Phytochemical profile, in vitro bioaccessibility, and anticancer potential of golden root (Rhodiola rosea L.) extracts.

The effects of water and ethanolic (40 %, 70 %, and 96 %) extraction on the Rhodiola rosea L. phytochemical profile (HPLC analysis), stability during extract drying, potential bioaccessibility in simulated gastric and intestinal conditions, and cytotoxic activity against human colorectal adenocarcinoma cells (Caco-2 and HT-29 cell lines) were investigated. The phytochemical profile, extractability, and stability during extract processing depend on the solvent type. In general, compounds derived from dry extracts were characterized by higher bioaccessibility than those extracted from powdered plant material. In the case of salidroside, tyrosol, and rosavins, one of the highest bioaccessibilities (often about 100 %) were found for the 70 % ethanolic extract after gastric digestion. Furthermore, the 70 % ethanolic extract most effectively reduced the viability of Caco-2 cells (IC50 85.8 µg∙mL-1). The results suggest that golden root extracts, in particular 70 % ethanolic extract, seem to be promising supplements for the food industry.

Effects of oleuropein on tumor cell growth and bone remodelling: Potential clinical implications for the prevention and treatment of malignant bone diseases.

Oleuropein (Ole) is the main bioactive phenolic compound present in olive leaves, fruits and olive oil. This molecule has been shown to exert beneficial effects on several human pathological conditions. In particular, recent preclinical and observational studies have provided evidence that Ole exhibits chemo-preventive effects on different types of human tumors. Studies undertaken to elucidate the specific mechanisms underlying these effects have shown that this molecule may thwart several key steps of malignant progression, including tumor cell proliferation, survival, angiogenesis, invasion and metastasis, by modulating the expression and activity of several growth factors, cytokines, adhesion molecules and enzymes involved in these processes. Interestingly, experimental observations have highlighted the fact that most of these signalling molecules also appear to be actively involved in the homing and growth of disseminating cancer cells in bones and, ultimately, in the development of metastatic bone diseases. These findings, and the experimental and clinical data reporting the preventive activity of Ole on various pathological conditions associated with a bone loss, are indicative of a potential therapeutic role of this molecule in the prevention and treatment of cancer-related bone diseases. This paper provides a current overview regarding the molecular mechanisms and the experimental findings underpinning a possible clinical role of Ole in the prevention and development of cancer-related bone diseases.

Spray-dried olive mill wastewater reduces Maillard reaction in cookies model system.

The network of the Maillard reaction can be influenced by the presence of polyphenols. In this paper, we evaluated the ability of secoiridoids to interact with asparagine and lysine tuning the formation of dietary advanced glycation end-products (d-AGEs), dicarbonyls and acrylamide. Olive oil mill wastewater polyphenol powders (OMWP) were added to glucose and lysine or asparagine in silica model systems to mimic water activity present in cookies. Results revealed that acrylamide, Amadori compounds and N-ε-carboxyethyllysine (CEL) were reduced to 50%, after 13 min at 180 °C; for the reduction of N-ε-carboxymethyllysine (CML), secoiridoids were effective only in model systems with the addition of acacia fiber and maltodextrin as coating agents. In cookies, OMWP at three different concentrations decreased the concentration of protein bound Amadori compounds, CML, CEL and dicarbonyls. Acrylamide and 5-hydroxymethylfurfural were reduced to 60% and 76% respectively, highlighting the ability of secoiridoids-based functional ingredients in controlling d-AGEs formation.

Encapsulation of stevia rebaudiana Bertoni aqueous crude extracts by ionic gelation - Effects of alginate blends and gelling solutions on the polyphenolic profile.

