In Vitro Synergistic Inhibitory Effects of Plant Extract Combinations on Bacterial Growth of Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common pathogens of healthcare-associated infections. Medicinal plants have long been used in the traditional treatment of diseases or syndromes worldwide. Combined use of plant extracts could improve the effectiveness of pharmacological action by obtaining synergism, acting on multiple targets simultaneously, reducing the doses of individual components, and minimizing side effects. We aimed to investigate the synergistic inhibitory effects of selected medicinal plants (Caesalpinia sappan L. (CS), Glycyrrhiza uralensis Fisch. (GU), Sanguisorba officinalis L. (SO), and Uncaria gambir Roxb. (UG)) on the bacterial growth of MRSA and its clinical isolates. SO and UG extracts generated the best synergistic interaction as adjudged by checkerboard synergy assays. MICs of the individual extracts decreased 4-fold from 250 to 62.5 µg/mL, respectively. The SO + UG combination was further evaluated for its effects on bacterial growth inhibition, minimum bactericidal/inhibitory concentration (MBC/MIC) ratio, and time-kill kinetics. The results indicate that the SO + UG combination synergistically inhibited the bacterial growth of MRSA strains with bactericidal effects. SO + UG combination also exhibited more potent effects against clinical isolates. In multistep resistance selection experiments, both standard and isolates of MRSA showed no resistance to the SO + UG combination even after repeated exposure over fourteen passages. Our data suggest that using plant extract combinations could be a potential strategy to treat MRSA infections.

Inhibitory Effects of Selected Medicinal Plants on Bacterial Growth of Methicillin-Resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious threat to global public health due to its capacity of tolerate conventional antibiotics. Medicinal plants are traditionally used to treat infectious diseases caused by bacterial pathogens. In the present study, 16 medicinal plants were screened for antibacterial activities to preselect more effective species. Ethanol extracts of selected medicinal plants (Caesalpinia sappan L., Glycyrrhiza uralensis Fisch., Sanguisorba officinalis L., and Uncaria gambir Roxb) were partitioned successively with different solvents (n-hexane, chloroform, ethyl acetate, 1-butanol, and water). Disc diffusion assay and broth microdilution were performed to evaluate the antibacterial activities of plant extracts and fractions against Staphylococcus aureus strains. Furthermore, the cytotoxicity of the extracts and fractions was determined against the human hepatoma (HepG2) and human lung carcinoma (A549) cell lines using a trypan blue exclusion method. A few extracts and fractions showed significant inhibitory effects on the bacterial growth of all tested strains, including multidrug-resistance (MDR) clinical isolates. The ethyl acetate fraction of C. sappan had the most potent effects with minimum inhibitory/bactericidal concentrations (MIC/MBC) of 31.2/62.5 µg/mL and showed low cytotoxicity with over 90% cell viability in both cells. Our results suggest that medicinal plants have considerable potential as alternatives to conventional antibiotics.

Distribution of the Trp64Arg polymorphism in the ß 3-adrenergic receptor gene in athletes and its influence on cardiovascular function.

BACKGROUND: The Trp64Arg polymorphism in the beta3-adrenergic receptor (beta3-AR) gene was extensively studied concerning the relationship with cardiovascular (CV) diseases, but few studies addressed this issue in athletes. AIM: To examine the relationship between the Trp64Arg polymorphism in the beta3-AR gene and several CV functions such as cardiac structure and function or blood biochemical parameters in Korean male controls and athletes. METHODS: We recruited a total of 114 study subjects, including 81 male athletes (8 long distance runners, 17 soccer, 8 baseball, 10 basketball, 8 volleyball, 8 ice hockey, 8 judo, 6 taekwondo and 8 gymnastics) and 33 controls. Two dimensional echocardiography was performed in order to assess the cardiac structure and function and blood biochemical parameters were measured. Genotyping of Trp64Arg polymorphism in the beta3-AR gene was also performed by the SNaPshot method. RESULTS: The genotype and allele distribution of Trp64Arg polymorphism in the beta3-AR gene were significantly different among each sporting discipline, showing the highest Arg allele frequency in volleyball and gymnastics (p < 0.05). Also, this polymorphism was significantly associated with serum HDL-cholesterol and glucose level in athletes only (p < 0.05). CONCLUSIONS: Our data showed the significant associations between the Trp64Arg polymorphism in the beta3-AR gene and some CV parameters such as serum HDL-cholesterol and glucose levels in athletes. However, further studies of the precise mechanism behind these associations are needed.