Effects of demethylfruticuline A and fruticuline A from Salvia corrugata Vahl. on biofilm production in vitro by multiresistant strains of Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis

Abstract

In this study, demethylfruticuline A (dfA) and fruticuline A (fA), two quinones representing the mayor diterpenoid components of the exudate produced by the aerial parts of Salvia corrugata, were assessed for their ability to modify surface characteristics, such as hydrophobicity, and to inhibit synthesis of biofilm in vitro by multiresistant Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis. Five strains of S. aureus (three meticillin-resistant and two meticillinsusceptible), five strains of S. epidermidis (four meticillin-resistant and one meticillinsusceptible) and eight vancomycin-resistant E. faecalis, all recently isolated from clinical specimens and capable of slime production, were studied. fA decrease by at least two-fold the hydrophobic properties of the S. aureus cell membrane but did not affect S. epidermidis or E. faecalis. Biofilm formation on polystyrene plates was quantified spectrophotometrically by established methodologies. Inhibition of biofilm formation was also confirmed by the Congo red agar plate assay. dfA and fA were more effective against S. aureus strains (>70% effect at subinhibitory concentrations) than against S. epidermidis in inhibiting slime synthesis. Against E. faecalis, dfA at subinhibitory concentration induced an inhibition of biofilm production of ca. 60%; fA was less active and more strain-dependent. Moreover, the two compounds were shown to posses chelating activity on divalent and trivalent metal cations.Interactions of fA and dfA with bacteria could be very complex, possibly being species-specific, and could depend not only on inhibition of exopolysaccharide synthesis but also on their chelating activity and on changes in the microorganism's surface, including cell hydrophobicity.

Antibacterial compounds from Salvia adenophora Fernald (Lamiaceae)

“…This is particularly so in consideration of the fact that the two groups of compounds may possess different and possibly novel mechanisms of molecular action, as shown by their ability to overcome the various traits of resistance to usual antibiotics carried by the Gram-positive pathogens thus far analyzed. None of these new active molecules inhibited the two Gram-negative species tested, nor C. albicans, in agreement with previous findings showing that natural compounds obtained from several plants, while active on Gram-positive species are generally inactive on Gram-negative organisms and fungi (Bisio et al, 2008;Schito et al, 2011). This lack of activity is probably due to the peculiar structure of the external layers of both groups of microorganisms, the Gram-negatives presenting a highly selective and hydrophobic outer membrane and C. albicans, a thick cell wall where b-glucans and chitin are abundant.…”

“…We recently described the antibacterial and anti-biofilm activity of two diterpene quinones from the exudation product of the fresh aerial parts of Salvia corrugata Vahl. against several Gram positive strains (Bisio et al, 2008;Schito et al, 2011). Prompted by these positive results we investigated Salvia adenophora Fernald, a Mexican species belonging to the http://dx.doi.org/10.1016/j.phytochem.2014.10.033 0031-9422/Ó 2014 Elsevier Ltd. All rights reserved.…”

Anti‐Inflammatory and Antihyperalgesic Activities of Ethanolic Extract and Fruticulin A from Salvia lachnostachys Leaves in Mice

“…Fruticulin A is a rare compound and was reported in only two other species of Salvia, S. fruticulosa [28] and S. corrugata [29]. Previous studies showed antibacterial [29, 30] and cancer chemopreventive activities of fruticulin A [31], but anti-inflammatory assays had not been performed with this compound. To test the contribution of fruticulin A to the activities observed in the extract, we tested the compound for anti-inflammatory and antihyperalgesic activities.…”

Potential of medicinal plants from the Brazilian semi-arid region (Caatinga) against Staphylococcus epidermidis planktonic and biofilm lifestyles

“…Polyphenols have received some attention recently regarding their antimicrobial effect upon microorganisms in biofilms, including a small number of studies involving S. epidermidis (Ferrazzano et al, 2009;Prabhakar et al, 2010;Schito et al, 2010). Sampaio et al (2009) showed that polyphenol-rich extracts of fruits from Caesalpiniea ferrea had antibiofilm activity in a multispecies biofilm model involving Streptococcus sp., Candida albicans and Lactobacillus casei.…”