Sonia Medina

Alcoholic fermentation induces melatonin synthesis in orange juice

Melatonin (N‐acetyl‐5‐methoxytryptamine) is a molecule implicated in multiple biological functions. Its level decreases with age, and the intake of foods rich in melatonin has been considered an exogenous source of this important agent. Orange is a natural source of melatonin. Melatonin synthesis occurs during alcoholic fermentation of grapes, malt and pomegranate. The amino acid tryptophan is the precursor of all 5‐methoxytryptamines. Indeed, melatonin appears in a shorter time in wines when tryptophan is added before fermentation. The aim of the study was to measure melatonin content during alcoholic fermentation of orange juice and to evaluate the role of the precursor tryptophan. Identification and quantification of melatonin during the alcoholic fermentation of orange juice was carried out by UHPLC‐QqQ‐MS/MS. Melatonin significantly increased throughout fermentation from day 0 (3.15 ng/mL) until day 15 (21.80 ng/mL) reaching larger amounts with respect to other foods. Melatonin isomer was also analysed, but its content remained stable ranging from 11.59 to 14.18 ng/mL. The enhancement of melatonin occurred mainly in the soluble fraction. Tryptophan levels significantly dropped from 13.80 mg/L (day 0) up to 3.19 mg/L (day 15) during fermentation. Melatonin was inversely and significantly correlated with tryptophan (r = 0.907). Therefore, the enhancement in melatonin could be due to both the occurrence of tryptophan and the new synthesis by yeast. In summary, the enhancement of melatonin in novel fermented orange beverage would improve the health benefits of orange juice by increasing this bioactive compound.

Fermented Orange Juice: Source of Higher Carotenoid and Flavanone Contents

The intake of bioactive compounds and moderate alcohol decreases the risk of cardiovascular diseases. These effects could be joined in a beverage created by a controlled alcoholic fermentation of orange juice. The influence of controlled alcoholic fermentation on the bioactive compound profile of orange juice has not been previously evaluated, and this is the purpose of the present study. Total and individual flavanones and carotenoids significantly increased throughout the fermentation. The reason for this was an enhanced extraction of these compounds from the pulp. Besides, the potential bioavailability of flavanones increased due to a higher content of hesperetin-7-O-glucoside (2-fold higher at the end of the fermentation process). Ascorbic acid did not undergo a significant change, and only total phenolics decreased. Antioxidant capacity was also evaluated. TEAC and FRAP values remained constant throughout the process. However, ORAC and DPPH values significantly increased. Correlation analysis concluded that the increase in ORAC and DPPH values could be due to enhancement of flavanones.

Melatonin content of pepper and tomato fruits: effects of cultivar and solar radiation.

We evaluated the effect of cultivar and solar radiation on the melatonin content of Capsicum annuum (pepper) and Solanum lycopersicum (tomato) fruits. The melatonin content of red pepper fruits ranged from 31 to 93ngg(-1) (dry weight). The melatonin content of tomato ranged from 7.5 to 250ngg(-1) (dry weight). We also studied the effect of ripeness on melatonin content and identified one group of pepper cultivars in which the melatonin content increased as the fruit ripened and another in which it decreased as the fruit ripened. Under shade conditions, the melatonin content in most of tomato cultivars tended to increase (up to 135%), whereas that of most pepper cultivars decreased (to 64%). Overall, the results also demonstrated that the melatonin content of the fruits was not related to carbon fluxes from leaves.

New UHPLC-QqQ-MS/MS method for quantitative and qualitative determination of free phytoprostanes in foodstuffs of commercial olive and sunflower oils

In this work, we propose a new quick and accurate analytical method by UHPLC-QqQ-MS/MS which is able to identify free phytoprostanes in olive and refined sunflower oils. The recovery provided high extraction efficiencies ranging from 102.90% to 140.64% using Strata-XAW cartridge. The intra-day and inter-day variations for all target compounds ranged from 2.24% to 13.64% and 0.01% to 13.69%, respectively, and the accuracies for these parameters varied from 80.33% to 119.64% and from 80.34% to 119.90%, respectively. Results obtained reflect that refined sunflower presented more series of phytoprostanes and a 20 and 8-fold higher quantity than two types of olive oil: Extra virgin olive oil and olive oil, (containing half virgin extra olive oil and half refined olive oil). The manufacture process could be the key for the different phytoprostane production since most of the plant oils are subjected to a refining treatment.

Dihomo-isoprostanes—nonenzymatic metabolites of AdA—are higher in epileptic patients compared to healthy individuals by a new ultrahigh pressure liquid chromatography–triple quadrupole–tandem mass spectrometry method

Oxidative stress is a biochemical state in which reactive oxygen species are generated and it has been associated with pathological states including epilepsy. Therein, neuroprostanes (NeuroPs) and dihomo-isoprostanes (Dihomo-IsoPs)-a series of compounds formed nonenzymatically through free radical-induced DHA, n-6 DPA, and AdA peroxidation-are implicated in the pathophysiological status of various human neurological diseases. A new, robust, and selective analytical method for the determination of 10 NeuroPs/Dihomo-IsoPs in human urine, using solid-phase extraction and UHPLC-QqQ-MS/MS in the multiple reaction monitoring mode (using a negative electrospray ionization interface), was developed. Nine NeuroPs/Dihomo-IsoPs were identified in 15 epileptic patients, matched with healthy volunteers. Among them, 17-F2t-Dihomo-IsoP, Ent-7(R)-7-F2t-Dihomo-IsoP, and Ent-7-epi-7-F2t-Dihomo-IsoP, derived from adrenic acid (AdA), were significantly higher in epileptic patients than in healthy volunteers. The validated method provided a high-throughput assay with a limit of detection and limit of quantification for each analyte of 0.10-5.90ngmL(-1) and 0.15-11.81ngmL(-1), respectively. The intra- and interday variations were lower than 14%. Dihomo-IsoPs have been considered as potential markers of epilepsy for the first time and their measurement may increase the understanding of the role of oxidative stress in neurological diseases, in intra vitam studies. The present study highlights a potential role of Dihomo-IsoPs as biomarkers in persons with epilepsy, though its mechanisms and possible implications should be the subject of further investigations.

