Differentiation of Ocimum species using UV-vis and FTIR spectroscopic fingerprinting combined with chemometrics

The genus Ocimum is widely used in traditional medicine. However, accurate species identification remains challenging due to close morphological similarities and chemical variability influenced by cultivation conditions. This study aimed to develop spectroscopic fingerprints for Ocimum basilicum L., Ocimum basilicum L. forma citratum Back., and Ocimum sanctum L. using ultraviolet-visible (UV-Vis) and Fourier Transform Infra-red (FTIR) spectroscopy combined with chemometric analysis. Spectral data were evaluated using Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) to assess species discrimination. UV-Vis spectroscopy showed characteristic absorption bands associated with phenolic compounds and flavonoids but exhibited partial overlap among species, resulting in 78.98% classification accuracy. In contrast, FTIR spectroscopy, particularly in the fingerprint region, enabled clear species differentiation with 100% classification accuracy. These findings demonstrate that FTIR-based chemometric analysis provides a rapid, non-destructive, and reliable approach for the authentication and quality control of Ocimum raw materials.