Abstract
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.
Graphical Abstract
Disclosure statement
The authors declare no conflict of interest.