Authentication of Cinnamomum verum (Ceylon cinnamon) in commercial products by qualitative and real-time quantitative PCR assays

Cinnamomum verum (Cinnamomum zeylanicum or Ceylon cinnamon) is an aromatic medicinal plant, popularly used as a culinary spice and in various herbal commodities. The increasing demand and high economic value make C. verum a vulnerable target of substitution by its allied plant species. The present study is aimed at developing highly specific qualitative PCR and quantitative real-time PCR (qPCR) methods to authenticate and quantify C. verum in cinnamon-containing food products. The method targeted the ITS2-26S rRNA region of C. verum, demonstrating acceptable performance criteria and a sensitivity down to 1.24 ng. Moreover, the qPCR method was developed employing binary sample mixtures, spanning the linear dynamic range (100 to 1%, w/w) of C. verum in an adulterant species (C. cassia). The trueness (− 8.67 to − 20.69%) of the quantitative approach was effectively evaluated using blind sample mixtures. The developed method was applied to analyze 10 commercial cinnamon products, which reflected the practice of both complete and partial substitution of the higher-cost C. verum with its related, lower-cost plant species. In conclusion, the established method with specificity could not only detect but also quantify C. verum products, thus providing an accurate and powerful tool for the authentication of cinnamon-containing foods.