We formulated and characterised two alginate blends for the encapsulation of stevia extract (SE) via ionic gelation through an extrusion technique. Calcium chloride in SE and calcium chloride solutions were assessed as crosslinkers to overcome phenolic losses by diffusion and increase encapsulation efficiency (EE). Regardless of the blend, all stevia-loaded beads exhibited high EE (62.7-101.0%). The size of the beads decreased as EE increased. Fourier transform infrared analysis showed increased hydrogen bonding between SE and alginates, confirming the successful incorporation of SE within the matrix. Untargeted metabolomics profiling identified 479 free and encapsulated polyphenolic compounds. Flavonoids (catechin and luteolin equivalents) were predominant in SE whereas tyrosols and 5-pentadecylresorcinol equivalents were predominant in all bead formulations. Three-common discriminant compounds were exclusive to each blend and were inversely affected by the crosslinking conditions. Both alginate blends have been shown to be feasible as carrier systems of stevia extracts independent of crosslinking conditions.

Gluten-free flours from cereals, pseudocereals and legumes: Phenolic fingerprints and in vitro antioxidant properties.

The interest in gluten-free (GF) products increases together with the increase in gluten-sensitive people. However, GF foods might have decreased nutritional quality as compared to the gluten containing counterparts. In this work, an investigation of the phenolic and antioxidant profile in 18 GF flours belonging to legumes, cereals and pseudocereals was achieved. Significant differences could be observed across samples. Total phenolic content was highest in violet rice flours, whereas total anthocyanins were highest in violet, nerone, and black rice flours. FRAP and ORAC antioxidant activities were correlated to phenolic contents and found to be higher in violet rice flours. Metabolomics highlighted a wide diversity in phenolics, with flavonoids (197 compounds ascribable to anthocyanins, flavones, flavanones, isoflavonoids, flavonols, and flavanols), phenolic acids (74 compounds belonging to hydroxycinnamics, hydroxybenzoics, and hydroxyphenylacetics), and tyrosol derivatives the most represented. Finally, OPLS-DA multivariate statistics outlined flavonoids, furofurans and phenolic acids as the most discriminant phenolics.

Structure-antioxidant activity relationship of ß-cyclodextrin inclusion complexes with olive tyrosol, hydroxytyrosol and oleuropein: Deep insights from X-ray analysis, DFT calculation and DPPH assay.

Olives and olive oil, a key food type of the Mediterranean diets, are packed with various important polyphenols including oleuropein (OLE), hydroxytyrosol (HTY) and tyrosol (TYR). OLE and HTY are highly powerful antioxidants and play a prime role in the therapeutics of free radical-related diseases. Their molecular stabilities and antioxidant properties can be improved by cyclodextrin (CD) encapsulation. Here, we present a systematic investigation on the inclusion complexes of ß-CD-TYR (1), ß-CD-HTY (2) and ß-CD-OLE (3) by combined single-crystal structure determination, DFT complete-geometry optimization and DPPH antioxidant assay. X-ray analysis and DFT calculation reveal the preference of inclusion geometry with deep protrusion of the aromatic ring moieties of TYR, HTY and OLE from the ß-CD O6-H-side, and the common host-guest stabilization scheme via intermolecular O-H⋯O hydrogen bonding interactions. No polyphenol OH group is shielded in the ß-CD cavity, in contrast to the structures of ß-CD-tea catechins complexes. The established host-guest O-H⋯O hydrogen bonds help to elevate antioxidant capacities of the olive polyphenols upon ß-CD encapsulation. The order of antioxidant activity 2 >3 ≫ 1 based on the DPPH measurement is in fair agreement with their relative thermodynamic stabilities derived from DFT calculation.

