The role of Gentiana lutea extracts in reducing UV-induced DNA damage.

Ultraviolet (UV) radiation can result in DNA damage, mainly through direct formation of pyrimidine dimers and generation of reactive oxygen species, which can lead to the skin disorders including cancer. In accordance with this, the use of natural antigenotoxins and/or antioxidants could contribute to human health protection. Considering that plants are rich in both, the aim of this study was to investigate UV-protective and antioxidative properties of yellow gentian (Gentiana lutea), being well established in pharmacopeias and traditional medicine. Tested extracts were derived from root and shoot of the in vitro cultivated plants. Prescreening of the genotoxic properties of UVC, UVA, and the extracts, as well as the extracts' antigenotoxicity were estimated by applying alkaline comet assay on normal fetal lung fibroblast (MRC-5) and human melanoma cells (Hs 294T). Antioxidant potential was tested in ferrous ions chelating ferric reducing antioxidant power and cupric reducing antioxidant capacity assays. Genotoxicity testing, which revealed moderate DNA-damaging potential of root extract on MRC-5 cells and high genotoxicity of shoot extract on both cell lines, pointed out nongenotoxic concentrations that could be used in antigenotoxicity assay. Doses of 63 and 3 J/cm2 for UVC and UVA, respectively, were established for antigenotoxicity study, since they induced sufficient DNA damage without notable cytotoxicity. Results of antigenotoxicity revealed strong protective effect of both extracts against UVC (the highest inhibitions 58% and 47%) and UVA (the highest inhibitions 69% and 60%), in Hs 294T and MRC-5 cells, respectively. Study of the antioxidative properties demonstrated stronger activity of shoot extract. Results obtained proved to be encouraging but further research of the UV-protective role of Gentiana lutea extracts and underlying molecular mechanisms is recommended.

Essential oils as adjuvants in endodontic therapy: myth or reality?

To enhance endodontics, the search for new antibacterials that can improve infected tooth root canal treatment is ongoing. As potent antibacterial and antibiofilm agents, essential oils (EOs) have been suggested as novel endodontic materials. Several studies indicate that EO-based irrigants and medicaments show promising reductive potential against the most important intracanal pathogen, Enterococcus faecalis, and notably contribute to intracanal biofilm eradication. In terms of additional benefits that EO-based endodontic materials can provide, their antioxidant and anti-inflammatory potential are also important, but they have only scarcely been explored in research. Investigations into the benefits of EO-based endodontic materials together with their biocompatibility are needed. The results presented in this review strongly encourage further research on this topic.

Chemical and Biological Investigations of Allium scorodoprasum L. Flower Extracts.

This study was designed to investigate the impact of different extraction solvent systems on the chemical composition and biological activities of Allium scorodoprasum L. (Amaryllidaceae)-the medicinal plant that was traditionally used as a remedy in the medieval period in the Balkans. Targeted chemical analysis of nine different extracts was performed by UHPLC(-)HESI-QqQ-MS/MS. Antimicrobial and antibiofilm activities of the extracts were investigated on sixteen clinical isolates of bacteria, yeasts and dermatomycetes, all isolated from infected human skin and corneal formations. Cytotoxicity and wound-healing properties were tested on human immortalized keratinocytes (HaCaT cell line). Antioxidant activity was assessed by six different assays, while beneficial potential against certain neurodegenerative diseases and type 2 diabetes was determined in selected enzyme inhibition assays coupled with molecular modeling. The results showed that the obtained extracts were rich in phenolic compounds, especially flavonoid glycosides such as rutin and kaempferol 3-O-glucoside. All of the extracts showed antimicrobial, wound-healing, antioxidant and anti-enzymatic properties. This study is the first of its kind, linking the medieval medicinal use of wild-growing flowers of A. scorodoprasum with contemporary in vitro scientific approaches.

Cymbopogon citratus essential oil: an active principle of nanoemulsion against Enterococcus faecalis root canal biofilm.

Aim: The objective was to formulate and characterize the nanoemulsion based on Cymbopogon citratus oil, intended for use in infected teeth root canal therapy. The investigation of the antioxidant and antibiofilm potential toward Enterococcus faecalis was aimed as well. Materials & methods: Characterization of oil (by GC/MS analysis) and nanoemulsion (by dynamic light scattering instrument), and determination of antibacterial (by microdilution assay), antibiofilm (by crystal violet assay) and antioxidant properties (by 2,2-diphenyl-1-picryl-hydrazyl-hydrate and thiobarbituric acid assay methods) were provided. Antibiofilm efficacy of irrigation procedure including nanoemulsion was screened on extracted teeth (by CFU-counting assay). Results: Notable antibacterial and antibiofilm activity, both against forming and preformed biofilms of oil, was observed. Irrigation involved nanoemulsion showed remarkable antibiofilm potential. Both substances induced some antioxidant activity. Conclusion: Results encourage further research with the aim of application of the nanoemulsion in dental practice.

