Exploring the chemical diversity of the essential oils of <i>Cinnamomum tamala</i> (Indian Bay Leaf) populations from the Indian Himalayas through GC-MS analysis combined with integrated chemometric resolution methods

Cinnamomum tamala (Lauraceae), commonly known as Indian Bay Leaf, is an economically important aromatic tree species widely used in food, flavour, cosmetic and pharmaceutical industries. The species exhibits considerable variation in essential oil yield and composition across its distribution range, necessitating a comprehensive assessment of its chemical diversity. In the present study, the yield and chemical composition of C. tamala leaf essential oil (CTLEO) of 72 accessions collected from eleven states representing three phytogeographical regions of Indian Himalayas, namely the Western Himalayas, Eastern Himalayas, and Northeastern Hills. were investigated. The essential oil yield varied in the range of 0.07-1.38% and GC-MS analysis identified a total of 124 phytoconstituents. Phenylpropanoids (26.08-68.12%) and oxygenated monoterpenes (4.98-37.46%) were the dominant chemical classes and (E)-cinnamaldehyde (25.12-66.14%), linalool (2.47-34.62%) and terpinolene (5.85-16.18%) were the major constituents in CTLEO. Multivariate chemometric analyses, including hierarchical clustering, principal component analysis (PCA), and partial least squares discriminant analysis (PLS-DA), revealed two major compositional groups distinguished primarily by differences in the relative abundance of (E)-cinnamaldehyde and linalool. Populations from the Western Himalayas were characterized by higher proportions of (E)-cinnamaldehyde, whereas those from the Eastern Himalayas and the Northeastern Hills contained comparatively higher levels of linalool. These findings demonstrate substantial phytochemical diversity within C. tamala across the Indian Himalayas and provide a valuable framework for the identification of chemically distinct populations with potential applications in food, flavour, cosmetic, and pharmaceutical industries. Further studies incorporating multi-season sampling and molecular analyses are required to validate the stability and genetic basis of the observed compositional groups.