Comparative GC–MS Analysis of Volatiles in Different Organs of Thymbra capitata (L.) Cav.: Effects of Analytical Method and Drying

Thymbra capitata (L.) Cav. is an aromatic Mediterranean species widely used as a culinary herb and valued for its medicinal properties. The present study investigated the volatile composition of different plant organs (petals, sepals, leaves, and roots) collected in Jerusalem, Israel, using three complementary GC-MS approaches: solvent extraction (Liq), static headspace (HS), and solid-phase microextraction (SPME). The influence of air-drying on volatile composition was also evaluated. Among the analytical methods tested, HS provided the broadest volatile profile with 57 identified compounds, whereas Liquid extraction yielded the highest relative abundances of thymol and carvacrol. SPME proved particularly effective for the detection of sesquiterpenes, especially β-caryophyllene. The volatile profiles differed considerably among plant organs. Floral and vegetative aerial parts were characterized by high proportions of p-cymene, γ-terpinene, thymol, and carvacrol, whereas roots exhibited a distinct composition dominated by α-pinene, limonene, and β-caryophyllene. Drying modified the relative abundances of several major constituents without changing the characteristic volatile profile of the species. Multivariate analysis revealed close relationships between selected aerial organs and confirmed that phenolic monoterpenes were the principal contributors to chemical variability within the plant. The results demonstrate that HS, SPME, and solvent extraction provide complementary information and together enable a comprehensive characterization of T. capitata volatiles. These findings contribute to understanding organ-specific phytochemical variability and support the selection of appropriate analytical and processing strategies for aromatic and medicinal plants.