Rediscovering medicinal Amazonian aromatic plants: Piper carpunya (Piperaceae) essential oil as paradigmatic study

Piper carpunya Ruiz & Pav. (Piperaceae) is a perennial aromatic shrub of Amazonian area of Ecuador and Peru, belonging to the ethnomedicine of these countries. The traditional preparations of the crude drug (fresh leaves used topically as is, and dried leaves in infusions or decoctions) are known for anti-inflammatory, antiulcer, antidiarrheal, antiparasitic effects, and wound healing properties. In light of this traditional evidence, chemical composition (GC-MS) and biological activity, i.e., antioxidant, antifungal (yeast) capacities, and genotoxicity, of Amazonian P. carpunya leaf essential oil (EO) have been investigated in order to valorize some of the putative ethnomedical effects. The EO was obtained through steam distillation of fresh leaves (yield: 7.6 g/kg [0.76%]; refractive index at 20°C: 1.49; density: 0.928 g/mL). Chemical characterization performed through GC-MS evidenced the presence of 21 compounds (96.2% of the total). The most abundant constituents were piperitone (26.2%), limonene (9.5%), elemicin (7.2%), and β-phellandrene (5.6%). In vitro DPPH antioxidant assay showed a weak radical scavenging ability (IC50) if compared to positive control. Low bioactivity of the EO was also demonstrated against yeast, but it showed an interesting synergistic activity (FIC index of EO+fluconazole) against Candida sp. strains. Ames test evidenced the safety of the EO concerning genotoxicity.