In Vitro Evaluation of Antimicrobial Photodynamic Therapy Associated with Hydroalcoholic Extracts of Schinopsis brasiliensis Engl.: New Therapeutic Perspectives.

OBJECTIVE: The aim of this study was to evaluate the photodynamic potential of extracts of Schinopsis brasiliensis Engl. on bacteria involved in several human infections. BACKGROUND DATA: Photodynamic therapy (PDT) involves the interaction of light with an appropriate and photosensitizer wavelength, and the prospect of existing photosensitive compounds in herbal extracts enhanced by the application of laser diode has been promising. METHODS: The antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis was obtained by the disk diffusion method on agar. The laser diode InGaAIP was used with 660 nm wavelength, 100 mW, and 4 J/cm(2), and the application was performed in a timely manner for 34 sec on each disk tested. The groups tested were: Laser and bark extract (B+L+); bark extract only (B+L-); Laser and leaf extract (F+L+); leaf extract only (F+L-); Laser and malachite green (M+L+); malachite green only (M+L-); and laser only (L+). RESULTS: There were significant differences between the B+L- and B+L+ groups (p=0.029) and between the L+F- and L+F+ groups (p=0.029) at various concentrations of the nebulized extracts of bark and leaf. Among the tested pathogens, S. aureus showed the highest zone of inhibition, 24.55±0.36 mm in group B+L+, 500 mg.mL(-1). CONCLUSIONS: PDT with malachite green was effective, and groups B+L+ and F+L+ showed excellent activity on the bacteria tested, suggesting the presence of photosensitizers in extracts of S. brasiliensis Engl.

Study bioprospecting of medicinal plant extracts of the semiarid northeast: contribution to the control of oral microorganisms.

Dental pathologies can be caused by plaque-forming bacteria and yeast, which reside in the oral cavity. The bacteria growing in dental plaque, a naturally occurring biofilm, display increased resistance to antimicrobial agents. The objective was the evaluation of a preclinical assay of medicinal plants of the semiarid region from the northeast against oral pathogenic microorganism, aiming at bioprospecting a new product. The selection of plant material for this study was based on the ethnobotanical data on the traditional use of plants from the semiarid region. The thirty extracts were subjected to the determination of antibiofilm activity against gram-positive, gram-negative bacteria and yeast. The hydroalcoholic extract which showed positive antibiofilm activity against most of the microorganisms tested in agar diffusion assay was further tested for the determination of minimum inhibitory concentration (MIC) and Bioassay with Artemia salina. Plant samples tested in this study exhibited good antibiofilm activity for the treatment of oral problems. The Schinopsis brasiliensis showed greater activity for Pseudomonas aeruginosa and Staphylococcus aureus, but toxicity against Artemia salina.