Antibacterial and anti-inflammatory properties of Santalum spicatum (R.Br.) A.DC. and Santalum album L. essential oils: activity against clinical isolates, modulation of ROS production in keratinocytes, and inhibition of eicosanoid pathway enzymes.

ETHNOPHARMACOLOGICAL RELEVANCE: Products derived from Santalum species have been valued for centuries in religious practices and traditional Chinese and Indian medicine for treating various conditions, including inflammatory and skin disorders. AIM OF THE STUDY: This study investigated the impact of two essential oils, S. album L. and S. spicatum (R.Br.) A.DC. on bacterial isolates obtained from skin samples, as well as their impact on mammalian cells and enzymes involved in the eicosanoid cascade. MATERIALS AND METHODS: Chemical composition was analyzed by GC-MS. Antibacterial activity against clinical isolates was assessed by broth microdilution to determine minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC). Cytotoxicity in HaCaT and HFF-1 cells was evaluated using the MTT and ROS assays. Inhibition of 5-lipoxygenase (5-LOX), cyclooxygenase (COX), and phospholipase A2 (PLA2) was also determined. RESULTS: α-Santalol and β-santalol were identified in both essential oils, with higher relative abundance in S. album. Both oils were active against Gram-positive isolates, with MIC values of 15.625-62.5 μg mL-1 and MBC values of 31.25-125 μg mL-1, showing bactericidal activity. No evident cytotoxicity and inhibition of ROS was observed below 500 μg mL-1. Both oils inhibited 5-LOX (S. album, 82.29 ± 8.85 μg mL-1; S. spicatum, 121.33 ± 52.03 μg mL-1) and PLA2 (100.12 ± 41.36 and 114.21 ± 17.25 μg mL-1, respectively), while S. spicatum also showed COX inhibitory activity. CONCLUSIONS: These findings demonstrate in vitro antibacterial activity against Gram-positive clinical isolates and modulation of eicosanoid-related enzymes, supporting further investigation of the biological relevance of both essential oils in inflammatory processes.