Antibacterial activity of ellagic acid-rich pomegranate rind extracts

Pomegranate fruit peel extracts have recently attracted interest because of their potential use as natural food preservatives and nutraceuticals. Antibacterial activities of standardized ellagic acid-rich pomegranate rind extracts were therefore studied in vitro. The extracts were prepared and standardized to contain 13% w/w ellagic acid by previously described methods [1]. The antibacterial activity of the ellagic acid-rich pomegranate rind extracts was evaluated against Staphylococcus aureus, S. epidermidis, Propionibacterium acnes, Salmonella typhimurium, S. typhi, Shigella sonnei and Escherichia coli using the disc diffusion and broth microdilution methods [2]. The extracts exhibited potent bacteriostatic effect against Gram-positive facultative anaerobic bacteria, S. aureus and S. epidermidis, with the same MIC values of 7.8µg/ml, and P. acnes, a Gram-positive anaerobe, with an MIC value of 15.6µg/ml. However, the extract was not active against any of the four Gram negative bacteria studied. The results from this study support the potential use of the standardized ellagic acid-rich pomegranate rind extracts as nutraceuticals for antibacterial proposes, especially against acne involved bacteria. However, the use of the extract as natural preservatives is not recommended due to its narrow spectrum antibacterial activity.

Acknowledgements: 1. National Research Council of Thailand 2. Prince of Songkla University

References: 1. Panichayupakaranant, P. et al. (2010) Pharm. Biol. 48: 201–205.

2. NCCLS (2008) NCCLS document M100-S9. National Committee for Clinical Laboratory Standard. Wayne.