Bioactive fraction of Rhodiola algida against chronic hypoxia-induced pulmonary arterial hypertension and its anti-proliferation mechanism in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhodiola algida var. tangutica (Maxim.) S.H. Fu is a perennial plant of the Crassulaceae family that grows in the mountainous regions of Asia. The rhizome and roots of this plant have been long used as Tibetan folk medicine for preventing high latitude sickness. AIM OF THE STUDY: The aim of this study was to determine the effect of bioactive fraction from R. algida (ACRT) on chronic hypoxia-induced pulmonary arterial hypertension (HPAH) and to understand the possible mechanism of its pharmacodynamic actions. MATERIALS AND METHODS: Male Sprague-Dawley rats were separated into five groups: control group, hypoxia group, and hypoxia+ACRT groups (62.5, 125, and 250mg/kg/day of ACRT). The chronic hypoxic environment was created in a hypobaric chamber by adjusting the inner pressure and oxygen content for 4 weeks. After 4 weeks, major physiological parameters of pulmonary arterial hypertension such as mPAP, right ventricle index (RV/LV+S, RVHI), hematocrit (Hct) levels and the medial vessel thickness (wt%) were measured. Protein and mRNA expression levels of proliferating cell nuclear antigen (PCNA), cyclin D1, p27Kip1 and cyclin-dependent kinase 4 (CDK4)) were detected by western blotting and real time PCR respectively. Chemical profile of ACRT was revealed by ultra performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (UHPLC-Q-TOF-MS/MS). RESULTS: The results showed that a successful HPAH rat model was established in a hypobaric chamber for 4 weeks, as indicated by the significant increase in mPAP, RV/LV+S, RV/BW and wt%. Compared with the normal group, administration of ACRT reduced mPAP, right ventricular hypertrophy, pulmonary small artery wall thickness, and damage in ultrastructure induced by hypoxia in rats. PCNA, cyclin D1, and CDK4 expression was reduced (p<0.05), and p27Kip1 expression increased (p<0.05) in hypoxia+ACRT groups compared to hypoxia. 38 constituents in bioactive fraction were identified by UHPLC-Q-TOF-MS/MS. CONCLUSION: Our results suggest that ACRT could alleviate chronic hypoxia-induced pulmonary arterial hypertension. And its anti-proliferation mechanism in rats based on decreasing PCNA, cyclin D1, CDK4 expression level and inhibiting p27Kip1 degradation.

Bioaccessibility of phenolic compounds following in vitro large intestine fermentation of nuts for human consumption.

A bioaccessibility study of polyphenols after in vitro simulated large intestine fermentation was carried out on edible nuts. Raw nuts were also analysed for total phenolic content and antioxidant potential, considering both bound and free phenolics. The highest phenolic content was found in walnuts, followed by pistachios extracts (596.9 and 410.1 mg gallic acid equivalents 100 g-1, respectively). Consistently, the total antioxidant capacity was highest in walnuts (3689.7 µM trolox equivalents 100 g-1) followed by peanuts and pistachios (3169.6 and 2990.1 µM trolox equivalents 100 g-1, respectively). Data showed high correlations between total phenolics and both antioxidant activities. The metabolomics-based phenolic profile depicted during in vitro fermentation showed a degradation of higher-molecular-weight phenolics over 48 hours of faecal fermentation, with a concurrent increase in low-molecular-weight compounds (hydroxybenzoic and hydroxycinnamic acids, alkylphenols, and tyrosols). Our findings indicate that nuts deliver polyphenols into the colon, with bioaccessibility values not negligible for alkylphenols, tyrosols and phenolic acids.

Impact of boiling on free and bound phenolic profile and antioxidant activity of commercial gluten-free pasta.

Cooking by boiling dry pasta could have varying degrees of influence on nutritional and functional components. In the present study, its effect on total phenolic content and antioxidant capacity, as well as on the comprehensive profile of free and bound phenolics, was investigated in six commercial gluten-free (GF) pasta products. Overall, the heat treatment caused a significant reduction (P<0.01) of the total phenolic content as well as FRAP reducing power and ORAC radical scavenging, with significant differences among the pasta samples considered. The highest values were recorded in free phenolic fraction remaining in black rice (41mggallic acid equivalents100g-1 and 25mmolTrolox Equivalents100g-1) and quinoa (24mggallic acid equivalents100g-1 and 14mmolTrolox Equivalents100g-1) cooked GF pasta. Significant correlations (P<0.01) could be found between total phenolics and both the antioxidant capacity assays performed. UHPLC-ESI/QTOF-MS mass profiling allowed confirming the spectrophotometric results, while identifying the amount of free and bound fractions. Among phenolic classes, lignans exhibited the highest decrease during the cooking process, followed by stilbenes and flavonoids. However, phenolic acids and other phenolics showed the highest stability. Furthermore, cooking by boiling strongly lowered the bound-to-free ratio of phenolic compounds, by an averaged factor ranging from 14-folds for flavonoids to 5-folds for other classes of phenolics.

