The antimicrobial effect of Rosmarinus officinalis extracts on oral initial adhesion ex vivo

OBJECTIVE In the last few decades, there has been a growing worldwide interest in the use of plant extracts for the prevention of oral diseases. The main focus of this interest lies in the identification and isolation of substances that limit the formation of microbial biofilm which plays a major role in the development of caries, periodontitis, and peri-implantitis. In this clinical ex vivo study, we investigated the antimicrobial effects of Rosmarinus officinalis extract against oral microorganisms within in situ initial oral biofilms. MATERIALS AND METHODS Initial in situ biofilm samples (2 h) from six healthy volunteers were treated ex vivo with R. officinalis extract at concentrations of 20 mg/ml and 30 mg/ml. The number of viable bacterial cells was determined by counting the colony-forming units. All surviving bacteria were isolated in pure cultures and identified using MALDI-TOF and biochemical testing procedures. Additionally, live/dead staining in combination with epifluorescence microscopy was used for visualizing the antimicrobial effects in the initial biofilms. RESULTS The number of colony-forming units in the R. officinalis-treated biofilms was significantly lower than in the untreated controls (p < 0.001). The reduction range of log10 was 1.64-2.78 and 2.41-3.23 for aerobic and anaerobic bacteria, respectively. Regarding the bacterial composition, large intra- and interindividual variability were observed. Except for Campylobacter spp., the average amount of all bacterial taxa was lower after treatment with R. officinalis than in the untreated biofilms. A total of 49 different species were detected in the untreated biofilms, while only 11 bacterial species were detected in the R. officinalis-treated biofilms. Live/dead staining confirmed that the R. officinalis-treated biofilms had significantly lower numbers of surviving bacteria than the untreated biofilms. CONCLUSIONS The treatment with R. officinalis extract has a significant potential to eliminate microbial oral initial biofilms. CLINICAL RELEVANCE The results of this study encourage the use of R. officinalis extracts in biofilm control and thus in the treatment of caries and periodontitis as a herbal adjuvant to synthetic substances

Antimicrobial Photoinactivation Using Visible Light Plus Water-Filtered Infrared-A (VIS + wIRA) and Hypericum Perforatum Modifies In Situ Oral Biofilms

Due to increasing antibiotic resistance, the application of antimicrobial photodynamic therapy (aPDT) is gaining increasing popularity in dentistry. The aim of this study was to investigate the antimicrobial effects of aPDT using visible light (VIS) and water-filtered infrared-A (wIRA) in combination with a Hypericum perforatum extract on in situ oral biofilms. The chemical composition of H. perforatum extract was analyzed using ultra-high-performance liquid chromatography coupled with high resolution mass spectrometry (UPLC-HRMS). To obtain initial and mature oral biofilms in situ, intraoral devices with fixed bovine enamel slabs (BES) were carried by six healthy volunteers for two hours and three days, respectively. The ex situ exposure of biofilms to VIS + wIRA (200 mWcm$^{-2}$) and H. perforatum (32 mg ml$^{-1}$, non-rinsed or rinsed prior to aPDT after 2-min preincubation) lasted for five minutes. Biofilm treatment with 0.2% chlorhexidine gluconate solution (CHX) served as a positive control, while untreated biofilms served as a negative control. The colony-forming units (CFU) of the aPDT-treated biofilms were quantified, and the surviving microorganisms were identified using MALDI-TOF biochemical tests as well as 16 S rDNA-sequencing. We could show that the H. perforatum extract had significant photoactivation potential at a concentration of 32 mg ml$^{-1}$. When aPDT was carried out in the presence of H. perforatum, all biofilms (100%) were completely eradicated (p = 0.0001). When H. perforatum was rinsed off prior to aPDT, more than 92% of the initial viable bacterial count and 13% of the mature oral biofilm were killed. Overall, the microbial composition in initial and mature biofilms was substantially altered after aPDT, inducing a shift in the synthesis of the microbial community. In conclusion, H. perforatum-mediated aPDT using VIS + wIRA interferes with oral biofilms, resulting in their elimination or the substantial alteration of microbial diversity and richness. The present results support the evaluation of H. perforatum-mediated aPDT for the adjunctive treatment of biofilm-associated oral diseases

