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

Abstract

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.

Evaluation of the Antioxidant, Cytotoxicity, Antibacterial, Anti-Motility, and Anti-Biofilm Effects of Myrothamnus flabellifolius Welw. Leaves and Stem Defatted Subfractions

“…The treated cultures of all the test bacteria exhibited phenotypic growth that was generally different from the control culture in two main ways: (1) the lag phase of bacterial growth was lengthened and/or (2) the growth rate of the planktonic culture was decreased resulting in a lower final absorbance value ( Figure 3 ). Similar bacterial growth-kinetic curve responses were previously reported by Jung et al [ 47 ], in which Caesalpinia sappan L. extracts lengthened the lag phase of methicillin-resistant S. aureus by 2 h before the culture reached the exponential phase. Moreover, a crude extract of Adiantum philippense was reported to have extended the lag phase of E. coli , S. aureus , P. aeruginosa , and S. flexneri [ 48 ].…”

Assessment of the phytochemical composition and antimicrobial properties of Tapinanthus bangwensis leaves hosted by the branches of Persea americana

“…3). However, the observed MLC values were higher than the MLC values of other medicinal plants reported in literature [25][26][27][28].The authors did not come across…”

Ulcer‐healing effects of jumihaidokuto extract in a mouse model of methicillin‐resistant Staphylococcus aureus causing skin infection

“…There are few traditional Chinese and Kampo medicines that are effective in healing wounds, and research is ongoing in assessing the effectiveness of hangeshashinto, hochuekkito, rokumigan, and shiunko [17][18][19][20]; however, to the best of our knowledge, JHT has not been recognized yet as having wound healing effect.…”

“…Furthermore, since the ulcer‐improving effect is almost the same as the contributing effect of PS, PR, and GL, another mechanism of action for PR and GL to improve mortality other than ulcer healing would be expected. It is possible that a direct anti‐bacterial effect of PR and GL may be involved [17]. However, at present, this point has been unresolved and further studies are needed.…”