Baicalin promotes the bacteriostatic activity of lysozyme on S. aureus in mammary glands and neutrophilic granulocytes in mice

Abstract

Staphylococcus aureus causes mastitis as a result of community-acquired or nosocomial infections. Lysozyme (LYSO) is an enzyme that is upregulated in many organisms during the innate immune response against infection by bacterial pathogens. Baicalin is a bioactive flavonoid that can bind to enzymes, often to potentiate their effect. Here we tested the effects of baicalin on the activity of LYSO using the S. aureus mastitis mouse model and neutrophilic granulocyte model of S. aureus infection. In our experiments, S. aureus counts decreased with increasing baicalin concentration. Furthermore, qPCR and western blot analyses showed that LYSO expression was unaffected by baicalin, while fluorescence quenching and UV fluorescence spectral analyses showed that baicalin binds to LYSO. To test whether this binding increased LYSO activity, we assessed LYSO-induced bacteriostasis in the presence of baicalin. Our results showed that LYSO-induced S. aureus bacteriostasis increased with increasing concentrations of baicalin, and that baicalin binding to LYSO synergistically increased the antibacterial activity of LYSO. These results demonstrate that baicalin enhances LYSO-induced bacteriostasis during the innate immune response to S. aureus. They suggest baicalin is a potentially useful therapeutic agent for the treatment of bacterial infections.

Untitled

“…Baicalin is a flavone glucuronide with extensive pharmacological effects including antibacterial, [61] antiallergic, [62] and anti-inflammatory [63] effects. Despite all these pharmacological effects, its low aqueous solubility limited its clinical application.…”

Baicalin Liposome Alleviates Lipopolysaccharide-Induced Acute Lung Injury in Mice via Inhibiting TLR4/JNK/ERK/NF-κB Pathway

“…Baicalin (5,6-dihydroxy-7-O-glucuronide flavone, BA) is the main effective constituent isolated from the roots of the Chinese medical herb Scutellaria baicalensis Georgi, which is widely used in pneumonia, hepatitis, atherosclerosis [ 8 ], and other conditions. Recent studies have indicated that BA has many pharmacological activities, like anti-inflammation [ 9 ], antioxidative stress [ 10 ], neuroprotective [ 11 ], and antibacterial [ 12 ]. Increasing researches have showed that BA has a protective effect on ALI induced by LPS [ 13 ].…”

Dietary lysozyme supplement alters serum biochemical makers and milk metabolite profile of sows via gut microbiota

“…Lysozyme functions by cleaving the β-1,4-glycosidic bond between N-acetylmuramic acid and N-acetylglucosamine residues of the bacterial peptidoglycan, causing a loss of cellular membrane integrity and cell lysis [1, 10]. Lysozyme was reported to be more effective against gram-positive bacteria [16, 17, 18], and it may also indirectly affect several gram-negative bacterial species [12, 19]. Previous studies revealed that lysozyme promotes the beneficial microbe community and reduces detrimental microbes within gut microbial communities [11, 20].…”