Volatile secondary metabolite pattern of callus cultures of Chamomilla recutita

The effects of various plant growth regulators and culture conditions on the production of volatile secondary metabolites from callus cultures of Chamomile (Chamomilla recutita) inflorescence were investigated and the most efficient conditions were determined. The essential oil composition was assayed by GC-MS analysis and found to contain chamomillol, gossonorol, cubenol, alpha -cadinol, (-)-alpha -bisabolol, 1-azulenethanol acetate and (-)-alpha -bisabolol acetate

Selective amination of secoiridoid glycosides to give monomeric pyridine, dimeric pyridine, and naphthyridine alkaloids

Treatment of the secoiridoids oleuropein (4), ligstroside (5) and methyloleoside (6) by beta -D-glucosidase in the presence of ammonium chloride led exclusively to monomeric pyridine alkaloids 7, 1, and 8. Dimeric 3,4,5-trisubstituted pyridines were obtained from methyloleoside (6) when ammonium chloride was generated in the reaction mixture by successive additions of ammonia and hydrochloric acid. The use of ammonium acetate permitted conversion of secoiridoids 4 and 5 into the naphthyridine alkaloid jasminine (3)

A new lignan glycoside and other constituents from Cephalaria ambrosioides

A new lignan glycoside, 1,5-dihydroxy-2-(4”-beta-D-glucopyranosyloxy-3”-methoxyphenyl)-6-( 4’-hydroxy-3’-methoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane, named ambrosidine (1), along with seven known compounds (four iridoids and three hydroxycinnamic esters) were isolated from the roots of Cephalaria ambrosioides. The structures of these compounds were determined by use of NMR and MS techniques and by chemical transformations. The cytotoxic activity of the novel compound 1 was evaluated against five human solid tumour cell lines

SYNTHESIS OF QUERCETIN-3-0-BETA-D-GLUCOPYRANOSYL-(1-]2)-BETA-D-XYLOPYRANOSIDE VIA ORTHOESTER METHODOLOGY

The synthesis of quercetin-3-O-beta-D-glucopyranosyl-(1–&gt;2)-beta-D-xylopyranoside [10], a flavonoid recently isolated from Kalanchoe prolifera, has been carried out via orthoester methodology

Chemistry of plants from Crete: Stachyspinoside, a new flavonoid glycoside and iridoids from Stachys spinosa

The new flavonoid glycoside stachyspinoside (1), and the three iridoids, 7-O-acetyl-8-epi-loganic acid (2), ajugol (3) and harpagide (4) were isolated from Stachys spinosa. The structures of these compounds were established on the basis of mass spectrometry (ESMS and tandem MS), one- and two-dimensional nuclear magnetic resonance experiments (COSY, COSY LR, HMQC, TOCSY and HMBC) as well as simple chemical derivatization

Antibacterial labdane-type diterpenes from the resin “ladano” of Cistus creticus subsp. creticus

The antibacterial activity of seven labdane-type diterpenes is reported. Five were isolated from the resin of the plant Cistus creticus, from which 13(E)-labd-13-ene, 8 alpha-ol-15-yl malonic acid (5)(1) is a new natural product, while the two others were hemisynthetic derivatives

Stereochemical effects in some acronycine derivatives

The stereochemical effects of 18 natural and synthetic 1,2-dihydro-1,2-disubstituted acronycine derivatives are reported. The conformation of the pyran D ring was determined by using J couplings and NOEs derived from 1D H-1 and D-2 NOESY spectra and molecular mechanics calculations. In the case of the 1-hydroxy derivatives the influence of the solvent, concentration and temperature on the H-1 chemical shifts suggests that aggregation phenomena take place in solution through the formation of an intermolecular hydrogen bond. Aggregation in the gas phase was confirmed by electrospray ionization mass Spectra. The assignment of the C-13 chemical shifts was made by 2D NMR techniques. A correlation between the relative stereochemistry at C(1) and C(2) on the D ring and the methyl group carbon chemical shifts was established. Copyright (C) 1999 John Wiley &amp; Sons, Ltd