The main objective of this study was the testing of natural compounds, such as Polygonum cuspidatum (PgnC) loaded into nanostructured lipid carriers (NLC), which can act as a "double-edged sword" aimed at simultaneously combating dangerous free radicals and inhibiting pro-inflammatory cytokines. Resveratrol-rich PgnC extract was paired with another phytochemical, Diosgenin (DSG), in NLC. The lipid nanocarriers carrying both herbals (NLC-DSG-PgnC) had spherical diameters (100 ± 2 50 nm), a polydispersity index of ~0.15, and electrokinetic potentials greater than -46.5 mV. Entrapment efficiencies of 65% for PgnC and 87% for DSG were determined by chromatographic and UV-Vis spectroscopy assays. Cell cytotoxicity analysis proved that 50 µg/mL of NLC-PgnC and dual-NLC ensured a biocompatible effect like the untreated cells. The dual-NLC assured a much slower in vitro release of DSG and PgnC (67% PgnC and 48% DSG) than the individual-NLC (78% PgnC and 47% DSG) after 4 h of experiments. NLC encapsulating PgnC presented a superior ability to capture cationic radicals: 74.5 and 77.9%. The chemiluminescence results pointed out the non-involvement of DSG in stopping oxygenated free radicals, while the antioxidant activity was maintained at a level higher than 97% for dual-NLC. NLC-DSG-PgnC ensured a promising capacity for inhibition of pro-inflammatory cytokine IL-6, ranging from 91.9 to 94.9%.
Keywords: free radical species; lipid delivery systems; long-live cationic radicals; phytochemical active principle; pro-inflammatory cytokines inhibition.