Antibacterial substances from leaves of Protium spruceanum (Burseraceae): in vitro and in silico evaluation

Due to the increase of bacterial resistance, the search for new antibiotics is necessary and the medicinal plants represent its most important source. The aim of this study was to evaluate the antibacterial property of extract and fractions from Protium spruceanum leaves, against pathogenic bacteria. By means of diffusion and microdilution assays, the crude extract was active against the nine bacteria tested being the hydromethanolic fraction the most active. During phytochemical procedures, procyanidin (1) and catechin (2) were identified as the main antibacterial constituents of this fraction. In silico results obtained using PASSonline tool indicated 1 and 2 as having good potential to interact with different targets of currently used antibiotics. These results no indicated potential to none DNA effect and indicated the cell wall as mainly target. Electrophoresis result supported that had no DNA damage. Cell wall damage was confirmed by propidium iodide test that showed increased membrane permeability and by cell surface deformations observed in scanning electronic microscopy. The in vitro assays together with the in silico prediction results establish the potential of P. spruceanum as source of antibacterial compounds that acts on important bacterial targets. These results contribute to the development of natural substances against pathogenic bacteria and to discovery of new antibiotics.

Clastogenicity of Piper cubeba (Piperaceae) seed extract in an in vivo mammalian cell system

The plant Piper cubeba is widely distributed in tropical and subtropical regions and is used medically for various purposes but has not yet been evaluated for genotoxicity. We used male and female Swiss mice and Wistar rats and the comet assay and micronucleus test to investigate the mutagenic potential of a crude extract of P. cubeba seeds. The rodents were administered 0.5 g kg-1, 1.0 g kg-1 and 1.5 g kg-1 of the extract by gavage. For the Swiss mice, peripheral blood was collected 24 h after treatment for the comet assay, and at 48 and 72 h for the micronucleus test. For the Wistar rats, peripheral blood and hepatic cells were collected for the comet assay and bone marrow cells were collected for the micronucleus test 24 h after treatment. At 1.5 g kg-1, the highest dose tested, the extract induced a statistically significant increase in both the mean number of micronucleated polychromatic erythrocytes and the level of DNA damage in the rodent cell types analyzed. Under our experimental conditions, the P. cubeba seed extract was genotoxic in vivo when administered orally to mice and rats.