Anca Miron

Advance on the Flavonoid C-glycosides and Health Benefits

The dietary flavonoids, especially their glycosides, are the most vital phytochemicals in diets and are of great general interest due to their diverse bioactivity. Almost all natural flavonoids exist as their O-glycoside or C-glycoside forms in plants. The dietary flavonoid C-glycosides have received less attention than their corresponding O-glycosides. This review summarizes current knowledge regarding flavonoid C-glycosides and their influence on human health. Among the flavonoid C-glycosides, flavone C-glycosides, especially vitexin, isoorientin, orientin, isovitexin and their multiglycosides are more frequently mentioned than others. Flavonoid C-monoglycosides are poorly absorbed in human beings with very few metabolites in urine and blood and are deglycosylated and degraded by human intestinal bacteria in colon. However, flavonoid C-multiglycosides are absorbed unchanged in the intestine and distributed to other tissues. Flavonoid C-glycosides showed significant antioxidant activity, anticancer and antitumor activity, hepatoprotective activity, anti-inflammatory activity, anti-diabetes activity, antiviral activity, antibacterial and antifungal activity, and other biological effects. It looks like that the C-glycosylflavonoids in most cases showed higher antioxidant and anti-diabetes potential than their corresponding O-glycosylflavonoids and aglycones. However, there is a lack of in vivo data on the biological benefits of flavonoid C-glycosides. It is necessary to investigate more on how flavonoid C-glycosides prevent and handle the diseases.

Intracellular signaling pathways of inflammation modulated by dietary flavonoids: The most recent evidence

ABSTRACT Dietary flavonoids, which occur in many plant foods, are considered as the most active constituents among the plant-derived ones in vitro and in vivo. To date, many studies have addressed the anti-inflammatory activity of flavonoids. However, their considerable structural diversity and in vivo bioavailability make them able to modulate different signaling pathways. The present review attempted to summarize and highlight a broad range of inflammation-associated signaling pathways modulated by flavonoids. Finally, based on the current scientists literature, structure-activity relationships were concluded. Dietary flavonoids have the ability to attenuate inflammation by targeting different intracellular signaling pathways triggered by NF-κB, AP-1, PPAR, Nrf2, and MAPKs. Identification of the main structural features required for the modulation of these inflammation-related pathways (hydroxylation pattern, C2=C3 double bond) have an important role to play in the development of new anti-inflammatory drugs.

Flavonoids as modulators of metabolic enzymes and drug transporters

Flavonoids, natural compounds found in plants and in plant‐derived foods and beverages, have been extensively studied with regard to their capacity to modulate metabolic enzymes and drug transporters. In vitro, flavonoids predominantly inhibit the major phase I drug‐metabolizing enzyme CYP450 3A4 and the enzymes responsible for the bioactivation of procarcinogens (CYP1 enzymes) and upregulate the enzymes involved in carcinogen detoxification (UDP‐glucuronosyltransferases, glutathione S‐transferases (GSTs)). Flavonoids have been reported to inhibit ATP‐binding cassette (ABC) transporters (multidrug resistance (MDR)–associated proteins, breast cancer–resistance protein) that contribute to the development of MDR. P‐glycoprotein, an ABC transporter that limits drug bioavailability and also induces MDR, was differently modulated by flavonoids. Flavonoids and their phase II metabolites (sulfates, glucuronides) inhibit organic anion transporters involved in the tubular uptake of nephrotoxic compounds. In vivo studies have partially confirmed in vitro findings, suggesting that the mechanisms underlying the modulatory effects of flavonoids are complex and difficult to predict in vivo. Data summarized in this review strongly support the view that flavonoids are promising candidates for the enhancement of oral drug bioavailability, chemoprevention, and reversal of MDR.

Antioxidant and antigenotoxic potential of Ramaria largentii Marr & D. E. Stuntz, a wild edible mushroom collected from Northeast Romania

Ramaria largentii Marr & D. E. Stuntz (orange coral mushroom) is a wild edible mushroom whose chemical composition and bioactivity have not been investigated. Herein, we present a study on the phenolic constituents, antioxidant and antigenotoxic effects of a hydromethanolic extract of the fruiting bodies. Total phenolic content, estimated by Folin-Ciocalteu assay, was found to be 42.33xa0±xa00.18xa0mg GAE/g. Protocatechuic and vanillic acids were detected by HPLC-DAD-ESI-MS. The extract showed good free radical scavenging and reducing capacities (EC50xa0=xa064.3xa0±xa00.2 and 61.54xa0±xa00.46xa0μg/mL, respectively). In normal Vero cells, the extract (100, 200 and 300xa0μg/mL) showed no genotoxic potential and moreover, almost completely protected DNA against H2O2-induced damage (2.09-7.91% tail DNA) (24 and 48xa0h pre-treatment). Taken together, the results of our study show that Ramaria largentii extract is devoid of genotoxicity and has a remarkable DNA protective activity against H2O2-induced damage.

WITHDRAWN: The paradox of natural flavonoid C-glycosides and health benefits: When more occurrence is less research

This article has been withdrawn at the request of the editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.

