In Vitro Analysis of Antioxidant, Antibacterial, and Antifungal Properties of Zingiber officinale, Syzygium aromaticum, Pimenta dioica, and Cinnamomum verum

Abstract

Natural alternatives to synthetic food additives are gaining traction due to growing concerns over potential health risks of synthetic compounds. Consumers are increasingly interested in naturally derived ingredients to enhance both food quality and safety. Spices traditionally used in Moroccan cuisine are ideal candidates in this regard due to their high content of bioactive compounds. This study aimed to evaluate the biological properties of four Moroccan spices: Zingiber officinale (ginger), Syzygium aromaticum (clove), Pimenta dioica (allspice), and Cinnamomum verum (cinnamon), and quantify their polyphenols and flavonoids contents. To this end, sixteen extracts were prepared using a sequential extraction method with solvents of increasing polarity: n-hexane, dichloromethane, methanol, and water. Antioxidant activity was assessed using 2, 2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assays, total phenolic and total flavonoid contents were determined by colorimetric method. The antimicrobial activity was determined using the agar well diffusion and microdilution methods. The polyphenol content ranged from 18.163 to 99.978 mg GAE/g, with the highest levels found in the aqueous clove extract, while flavonoid levels ranged from 5.68 to 44.05 mg QE/g. Clove’s dichloromethane extract showed the highest activity against Listeria monocytogenes, while its hexane extract was most effective against Escherichia coli and Enterococcus faecalis. Cinnamon’s methanol extract showed the greatest potency against Staphylococcus aureus. For the antifungal activity, both clove and cinnamon were consistently effective across multiple solvents extracts. Driven by their impressive bioactive properties, these Moroccan spices could play a valuable role as natural food preservatives and health-enhancing food additives.