Extracts from the Leaf of Couroupita guianensis (Aubl.): Phytochemical, Toxicological Analysis and Evaluation of Antioxidant and Antimicrobial Activities against Oral Microorganisms

The study of phytotherapy in dentistry holds great relevance because of the scarcity of research conducted on the treatment of oral pathologies, specifically, caries and periodontal disease. Therefore, this research aimed to analyze the chemical composition of extracts from Couroupita guianensis Aubl. leaves, evaluate their toxicity, and assess their antioxidant and antimicrobial properties against Staphylococcus aureus, Streptococcus mutans, and Candida albicans. Three extracts were prepared using assisted ultrasound and the Soxhlet apparatus, namely, Crude Ultrasound Extract (CUE), Crude Soxhlet Extract (CSE), and the Ethanol Soxhlet Extract (ESE). Flavonoids, tannins, and saponins were detected in the chemical analysis, while LC-DAD analysis revealed the presence of caffeic acid, sinapic acid, rutin, quercetin, luteolin, kaempferol, and apigenin in all extracts. GC-MS analysis identified stigmasterol and β-sitosterol in the CUE and CSE. The ESE showed higher antioxidant activity (2.98 ± 0.96 and 4.93 ± 0.90) determined by the DPPH• and ABTS•(+) methods, respectively. In the toxicity evaluation, the CUE at 50 μg/mL and the ESE at 50 μg/mL stimulated the growth of Allium cepa roots, while all extracts inhibited root growth at 750 μg/mL. None of the extracts exhibited toxicity against Artemia salina. Antibacterial activity was observed in all extracts, particularly against the microorganisms S. aureus and S. mutans. However, no antifungal activity against C. albicans was detected. These results suggest that extracts of C. guianensis have therapeutic potential for controlling microorganisms in the oral microbiota.