Sanchen powder extract combined with vancomycin against methicillin-resistant Staphylococcus aureus

Abstract

Objective: To explore the effects of the extract of Sanchen powder (ESCP) combined with vancomycin on methicillin-resistant Staphylococcus aureus (MRSA) planktonic cells, biofilms, and virulence factors. Methods: The herbs in Sanchen powder (SCP) were extracted separately with 50% ethanol. Then, the content of hydroxysafflower yellow A (HSYA) and cholic acid in the extract of artificial cattle bezoar (artificial Calculus bovis) and safflower (Carthamus tinctorius L.) was measured by ultraviolet visible-vis spectrophotometry and high-performance liquid chromatography. The effects of ESCP combined with vancomycin on MRSA by observing its biofilm viability were assessed using a 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium5-carboxanilide reduction assay and scanning electron microscopy. Additionally, enzyme activity was measured by plasma coagulase test and DNase test. Results: The cholic acid content of the artificial C. bovis extract was 7.34 (0.81) mg/g, and the HSYA content of the C. tinctorius extract was 9.18 (0.09) mg/g. The minimal inhibitory concentrations of ESCP and vancomycin were 25.6 mg/mL and 2 μg/mL. The minimum bactericidal concentration of ESCP was 51.2 mg/mL. ESCP combined with vancomycin could inhibit the expression of coagulase and bacteria in mature biofilms. Neither ESCP nor vancomycin had a significant effect on DNase. Conclusion: This study is the first to show that ESCP combined with vancomycin inhibits coagulase and MRSA embedded in mature biofilms and that it represents a promising treatment for MRSA infection.

Keywords

• Tibetan medicine
• Sanchen powder
• Vancomycin
• Methicillin-resistant Staphylococcus aureus
• Antibacterial effect
• Traditional Chinese medicine