Antimicrobial effect and resistant regulation of Glycyrrhiza uralensis on methicillin-resistant Staphylococcus aureus.

In the present study, we investigated antimicrobial activity of Glycyrrhiza uralensis against various strains of methicillin-resistant Staphylococcus aureus (MRSA) (KCCM 11812, 40510, 40512). Glycyrrhiza uralensis was extracted by 80% MeOH and fractionated by organic solutions. The extract and fractions showed antimicrobial activity against standard S. aureus as well as MRSA. In the minimum inhibitory concentration test, G. uralensis showed 0.25 mg mL(-1) in hexane fraction and 0.10-0.12 mg mL(-1) in chloroform fraction. Especially, chloroform fraction showed 2.5 times higher antimicrobial activity than penicillin. Furthermore, chloroform fraction correlated with MRSA gene expression (MecA, MecI, MecRI, FemA). These results suggest that G. uralensis may have potent antimicrobial activity and thus, this medicinal herb can be a suitable phytotherapeutic agent for treating MRSA infections.

Effect of Saliva miltiorrhiza bunge on antimicrobial activity and resistant gene regulation against methicillin-resistant Staphylococcus aureus (MRSA).

This study was conducted in an effort to evaluate the antimicrobial activity and antibiotic-resistant gene regulation from Saliva miltiorrhiza Bunge on methicillin-resistant Staphylococcus aureus (MRSA). A variety of solvent fractions and methanol extracts of S. miltiorrhiza Bunge were tested in order to determine its antimicrobial activities against S. aureus and MRSA. As a result, the hexane fraction of S. miltiorrhiza Bunge evidenced the highest levels of antimicrobial activity against S. aureus and MRSA. The MICs of the hexane fraction against various MRSA specimens were 64