PLGA-based polymeric nanoparticle delivery of a bioactive Houttuynia cordata extract: modulation of anticancer and antibacterial responses.

PLGA-based encapsulation of bioactive plant extracts offers a strategy for improving their formulation characteristics and potentially modulating their biological responses. In this study, the medicinal plant Houttuynia cordata Thunb. (HC) was investigated through fraction-guided screening and nanoparticle delivery. Sequential solvent fractions were evaluated against HepG2 hepatocellular carcinoma cells using neutral red uptake and apoptosis assays. The most active acetone fraction (AceHCE) exhibited pronounced cytotoxicity and induced ∼64.5% apoptosis. AceHCE was encapsulated into poly(lactic-co-glycolic acid) (PLGA) polymeric nanoparticles (PNPs) stabilised with poloxamer 188. The optimised PNPs (∼91 nm) showed a narrow size distribution, negative surface charge, high entrapment efficiency (∼89%), and favourable physical stability. The nanoformulation exhibited a higher apparent IC50 (∼157 µg mL-1 based on total PNP concentration), corresponding to an AceHCE-equivalent concentration of approximately 28.3 µg mL-1. The optimised PNPs also exhibited antibacterial activity, with MIC values of 20 mg mL-1 against Staphylococcus aureus and Vibrio cholerae.