comprehensive comparative analysis of lippia citriodora and stachys lavandulifolia from iran: integrating gc-ms, micromorphological, and 18s rrna phylogenetic approaches

This study presents an integrated characterization of two medicinal lamiaceae species, lippia citriodora (lemon verbena) and stachys lavandulifolia (mountain tea), cultivated and commercialized in iran. micromorphological observations revealed distinct anatomical features between academic and market samples. in lippia citriodora, university-grown samples exhibited abundant glandular trichomes with multicellular globular heads, well-organized parenchymal cells, and uniformly distributed anomocytic stomata, indicating species purity and high quality, whereas these traits were underdeveloped in market samples. gc–ms analysis demonstrated qualitative and quantitative variations in essential oil composition: market samples showed limonene and citral dominance, while academic specimens contained higher carvacrol and citral levels with enhanced compound diversity. in stachys lavandulifolia, samples from shiraz and shahreza showed quantitative differences in volatile profiles; thymol was dominant in the shiraz specimen (69.03%) and n hexadecanoic acid (18.16%) in shahreza. molecular analysis of 18s rrna sequences confirmed species identity and revealed minimal intra species variation (≈97% identity), with conserved sequence blocks suitable for genus level primer design. phylogenetic reconstruction validated the taxonomic classification and identified evolutionary differentiation across populations. altogether, chemical, anatomical, and genetic evidence supports the authenticity of both plants and highlights environmental influences on their phytochemical characteristics. this integrated approach provides a reliable foundation for authenticity verification and quality control of medicinal plants in iran's herbal market.