Antibacterial, anti-inflammatory and anti-allergic activities of standardised pomegranate rind extract

Antibacterial, anti-inflammatory and anti-allergic activities of standardised pomegranate rind extract (SPRE) containing 13% w/w ellagic acid were studied in vitro. The antibacterial activity of SPRE was determined using the disc diffusion and broth microdilution methods. SPRE exhibited a potent bacteriostatic effect against Propionibacterium acnes, a Gram-positive anaerobe, with a MIC of 15.6 μg/ml, and Gram-positive facultative anaerobic bacteria, Staphylococcus aureus and Staphylococcus epidermidis, with MICs of 7.8–15.6 μg/ml. Anti-inflammatory activity of SPRE was evaluated by measuring the inhibition of nitric oxide (NO) production by murine macrophage-like RAW264.7 cells. SPRE exhibited a potent NO inhibitory effect, with an IC50 of 10.7 μg/ml. Evaluation of the anti-allergic activity showed that SPRE inhibited the release of β-hexosaminidase from antigen-stimulated rat basophilic leukemia (RBL-2H3) cells with an IC50 of 20.9 μg/ml. In addition, SPRE exhibited only moderate cytotoxicity on human keratinocyte cells, with CC50 of 33.6 μg/ml. These findings support the potential use of SPRE as a nutraceutical for antibacterial, anti-inflammatory and anti-allergic proposes.