Micropropagação, morfologia dos tricomas foliares, análise química e atividade larvicida do óleo essencial de Gymneia interrupta (Pohl ex Benth.) Harley & J.F.B.Pastore

Abstract

Gymneia interrupta, an endemic species of the Cerrado and Amazon biomes and a member of the Lamiaceae family, exhibits promising ethnopharmacological potential, with antibacterial, antifungal, and antirheumatic properties. However, it is vulnerable to extinction due to its restricted distribution and predatory harvesting. Aiming to contribute to its conservation and sustainable use, this thesis developed a micropropagation protocol for large-scale production of plants with phytosanitary quality, evaluated the morphology of leaf glandular trichomes, analyzed the chemical composition of the essential oil, and tested its larvicidal activity against Aedes aegypti larvae. The micropropagation protocol included in vitro germination tests with gibberellic acid (GA3), with the 578 μM concentration yielding the best results. For in vitro establishment, MS, 1⁄2 MS, and WPM media were tested, with WPM considered the most suitable due to seedling performance and cost-effectiveness. During the multiplication phase, BAP concentrations of 0.750 and 1.000 mg·L−1 promoted the highest number of shoots per explant. Rooting was more efficient with 1.0 and 1.5 mg·L−1 of IBA. During acclimatization, plantlets with long roots and substrate T3 (2:1:3 of Terral Solo®, topsoil, and sand) showed the highest survival and vegetative development rates. Micromorphological analysis identified capitate and peltate glandular trichomes in G. interrupta leaves under different cultivation conditions. Histochemical tests revealed the presence of lipids, essential oils, terpenes, and phenolic compounds in the trichomes, reinforcing their role in the production of bioactive metabolites. The chemical composition of the essential oil, analyzed by GC-MS, identified β-caryophyllene, germacrene D, and bicyclogermacrene as major constituents. In larvicidal bioassays, the essential oil showed significant activity, with LC50 below 50 μg·mL−1. The species also demonstrated good adaptation to ex vitro conditions and maintenance of its morphochemical characteristics. The results of this study highlight the potential of G. interrupta as a source of bioactive compounds with natural insecticidal action and provide support for its conservation through micropropagation. This research contributes to the valorization and sustainable use of native species, combining biodiversity conservation strategies with biotechnological and pharmacological applications.