Chemical Composition and Ixodicidal Activity of <i>Copaifera reticulata</i> Ducke Oleoresin and Its Sesquiterpenic (Volatile) and Diterpenic (Resin) Fractions against <i>Rhipicephalus microplus</i> Larvae

High Resolution Image Download MS PowerPoint Slide The species Copaifera reticulata Ducke, native to the Amazon, produces oleoresin rich in terpenoid compounds with potential for controlling Rhipicephalus microplus, a cattle tick responsible for significant losses in livestock production. This study aimed to characterize the chemical constituents of the oleoresin (OR) and its sesquiterpenic (volatile, VF) and diterpenic (resin, RF) fractions by GC–MS and to evaluate their ixodicidal activity against R. microplus larvae through the Larval Immersion Test (LIT). The oleoresin and volatile fraction were dominated by sesquiterpenes, whereas the resin fraction was enriched in diterpenes. Ixodicidal tests showed that the RF was the most effective fraction, achieving 100% larval mortality at moderate concentrations (LC 50 = 3.35 mg/mL; LC 95 = 7.22 mg/mL), followed by the OR (LC 50 = 8.84 mg/mL; LC 95 = 27.34 mg/mL), while the VF showed lower activity (LC 50 = 45.28 mg/mL; LC 95 = 89.41 mg/mL). These results demonstrate that ixodicidal activity depends on the composition and stability of terpenoids, particularly diterpenes, highlighting the RF as the most effective fraction and reinforcing the potential of C. reticulata as a natural alternative for tick control.