## 4 Conclusions  
The current study employed a comparative multiplex metabolomics-based investigation of various cinnamon bark derived from different species based on SPME-GC/MS, UV/Vis, and NMR platforms. Comparison with commercially available products was attempted to find a correlation by studying their origin and how they relate to authenticated samples. SPME/GC-MS aimed at VOCs profiling, while UV/Vis and NMR explored non-volatile constituents. SPME/GC-MS showed more valuable models regarding the origin of commercially available cinnamon products revealing that CP-1 and CP-3 were more associated with CA, while CP-2 and CP-4 were derived from higher cinnamon grade sources. These findings were attributed to the higher coumarin and low (\(E\))-cinnamaldehyde contents in CP-1 and CP-3. It is observed that the presence of coumarin as a marker of \(C\). _tamala_ is reported in the current study for the first time. In addition, geographical origin appeared not to affect VOCs profile in examined cinnamon accessions. In comparison, NMR-based analyses revealed that (\(E\))-methoxy cinnamaldehyde, (\(E\))-cinnamaldehyde, and coumarin were richer in CV, CA, and CI, respectively. Such differences might be explained by the different applied extraction and analytical approaches. Furthermore, niacin and ascorbic acid accounted for CP-3 discrepancy in modeling results using NMR. It could be concluded from quantitative NMR that the origin of commercial products (CP-1, CP-2, and CP-4) are, to a great extent, consistent with the labeled information provided by the manufacturer, while CP-3 barely showed any cinnamon metabolites, which was inconsistent with the labeled information. Furthermore, UV/Vis showed interesting results revealing that proanthocyanidin and (\(E\))-cinnamic acid were more characteristic for CV and CI, respectively. Moreover, the official CV proved its high quality, showing a unique compositional profile different from CA, confirmed by the three employed analytical platforms. Such valuable information can be applied further to other commercial products containing cinnamon in mixtures with other herbs studying the possible interferences from other phytochemical constituents. Moreover, the various potential bioactivities of cinnamon drugs, such as antioxidant and anti-microbial activities, may be related to the bioactives content revealed in this study which can be employed in future chemometric models to aid and relate compositional makeup to other effects in cinnamon drugs. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/metabo12070614/s1](https://www.mdpi.com/article/10.3390/metabo12070614/s1)]([https://www.mdpi.com/article/10.3390/metabo12070614/s1](https://www.mdpi.com/article/10.3390/metabo12070614/s1)), Figure S1: Heatmap analysis for all cinnamon samples based on SPME/GC-MS. The \(Y\)-axis represents the retention time (min) of the volatiles peak. The peak retention times for all samples and code are listed in Table S1 and Table 1, respectively. \(Y\)-axis to the right shows retention times in min showing relative abundance among cinnamon specimens. Figure S2: PCA score plot (A and C) and loading plot (B and D) for authenticated and commercial cinnamon samples, respectively, of cinnamon volatiles analyzed by SPME/GC-MS. The samples code is listed in Table 1, Figure S3: OPLS-DA score plot (A) and loading plot (B) of authenticated drugs for cinnamon volatiles analyzed by SPME/GC-MS. Samples code is listed in Table 1, Figure S4: OPLS-DA for authentication of _Cinnamomum verum_ against other _Cinnamomum_ species for volatiles analyzed by SPME/GC-MS. (A) and (D) are score plot showing validation parameters, (B) and (E) are permutation plot, and (C) and (F) are S-plot for analysis CA and CI vs. other authenticated cinnamon species. The samples code is listed in Table 1, Figure S5: Unsupervised heatmap analysis of all cinnamon dataset. (A) Full-scale (\(\delta\)H 0.0-10.0 ppm) and (B) aromatic region (\(\delta\)H 5.5-10.0 ppm).