Angela Bisio

Salvinorin A exerts opposite presynaptic controls on neurotransmitter exocytosis from mouse brain nerve terminals

We investigated the effects of salvinorin A on the basal and the 12 mM K(+)-evoked release of preloaded [(3)H]noradenaline ([(3)H]NA) and [(3)H]serotonin ([(3)H]5-HT) from mouse hippocampal nerve terminals (synaptosomes), as well as on the basal and 12mM K(+)-evoked release of preloaded [(3)H]dopamine ([(3)H]DA) from mouse striatal and prefrontal cortex (PFc) synaptosomes. Salvinorin A (0.1-1000 nM) failed to affect the basal release of amines, but inhibited the 12 mM K(+)-evoked, Ca(2+)-dependent, exocytotic-like release of [(3)H]5-HT and [(3)H]DA. At the same concentration, salvinorin A facilitated the 12 mM K(+)-evoked, Ca(2+)-dependent, exocytotic-like release of [(3)H]NA. These effects could not be observed in pertussis toxin (PTx) entrapped synaptosomes. The broad spectrum kappa-opioid receptor (KOR) antagonist norbinaltorphimine (norBNI, 1-100 nM) antagonized the inhibition of [(3)H]5-HT and [(3)H]DA exocytosis as well as the facilitation of [(3)H]NA overflow induced by 100 nM salvinorin A. The KOR agonist U69593 (1-100 nM) mimicked salvinorin A in inhibiting [(3)H]5-HT and of [(3)H]DA exocytosis, its effect being prevented by norBNI, but leaving unchanged the K(+)-evoked release of [(3)H]NA. The effects of Salvinorin A on neurotransmitter exocytosis were not prevented by the selective mu opioid (MOR) receptor antagonist CTAP (10-100 nM), whereas facilitation of [(3)H]NA exocytosis, but not inhibition of [(3)H]5-HT and [(3)H]DA K(+)-evoked release, was counteracted by the delta opioid receptor (DOR) antagonist naltrindole (1-100 nM). We conclude that salvinorin A presynaptically modulates central NA, 5-HT, and DA exocytosis evoked by a mild depolarizing stimulus by acting at presynaptic opioid receptors having different pharmacological profiles.

Chemical composition of essential oils from some Salvia species

The essential oils from Salvia aurea L., Salvia ianthina Otto et A. Dietr., Salvia iodantha Fernald and Salvia cinnabarina M. Martens et Galeotti were analysed by means of GC/MS. A total of 89 components were identified and the variation of composition during the year of the first three species was studied. The antimicrobial activity of the essential oil from Salvia aurea L. was also tested.

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

In this study, demethylfruticuline A (dfA) and fruticuline A (fA), two quinones representing the major 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 meticillin-susceptible), five strains of S. epidermidis (four meticillin-resistant and one meticillin-susceptible) 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 possess 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 microorganisms surface, including cell hydrophobicity.

Antimicrobial Activity of the Ornamental Species Salvia corrugata, a Potential New Crop for Extractive Purposes

As a part of our search for biologically active compounds from cultivated Salvia spp. we investigated Salvia corrugata Vahl. The activity of two isolated icetaxane diterpene quinones, fruticuline A and demethylfruticuline A, was assessed against 46 bacterial pathogens, mostly resistant to several primary antibiotics. The MIC for all the inhibited Gram-positive pathogens tested showed a very narrow distribution and ranged from 32 to 64 mg/L, regardless of their resistance patterns to other antibiotics. Demethylfruticuline A was shown to be highly bactericidal (>3 log(10) CFU decrease within 24 h) against Staphylococcus aureus and S. epidermidis and bacteriostatic against Enterococcus faecalis and E. faecium. Fruticuline A manifested bacteriostatic activity against all tested strains. S. corrugata can be viewed as an interesting source for these diterpenes, which, if well tolerated in vivo, may represent new medical agents useful for the treatment of serious infections caused by resistant Gram-positive pathogens.

Phytotoxic clerodane diterpenes from Salvia miniata Fernald (Lamiaceae).

Our ongoing research to identify natural growth inhibitors with diterpene and triterpene skeletons exuding from the surface of the aerial parts of Salvia species led us to study Salvia miniata Fernald. Ten clerodane diterpenoids were found, along with three known diterpenes. Most of the isolated compounds from S. miniata inhibited the germination of Papaver rhoeas L. and Avena sativa L. in Petri dish experiments. Parallel results have been obtained in experiments carried out to evaluate the subsequent growth of the seedlings of the target species in the presence of the tested compounds.

