Antibacterial Potential of Myristica fragrans (Nutmeg) Pericarp Extract Against Selected Bacterial Strains

Abstract

Background: Due to the increasing bacterial resistance to currently available antimicrobial agents, there is a necessity to find out alternative antibacterial drugs with different chemical compositions and modes of action. Plant extracts play a significant role as potential antibacterial agents that can be developed into antibacterial drugs. Myristica fragrans (Nutmeg) is such a plant which has been used in indigenous medicinal systems as a medication for wound healing and diarrhoea. Objectives: To investigate the in vitro antibacterial potential of M. fragrans pericarp which is a waste in spice production industry and to determine the Minimum Inhibitory Concentration (MIC) values and Minimum Bactericidal Concentration (MBC) values to determine whether the test extract is bactericidal or bacteriostatic. Methods: Ethanolic extract of M. fragrans dried pericarp was tested against two Gram negative bacterial strains and two Gram positive bacterial strains namely Staphylococcus aureus (ATCC 29213), Bacillus cereus (ATCC 21366), Escherichia coli (ATCC 25922) and Salmonella typhimurium (ATCC 39183), respectively using MTT (3-(4, 5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) assay. Chloramphenicol was used as the positive control. Mixture without the extract was used as the negative control. The mechanism of antibiosis of the test extract was determined using MBC/MIC ratio. Statistical analysis was done by using IBM SPSS 23.0 software. Results: All tested bacterial strains showed to be susceptible to ethanolic extract of M. fragrans pericarp extract. The obtained MIC values of S. aureus, B. cereus, E. coli and S. typhimurium are 550±27, 450±35, 425±34 and 375±23 mg/L, respectively. The MBCs are 1500±30, 1700±30, 1500±25 and 1700±30 mg/L. All strains were recognized as bacteriostatic. Conclusions: These preliminary results disclose the ethnobotanical significance of M. fragrans pericarp and its potential to be used in antibacterial drug development.