In Vitro Study of Two Edible Polygonoideae Plants: Phenolic Profile, Cytotoxicity, and Modulation of Keap1-Nrf2 Gene Expression.

Polygonum aviculare and Persicaria amphibia (subfam. Polygonoideae) are used in traditional cuisines and folk medicine in various cultures. Previous studies indicated that phytochemicals obtained from Polygonoideae plants could sensitize chemoresistant cancer cells and enhance the efficacy of some cytostatics. Here, the cytotoxic properties of chemically characterized ethanol extracts obtained from P. aviculare and P. amphibia, individually and in combination with doxorubicin (D), were determined against hepatocarcinoma HepG2 cells. Phenolic composition, cell viability, cell cycle, apoptosis, and the expression of Keap1 and Nrf2 were examined by following methods: LC-MS/MS, LC-DAD-MS, MTT, flow cytometry, and qRT-PCR. Extracts were rich in dietary polyphenolics. Synergistic cytotoxicity was detected for extracts combined with D. The observed synergisms are linked to the interference with apoptosis, cell cycle, and expression of Keap1-Nrf2 genes involved in cytoprotection. The combined approach of extracts and D could emerge as a potential pathway of chemotherapy improvement.

New insight into the antigenotoxic activity of Gentiana lutea extracts - Protective effect against food borne mutagens.

Food mutagens formed from amino acids during heating of meat have the potential to induce serious consequences on human health. As a result, the identification of naturally occurring, genoprotective agents, is of great importance. The aim of this study was to chemically characterize a root and leaf extracts of Gentiana lutea and to investigate the antigenotoxic effects of extracts and pure constituents (gentiopicroside and mangiferin). Antigenotoxic effects were shown for combinations with the food borne mutagens IQ and PhIP using hepatoma HepG2 cells. Furthermore, their antioxidant activity and their capacity to modulate Nrf2 expression and affect the glutathione redox status were tested. Chemical analyses showed that the most abundant constituents found in root extract are gentiopicroside and sweroside. On the other hand, homoorientin and isovitexin were the dominant ones in leaf extract. Strong genoprotective activities of all tested compounds against both mutagens were observed in alkaline comet assays (up to 77% of tail intensity inhibition, p < 0.001). The protection against glutathione depletion was partially due to the radical scavenging activity and up-regulation of Nrf2 expression by the substances. The results of this study strongly encourage further investigations of the antimutagenic properties of G. lutea.

Anti-Virulence Potential and In Vivo Toxicity of Persicaria maculosa and Bistorta officinalis Extracts.

Many traditional remedies represent potential candidates for integration with modern medical practice, but credible data on their activities are often scarce. For the first time, the anti-virulence potential and the safety for human use of the ethanol extracts of two medicinal plants, Persicaria maculosa (PEM) and Bistorta officinalis (BIO), have been addressed. Ethanol extracts of both plants exhibited anti-virulence activity against the medically important opportunistic pathogen Pseudomonas aeruginosa. At the subinhibitory concentration of 50 µg/mL, the extracts demonstrated a maximal inhibitory effect (approx. 50%) against biofilm formation, the highest reduction of pyocyanin production (47% for PEM and 59% for BIO) and completely halted the swarming motility of P. aeruginosa. Both extracts demonstrated better anti-quorum sensing and antibiofilm activities, and a better ability to interfere with LasR receptor, than the tested dominant extracts' constituents. The bioactive concentrations of the extracts were not toxic in the zebrafish model system. This study represents an initial step towards the integration of P. maculosa and B. officinalis for use in the treatment of Pseudomonas infections.

Chemical characterization, antioxidant, genotoxic and in vitro cytotoxic activity assessment of Juniperus communis var. saxatilis.

Chemical composition and antioxidative, genotoxic and cytotoxic potential of essential oil (EO) and post-distillation waste (PDW) of Serbian Juniperus communis L. var. saxatilis Pall. was studied in human lung carcinoma (A549) and normal lung fibroblast (MRC-5) cells. GC-MS analysis identified 93.95% of total EO content and determined α-pinen as a dominant component (23.61%). LC-MS/MS analysis of PDW pointed at rutin (12.2 mg g-1) and quinic acid (11.1 mg g-1) as the most abundant. Antioxidativity of PDW was strong in DPPH (IC50 was 5.27 µg mL-1), and moderate in TBA and FRAP assays. Both substances were more cytotoxic to A549 than to MRC-5 cells. Obtained IC50 values were 69.4 µg mL-1 and 120 µg mL-1 for EO, and 1.27 mg mL-1 and 2.86 mg mL-1 for PDW, respectively. PDW was genotoxic (0.3 mg mL-1 and 1 mg mL-1 in A549 and MRC-5 cells, respectively) and induced apoptosis and arrested cell cycle in G2/M phase in A549 cells (0.3 mg mL-1). In mixtures with doxorubicin cytotoxicity of EO and PDW increased, and combination index values (0.12-0.18) revealed clear synergistic effect, stronger in cancer cells. This indicates that J. communis var. saxatilis could decrease the chemotherapeutic doses of doxorubicin, potentially reducing its side effects.

