Antioxidant and Cytotoxic Properties of <i>Piper</i> spp. Volatile Oils That Inhibit Pathogenic Microorganisms

ABSTRACT Species of the genus Piper are used to treat diseases caused by microorganisms, such as urinary tract infections and chickenpox. These plants possess essential oils with proven antimicrobial and cytotoxic activity. Given the potential biological activity of Piper species, this study aimed to evaluate the antimicrobial, cytotoxic, and antioxidant properties of five essential oils (EOs) from the Piper genus native to the Amazon region. The EOs were extracted by hydrodistillation and characterised by GC–MS. Their antioxidant capacity was assessed using the DPPH radical, and their toxicity was evaluated against both cancerous and non‐cancerous cells. Additionally, they were evaluated against pathogenic fungi, bacteria, and yeasts of the genus Candida . The main compounds identified in the essential oils of Piper spp. included dillapiole (83.46%–80.26%) in P. aduncum ; β‐selinene (17.77%), ( E )‐iso‐ γ ‐bisabolene (17.71%) and γ ‐terpinene (12.75%) in P. hispidum ; ( E )‐caryophyllene (18.02%) and α ‐humulene (10.79%) in P. hostimannianum ; and ( E )‐iso‐ γ ‐bisabolene (26.85%) in P. marginatum . The samples were fungicidal against Candida , with MICs ranging from 62.5 to 250 μg/mL. They were fungistatic against Penicillium adametzii , Aspergillus flavus , and A. niger , with MICs of 1000 μg/mL. Volatile oils of P. hostmannianum and P. marginatum exhibited low antioxidant activity. The volatile oils of Piper aduncum and Piper marginatum reduced the viability of MDA‐MB‐231 cells by up to 41.34% at concentrations of 50 μg/mL and 3 μg/mL, respectively, after 48 h of exposure. This study demonstrated that essential oils from Amazonian Piper species are promising candidates for developing technologies aimed at treating breast cancer, combating fungal infections, or even preserving food.