Formulation of Gamma-Oryzanol Encapsulated Nanoparticles and Their Modulation Effects on Inducible Nitric Oxide Synthase and Nitric Oxide in LPS-Stimulated RAW 264.7 Macrophages

Background/Objectives: Gamma-oryzanol (ORZ), a bioactive compound extracted from rice bran oil, has health-promoting properties but limited therapeutic use due to poor stability and bioavailability. This study aimed to synthesize gamma-oryzanol-encapsulated nanoparticles (ORZ-NPs) and investigate their anti-inflammatory effects in lipopolysaccharide-stimulated RAW 264.7 macrophages. Methods: ORZ-NPs were synthesized via nanoprecipitation and characterized by dynamic light scattering and transmission electron microscopy. ORZ content was assessed using high performance liquid chromatography. In vitro release was determined using a dialysis method. Inducible nitric oxide synthase (iNOS) was assessed by Western blotting, nitric oxide (NO) by Griess assay, and tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) by enzyme-linked immunosorbent assay. Results: ORZ-NPs exhibited spherical morphology with a mean particle size of 93.320 ± 2.027 nm, polydispersity index 0.149 ± 0.025, and zeta potential -22.400 ± 0.252 mV. ORZ remained stable for 90 days. In vitro release reached 70% at 24 h in PBS (pH 7.4). At 50 μg mL^-1, ORZ-NPs significantly decreased iNOS and NO production (approximately 65% of control, p < 0.01), without affecting TNF-α or IL-6. Conclusions: ORZ-NPs demonstrate selective anti-inflammatory activities by suppressing iNOS and NO production while pro-inflammatory cytokines remain unaffected. These findings suggest a partial modulatory effect on the inflammatory signaling pathway.