A new ultra-rapid UHPLC/MS/MS method for assessing glucoraphanin and sulforaphane bioavailability in human urine

Sulforaphane (SFN) is the product of the enzymatic hydrolysis of glucoraphanin (GR), the main glucosinolate present in broccoli sprouts. The beneficial actions attributed to SFN are mainly supported by in dietary study not clear. Surely the panellists ate more than just the broccoli portion - please clarify vitro experiments; further in vivo assays are necessary to analyse the described biological actions in humans. A new ultra-fast, accurate, robust, and selective UHPLC/MS/MS procedure (2-min chromatogram; >87% recovery; LOQ and LOD of 20-156 and 4-20nmol L(-1), respectively; and intra- and inter-day variations lower than 10%) was used for the simultaneous determination of GR and SFN in human urine. The analytical capacity of this novel method was further tested by determining the bioavailability of GR and its metabolic derivatives in urine from volunteers after the consumption of ½ and 1 servings of broccoli sprouts (30 and 60g, respectively). Bioavailability values for SFN of up to 40% after a single intake of both ½ and 1 servings showed the suitability of the new method for the determination of exogenous metabolites following dietary interventions.

Non-targeted metabolomic approach reveals urinary metabolites linked to steroid biosynthesis pathway after ingestion of citrus juice

Citrus juice intake has been highlighted because of its health-promoting effects. LC-MS based metabolomics approaches are applied to obtain a better knowledge on changes in the concentration of metabolites due to its dietary intake and allow a better understanding of involved metabolic pathways. Eight volunteers daily consumed 400 mL of juice for four consecutive days and urine samples were collected before intake and 24h after each citrus juice intake. Urine samples were analysed by nanoHPLC-q-TOF, followed by principal component analysis (PCA) and Students t-test (p<0.05). PCA showed a separation between two groups (before and after citrus juice consumption). This approach allowed the identification of four endocrine compounds (tetrahydroaldosterone-3-glucuronide, cortolone-3-glucuronide, testosterone-glucuronide and 17-hydroxyprogesterone), which belonged to the steroid biosynthesis pathway as significant metabolites upregulated by citrus juice intake. Additionally, these results confirmed the importance of using the non-targeted metabolomics technique to identify new endogenous metabolites, up- or down-regulated as a consequence of food intake.

Discovery of human urinary biomarkers of aronia‐citrus juice intake by HPLC‐q‐TOF‐based metabolomic approach

Metabolomics has emerged in the field of food and nutrition sciences as a powerful tool for doing profiling approaches. In this context, HPLC‐q‐TOF‐based metabolomics approach was applied to unveil changes in the urinary metabolome in human subjects (n = 51, 23 men and 28 women) after regular aronia‐citrus juice (AC‐juice) intake (250 mL/day) during 16 weeks compared to individuals given a placebo beverage. Samples were analyzed by HPLC‐q‐TOF followed by multivariate data analysis (orthogonal signal filtering‐partial least square discriminant analysis) that discriminated relevant mass features related to AC‐juice intake. The results showed that biomarkers of AC‐juice intake including metabolites coming from metabolism of food components as proline betaine, ferulic acid, and two unknown mercapturate derivatives were identified. Discovery of new biomarkers of food intake will help in the building up of the food metabolome and facilitate future insights into the mechanisms of action of dietary components in population health.

Physical activity increases the bioavailability of flavanones after dietary aronia-citrus juice intake in triathletes

Control and triathlete volunteers (n=8 and n=15, respectively) were given 400 mL and 200 mL of aronia-citrus juice (AC-juice), respectively. The 24h urine samples were hydrolysed to determine the flavanones concentration by UPLC-QqQ-MS/MS. The flavanones metabolites in both groups of volunteers were glucuronides, sulfates, and sulfo-glucuronides, and the total excretion of flavanones increased fivefold in the triathletes compared with the control volunteers. The increase of ninefold in the homoeriodictyol of triathletes compared to control volunteers may suggest the overactivation of the microbiota metabolism caused by physical exercise. No differences concerning the bioavailability were detected between men and women in controlboth groups. The AC-juice could provide synergistic effects on health due to the increase in the bioavailability of flavanones, avoiding the deleterious effects caused by the overdosage of nutritional supplements.

The intake of broccoli sprouts modulates the inflammatory and vascular prostanoids but not the oxidative stress-related isoprostanes in healthy humans

Current evidence supports the positive association between the consumption of plant foods and health. In this work, we assessed the effect of consuming a half-serving (30 g) or one serving (60 g) of broccoli sprouts on the urinary concentrations of biomarkers of oxidative stress (isoprostanes) and inflammation (prostaglandins and thromboxanes). Twenty-four volunteers participated in the project. A quantitative determination of sulforaphane and its mercapturic derivatives, eicosanoids, and total vitamin C in urine was performed. The intake of broccoli sprouts produced an increase in the urinary concentrations of sulforaphane metabolites and vitamin C. Among the 13 eicosanoids analyzed, tetranor-PGEM and 11β-PGF2α as well as 11-dehydro-TXB2 showed a significant decrease in their urinary concentrations after the ingestion of broccoli sprouts. Therefore, the consumption of broccoli sprouts modulated the excretion of biomarkers linked to inflammation and vascular reactions without exerting a significant influence on the oxidation of phospholipids in vivo.