Antimicrobial effect and resistant regulation ofGlycyrrhiza uralensison methicillin-resistantStaphylococcus aureus

Abstract

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.

18β-Glycyrrhetinic Acid Inhibits Methicillin-Resistant Staphylococcus aureus Survival and Attenuates Virulence Gene Expression

“…1A). These data in part support previously published work showing the bactericidal effects of various crude fractions of licorice root extracts-such as hexane-fractionated licorice root or acetone extraction (18,(23)(24)(25). However, these data are in contrast to a recently published study showing no antibacterial effect of GRA against various strains of S. aureus (29).…”

“…This correlated with data obtained from the growth curves, demonstrating no visible growth of bacteria at 62.5 g/ml GRA. These results are congruent with previously published results on the antibacterial effects of crude licorice extracts (18,(23)(24)(25). GRA reduces severity of MRSA skin infection.…”

“…Previous studies have shown the effects of various licorice extracts on MRSA gene expression in vitro, including changes in genes such as mecA and hla (18,29). To determine if GA or GRA had any influence on virulence factor expression, we incubated USA300 with a sublethal dose of GRA or GA (52.5 g/ml) and measured transcript abundance of key S. aureus virulence factors saeR, hla, RNAIII, sbi, and mecA 1 h postexposure.…”

“…Additionally, licorice flavonoids were shown to increase the susceptibility of MRSA strains to oxacillin, a ␤-lactam antibiotic (17). A crude chloroform fraction of licorice root decreased the expression of the methicillin resistance genes mecA, mecI, and mecRI (18). However, no clear mode of action has been defined for any of these effects.…”

Antibacterial Activities of Fermented Sayuksan Ingredient Extracts for Multidrug-resistant Strains

“…현대과학의 발전에도 불구하고 많은 사람들이 한의학에 관 심을 표명하고 있으며, 일부 한약제제의 경우 급성이 아닌 만 성질환의 경우에 효과를 인정받고 있다. 오래전부터 지속적 으로 이용되어 온 한약재들은 기본적으로 인체 안전성을 가 지고 있고, 본질적으로 인체에 유용한 생리활성 유효성분이 있을 것으로 기대되기 때문에 한약재와 같은 천연 약물의 이 용에 관심을 두고 있다 [14][15][16][17]. 본 연구에서는 methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE)와 최근 증가하고 있는 다제내성균인 multi drug-resistant Pseudomonas aeruginosa와 multi drug-resistant Acinetobacter baumannii에 대한 항생물질 개발을 목표로 하여 감초, 지실, 시호 와 백작약 추출물의 유산균 발효를 통한 새로운 천연 항생제 로서의 개발 가능성의 기초 자료로 활용하고자 감초, 지실, 시호와 백작약 추출물의 발효 전후의 항균활성 및 항산화활 성을 비교하고자 한다.…”