Chemical composition and antifungal activity of Piper auritum Kunth and Piper holtonii C. DC. against phytopathogenic fungi Composición química y actividad antifúngica de Piper auritum Kunth y Piper holtonii C. DC. contra hongos fitopatogénicos

The growth of fungi during pre - and postharvest of fruits may cause spoilage and result in a reduction in quality and quantity. The aim of the present work was to investigate the efficacy of four extracts (n-hexane, dichlorometane, ethyl acetate, and methanol) and the essential oil of Piper auritum Kunth and P. holtonii C. DC. on the growth inhibition of three important postharvest pathogens of fruits (Colletotrichum acutatum, C. gloeosporioides, and Botryodiplodia theobromae). The in vitro antifungal activity was assayed following the poisoned food technique. The results showed that both n-hexane extract (HE) as essential oil (EO) displayed a relative good control against the three pathogens, being the originating materials of P. holtonii the most actives. Mycelial growth of C. acutatum, C. gloeosporioides, and B. theobromae was significantly inhibited at 400 μg mL-1. Additionally, the chemical composition of the bioactive materials was analyzed by gas chromatography-mass spectrometry (GC-MS). Safrole (64.54/56.88%) and apiol (64.24/57.20%) were the major constituents of the EO/HE from P. auritum and P. holtonii respectively. Structural identification was also confirmed by nuclear magnetic resonance. Both compounds exhibited significant antifungal properties. It can be concluded that EOs/HEs from P. auritum and P. holtonii, and their major constituents, have interesting applications to control plant pathogenic fungi. El crecimiento de hongos durante pre- y poscosecha de frutas puede causar el deterioro y resultar en una reduccion en la calidad y cantidad. El objetivo del presente trabajo fue investigar la eficiencia de cuatro extractos (n-hexano, diclorometano, acetato de etilo, y metanol) y el aceite esencial de Piperauritum Kunth y P. holtonii C. DC. en la inhibición del crecimiento de tres importantes patogenos de pre- y poscosecha de frutas (Colletotrichum acutatum, C. gloeosporioides y Botryodiplodia theobromae). La actividad antifúngica in vitro se evaluó siguiendo la técnica del alimento envenenado. Los resultados mostraron que tanto el extracto en n-hexano (HE) como el aceite esencial (EO) exhibieron un relativo buen control contra ambos patógenos, siendo los materiales provenientes de P. holtonii los más activos. El crecimiento micelial de C. acutatum, C. gloeosporioides y B. theobromae se inhibió significativamente a 400 μg mL-1. Adicionalmente, se analizó la composición química de los materiales bioactivos mediante cromatografía de gases-espectrometría de masas (CG-EM). Safrol (64.54/56.88%) y apiol (64.24/57.20%) fueron los componentes may