Antifungal and Herbicidal Potential of Piper Essential Oils from the Peruvian Amazonia.

The chemical composition of essential oils (EOs) from ten Peruvian Piper species ( Piper coruscans , Pc; P. tuberculatum , Pt; P. casapiense , Pcs; P. obliquum , Po; P. dumosum , Pd; P. anonifolium , Pa; P. reticulatum , Pr; P. soledadense , Ps; P. sancti-felicis , Psf and P. mituense , Pm) has been studied, along with their antifungal and phytotoxic activities. These EOs contained β-bisabolene/nerolidol (Pc), β-bisabolene/δ-cadinene/caryophyllene (Pt), caryophyllene oxide (Pcs), bicyclogermacrene/10-epi-Elemol (Po), bicyclogermacrene/germacrene-D/apiol (Pd), caryophyllene/germacrene-D (Pa), germacrene-D (Pr), limonene/apiol (Ps), apiol (Psf), and apiol/bicyclogermacrene (Pm) as major components, and some are described here for the first time (Ps, Pcs, Pm). A composition-based dendrogram of these Piper species showed four major groups (G1: Pc and Pt, G2: Pcs, Po, Pd, Pa, and Pr, G3: Ps, and G4: Psf and Pm). The spore germination effects ( Aspergillus niger , Botrytis cinerea , and Alternaria alternate ) and phytotoxicity ( Lolium perenne and Lactuca sativa ) of these EOs were studied. Most of these Piper essential oils showed important activity against phytopathogenic fungi (except G1), especially against B. cinerea . Similarly, most of the essential oils were phytotoxic against L. perenne (except G1), with P. sancti-felicis (G4), P. casapiense (G2), and P. reticulatum (G2) being the most effective. Caryophyllene oxide, β-caryophyllene, β-pinene, limonene, α-humulene, and apiol were evaluated against B. cinerea , with the most effective compounds being β-pinene, apiol, and limonene. This work demonstrates the species-dependent potential of essential oils from Peruvian Piper species as fungicidal and herbicidal agents.