vitro antibacterial activity of three Indian spices against methicillin-resistan staphylococcus aureus

ABSTRACT

To explore the in vitro antibacterial activity of ethanolic extracts of cinnamon [Cinnamomum zeylanicum; CIN], clove [Syzygium aromaticum, CLV] and cumin [Cuminum cyminum, CMN] against clinical isolates of methicillin resistant Staphylococcus aureus [MRSA], from Kolkata, India. The CIN, CLV and CMN were tested for their antibacterial activity against MRSA by in vitro methods. Minimum inhibitory concentration [MIC] values of the three extracts were determined, and time-kill studies were performed in order to investigate the bactericidal activity of the extracts [at the MIC level] for the isolates. The killing efficacy of the extracts was determined at various concentrations. The zone diameter of inhibition [ZDI] obtained due to CIN, CLV and CMN ranged between 22-27 mm, 19-23 mm and 9-15 mm, respectively; while the MICs, for the isolates, were in the range of 64-256, 64-512 and 128-512 microg/ml, respectively. When tested for their MIC levels; the CIN and CLV were found to be bactericidal after 6 hrs of incubation, while CMN showed bactericidal activity after 24 hrs. However, when tested at various concentrations; CIN, CLV and CMN displayed bactericidal activity against S. aureus, after 24 hrs of incubation, at 200, 200 and 300 microg/ml, respectively. The C. zeylanicum and S. aromaticum showed the strongest in vitro antibacterial activity followed by C. cyminum against MRSA, and such findings could be considered a valuable support in the treatment of infection and may contribute to the development of potential antimicrobial agents for inclusion in anti- S. aureus regimens