Antibacterial compounds from Salvia adenophora Fernald (Lamiaceae)

From the aerial parts of Salvia adenophora Fernald four derivatives of 12-oxo-phytodienoic acid (1-4) together with five clerodane diterpenoids (5, 6, 8-10), and one known diterpene (7) have been isolated. Compounds 1-6 and 8-10 are described for the first time. The structures were established by extensive 1D, 2D NMR and HRESI-TOFMS spectroscopic methods. Finally, the absolute configuration has been established by comparing of experimental and quantum chemical calculation of ECD spectra. Despite a total lack of antimicrobial activity of the plant extract, hinting to the existence of antagonistic interactions in the crude material, three oxylipins (2-4) displayed a promising inhibition on Gram-positive multidrug-resistant clinical strains including Staphylococcus aureus, Streptococcus agalactiae and, particularly, Staphylococcus epidermidis, while the compounds 9 and 10 revealed a specific and strain-dependent activity against S. epidermidis. Interestingly, the inhibition provided by these compounds was independent of the resistance patterns of these pathogens to classic antibiotics. No action was reported on Gram-negative strains nor on Candida albicans. These results confirm that clerodanes and, particularly, prostaglandin-like compounds can be considered as interesting antimicrobial agents deserving further study.

Cancer chemopreventive diterpenes from Salvia corrugata

NMR and NP-HPLC-UV profiling of the exudate of Salvia corrugata revealed that its secondary metabolite composition was largely dominated by α-hydroxy-β-isopropyl-benzoquinone diterpenoids. Among them, four diterpenes not described previously were isolated and identified as fruticulin C (3), 7α-methoxy-19-acetoxy-royleanone (4), 7α,19-diacetoxy-royleanone (5), and 7-dehydroxy-conacytone (7). In addition, the known diterpenes fruticulin A (1), demethyl-fruticulin A (2) and 7α-O-methyl-conacytone (6) were also obtained. The isolated compounds were evaluated for their cancer chemopreventive activity by measuring quinone reductase induction activity and histone deacetylase inhibition. Three compounds (1, 2 and 5) showed promising activity.

Clerodane diterpenoids from Salvia blepharophylla

Abstract Two clerodane diterpenoids, blepharolides A and B, have been isolated from Salvia blepharophylla Brandegee ex Epling. Their structures were determined using a combination of one- and two-dimensional NMR techniques. The relative stereochemistry for blepharolide A was determined by X-ray diffraction. To our knowledge this is the first crystal structure determination of a 5,6-unsaturated octahydro-1H-cyclopropa[a]naphthalene derivative.

Carnosic acid induces proteasomal degradation of Cyclin B1, RB and SOX2 along with cell growth arrest and apoptosis in GBM cells.

BACKGROUND Carnosic acid (CA) is a diterpenoid found in Rosmarinus officinalis L. and Salvia officinalis L. as well as in many other Lamiaceae. This compound is reported to have antioxidant and antimicrobial properties. In addition, a number of reports showed that CA has a cytotoxic activity toward several cancer cell lines. PURPOSE The aim of this study was to establish whether CA has any specific antiproliferative effect toward human glioblastoma (GBM) cells and to analyze the molecular mechanisms involved. METHODS We evaluated cell survival by MTT assay, apoptosis and DNA content by flow cytometry, protein expression and phosphorylation by immunoblot analyses. RESULTS Our results showed that CA inhibited cell survival on both normal astrocytes and GBM cells. In GBM cells, in particular, CA caused an early G2 block, a reduction in the percentage of cells expressing Ki67, an enhanced expression of p21(WAF) and induced apoptosis. Furthermore, we showed that CA promoted proteasomal degradation of several substrate proteins, including Cyclin B1, retinoblastoma (RB), SOX2, and glial fibrillary acid protein (GFAP), whereas MYC levels were not modified. In addition, CA dramatically reduced the activity of CDKs. CONCLUSION In conclusion, our findings strongly suggest that CA promotes a profound deregulation of cell cycle control and reduces the survival of GBM cells via proteasome-mediated degradation of Cyclin B1, RB and SOX2.

Anti-inflammatory and analgesic activity of carnosol and carnosic acid in vivo and in vitro and in silico analysis of their target interactions

The diterpenoids carnosol (CS) and carnosic acid (CA) from Salvia spp. exert prominent anti‐inflammatory activities but their molecular mechanisms remained unclear. Here we investigated the effectiveness of CS and CA in inflammatory pain and the cellular interference with their putative molecular targets.