Larissa Rodrigues Jales Martins^1,2, Nadia Eligia Nunes Pinto Paracampo³, Paulo Riceli Vasconcelos Ribeiro², Hélcio Silva dos Santos¹, Jane Eire Silva Alencar de Menezes¹, Amanda Maria Barros Alves¹, Kirley Marques Canuto²

Simira paraensis, commonly known as araribá-rosa, is a small tree native to northern, northeastern, and central-western regions of Brazil. It is notable for producing a red pigment traditionally used as a natural food coloring. Phytochemical studies of the Simira genus highlight the predominance of beta-carbonyl indole alkaloids, compounds known for their effects on the central nervous system. However, scientific data on S. paraensis remain scarce or unavailable. This study employed a metabolomic approach to characterize the chemical profile and assess the anxiolytic potential of S. paraensis bark. The powdered bark was extracted via ultrasound-assisted extraction using methanol (pH = 2) for 2 hours, yielding a red extract (SP-BME) after solvent removal. Dereplication analysis was performed using Ultra-Performance Liquid Chromatography with Electrospray Ionization coupled to Quadrupole and Time-of-Flight Mass Spectrometry (UPLC-ESI-QToF-MS/MS) in both positive and negative ionization modes. Anxiolytic activity was evaluated in zebrafish using the light/dark test following oral administration of the extract (20 µL) at doses of 40, 200, and 400 mg kg^-1. Diazepam (4 mg kg^-1) and 3% DMSO were used as positive and negative controls, respectively. To assess GABAergic involvement, fish were pretreated with flumazenil (4 mg kg^-1) prior to testing. The UPLC-ESI-QToF-MS/MS analysis of SP-BME revealed 21 peaks tentatively identified as beta-carbonyl indole alkaloids, along with phenolic acids, their derivatives, and iridoids. The extract exhibited significant anxiolytic effects at all tested concentrations, which appeared to be mediated via the GABA_A receptor. These results suggest that S. paraensis shares phytochemical similarities with other Simira species and that its anxiolytic activity is likely due to the presence of beta-carbonyl indole alkaloids. The findings highlight S. paraensis as a promising natural source of bioactive colorants with potential pharmacological applications.

Agradecimentos: EMBRAPA, Funcap