Effects of Clausena lansium leaves volatile oil emulsion against Staphylococcus aureus in mice via autophagy modulation.

BACKGROUND

Volatile oil from fresh Clausena lansium (Lour.) Skeels (Rutaceae) (common name Wampee) has been previously extracted by our group from fresh C. lansium leaf and its components were qualitative and quantitatively analyzed by GC-MS. It altered the cell membrane permeability of Staphylococcus aureus and reduced the levels of inflammation factors. However, previous in vivo reports on the anti-inflammatory and the antibacterial properties against S. aureus are scarce.

HYPOTHESIS/PURPOSE

To evaluate the protective in vivo effects of Wampee leaves volatile oil emulsion (WVOE) against S. aureus-induced pneumonia and elucidate the underlying mechanisms of action.

METHODS

Wild-type and nucleotide oligomerization domain-like receptor protein 3 (NLRP3)-deficient mice were used. Mice were treated with WVOE for 7 days, and subjected to S. aureus infection by nasal administration on day 5 for 48 h. Lung and blood samples were collected for assessing lung damage and protein abundance. Lung bacterial load, wet/dry ratio, C-reactive protein (CRP) levels, inflammatory cytokines secretion, and lung histopathological injury were examined.

RESULTS

WVOE effectively reduced lung bacterial load, wet/dry ratio, and CRP levels increased following S. aureus infection in mice. WVOE decreased the secretion of inflammatory cytokines (IL-6 and TNF-α) and lung histopathological injury, and suppressed the NF-κB pathway and NLRP3 inflammasome activation. NLRP3

CONCLUSION

WVOE regulated the PI3K/AKT/mTOR pathway and enhanced autophagy, with NLRP3 playing a crucial role. WVOE exhibited protective effects against S. aureus-induced pneumonia by inhibiting NLRP3 inflammasome activation and enhancing autophagy. These findings expand the understanding of antibacterial properties of WVOE, and provide novel insights into the therapeutic potential of WVOE in managing S. aureus infections.

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Déclaration de conflit d'intérêts

Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Yong-Ming He reports financial support was provided by Department of Agriculture and Rural Affairs of Guangdong Province .