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.

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In this study, we developed tissue culture protocol of Salvia dolomitica, a particularly fragrant sage and we evaluated the yield and the profile of essential oil (EO) produced from plants grown in vivo compared to in vitro plant material cultured in two light intensity growth conditions. Plant extracts secreted from glandular trichomes are, in Lamiacea, a valuable source of biologically active volatile compounds. Microscopical observations permitted to\ud describe, for the first time, secretory structures from S. dolomitica leaves developed in vitro showing morphological identity to in vivo glands. The yield of EO obtained from light-stressed in vitro plants was higher than which obtained from the non-stressed in vitro plants and threefold higher that\ud in vivo plants. Phytochemical analysis of EOs and volatile compounds showed quali-quantitative differences between\ud S. dolomitica in vitro grown plantlets and those from open field. a-Pinene, b-phellandrene and borneol accumulated\ud predominantly in micropropagated plants while b-caryophyllene, a-guaiene, d-cadinene and valencene in in vivo\ud material. Both EO and SPME analysis had the same trend: the percentage of total sesquiterpenes decreased strongly\ud in vitro, on the contrary the total monoterpenes are abundant. The effect of the high light treatment on aromatic profile\ud demonstrating that this stress can affect the EO composition and this can be exploited by researchers to address the\ud accumulation of valuable amounts of EO