Comparison of High-Performance Liquid Chromatography (HPLC) Profiles and Antimicrobial Activity of Different <em>Cinnamomum</em> Species in Sri Lanka

The demand for Ceylon cinnamon (Cinnamomum verum syn. C. zeylanicum ) is consistent due to its superior characteristics. Besides that, Sri Lanka is home to seven other wild species: Cinnamomum capparu-coronde, Cinnamomum citriodorum, Cinnamomum dubium, Cinnamomum litseifolium, Cinnamomum ovalifolium, Cinnamomum rivulorum, and Cinnamomum sinharajaense. Since cinnamon bark contains more than seventy bioactive compounds, it possesses various pharmacological and health benefits, including antimicrobial activity. Even though there is some literature on the antimicrobial activity and chemical composition of C. verum, wild species have not been studied yet. The present study evaluated the antimicrobial activity and biochemical compounds of Cinnamomum species found in Sri Lanka using bark methanol extract and crude. Trans-cinnamaldehyde, cinnamyl alcohol, cinnamyl acetate, coumaric acid, and coumarin were quantified using HPLC techniques. The antimicrobial properties were evaluated by disc diffusion assay against two standard pathogenic strains, Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853. There were no detectable coumarin or coumaric acid levels in any of the species. The highest trans-cinnamaldehyde content and antimicrobial activity were observed in C. verum, followed by C. sinharajaense and C. capparu-coronde. Further, C. ovalifolium, C. dubium, and C. rivulorum did not show positive inhibition zones against the two pathogenic strains and detectable levels of trans-cinnamaldehyde. Moreover, the results showed a strong positive correlation between antimicrobial activity and trans-cinnamaldehyde content. The results suggest that the antibacterial activity of C. sinharajaense and C. capparu-coronde should be tested against a broader range of pathogenic strains and could be useful in future breeding programs.