Title : Contribution to the chemical and biological standardization of a Piper aduncum L. extract for the management of gulupa (Passiflora edulis f. edulis) phytopathogens
Abstract:
Gulupa (Passiflora edulis f. edulis) is an important Colombian export crop whose productivity and fruit quality are significantly affected by phytopathogenic fungi, including species of Fusarium, Cladosporium, and Colletotrichum. Conventional disease management relies heavily on synthetic fungicides; however, the emergence of resistant fungal populations, environmental concerns, and increasingly stringent pesticide-residue requirements in international markets highlight the need for effective and sustainable phytosanitary alternatives. Species of the genus Piper (Piperaceae) are recognized as promising sources of antifungal specialized metabolites, although the chemical variability inherent to botanical extracts may compromise batch-to-batch reproducibility. Therefore, establishing standardized extraction procedures and chemical markers is essential for advancing their development as plant-based crop protection products. This study aimed to contribute to the chemical and biological standardization of Piper aduncum L. extracts with antifungal potential against phytopathogens associated with gulupa crops. Ethanolic extracts from leaves, stems, and inflorescences of two P. aduncum accessions were initially obtained by maceration and percolation and compared in terms of extraction yield and reproducibility. Antifungal activity was evaluated against selected Fusarium, Cladosporium, and Colletotrichum strains using mycelial growth inhibition assays and concentration–response analysis. An HPLC-DAD method was simultaneously developed to establish the chromatographic profile and identify potential chemical markers. Subsequently, a 2 × 3 × 3 full factorial design was used to evaluate the influence of ethanol–water composition, plant material-to-solvent ratio, and extraction time on process performance. Maceration showed greater reproducibility than percolation, with coefficients of variation generally below approximately 4%, whereas percolation reached values close to 7%. The factorial analysis confirmed that solvent composition, solid-to-solvent ratio, and extraction time significantly influenced extraction yield (p < 0.001), allowing the identification of a defined operating region combining hydroethanolic solvent systems, relatively high solvent-to-plant ratios, and extended extraction times. Among the evaluated plant organs, leaf extracts showed the strongest antifungal response, with mycelial growth inhibition exceeding 90% and approaching complete inhibition against the most susceptible phytopathogens. Chromatographic profiling revealed three predominant signals consistently detected in extracts from aerial tissues, which are currently being investigated as potential markers for chemical standardization. Overall, these findings demonstrate that controlled maceration conditions can generate P. aduncum extracts with reproducible yields, consistent chromatographic profiles, and strong antifungal activity. These results provide a foundation for further marker identification, extract standardization, and development of sustainable botanical alternatives for the management of fungal diseases in gulupa crops. This study was funded by the Sistema General de Regalías of Colombia under project BPIN 2023000100058. Research activities on Colombian biodiversity were conducted under Genetic Resource Access Contract No. 121 of January 22, 2016, and its Amendment (Otrosí) No. 21, executed between the Ministerio de Ambiente y Desarrollo Sostenible and the Universidad Nacional de Colombia.
