Encapsulation of Nelumbo nucifera Leaf Extract in Chitosan for Improved Antioxidant and Anti-breast Cancer Activities Against MCF-7 Cell Lines Through PI3K/mTOR Inhibition

Abstract

The development of plant extracts as a phytomedicine is an emerging trend in the pharmaceutical industry. This study aimed to synthesize Nelumbo nucifera leaf extract (NL) into chitosan nanoparticles by ionic gelation using sodium trypolyphosphate as the cross-linking agent. The characteristic of Nelumbo nucifera leaf extract loaded into chitosan encapsulate (NLCE) was analyzed for encapsulation efficiency (UV-Vis), particle size and polydispersity (PSA), morphology (SEM), chemical interaction (FTIR), phytochemical profile (LC-HRMS), and thermal stability (DSC). In addition, the biological activity of NLCE was conducted using antioxidant and anti-breast cancer activity against MCF-7 cells. Subsequently, the NLCE formed spherical particles with a size range of 200-600 nm (median of 350 nm, PI of 1.07). The FTIR analysis illustrated the reaction between chitosan and TPP at 1,315 cm−1 as a stretching vibration of the P = O group, while LC-HRMS confirmed the presence of secondary metabolites, including erteberel, hyperoside, 5,7-dihydroxy-2-(2,3,4-trihydroxyphenyl)-4H-chromen-4-one, miquelianin, 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-4-oxo-4H-chromen-3-yl 6-O-β-D-xylopyranosyl-β-D-glucopyranoside, and senkyunolide B. NLCE also exhibited good stability under high temperature. Additionally, the NLCE demonstrated an antioxidant activity against DPPH and ABTS radicals dependent on concentration manner. The inhibitory concentration 50 (IC50) of NLCE showed better antioxidant properties than NL and chitosan. Similar to the antioxidant properties, the NLCE demonstrated cytotoxic and antiproliferation effects dependent on concentration manner against MCF-7 cells. The anti-breast cancer effect of NLCE was revealed by cell cycle arrest induction in G2/M phases, which promotes apoptosis of MCF-7 cells. As a mechanism, the NLCE promoted inhibition of PI3K and mTOR proteins, that known as regulators of cell cycle and apoptosis in cancer cells. Overall, these findings confirm the successful development of NLCE with enhanced physicochemical stability and potent biological activities. NLCE represents a promising phytomedicine value of chitosan-based nanoencapsulation to improve the bioactivity and therapeutic prospects of plant-derived compounds.