Chemometric profiling of leaf essential oils in <i>Curcuma caesia</i> Roxb. reveals region-specific chemotypes across Eastern India

Roxb. (black turmeric) is a perennial aromatic herb widely valued for its medicinal properties, yet studies have largely focused on rhizomes, leaving leaf essential oils (EOs) underexplored. This study investigated the chemotypic diversity of leaf EOs from 53 eco-region-based accessions across Eastern India. Hydrodistillation yielded pale to dark yellow oils with marked variation (0.2-0.75% v/w), reflecting environmental influences. GC-MS analysis identified 47 metabolites (90.61-97.88%), predominantly furans, monoterpenes, and sesquiterpenes. Three distinct chemotypes-curzerenone-rich, eucalyptol-rich, and epicurzerenone-rich-were identified. Chemometric analyses (AHC, PCA, K-means, PLS-DA, sPLS-DA) revealed strong eco-regional structuring across Odisha, West Bengal, Assam, Meghalaya, and Andhra Pradesh. The results highlight substantial intra-specific chemical diversity in leaf EOs, comparable to rhizomes, establishing leaves as a sustainable phytochemical resource for conservation, germplasm selection, and bioprospecting.