The aim of this study was to evaluate the inhibitory activity of the commercially available essential oils of Mentha spicata (spearmint) and Eucalyptus globulus (eucalyptus) on Streptococcus mutans ATCC 25175 biofilms in vitro, emulating dental plaque conditions. The composition of the essential oils (EOs) was determined using gas chromatography coupled with mass spectrometry (GC-MS), with the main metabolites being Carvone (57.93%) and Limonene (12.91%) for Mentha spicata and 1,8-Cineole (Eucalyptol) (65.83%) for Eucalyptus globulus. The inhibitory activity was evaluated using the methods of agar-well diffusion and colorimetric microdilution. The inhibition halos were 18.3 ± 0.47 mm and 27.0 ± 0.82 mm, and the MICs were 1.8484 mg/mL and 1.9168 mg/mL for the EOs of Mentha spicata and Eucalyptus globulus, respectively. The activity against the biofilms was evaluated on a substrate of bovine enamel pieces using a basal mucin medium (BMM) in anaerobic conditions with daily sucrose exposition cycles in order to emulate oral cavity conditions. The EOs were applied in a concentration of 0.5% in a sterile saline vehicle with 1% polysorbate 20. After 72 h of cultivation, a significant reduction was observed (p < 0.001%) on the biofilm biomass, which was evaluated by its turbidity in suspension and using a count of the recoverable organisms with regards to the control. The effects of the Eos were not significantly distinct from each other. The EOs showed antimicrobial activity against both the Streptococcus mutans planktonic and biofilm cultures. Thus, EOs may have great potential for the development of pharmaceutical and sanitary products for oral health.

Aloysia triphylla is widely used in traditional medicine from Peru for its sedative, digestive and anti-inflammatory properties. However, comprehensive studies on the biological activities of its essential oil (EO), particularly from Peruvian sources, remain limited. This study aimed to analyze the chemical composition and enantiomeric profile of A. triphylla EO and evaluate its antibacterial, antioxidant, anticholinesterase, and cytotoxic activities. The EO was obtained by steam distillation and analyzed using gas chromatography–mass spectrometry (GC-MS). A total of 62 compounds were identified, with (E)-caryophyllene (16.80%), β-pinene (9.96%), and germacrene D (10.00%) being the major components. Enantiomeric analysis revealed specific chiral signatures, including (−)-α-pinene, (+)-limonene, and (R)-(−)-linalool. The EO exhibited significant antibacterial activity, particularly against Bacillus subtilis (MIC = 5 µg/mL), and weak antioxidant activity (IC₅₀ = 7720 and 4648 µg/mL for DPPH and ABTS, respectively). Additionally, the EO demonstrated moderate acetylcholinesterase inhibition (IC₅₀ = 87.8 µg/mL) and cytotoxicity in the Artemia salina assay (LC₅₀ = 964 µg/mL). These findings suggest that A. triphylla EO possesses promising bioactivities with potential applications in pharmaceutical and cosmetic fields.

El eugenol es un alilbenceno con actividad antifúngica, diversos estudios han demostrado su capacidad de inhibir el crecimiento de Candida albicans. Se ha propuesto la formación de aductos entre un derivado del eugenol (2-metoxi-4-alilideno-2,5-hexadieno-1-ona) y glutatión como un mecanismo de estrés oxidativo. Asimismo, otro derivado del eugenol, epóxido de eugenol, tiene teóricamente la capacidad para formar aductos. Por lo tanto, este estudio determinó in silicolas propiedades fisicoquímicas de estos aductos y su reactividad en microorganismos aeróbicos. Se encontró que estos aductos tienen baja hidrofobicidad, por lo que, tendrían baja capacidad para atravesar membranas biológicas y por tanto una distribución intracelular. Asimismo, las reacciones químicas que originan estos aductos son termodinámicamente favorables. Por último, estos aductos son susceptibles a modificaciones químicas en microorganismos aeróbicos; estas reacciones podrían ser catalizadas por enzimas como el citocromo P450.