Bioactive terpenoids from desert shrubs for durable wood protection: Chemistry, delivery systems, and circular bioresource integration

The demand for low-toxicity wood protectants is accelerating the search for plant-derived alternatives. Terpenoids from desert-adapted shrubs combine antimicrobial, insecticidal, hydrophobic, and photoprotective functions yet remain underused in wood protection. This review brings together the chemistry, bioactivity, and application potential of guayule (Parthenium argentatum), creosote bush (Larrea tridentata), physic nut (Jatropha curcas), spurges (Euphorbia spp.), and gum rockrose (Cistus ladanifer). Key terpenoids are classified by structure and mechanisms of action are mapped against decay fungi and termites. Delivery platforms, including solvent-free resin-oil blends, micro/nanoencapsulation, and biopolymer matrices, were evaluated with emphasis on persistence, UV stability, and substrate compatibility. A solvent-free valorization example using guayule resin illustrates circular-bioeconomy integration. Environmental and regulatory considerations, commercial readiness, and research gaps (standardized field trials, fractionation for consistency, genotype/agronomy improvements) are highlighted. Desert-shrub terpenoids emerge as multifunctional, eco-friendly agents for durable wood protection and pest management, offering a scalable pathway toward circular bioresource innovation.