Cold storage of 'Manzanilla de Sevilla' and 'Manzanilla Cacereña' mill olives from super-high density orchards.

The suitability of the cold storage (2°C) of fruit to maintain the quality of 'Manzanilla de Sevilla' and 'Manzanilla Cacereña' intended for virgin olive oil extraction was investigated. This temperature was effective in keeping the best commercial category of oil quality in both manually harvested olives and in mechanically harvested 'Manzanilla Cacereña' fruits for 11days. Mechanical harvesting induced significant decreases in oxidative stability and in the main phenolic compounds contents in the oils during cold storage and, only initially, in the total volatiles, regardless of the cultivar considered. However, the contents of volatile esters, associated to fruity flavor, were always higher in the oils from mechanically harvested fruits. 'Manzanilla de Sevilla' oils exhibited higher total volatiles during fruit cold storage, regardless of the harvesting system used.

Phenolic profile and fermentation patterns of different commercial gluten-free pasta during in vitro large intestine fermentation.

The fate of phenolic compounds, along with short-chain fatty acids (SCFAs) production kinetics, was evaluated on six different commercial gluten-free (GF) pasta samples varying in ingredient compositions, focussing on the in vitro faecal fermentation after the gastrointestinal digestion. A general reduction of both total phenolics and reducing power was observed in all samples, together with a substantial change in phenolic profile over 24h of faecal fermentation, with differences among GF pasta samples. Flavonoids, hydroxycinnamics and lignans degraded over time, with a concurrent increase in low-molecular-weight phenolic acids (hydroxybenzoic acids), alkylphenols, hydroxybenzoketones and tyrosols. Interestingly, discriminant analysis also identified several alkyl derivatives of resorcinol as markers of the changes in phenolic profile during in vitro fermentation. Furthermore, degradation pathways of phenolics by intestinal microbiota have been proposed. Considering the total SCFAs and butyrate production during the in vitro fermentation, different fermentation kinetics were observed among GF pasta post-hydrolysis residues.

LC-MS phenolic profiling combined with multivariate analysis as an approach for the characterization of extra virgin olive oils of four rare Tunisian cultivars during ripening.

In this work, the phenolic composition of four rare cultivars grown under the same agronomical and environmental conditions was studied. This is to test the effects of cultivars and ripening index essentially on phenolic composition in olive oils as well as tocopherols composition, organoleptic profiling and oxidative properties. Furthermore, some agronomical traits were determined in which a general increase in the size of the fruit and oil contents were recorded for all cultivars. The phenolic fractions were identified and quantified using liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS) in multiple reaction monitoring mode (MRM). A total of 13 phenolic compounds belonging to different chemical families were determined. Qualitative and quantitative differences in phenolic composition were observed among cultivars and also among sampling times. On the contrary to the agronomical traits, a general decrease (p<0.05) of total phenolic compounds was observed during maturation. Likewise, a decrease in tocopherols concentrations and oxidative properties was observed.

Perceived bitterness character of beer in relation to hop variety and the impact of hop aroma.

The impact of hop variety and hop aroma on perceived beer bitterness intensity and character was investigated using analytical and sensory methods. Beers made from malt extract were hopped with 3 distinctive hop varieties (Hersbrucker, East Kent Goldings, Zeus) to achieve equi-bitter levels. A trained sensory panel determined the bitterness character profile of each singly-hopped beer using a novel lexicon. Results showed different bitterness character profiles for each beer, with hop aroma also found to change the hop variety-derived bitterness character profiles of the beer. Rank-rating evaluations further showed the significant effect of hop aroma on selected key bitterness character attributes, by increasing perceived harsh and lingering bitterness, astringency, and bitterness intensity via cross-modal flavour interactions. This study advances understanding of the complexity of beer bitterness perception by demonstrating that hop variety selection and hop aroma both impact significantly on the perceived intensity and character of this key sensory attribute.

