Inhaling Odor-Active Compounds of <i>Osmanthus fragrans</i> Var. <i>aurantiacus</i> Suppresses Inflammation-Related Transcriptomic Signatures in LPS-Exposed SD Rat Brains: Applications of GC–MS–O and RNA Sequencing

This study investigated the effects of nasal inhalation of <i>Osmanthus fragrans</i> var. <i>aurantiacus</i> (OFA) extract in lipopolysaccharide (LPS)-challenged rats. Electronic nose analysis of the OFA extracts identified 25 volatile organic compounds. Gas chromatography-mass spectrometry-olfactometry (GC-MS-O) analysis revealed that <i>β</i>-ionone, linalool, and related derivatives are the primary odor-active compounds in the OFA extract. LPS exposure increased pro-inflammatory markers like tumor necrosis factor-alpha, caused organ hypertrophy in the liver, lungs, and spleen, and altered transcriptional profiles linked to nuclear factor-kappa B (NF-<i>κ</i>Β) and immune pathways. RNA sequencing of brain tissues showed that while LPS strongly elevated NF-<i>κ</i>Β and cytokine pathways, this effect was less pronounced in OFA-treated rats, indicating reduced LPS-driven inflammation at the transcriptome level. Overall, these findings highlight the potential of OFA extract, abundant in <i>β</i>-ionone and linalool, to mitigate inflammatory signaling and improve select metabolic markers in an LPS-induced inflammatory model.