Anatomical Description and in vitro Evaluation of the Antibacterial Potential of Aristolochia esperanzae Kuntze (Aristolochiaceae) Extract on Oral Micro-organisms

Background: Aristolochia esperanzae Kuntze (Aristolochiaceae) is a plant present in the Brazilian flora, with few studies in the dental area, but used in integrative therapies to treat some health problems. Objectives: The initial purpose was to make an anatomical description of A. esperanzae and then test its antibacterial activity and minimum inhibitory concentration (MIC) on specific oral micro-organisms‑Streptococcus mutans, Porphyromonas gingivalis and Enterococcus faecalis. Materials and Methods: For the pharmacognostic study, the samples were fixed in formaldehyde, acetic acid and 70% ethyl alcohol and stored in 70% ethanol. For the in vitro study, to obtain the essential oil (OE) and hydrolate, the plant material was mechanically macerated and subjected to hydrodistillation in Clevenger and then frozen until the time of testing. The EO was diluted in dimethylsulfoxide and the tests performed were agar diffusion (disc‑diffusion) with isolated bacteria and MIC. A 0.12% chlorhexidine digluconate solution was used as a positive control and 0.9% sodium chloride as a negative. Results: The anatomical study showed the presence of hook‑shaped trichomes and stomatal complexes. Regarding the microbiological results, they were negative for the extracts used. Conclusion: The anatomical findings may guide future studies related to the pharmacognostic properties of A. esperanzae and both OE and hydrolate did not have an antibacterial effect against S. mutans, P. gingivalis and E. faecalis.