Linalool-rich essential oils from the Amazon display antidepressant-type effect in rodents

Ethnopharmacological relevance The essential oils of the leaves of Aniba rosaeodora (pau-rosa), Aniba parviflora (macacaporanga) and Aeollanthus suaveolens (catinga-de-mulata), rich in linalool, are used in the traditional medicine of the Brazilian Amazon for its effects on the central nervous system, such as sedative, anticonvulsant and antidepressant, among other therapeutic properties. Aim of the study To analyze the chemical composition of these oils and to evaluate their neurobehavioral effects in rodents, based on different and established behavioral tests. Material and methods The oils were distilled and analyzed by GC and GC-MS. Male Wistar rats received intraperitoneal doses of the oils of pau-rosa (3.5 and 35 mg/kg), macacaporanga (8.5 and 85 mg/kg) and catinga-de-mulata (7.5 and 75 mg/kg), in addition to a linalool standard (30 mg/kg). The neurobehavioral effects were evaluated using the tests: Open Field (spontaneous locomotion activity), Elevated Plus Maze (anxiolytic- type activity), Splash and Forced Swimming (antidepressive-type activity) and the Inhibitory Avoidance (memory retention). Results The three oils (highest dose) and standard linalool presented significant antidepressant activity in rodents. Linalool was identified as the major constituent of the oils (pau-rosa, 88.6%, macacaporanga, 45%, catinga-de-mulata, 49.3%). The standard linalool used was 97.0%. Conclusion The pau-rosa, macacaporanga, and catinga-de-mulata oils presented antidepressant activity due to the presence of linalool, which, by the final synergistic action of other constituents found in oils, may have contributed to the increase or reduction of this behavioral effect in the treated animals. A relevant fact is that there was no compromise of spontaneous locomotion and the memory retention in the rodents.