Direct study of minor extra-virgin olive oil components without any sample modification. 1H NMR multisupression experiment: A powerful tool.

Proton Nuclear Magnetic Resonance (1H NMR) was employed to study monovarietal commercial Spanish extra-virgin olive oils (EVOO) (Arbequina, Arroniz, Cornicabra, Hojiblanca and Picual). Each sample was analyzed by a standard pulse and by an experiment suppressing the main lipid signals, enabling the detection of signals of minor components. The aim was to determine the possibilities of both 1H NMR approaches to characterize EVOO composition, focusing on acyl groups, squalene, sterols, triterpene acids/esters, fatty alcohols, wax esters and phenols (lignans, tyrosol, hydroxytyrosol, oleocanthal, oleacein, oleokoronal, oleomissional, ligstrodials and oleuropeindials), and to determine hydrolysis and oxidation levels. The signal assignments (in deuterated chloroform) are thoroughly described, identifying for the first time those of the protons of esters of phytol and of geranylgeraniol. Correct signal assignment is fundamental for obtaining sound results when interpreting statistical data from metabolomic studies of EVOO composition and adulteration, making it possible to differentiate and classify oils.

CYP2D6 and CYP2A6 biotransform dietary tyrosol into hydroxytyrosol.

The dietary phenol tyrosol has been reported to be endogenously transformed into hydroxytyrosol, a potent antioxidant with multiple health benefits. In this work, we evaluated whether tyrosine hydroxylase (TH) and cytochrome P450s (CYPs) catalyzed this process. To assess TH involvement, Wistar rats were treated with α-methyl-L-tyrosine and tyrosol. Tyrosol was converted into hydroxytyrosol whilst α-methyl-L-tyrosine did not inhibit the biotransformation. The role of CYP was assessed in human liver microsomes (HLM) and tyrosol-to-hydroxytyrosol conversion was observed. Screening with selective enzymatic CYP inhibitors identified CYP2A6 as the major isoform involved in this process. Studies with baculosomes further demonstrated that CYP2D6 and CYP3A4 could transform tyrosol into hydroxytyrosol. Experiments using human genotyped livers showed an interindividual variability in hydroxytyrosol formation and supported findings that CYP2D6 and CYP2A6 mediated this reaction. The dietary health benefits of tyrosol-containing foods remain to be evaluated in light of CYP pharmacogenetics.

Olive mill wastewater microconstituents composition according to olive variety and extraction process.

Olive oil production yields a considerable amount of wastewater, a powerful pollutant that is currently discarded but could be considered as a potential source of valuable natural products due to its content in phenolic compounds and other natural antioxidants. The aim of this work was to explore the variability in olive mill wastewater composition from Algerian olive oil mills considering extraction processes (traditional discontinuous press vs 3-phases centrifugal system) and olive varieties (Azerraj, Sigoise, Chemlal). Whereas pH, dry or organic matter content didn't vary, there was a significant difference in ash content according to extraction process and olive variety. Carotenoid content was 2.2-fold higher with 3-phases than with press systems whereas tocopherol content was not significantly different. Among the phenolic compounds quantified, tyrosol was usually the most abundant whereas oleuropein concentrations were highly variable. Differences in phenolic compound concentrations were more pronounced between olive varieties than between processes.

Rapid screening and identification of phenolic antioxidants in Hydrocotyle sibthorpioides Lam. by UPLC-ESI-MS/MS.

