Title : Antifungal potential of Piper species for the control of Trichophyton rubrum associated with dermatophytosis
Abstract:
Dermatophytosis is a superficial fungal infection caused by keratinophilic fungi that primarily affects the skin, hair, and nails. Trichophyton rubrum is the most prevalent etiological agent and represents a persistent clinical challenge because of diagnostic limitations, recurrent infections, prolonged treatments, adverse effects associated with conventional antifungals, and the increasing emergence of resistant strains. These limitations highlight the need to identify new antifungal agents with improved efficacy and safety profiles. Plant-derived natural products constitute a valuable source of structurally diverse bioactive compounds. In this context, the genus Piper (Piperaceae) is of particular interest because of its broad geographic distribution, traditional medicinal uses, chemical diversity, and wide range of reported biological activities. Nevertheless, numerous species remain insufficiently investigated regarding their phytochemical composition and antifungal potential. This study aimed to evaluate the in vitro antifungal activity of six Piper species against T. rubrum. Plant material was collected in the department of Chocó, Colombia, and ethanolic extracts of leaves, stems, and inflorescences were obtained by maceration. Preliminary antifungal screening was performed using the broth microdilution method at a concentration of 1000 µg/mL. Extracts producing at least 70% inhibition of fungal growth were considered active and selected for concentration–response assays over a range of 1–2000 µg/mL to determine their half-maximal inhibitory concentrations (IC??). The evaluated extracts showed species- and plant-organ-dependent differences in antifungal activity. The most active samples exhibited IC?? values below 50 µg/mL, while the remaining active extracts showed values broadly distributed between approximately 30 and 300 µg/mL. Overall, extracts from P. peltatum displayed the strongest inhibitory activity, whereas extracts from P. aduncum, P. umbellatum, P. tuberculatum, P. tricuspe, and P. squamulosum exhibited varying degrees of activity against the dermatophyte. To the best of our knowledge, this study provides the first comparative evidence of the antifungal activity of extracts from these species against T. rubrum. These findings support the potential of Piper species as sources of bioactive compounds for the development of antifungal agents. Further phytochemical and pharmacological studies are required to identify the metabolites responsible for the observed activity, elucidate their mechanisms of action, and assess their potential for the development of phytopharmaceutical alternatives for dermatophytosis management. This study was funded by the Sistema General de Regalías under project BPIN 2023000100047. The collection of plant material and access to genetic resources and their derived products were covered by Contract No. 121 of 22 January 2016 and Otrosí No. 21, signed between the Ministerio de Ambiente y Desarrollo Sostenible and the Universidad Nacional de Colombia.
