Evaluation of the antibacterial synergism of two plant extracts belonging to Bignoniaceae family and development of a topical formulation

TORRES C. A; CRISTINA MARISEL PÉREZ ZAMORA,; MARÍA BEATRIZ NUÑEZ; MARÍA INÉS ISLA; ANA M. GONZALEZ; IRIS CATIANA ZAMPINI

BRAZILIAN JOURNAL OF PHARMACEUTICAL SCIENCES

UNIV SAO PAULO

Lugar: Ribeirao Preto; Año: 2022 vol. 22

1984-8250

Fridericia caudigera and Cuspidaria convoluta (Bignoniaceae) species, which grow in thenorthwest of Argentina, have shown antibacterial effect against strains isolated from skininfections, and each one displayed synergism with commercial antibiotics. The aims of thiswork were to evaluate the antibacterial activity and toxicity of the combination of these twoplant species, and to design a stable gel for topical use including the blend of extracts. Thecombination of extracts was evaluated for synergistic effects (chequerboard assay), genotoxicity(Ames test) and cytotoxicity (Artemia salina test). A gel was subsequently formulated with thecombination of extracts using carboxymethylcellulose as a polymer. The following physicochemicalcharacteristics of the gel formulation: pH, viscosity, spreadability and total phenolcontent, as well as resistance to severe temperature changes, biological activity (diffusionin agar), in vitro permeation (Franz cells) and primary dermal irritation (Draize test) wereanalyzed. The combination of extracts showed a synergistic effect on pathogenic bacteria andwas not toxic in the in vitro tests. The gel was stable and retained the antimicrobial activity ofthe original extracts. The formulation proposed in this work could constitute an alternative forprimary skin infections since it proved to be safe for topical administration.