Cinnamomum verum: a review of the composition and identity of Ceylon cinnamon

The most robust finding of the review is descriptive: Cinnamomum verum possesses a complex chemical composition, and certain aromatic molecules appear frequently in its essential oils. In practical terms, it is incorrect to attribute the identity of Ceylon cinnamon to a single substance. The authors identify cinnamaldehyde and eugenol as characteristic compounds, along with caryophyllene, cinnamyl acetate, and cinnamic acid. They also summarize studies that have observed antioxidant, antimicrobial, anti-inflammatory, and metabolic activities. However, an activity observed in a test tube means that an extract or molecule has shown an effect in that specific model; it does not prove that the same response occurs in a person consuming the spice. The review does not provide a single quantitative estimate of clinical efficacy. For this reason, its results guide research but do not define certain therapeutic benefits.

This publication is relevant because it clarifies an often-overlooked step: before discussing properties or safety, one must know which species and which part of the plant were studied. The botanical species acts as an identity document for the plant material. If two products sold as cinnamon come from different species, they may have different chemical profiles and are not automatically interchangeable. Singh and colleagues (2021) therefore provide a basis for linking Ceylon cinnamon to Cinnamomum verum and its main constituents. The limitation is equally important: the review does not, on its own, establish which markers allow for the identification of every commercial product, nor does it prove that a chemical profile corresponds to a specific health effect. Targeted authenticity analyses and separate biological studies are required.

As this is a review, Singh et al. (2021) are dependent on the quality and heterogeneity of previously published studies. The synthesis brings together results obtained with different materials, such as extracts, essential oils, and individual compounds, as well as non-comparable experimental models. Therefore, it does not allow the reported pharmacological activities to be translated into treatment recommendations. Furthermore, the summary of the publication does not report a quantitative meta-analysis, an overall clinical effect, or criteria that would allow for the estimation of an effective dietary dose. The presence of cinnamaldehyde or eugenol does not prove that they are the sole agents responsible for the observed responses, nor that they are present in the same quantity in all products. Finally, the work focuses on Cinnamomum verum: the difference compared to cassia is plausible from a botanical and chemical standpoint, but requires specific experimental confirmation.

The distinction between species is confirmed by independent analytical studies. Wu and colleagues compared the bark of Cinnamomum cassia and Cinnamomum verum using metabolomics, which is an extensive analysis of the small molecules present. They identified distinct profiles and proposed markers, including proanthocyanidins and alkaloids; the number of samples is not reported in the accessible report. This directly supports the transition from species to chemical profile, with moderate confirmation because it concerns bark samples analyzed in the laboratory, not all commercial products [1].

Farag and colleagues extended the comparison to four Cinnamomum species. The experimental study annotated 74 secondary metabolites and 51 primary metabolites; it found a higher abundance of cinnamates in C. verum and coumarin in C. cassia. The result converges with the review's narrative, showing that the difference does not depend on a single compound. The confirmation is direct but limited to defined samples and analytical methods [2].

An investigation of 52 commercial products then showed that the identity declared on the label may not coincide with the analyzed material. Ghidotti and colleagues used elemental profiles, confirmed with other analyses, to identify substitutions or irregularities. This provides practical support for the importance of botanical identification, even without measuring biological effects in humans [3].

The available evidence does not deny the average difference between species, but shows that there is no immutable profile for every specimen. Xavier and colleagues analyzed nine samples of Cinnamomum verum leaves, five cultivated and four commercial. The percentages of eugenol, benzyl benzoate, cinnamyl acetate, and cinnamaldehyde varied widely. This indicates that even within the same species, there can be chemotypes, meaning groups with different chemical compositions. This finding reduces the validity of classifications based on a single marker, especially because it concerns leaves and not bark [4].

A second experimental study on 71 accessions of Cinnamomum cassia detected phenotypic, chemical, and genetic variations, with three groups identified by population analyses. The authors also evaluated 12 bark samples for certain volatile oil constituents. This suggests that the origin of the material and internal variability can influence the profile of cassia. It does not contradict the distinct identity of C. verum, but it suggests that cassia should not be treated as having a unique and constant composition [5].