Ultrasound-assisted combined with natural deep eutectic solvents for Platycodon grandiflorum polysaccharides extraction: Process optimization and evaluation of anti-lung cancer activity.

Platycodon grandiflorum (PG) is a traditional medicinal herb with a history of >2000 years, exhibiting various biological activities. However, its anti-lung cancer potential remains largely unexplored. This study aimed to extract Platycodon grandiflorum polysaccharides (PGP) using an environmentally friendly natural deep eutectic solvent (NADES) system and evaluate their anti-lung cancer activity. An NADES system composed of choline chloride and oxalic acid (1:3 M ratio) was selected based on carbohydrate yield. The extraction conditions were optimized using Box-Behnken design (BBD). The structural characterization of PGP was performed using ultraviolet spectroscopy, fourier transform infrared (FT-IR) spectroscopy, and high-performance liquid chromatography (HPLC), revealing that PGP are glucans with a molecular weight of 7.036 kDa and a glucose content of 92.8 %. Biological assays demonstrated that PGP promoted ferroptosis in H1299 cells through mitochondrial dysfunction, lipid peroxidation (LPO), and overproduction of reactive oxygen species (ROS). Also, PGP inhibited cell migration by modulating epithelial-mesenchymal transition(EMT)-related protein expression. These findings provide novel insights into the pharmacological basis of PG and support its potential application in lung cancer therapy.