Screening and detection of antimicrobials from Dai pharmaceuticals against clinical diseases by methicillin‐resistant Staphylococcus aureus

Oroxylum indicum is one of the valuable Dai pharmaceuticals; the dry seeds and bark of O. indicum were used to treat acute cough, sore throat and so on. Of the seven compounds from O. indicum were determined and obtained using the bioassay‐guided method. Among them, compound 7 was obtained from the plant for the first time. Eight bacterial strains and one yeast fungi were exposed to the compounds. Minimum inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) or minimum fungicidal concentrations were determined according to the standard broth microdilution method. Baicalein (2) exhibited relative strong antibacterial activities with MIC of 8 μg ml−1 and MBC of 16 μg ml−1 against three MRSA strains of Staphylococcus aureus of SCCmec III type, whereas flavonoids 3, 5 and 7 showed some degree of activities against methicillin‐susceptible S. aureus (MSSA, ATCC 25923). The findings may offer new evidence that why O. indicum was used widely in Dai peoples’ life. Significance and Impact of the Study: Oroxylum indicum is one of the valuable Dai pharmaceuticals. This is the first report of in vitro antibacterial activity of isolated flavonoids from O. indicum against clinical drug‐resistant isolates. Baicalein (2) exhibited relative strong antibacterial activities with MIC of 8 μg ml−1 and MBC of 16 μg ml−1 against three MRSA strains of Staphylococcus aureus of SCCmec III type. The findings may offer new evidence that why O. indicum was used widely in Dai peoples’ life.