The Antibacterial Effect of Urena Lobata L. Fromv Guangxi on Mice with Staphylococcus Aureus Pneumonia

BACKGROUND Alcohol extract from the root of Urena lobata L. (ULL) had broad spectrum antimicrobial activity. Studies in vitro have sho that ULL aqueous extract has antibacterial effect on S. aureusis, and the combination therapy of the ULL aqueous extract with cefazolin sodium showed additive effect. MATERIALS AND METHODS The mice underwent nasal inhalation with S. aureus, a subset of mice were intra-gastric gavage with ULL and/or intravenous injection cefazolin sodium twice daily. After being exposed to S. aureus for 5 days, 10 days and 14 days respectively, the white blood cells count (WBC), neutrophils absolute value (NEU) and the neutrophil percentage (NEU%) in peripheral blood, as well as the levels of serum immunoglobulin (Ig) G and IgM were determined using commercial kits. The colony count of S. aureus, the levels of interleukin (IL) -6 and IL-10 of mice lung tissue were detected, and the pathological changes of lung tissue were examined using H & E staining. RESULTS ULL significantly protected against S. aureus pneumonia, as evidenced by the remarkable decrease in the rate of S. aureus colony count/lung weight, WBC, NEU and NEU% in peripheral blood, as well as the attenuation of lung histopathological damage. Additionally, ULL+cefazolin could have markedly reduced the rate of S. aureus colony count/lung weight when compared with cefazolin. Furthermore, ULL and ULL+cefazolin both could significantly decrease the serum levels of IgG and IgM, and the levels of IL-6, IL-10 in mice lung tissue. CONCLUSION This study first demonstrated that ULL may have potential use as a therapeutic agent for S. aureus pneumonia, and the roles of IgG, IgM, IL-6 and IL-10 in ULL protection against S. aureus pneumonia remain to be further studied.