Potential of Nutmeg (<em>Myristica fragrans</em> Houtt) Leaf Extracts as a Source of Functional Ingredients with Antibacterial, Antifungal and Antioxidant Activities

Abstract

Purpose: The objectives of this study were to evaluate inhibition activities of acetone, chloroform, ethanol and hot water extracts of nutmeg (Myristica fragrans Houtt.) leaves against Salmonella enterica, Listeria monocytogenes, Shigella dysenteriae, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Aspergillus niger and, to assess the in vitro antioxidant activities and to discover the active compound profile of chloroform extract of nutmeg leaf. Research Method: Agar well diffusion and agar disc diffusion methods were used to evaluate the antibacterial activity and the antifungal activity of the extracts respectively. Antioxidant activities of the acetone extract were evaluated through DPPH, FRAP, ABTS+ radical scavenging and Ferrous Iron Chelating assays. The total phenolic content (TPC) of the acetone extract was determined using the Folin-Ciocalteu assay. Findings: All the extracts showed inhibitory activity for the tested bacteria at different intensities and it was found that the selection of the extraction solvent is important to get the maximum inhibition against different bacterium. Acetone and chloroform extract (20%) showed the highest inhibition against A. niger (49.42% and 51.52% respectively). Acetone extract showed strong antioxidant activities, 715.78 ±51.09 in FRAP (mg of Trolox /g of leaves), 65.56±0.93 in DPPH (mg of Ascorbic acid /g of leaves), 31.67± 0.49 in ABTS+ (mg of Trolox equivalent/g of leaves), 10.87±1.85 in Ferrous Ion chelating (mg of EDTA/g of leaves) and, higher percentages of total phenolic content of 895.12 ±44.24 TPC (mg GAE /g of leaves). Myristic acid was detected as the major compound (57.36%) in GC-MS analysis and that may be the major compound responsible that offers a great potential to use as antibacterial, antifungal and antioxidant agent of nutmeg leaf. Originality/ Value: Results revealed that the nutmeg leaf possesses marked biological activities and showed a great potential to use for the management of human pathogenic bacteria, plant pathogenic fungi, and oxidative stress-associated chronic diseases.