Effect of Allium flavum L. and Allium melanantherum Panc. Extracts on Oxidative DNA Damage and Antioxidative Enzymes Superoxide Dismutase and Catalase.

Allium flavum L. and Allium melanantherum Panc. are wild growing plants used in traditional diet in Balkan region. While chemical composition and some biological activities of A. flavum have been reported, A. melanantherum, as an endemic in the Balkan Peninsula, has never been comprehensively examined. After chemical characterization of A. melanantherum, we examined the protective effect of methanol extracts of both species against t-butyl hydro-peroxide (t-BOOH)-induced DNA damage and mutagenesis. The bacterial reverse mutation assay was performed on Escherichia coli WP2 oxyR strain. DNA damage was monitored in human fetal lung fibroblasts (MRC-5) with alkaline comet assay. Obtained results indicated that extracts reduced t-BOOH-induced DNA damage up to 70 and 72% for A. flavum and A. melanantherum extract, respectively, and showed no effect on t-BOOH-induced mutagenesis. Since the results indicated modulatory effect on cell-mediated antioxidative defense, the effect of extracts on total protein content, and superoxide dismutase (SOD) and catalase (CAT) amounts and activities were monitored. Both extracts increased total protein content, while the increase of enzyme amount and activity was obtained only with A. melanantherum extract and restricted to CAT. The activity of CuZnSOD family was not affected, while SOD1 and SOD2 amounts were significantly decreased, indicating potential involvement of extracellular CuZnSOD. Obtained results strongly support the traditional use of A. flavum and A. melanantherum in nutrition and recommend them for further study.

Essential oil variability in natural populations of Picea omorika, a rare European conifer.

This study is the first report on the composition and variability of essential oil in the relic, endemic, and vulnerable tree species Serbian spruce, Picea omorika, in its natural populations. In the needles of 108 trees of four natural populations, 49 components of essential oils were identified. The main compounds were bornyl acetate (29.2%), camphene (18.7%), and alpha-pinene (12.9%). Fourteen additional components had the contents of up to 0.5%: alpha-cadinol (6.1%), limonene (5.8%), santene (3.5%), (E)-hex-2-enal (2.9%), T-cadinol (2.9%), delta-cadinene (2.3%), tricyclene (2.1%), myrcene (1.6%), beta-pinene (1.2%), borneol (0.9%), germacrene D (0.9%), alpha-muurolene (0.6%), and two unidentified compounds. Population IV from Milesevka Canyon had a much higher content of bornyl acetate (42.9%). Populations I-III from Mt. Tara were more abundant in sesquiterpenes (up to 18.2%). The content of bornyl acetate, the multi-variation analyses according to seven selected components, especially the cluster analysis and genetic analysis of alpha-cadinol, which suggested the monogenic type of heredity, showed a clear differentiation of the two geographic areas, the similarity of populations I-III from the area of Mt. Tara, and the separation of the population IV from Milesevka Canyon.

Protective effect of basil (Ocimum basilicum L.) against oxidative DNA damage and mutagenesis.

Mutagenic and antimutagenic properties of essential oil (EO) of basil and its major constituent Linalool, reported to possess antioxidative properties, were examined in microbial tests. In Salmonella/microsome and Escherichia. coli WP2 reversion assays both derivatives (0.25-2.0 microl/plate) showed no mutagenic effect. Salmonella. typhimurium TA98, TA100 and TA102 strains displayed similar sensitivity to both basil derivatives as non-permeable E. coli WP2 strains IC185 and IC202 oxyR. Moreover, the toxicity of basil derivatives to WP2 strains did not depend on OxyR function. The reduction of t-BOOH-induced mutagenesis by EO and Linalool (30-60%) was obtained in repair proficient strains of the E. coli K12 assay (Nikolic, B., Stanojevic, J., Mitic, D., Vukovic-Gacic, B., Knezevic-Vukcevic, J., Simic, D., 2004. Comparative study of the antimutagenic potential of vitamin E in different E. coli strains. Mutat. Res. 564, 31-38), as well as in E. coli WP2 IC202 strain. EO and Linalool reduced spontaneous mutagenesis in mismatch repair deficient E. coli K12 strains (27-44%). In all tests, antimutagenic effect of basil derivatives was comparable with that obtained with model antioxidant vitamin E. Linalool and vitamin E induced DNA strand breaks in Comet assay on S. cerevisiae 3A cells, but at non-genotoxic concentrations (0.075 and 0.025 microg/ml, respectively) they reduced the number of H(2)O(2)-induced comets (45-70% Linalool and 80-93% vitamin E). Obtained results indicate that antigenotoxic potential of basil derivatives could be attributed to their antioxidative properties.