toxicity testing in rats showed no adverse effects at doses up to 5000 mg/kg. Overall, this study addresses the formulation gap for stabilizing phenolic-rich plant extracts, demonstrating that CS-TPP microcapsules are safe, effective, and suitable for further development as nutraceutical or pharmaceutical agents.