In vitro Antimicrobial Activity of Cinnamomum zeylanicum Bark Extracts: A Potential Natural Preservative

Abstract

The present study aims to evaluate the efficacy of natural plant extracts as potential food preservatives, with a specific focus on Cinnamomum zeylanicum. Cinnamomum zeylanicum, one of the oldest spices used in culinary traditions, is well-documented for its diverse biological activities, including anti-inflammatory, anti-carcinogenic, anti-mutagenic, and potent antioxidant effects. In this investigation, the antimicrobial activity of C. zeylanicum bark extract was assessed against two food-spoiling bacterial strains: Pseudomonas spp. and Escherichia coli. Extracts were prepared using three different solvents—distilled water, ethanol, and acetone—to evaluate solvent-dependent efficacy. At a dilution of 10⁻³, none of the extracts exhibited observable antimicrobial activity against either bacterial strain. However, at a higher dilution of 10⁻⁶, the acetone extract demonstrated the most pronounced antimicrobial effect. For E. coli, the acetone extract produced a zone of inhibition measuring 12.33 ± 1.5 mm, with an activity index of 0.4304. Against Pseudomonas spp., the zone of inhibition was 11.66 ± 1.5 mm, with an activity index of 0.434. In comparison, the methanolic extract yielded a zone of inhibition of 10.33 ± 0.58 mm and an identical activity index of 0.4304 for E. coli, while for Pseudomonas spp., the inhibition zone measured 10 ± 1 mm with an activity index of 0.434. These findings underscore the superior antimicrobial potential of the acetone extract of C. zeylanicum bark, particularly at higher dilutions, and support its application as a natural and effective alternative to synthetic food preservatives.