Synergistic potential of Bauhinia holophylla leaf extracts with conventional antifungals in the inhibition of Candida albicans: A new approach for the treatment of oral candidiasis

Stéfani de Oliveira Rosa; Adriana Araújo de Almeida-Apolonio; João Víctor de Andrade Dos Santos; Cleison da Rocha Leite; Wellinton Jhon Cupozak-Pinheiro; Claudia Andréa Lima Cardoso; Thiago Luis Aguayo de Castro; Deisiany Gomes Ferreira; Melyssa Negri; Kelly Mari Pires de Oliveira

doi:10.1016/j.archoralbio.2024.106133

Synergistic potential of Bauhinia holophylla leaf extracts with conventional antifungals in the inhibition of Candida albicans: A new approach for the treatment of oral candidiasis

Arch Oral Biol. 2024 Nov 16:170:106133. doi: 10.1016/j.archoralbio.2024.106133. Online ahead of print.

Affiliations

¹ Faculty of Health Sciences, Federal University of Grande Dourados, Dourados, MS 79804-970, Brazil.
² Faculty of Health Sciences, Federal University of Grande Dourados, Dourados, MS 79804-970, Brazil; State University of Mato Grosso do Sul, Dourados, MS 79804-970, Brazil.
³ Faculty of Exact Sciences and Technology, Federal University of Grande Dourados, Dourados, MS 79804-970, Brazil.
⁴ State University of Mato Grosso do Sul, Dourados, MS 79804-970, Brazil; Postgraduate in Natural Resources, State University of Mato Grosso do Sul, Dourados, MS 79804-970, Brazil.
⁵ Department of Clinical Analysis and Biomedicine, Division of Medical Mycology, State University of Maringá, Maringá, PR 87020-900, Brazil.
⁶ Faculty of Health Sciences, Federal University of Grande Dourados, Dourados, MS 79804-970, Brazil; Faculty of Biological and Environmental Sciences, Federal University of Grande Dourados, Dourados, MS 79804-970, Brazil. Electronic address: kmpoliveira@hotmail.com.

PMID: 39581119
DOI: 10.1016/j.archoralbio.2024.106133

Abstract

Objective: This study investigated the combination of Bauhinia holophylla (Bong.) Steud. leaf extracts with conventional antifungal agents, highlighting the extracts' potential as adjuvants in treating oral candidiasis.

Design: Ethanolic and aqueous extracts of B. holophylla leaves were analyzed using ultra-high-performance liquid chromatography with a diode array detector (UHPLC-DAD) to assess their chemical composition. Their Minimum Inhibitory Concentration (MIC) against standard strains of Candida albicans and isolates from oral mucosa was determined. Additionally, the potential synergistic effects with chlorhexidine gluconate, nystatin, and fluconazole were investigated, along with their impact on inhibiting and disrupting biofilm formation, germ tube formation of C. albicans, and cytotoxicity in human erythrocytes.

Results: Protocatechuic acid, epicatechin, and rutin were identified in both extracts. They exhibited fungistatic activity with a median minimum inhibitory concentration (MIC₅₀) of 15.62 µg/mL for the ethanolic extract (EEB) and 62.50 µg/mL for the aqueous extract (AEB) against C. albicans. In growth kinetics, both extracts reduced the viable cell count of C. albicans by 2 logs after 24 h compared to the positive control. The extracts reduced germ tube formation by 81.6 % for EEB and 86.3 % for AEB. The synergistic combination with fluconazole and nystatin resulted in a 50 % reduction in the concentration required to inhibit C. albicans growth. No hemolytic activity was detected in human erythrocytes at the tested concentrations.

Conclusion: Both ethanolic and aqueous extracts show promising potential as adjuvants in managing oral candidiasis. Notably, the aqueous extract is advantageous due to its non-toxic solvent, cost-effectiveness, and ease of preparation.

Keywords: Antifungal activity; Bauhinia holophylla (Bong.) Steud; Candida albicans; Medicinal plants; Oral pathogen.