• An overview on antimicrobial properties of red onion peel extract
  • Malihe Safarioun,1 Leila Shokrzadeh,2,* Homa Mollaei,3
    1. Department of Biology, Shandiz Institute of Higher Education, Mashhad, Iran.
    2. Department of Biology, Shandiz Institute of Higher Education, Mashhad, Iran.
    3. Department of Biology, Faculty of sciences, University of Birjand, Birjand, Iran


  • Introduction: Onion (Allium cepa L.) is the second important horticultural crop worldwide. Red onion as one of the most valuable cultivars, is a powerful source of bioactive components such as phenol and flavonoid that has many applications in pharmacology as antioxidant, anticancer and antimicrobial. Quercetin 3,4′-diglucolside, quercetin 4′-monoglucoside and quercetin are the most flavonols in the red onion extract. Moreover, studies showed that level of this components in the peel extract is more than the bulb.
  • Methods: In this systematic review study, we discuss on the antimicrobial properties of red onion peel extract. To this end, we used recent reports in databases including pubmed, scopus, ISC and google scholar since 2019 via searching the relevant key words, antimicrobial properties, antibacterial effects and red onion. From about 70 reports, those are related to red onion peel extract were included in this study.
  • Results: Results from reviewing about 30 papers, showed that, onion peel extract has significant antimicrobial effects, although the exact component which has the most antimicrobial activity is still unknown. It has been reported that Gram-positive bacteria like Bacillus cereus, Staphylococcus aureus, Microcroccus luteus, and Listeria monocytogenes were more sensitive to this extract, compared to Gram-negative bacteria like Escherichia coli and Pseudomonas aeruginosa. Dhowlaghar et el. in 2023, indicated that red onion peel has inhibiting effect on the growth of Listeria monocytogenes, a gram-positive bacterium, available in different foods like meat and dairy products and may cause serious disease. Also, in the same year, Momoh et al reported antimicrobial activity of aqueous red onion peel extract on two bacterial strains Staphylococcus aureus (gram positive) and Escherichia coli (gram negative). Both of these are mentioned as gastrointestinal diseases agents. In 2021, Ginda Haro and collages assessed the antimicrobial properties of red onion peel extract and their results proved the antibacterial capacity of this extract on Staphylococcus aureus, Escherichia coli and Candida albicans. Former, Alok Sagar et al. studies the antimicrobial effects of polyphenolic extracts against six pathogenic bacteria, from onion peel from fifteen cultivars. Their results showed that red onion peel extract is the second effective one specially against Streptococcus agalactiae and Pseudomonas aeruginosa. These bacteria may cause diarrhea.
  • Conclusion: The data suggest that red onion peel extract could be potentially used as an antimicrobial complement to prevent and treat infectious disease. However, as every year, a large amount of red onion peel discard as agricultural waste, using it could in pharmaceutical industries could be beneficial and economical.
  • Keywords: Antimicrobial properties. Red onion peel extract. Antibactrial properties.