Antioxidant, Antibacterial and Tyrosinase Inhibiting Activities of Extracts from Myristica fragrans Houtt
Suguna Paneerchelvan
School of Biosciences, Taylor’s University, No. 1, Jalan Taylor’s 47500 Subang Jaya, Malaysia
How- Yee Lai *
School of Biosciences, Taylor’s University, No. 1, Jalan Taylor’s 47500 Subang Jaya, Malaysia
Kasipathy Kailasapathy
School of Science and Health, University of Western Sydney, 3, Sir John Jamison Circuit, Glenmore Park, NSW 2745, Australia
*Author to whom correspondence should be addressed.
Abstract
Aims: To evaluate the antioxidant, antibacterial and tyrosinase inhibiting activities of the methanolic extracts of the leaf and fruit pericarp from Myristica fragrans.
Study Design: In vitro assays.
Place and Duration of Study: School of Biosciences, Taylor’s University (Jan – December 2013)
Methodology: Total phenolic content (TPC) was assessed using Folin-Ciocalteu’s method. The antioxidant activity was evaluated via radical scavenging against 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric ion reducing power (FRP) and ferrous ion chelating (FIC). Antibacterial activity was assessed using disc diffusion on four Gram-positve bacteria: M. luteus, E. faecalis, S. aureus, B. cereus and three Gram-negative bacteria: P. aeruginosa, E. coli and K. pneumoniae, followed by determination of minimum inhibitory concentration and minimum bactericidal concentration using broth dilution assays. Tyrosinase inhibiting activity was assessed using L-3,4-dihydroxyphenylalanine, L-DOPA as the substrate.
Results: The methanolic leaf extracts exhibited significantly higher TPC 2712-2779 mg gallic acidequivalent/100 g in contrast to that obtained from the pericarp. The leaf extracts also exhibited significantly stronger DPPH radical scavenging activity (2962-3787 mg ascorbic acid equivalent/100 g), ferric reducing activity (1383-1653 mg gallic acid equivalent/100 g) and chelating activity, as compared to the pericarp extracts. Leaf extracts were effective against all Gram-positve bacteria tested: M. luteus, E. faecalis, S. aureus, B. cereus (minimum inhibitory concentration 250-500 μg/mL; minimum bactericidal concentration 250-500 μg/mL). Studies on the tyrosinase inhibiting properties for applications in preventing food browning or treating hyperpigmentation disorders, showed significantly stronger activities exhibited by the leaf extracts (80-81%) as compared to that shown by pericarp (27-31%).
Conclusion: The present results suggest that nutmeg leaf could be employed as a natural antioxidant, antibacterial and tyrosinase inhibiting agent for applications in pharmaceuticals or in functional foods.
Keywords: Antibacterial, antioxidant, Myristica fragrans, nutmeg, phenolic, tyrosinase inhibition