Comparative Study of Antibacterial Activity and Preliminary Phytochemical Screening of Leaves and Seeds of Myristica fragrans

Abstract

Myristica fragrans belongs to the family Myristicaceae (English: Nutmeg). In traditional medicine, leaves and seeds are the ingredients of Parankikilangu choornam, Periyapatpam and Vellaruku patpam. The aim of this study was to determine the antibacterial activity and Minimum Inhibitory Concentration (MIC) of decoction and methanolic extracts of leaf and seed of M. fragrans against Staphylococcus aureus NCTC 6571, five Methicilline resistant S aureus (MRSA) strains, Pseudomonas aeruginosa NCTC - 10662 and Escherichia coli NCTC -10418. Leaves and seeds used to prepare the decoction and methanolic extracts. These were chemically tested qualitatively for the presence of functional groups of compounds. Screening for antibacterial activity was done using the cut well diffusion method and MIC determined using the agar dilution method. In the cut well method, the decoction and methanolic extract of leaf of M. fragrans showed inhibitory activity against S aureus NCTC 6571 and all five MRSA strains. The diameter of the zone of inhibition produced by the decoction (16.0 ± 0.0 mm - 18.6±0.5 mm) and methanolic extract (18.0 ± 0.0 mm - 19.0±0.0 mm) are almost equal. The decoction of leaf of M. fragrans was inhibitory to S aureus NCTC 6571 and the five MRSA strains up to a dilution of 1/10. The methanolic extract of seed showed activity against S aureus NCTC 6571 and the five MRSA strains (17.0 ± 0.0 mm - 17.5±0.4 mm). The MIC of methanolic extract of leaf and seed were 1.0 mg/ml and 5 mg/ml for S aureus and all tested MRSA strains. The leaf of M. fragrans contains flavonoid, terpenoid, steroids, alkaloids and tannin and seed contains of terpenoid, alkaloid and cardiac glycosides. Both decoction and methanolic extract of leaf and seed of M. fragrans inhibits the growth of methicillin sensitive as well as methicillin resistant S aureus. The leaves of this plant demonstrated higher activity compared with the seed.