Biodegradation and Detoxification Efficiency of Azo-Dye Reactive Orange 16 by Pichia kudriavzevii CR-Y103

In consideration of the hazards associated with the presence of the textile azo-dye and their biotransformation products in the environment, the goal of this work was to study bioremediation process by the yeast strain Pichia kudriavzevii CR-Y103 related to the ability to degrade and detoxify the sulfonated Reactive Orange 16 azo-dye. In experimental conditions, the optimal inoculum/dye concentration ratio required for complete decolorization (100%) of culture medium and biomass within 24xa0h has been 1xa0gxa0L−1 yeast cell (dry weight)/50xa0mgxa0L−1 Reactive Orange 16. In the presence of 400xa0mgxa0L−1 of Reactive Orange 16 (RO16), 95% of the dye was removed after 72xa0h of incubation. Also, the yeast strain could decolorize other eight textile dyes (56.48–99.98% decolorization within 24xa0h). NADH-DCIP reductase and azo reductase activities were significantly increased (ca. 5.4 times and ca. 37 times, respectively) during the decolorization process. UV-VIS spectra, high-performance liquid chromatography (HPLC), and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the presence of new biotransformation products in extracted metabolites, highlighting the partial biodegradation of the dye by the new yeast isolate. The phytotoxicity evaluation strongly supported the decreased toxicity of biodegraded products as minor inhibition on germination (%), root and shoots elongation of T. pratense L. and T. aestivum L. seedlings. Increasing of mitotic index value and decreasing the frequency of chromosomal aberrations in tested plant meristem cells treated with biodegraded products, compared with RO16 treatment (500xa0ppm), confirmed their slightly toxic nature. A cell viability assay also confirmed the reduced toxicity of biodegraded products on healthy monkey kidney cells (Vero cells).

HPLC‐DAD‐ESI‐Q‐TOF‐MS/MS profiling of Verbascum ovalifolium Donn ex Sims and evaluation of its antioxidant and cytogenotoxic activities

INTRODUCTIONnPlant species of Verbascum genus have been intensively investigated in the last decades but most studies focused on evaluation of their biological activities; there are only few studies dealing with their chemical characterisation.nnnOBJECTIVEnDetailed investigation of the qualitative and quantitative chemical composition, antioxidant and cytogenotoxic activities of a previously non-studied Verbascum species (V. ovalifolium Donn ex Sims).nnnMETHODSnQualitative analysis of secondary metabolites was performed by HPLC-DAD-ESI-Q-TOF-MS/MS, whereas quantitative data were obtained through HPLC-DAD. Antioxidant activity was evaluated using in vitro assays; cytotoxic and genotoxic effects were assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium (MTT) and comet assays, respectively.nnnRESULTSnMore than 50 secondary bioactive metabolites belonging to various classes (iridoids, phenylethanoids, flavonoids, phenolic acids) were detected in the methanolic extract of V. ovalifolium and its fractions. The fragmentation pathways of acylated catalpol-type iridoid diglycosides are thoughtfully described herein. The extracts showed good free radical scavenging and ferric ion reducing properties correlated with phenolic, flavonoid, chlorogenic acid and verbascoside contents. Moreover, 24xa0h treatment of SK-MEL-2 cells with V. ovalifolium extracts produced significant changes in terms of tumour cell viability. The crude extract and the ethyl acetate fraction showed no important signs of cytogenotoxicity in non-tumour cells.nnnCONCLUSIONnThe performed phytochemical and biological analyses contribute to the preclinical knowledge about V. ovalifolium and they could help exploiting it in novel herbal medicinal products.

Antibacterial activity of traditional spices against lower respiratory tract pathogens: combinatorial effects of Trachyspermum ammi essential oil with conventional antibiotics

The aim of this study was to investigate the effects of ajowan essential oil (AjEO)/thymol and antibiotics combinations against three standard strains and six resistant clinical isolates of major respiratory bacteria (Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae). The broth microdilution method was conducted to determine the minimum inhibitory concentrations (MIC) of essential oil/thymol and antibiotics. The checkerboard method was used to investigate the interactions between the essential oil/thymol and antibiotics by means of the fractional inhibitory concentration index (FICI). The chemical composition of essential oil was also analysed by GC–MS and GC‐FID. Thymol (50·75%), γ‐terpinene (25·94%) and p‐cymene (18·31%) were identified as major constituents of the oil. The most sensitive organisms to ajowan volatile oil were Strep. pneumoniae bacteria (MIC = 0·125–0·5 mg ml−1). Synergistic effects were observed with AjEO/thymol and amoxicillin combinations on methicillin‐resistant Staph. aureus clinical isolates (FICI = 0·37–0·50) and with essential oil and ciprofloxacin combinations against P. aeruginosa ATCC 27853, Staph. aureus ATCC 25923 and penicillin (P)‐resistant Strep. pneumoniae bacteria (FICI = 0·37–0·50). Combination of thymol and ciprofloxacin produces synergistic effects only against P. aeruginosa ATCC 27853 and P‐resistant Strep. pneumoniae clinical isolate (FICI = 0·46–0·49).