Bioassay-guided discovery of antibacterial agents: in vitro screening of Peperomia vulcanica, Peperomia fernandopoioana and Scleria striatinux

Abstract

BackgroundThe global burden of bacterial infections is high and has been further aggravated by increasing resistance to antibiotics. In the search for novel antibacterials, three medicinal plants: Peperomia vulcanica, Peperomia fernandopoioana (Piperaceae) and Scleria striatinux (Cyperaceae), were investigated for antibacterial activity and toxicity.MethodsCrude extracts of these plants were tested by the disc diffusion method against six bacterial test organisms followed by bio-assay guided fractionation, isolation and testing of pure compounds. The minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations were measured by the microdilution method. The acute toxicity of the active extracts and cytotoxicity of the active compound were performed in mice and mammalian cells, respectively.ResultsThe diameter of the zones of inhibition (DZI) of the extracts ranged from 7–13 mm on Escherichia coli and Staphylococcus aureus of which the methylene chloride:methanol [1:1] extract of Scleria striatinux recorded the highest activity (DZI = 13 mm). Twenty-nine pure compounds were screened and one, Okundoperoxide, isolated from S. striatinux, recorded a DZI ranging from 10–19 mm on S. aureus. The MICs and MBCs indicated that the Peperomias had broad-spectrum bacteriostatic activity. Toxicity tests showed that Okundoperoxide may have a low risk of toxicity with an LC50 of 46.88 μg/mL.ConclusionsThe antibacterial activity of these plants supports their use in traditional medicine. The pure compound, Okundoperoxide, may yield new antibacterial lead compounds following medicinal chemistry exploration.

Medicinal plants in the treatment ofHelicobacter pyloriinfections

“…The antibacterial (Mbah et al, 2012) and antiplasmodial activity (Efange et al, 2009) of Scleria striatinux De Wild (Cyperaceae) have been reported recently. Ndip et al evaluated the anti-H. pylori activity of 10 selected medicinal plant extracts from North West Cameroon on 15 isolates.…”

Toxicidad oral aguda de los extractos etanólicos de Eucalyptus globulus, Morinda citrifolia, Peperomia glauca, Schinus molle y Zea mays en ratones BALB/c 53

“…En la prueba de toxicidad oral aguda no se reportaron muertes ni signos de toxicidad con el extracto de M. citrifolia, como lo demuestran diversos estudios con los extractos preparados de sus frutos (21) a pesar de algunos casos reportados de toxicidad en humanos por consumo de jugo de noni (22) . En la variedad de P. glauca (pino) no se encontraron estudios previos de toxicidad aguda, pero los resultados encontrados se corresponden con investigaciones en otros miembros del género Peperomia que no demuestran signos de toxicidad o muertes en animales de experimentación (23) . Los grupos que recibieron los extractos etanólicos de Schinus molle y Z. mays tampoco mostraron muertes o cambios comportamentales, a pesar de estudios previos en el caso del molle, en donde los animales de experimentación mostraron signos de hiperactividad con el extracto etanólico de esta planta, producido probablemente por la alteración en la neurotransmisión dopaminérgica o en otros sistemas (24) .…”

Antimicrobial and Antioxidant Activities of Selected Plants Used by Populations From Juruena Valley, Legal Amazon, Brazil

“…The potential bactericidal effects of the extracts were determined per the method of Mbah et al [18]. An aliquot (10 µl) of bacterial cells from the MIC test plate was subcultured on solid Müller-Hinton agar by making streaks on the surface of the agar and incubating at 37 °C for 1-2 d, and for plates where there was no visible fungal growth, the same was plated on Sabouraud agar and was incubated for 2 d in the case of yeast-like fungi, 3 d for filamentous fungi or 3-21 d for the dermatophytes.…”