Chemical composition and antifungal activity of Piper auritumKunth and Piper holtoniiC. DC. against phytopathogenic fungi.

Rodrigo Pineda M.1, Samuel Vizcaíno P.1, Carlos M. García P.1, Jesús H. Gil G.1, 2, Diego L. Durango R.1*

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 1H 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.

Keywords: Piperaceae, essential oil, apiol, Colletotrichum, Botryodiplodia.
1Universidad Nacional de Colombia-Sede Medellín, Facultad de Ciencias, Calle 59ª 63-020 Autopista Norte, AA 3840, Medellín, Colombia. *Corresponding author (dldurango@unal.edu.co).
2Universidad Nacional de Colombia-Sede Medellín, Facultad de Ciencias Agropecuarias, Calle 64 x Carrera 65 Autopista NOrte, AA 1779, Medellín, Colombia.