Integrated molecular and chemical authentication of Thymus species: implication for industrial quality control

Ebadi, Mostafa; Mollaei, Saeed; Valinejad, Shaghayegh

doi:10.22034/jmpb.2026.372780.2189

Integrated molecular and chemical authentication of Thymus species: implication for industrial quality control

Articles in Press

Document Type : Research Article

Authors

¹ Department of Biology, Faculty of Science, Azarbaijan Shahid Madani University, Tabriz, Iran

² Department of Chemistry, Faculty of Science, Azarbaijan Shahid Madani University, Tabriz, Iran

10.22034/jmpb.2026.372780.2189

Abstract

This study integrates molecular, phytochemical, and morphological approaches to accurately identify and characterize Thymus species commonly sold in local herbal markets of northwestern Iran, aiming to support industrial standardization and quality control of thyme-based products. Dried plant samples from Ahar (TA1, TA2) and Kaleybar (TK) were analyzed using internal transcribed spacer region of ribosomal DNA (ITS-rDNA) barcoding, essential oil profiling, and leaf morpho-anatomy. DNA barcoding identified two Thymus species: T. kotschyanus (TA1, TA2) and T. pubescens (TK), with sequence similarity exceeding 98%. The Maximum Likelihood phylogenetic tree supported their genetic divergence, consistent with chemotypic differentiation observed in essential oil composition. Gas Chromatography-Mass Spectrometry (GC–MS) analysis revealed thymol (52.11–67.51%) as the dominant compound in T. kotschyanus, classifying it as a thymol chemotype, whereas T. pubescens exhibited a linalool–thymol chemotype characterized by high linalool (29.81%) and 1,8-cineole (12.15%) levels. Principal Component Analysis (PCA) distinctly separated the two species based on their chemical profiles, accounting for 85.3% of the total variance. Morphological comparison further confirmed diagnostic traits: T. pubescens with two pairs of lateral veins and narrow lanceolate leaves, and T. kotschyanus with three pairs of lateral veins and broader ovate leaves. The integrative evidence highlights the significance of molecular authentication and chemotaxonomy in preventing species misidentification, which may affect both the therapeutic efficacy and commercial value of thyme products. These findings provide a scientific foundation for the industrial application and quality control of Thymus-derived essential oils. The proposed integrated workflow offers a practical and cost-effective solution for routine quality assurance in the herbal product industry.

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