Volatile Organic Compounds and Beyond: Chemical Diversity and Biological Activities of Dittrichia viscosa

Dittrichia viscosa (L.) Greuter is a Mediterranean species widely recognized for its remarkable ecological plasticity and its rich repertoire of secondary metabolites, among which volatile organic compounds (VOCs) play a central role. This review provides an integrative synthesis of current knowledge on D. viscosa, with a primary focus on its VOCs, including their extraction techniques, chemotypic variability, and biological activities, while contextualizing these compounds within the species' broader phytochemical and ecological framework. Available evidence indicates that VOC profiles are dominated by terpenoids, particularly oxygenated sesquiterpenes and monoterpenes. The composition of volatile fractions is strongly influenced by extraction methodology, plant organ, developmental stage, and geographic origin, resulting in pronounced chemotypic variability across Mediterranean populations. Beyond their direct bioactivity, VOCs are considered in their ecological context, particularly in relation to glandular trichome-mediated secretion, plant-insect interactions, and potential applications in integrated pest management. Non-volatile metabolites are also discussed to provide a comprehensive view of the species' bioactive potential. Overall, D. viscosa emerges as a multifunctional species in which VOCs are a pivotal, though not isolated, component of a complex phytochemical system with promising applications in agriculture, pharmacology, and environmental management. While the convergence of multiple studies supports the biological potential of D. viscosa and its metabolites, particularly in vitro, the translation of these findings into in vivo efficacy and safety remains an important area for future research. This integrative perspective highlights the need for standardized analytical approaches and chemotype-aware studies to fully exploit the biological and biotechnological potential of this Mediterranean species.