The aim of the study was to identify the phenolic compounds present in Hydrocotyle sibthorpioides (HS), Centella asiatica (CA) and Amaranthus viridis (AV) extracts and investigate their respective antioxidant activities. Herein, an ultra-high pressure liquid chromatography-mass spectrometer (UPLC-MS/MS) analytical method has been developed for the separation, and systematic characterization of the phenolic compounds in HS, CA and AV extracts and was compared along with ten standard phenolic compounds. Additionally, in vitro antioxidant activity of the phenolic compounds was also determined. The HS extract revealed excellent antioxidant activity such as 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (IC50=19.7 ± 1.2 µg/mL), total reduction capability (0.169 ± 0.003 at 100 µg/mL), nitric oxide radical scavenging activity (IC50=39.33 ± 3.2 µg/mL), metal chelating activity (IC50=56.51 ± 3.6 µg/mL) and inhibition of lipid peroxidation (IC50=12.34 ± 2.3 µg/mL) as compared to CA and AV extracts. Furthermore, catechin, epicatechin, quercetin and chlorogenic acid were found to be the major components responsible for the antioxidant activity of the HS extract as evidenced from UPLC-MS/MS. Taken together, this study demonstrates the promising antioxidant properties of the HS extract, which can further be utilized in various pharmaceutical, food, and agricultural applications.

De novo biosynthesis of Gastrodin in Escherichia coli.

Gastrodin, a phenolic glycoside, is the key ingredient of Gastrodia elata, a notable herbal plant that has been used to treat various conditions in oriental countries for centuries. Gastrodin is extensively used clinically for its sedative, hypnotic, anticonvulsive and neuroprotective properties in China. Gastrodin is usually produced by plant extraction or chemical synthesis, which has many disadvantages. Herein, we report unprecedented microbial synthesis of gastrodin via an artificial pathway. A Nocardia carboxylic acid reductase, endogenous alcohol dehydrogenases and a Rhodiola glycosyltransferase UGT73B6 transformed 4-hydroxybenzoic acid, an intermediate of ubiquinone biosynthesis, into gastrodin in Escherichia coli. Pathway genes were overexpressed to enhance metabolic flux toward precursor 4-hydroxybenzyl alcohol. Furthermore, the catalytic properties of the UGT73B6 toward phenolic alcohols were improved through directed evolution. The finally engineered strain produced 545mgl(-1) gastrodin in 48h. This work creates a new route to produce gastrodin, instead of plant extractions and chemical synthesis.

Fermentation of table olives by oleuropeinolytic starter culture in reduced salt brines and inactivation of Escherichia coli O157:H7 and Listeria monocytogenes.

The effect of an autochthonous starter culture developed by oleuropeinolytic strains belonging to the Lactobacillus plantarum group on the physicochemical and microbiological characteristics and the biophenol content of table olives fermented under reduced salt conditions was studied. Black (cv. Kalamata) and green (cv. Chalkidikis) olives were fermented in two different kinds of brine (Brine A containing 2.3% NaCl, 32.3mM Ca-acetate and 33.9mM Ca-lactate and Brine B containing 4% NaCl, pH5.0 in both brines). The sensory attributes of olives fermented by oleuropeinolytic starter culture assessed by a trained panel did not differ significantly compared with industrial processing. It is possible to carry out significant changes in table olive processing applying a completely microbiological procedure using oleuropeinolytic strains of the L. plantarum group as both the debittering and the fermentation agent in order to achieve improved sensorial and nutritional characteristics of the final product. Table olives processed by the suggested methodology may constitute a good source of biophenols in the diet, especially hydroxytyrosol and tyrosol. The inactivation potential of Escherichia coli O157 EDL-932 and Listeria monocytogenes Scott A in olives fermented by oleuropeinolytic starter culture was evaluated. The population of each pathogen in olive homogenates of both cultivars is inactivated by more than 6logCFU/ml in less than 24h. When whole fermented olives were submerged in peptone/saline (containing 6.7logCFU/ml of the relevant bacterial pathogen) for 30min followed by rinsing in distilled water, the population of viable foodborne pathogens dropped more than 4 logs in olive pulp. During subsequent storage at 22 or 4°C the population of L. monocytogenes Scott A was further eliminated under the detection limit in both olive cultivars whereas the population of E. coli O157 EDL-932 could be detected in olives stored in peptone/saline at 22°C for 7days. The inhibitory effect of olives fermented by oleuropeinolytic starter culture in reduced salt brines on pathogens is due to the antimicrobial activity of the phenolic compounds and the antagonistic action of the associated microflora.