Liquiritigenin prevents Staphylococcus aureus-mediated lung cell injury via inhibiting the production of α-hemolysin.

Staphylococcus aureus is a significant Gram-positive bacterium that is associated with a broad spectrum of diseases ranging from minor skin infections to lethal pneumonia, endocarditis, and toxinoses. α-Hemolysin is one of the most important exotoxins that contribute to the pathogenesis of S. aureus infections. Liquiritigenin is one of the most significant active components in licorice. In this study, hemolysis, western blot, and real-time reverse transcription-PCR assays were performed to investigate the impact of liquiritigenin on the production of S. aureus α-hemolysin. The results showed that low concentrations of liquiritigenin remarkably decreased S. aureus α-hemolysin production in a dose-dependent manner. Using live/dead cell staining and lactate dehydrogenase assays, we found that liquiritigenin could protect human lung cells (A549) from α-hemolysin-mediated injury. The data indicated that this compound could potentially be useful in developing drugs aiming at staphylococcal α-hemolysin.

Leber's hereditary optic neuropathy companied with multiple-related diseases.

Objective: To elucidate the clinical, radiologic characteristics of Leber's hereditary optic neuropathy (LHON) associated with the other diseases. Materials and methods: Clinical data were retrospectively collected from hospitalized patients with LHON associated with the other diseases at the Neuro-Ophthalmology Department at the Chinese People's Liberation Army General Hospital (PLAGH) from December 2014 to October 2018. Results: A total of 13 patients, 24 eyes (10 men and 3 women; mean age, 30.69 ± 12.76 years) with LHON mitochondrial DNA (mtDNA) mutations, were included in the cohort. 14502(5)11778(4)11778 &11696(1)12811(1)11696(1)3460(1). One patient was positive for aquaporin-4 antibody (AQP4-Ab), and two were positive for myelin oligodendrocyte glycoprotein antibody (MOG-Ab). Three patients were associated with idiopathic optic neuritis (ON). Two patients were with compression optic neuropathy. Three patients were with the central nervous system (CNS) diseases. One patient was with proliferative diabetic retinopathy (PDR) and one with idiopathic orbital inflammatory syndrome (IOIS). At the onset, visual acuity (VA) in eighteen eyes was below 0.1, one eye was 0.5, five eyes were above 0.5, while VA in sixteen eyes was below a 0.1 outcome, three eyes experienced moderate vision loss. MRI images showed T2 lesions and enhancement in nine patients who received corticosteroids treatment; additional immune modulators treatment was performed on two patients. None of the patients had relapse during the follow-up time. Conclusion: Leber's hereditary optic neuropathy can be accompanied with multiple-related diseases, especially different subtypes of ON, which were also exhibited with IOIS and compression optic neuropathy for the first time in this cohort. This condition may be a distinct entity with an unusual clinical and therapeutic profile.

Peppermint oil decreases the production of virulence-associated exoproteins by Staphylococcus aureus.

The present study aimed to evaluate the antimicrobial activity of peppermint oil against Staphylococcus aureus, and further investigate the influence of peppermint oil on S. aureus virulence-related exoprotein production. The data show that peppermint oil, which contained high contents of menthone, isomenthone, neomenthol, menthol, and menthyl acetate, was active against S. aureus with minimal inhibitory concentrations (MICs) ranging from 64-256 µg/mL, and the production of S. aureus exotoxins was decreased by subinhibitory concentrations of peppermint oil in a dose-dependent manner. The findings suggest that peppermint oil may potentially be used to aid in the treatment of S. aureus infections.

Allicin reduces the production of α-toxin by Staphylococcus aureus.

Staphylococcus aureus causes a broad range of life-threatening diseases in humans. The pathogenicity of this micro-organism is largely dependent upon its virulence factors. One of the most extensively studied virulence factors is the extracellular protein α-toxin. In this study, we show that allicin, an organosulfur compound, was active against S. aureus with MICs ranged from 32 to 64 µg/mL. Haemolysis, Western blot and real-time RT-PCR assays were used to evaluate the effects of allicin on S. aureus α-toxin production and on the levels of gene expression, respectively. The results of our study indicated that sub-inhibitory concentrations of allicin decreased the production of α-toxin in both methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) in a dose-dependent manner. Furthermore, the transcriptional levels of agr (accessory gene regulator) in S. aureus were inhibited by allicin. Therefore, allicin may be useful in the treatment of α-toxin-producing S. aureus infections.

Glycyrrhetinic acid protects mice from Staphylococcus aureus pneumonia.

In the present study, the antimicrobial activity of glycyrrhetinic acid (GA) against Staphylococcus aureus, and its influence on the production of S. aureus alpha-haemolysin (Hla) were investigated, along with the in vivo activity of GA against S. aureus-induced pneumonia. GA could not inhibit the growth of S. aureus, but the secretion of Hla by S. aureus was significantly inhibited by low concentrations of GA in a dose-dependent manner. Furthermore, in vivo data show that GA provides protection against staphylococcal pneumonia in a murine model system.