Antibacterial activity of prenylated benzopyrans from Peperomia obtusifolia (Piperaceae)

• Published in: Natural product research Vol. 35; no. 10; pp. 1706 - 1710
• Main Authors: Ruiz Mostacero, Nathalie, Castelli, María Victoria, Cutró, Andrea Carmen, Hollmann, Axel, Batista, João Marcos, Furlan, Maysa, Valles, Julieta, Fulgueira, Cecilia Luisa, López, Silvia Noelí
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 19.05.2021; Taylor & Francis Ltd
• Subjects: antibacterial; Antibacterial activity; Antibiotic resistance; Bacteria; Bioassays; CA-MRSA; Carboxylic acids; Dichloromethane; Drug resistance; Fluorescence; Fractionation; Gram-positive bacteria; Hexanes; Medicinal plants; Membranes; Methicillin; Minimum inhibitory concentration; MRSA; Peperomia obtusifolia; Prenylated benzopyrans; Snake bites; Staphylococcus aureus; Staphylococcus infections; Vancomycin; Zeta potential; Peperomia obtusifolia; MRSA; CA-MRSA; Prenylated benzopyrans; antibacterial; zeta potential; Staphylococcus aureus
• ISSN: 1478-6419; 1478-6427
• DOI: 10.1080/14786419.2019.1628751

Peperomia obtusifolia is a herbaceous perennial plant native to the Americas reported as a traditional medicine to treat snake bites and as a skin cleanser. The bioassay-guided fractionation of crude extracts from aerial parts of P. obtusifolia against a panel of clinically important fungi and bacteria, showed that hexane and dichloromethane extracts demonstrated selective bacterial inhibition, allowing the isolation of the known compounds peperobtusin A (1), and 3,4-dihydro-5-hydroxy-2,7-dimethyl-8-(3"-methyl-2"-butenyl)-2-(4'-methyl-1',3'-pentadienyl)-2H-1-benzopyran-6-carboxylic acid (2) from dichloromethane extract. Compound 2 was active against Gram-positive bacteria including community acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) isolates and an Enterococcus faecalis vancomycin-resistant strain, with minimal inhibitory concentration (MIC) values of 4 μg/mL (10.8 μM) and 8 μg/mL (21.6 μM) respectively. The interaction of compound 2 with the bacterial membrane was demonstrated by means of Zeta potential experiments on S. aureus, then confirming the membrane damage by fluorescent microscopy experiments.