Citrus sinensis Essential Oils an Innovative Antioxidant and Antipathogenic Dual Strategy in Food Preservation against Spoliage Bacteria.

The present study evaluates the chemical compositions and antioxidant and antipathogenic properties of commercial orange (Citrus sinensis (L.) Osbeck) essential oils obtained using the cold-press method (EOP) and the cold-press method followed by steam distillation (EOPD). The chemical compositions of the volatilizable fractions, determined by gas chromatography-mass spectrometry, were similar in both samples. A relatively large amount of γ-terpinene was found in the EOPD (1.75%) as compared to the EOP (0.84%). Monoterpene hydrocarbons with limonene (90.4-89.8%) followed by myrcene (3.2-3.1%) as the main compounds comprised the principal phytochemical group. The non-volatile phenolics were eight times higher in the EOP than in the EOPD. Several assays with different specificity levels were used to study the antioxidant activity. Although both essential oils presented similar reducing capacities, the radical elimination ability was higher for the EOP. Regarding the antipathogenic properties, the EOs inhibited the biomass and cell viability of Staphylococcus aureus and Pseudomonas aeruginosa biofilms. Furthermore, both EOs similarly attenuated the production of elastase, pyocyanin, and quorum-sensing autoinducers as assessed using Gram-negative bacteria. The EOP and EOPD showed important antioxidant and antipathogenic properties, so they could represent natural alternatives to extend the shelf life of food products by preventing oxidation and contamination caused by microbial spoilage.

Prosopis alba Seed as a Functional Food Waste for Food Formulation Enrichment.

The present study describes how flour and phenolic enriched extracts (PEE) are obtained from seed (food waste) of 10 different P. alba (algarrobo blanco) clones and their characterization to be used as non-conventional sources of potential functional ingredients. Seed flour and PEE obtained from Argentinian P. alba cultivars were chemically characterized. The antioxidant capacity was also determined. The results showed variability in macronutrient composition of seed flour obtained from different clones. Among them, seed flour obtained from P4, P5, P6, P10, P12, and P13 clones showed a higher protein and fiber content than the other clones. On the other hand, PEE obtained from P6, P7, and P10 clones showed the highest content of phenolic component (7.32-8.58 mg GAE/g flour). The extracts obtained from them also showed high antioxidant activity (scavenging activity on ABTS•+, HO•, and H2O2). C-glycosyl flavones, including vicenin II, isoschaftoside, schaftoside, vitexin, and isovitexin were the major components extracted in all clones. These compounds have remarkable properties for disease prevention linked to oxidative stress. Therefore, the P. alba seed could be considered as functional food waste with a great potential to be used as a novel renewable and sustainable material for the production of bioactive food formulations.

Grapefruit essential oils inhibit quorum sensing of Pseudomonas aeruginosa.

Citrus essential oils are used in food to confer flavor and aromas. The citrus essential oils have been granted as GRAS and could be used as antimicrobial additives to control bacterial quorum sensing from potential food bacterial pathogens. The chemical composition and inhibitory activity of Citrus paradisi (grapefruit) essential oils obtained by cold-pressed method (EOP) and cold-pressed method followed by steam distillation, against Pseudomonas aeruginosa were determined. The GC-MS analyses of the oil indicated the amount of the essential oil components was highest with D-limonene in both cases. However, the extraction method modified the chemical composition. EOP had higher amount of coumarins and flavonoid as well as less oxygenated terpenoids. At 0.1 mg/mL essential oils were not able to modify the bacterial development but inhibited the P. aeruginosa biofilm production between 52% and 55%, sessile viability between 45% and 48%, autoinducer production and elastase activity between 30% and 56%. Limonene was less effective at inhibiting P. aeruginosa than the essential oils, suggesting a synergistic effect of the minor components. According to our results, grapefruit essential oils could be used as a food preservative to control P. aeruginosa virulence.

Prosopis nigra Mesocarp Fine Flour, A Source of Phytochemicals with Potential Effect on Enzymes Linked to Metabolic Syndrome, Oxidative Stress, and Inflammatory Process.

This work is part of the search in native food matrices from arid regions of Argentina of interest to improve human health. Prosopis species are ethnic food resources in South America capable of growing in arid and semi-arid environments. This work was focused to determine the nutritional and phytochemical composition of Prosopis nigra fine flour and to evaluate its biological properties. Flour showed a high level of sucrose (30.35 g/100 g flour), fiber (6.34 g/100 g flour), polyphenols (0.45 g GAE/100 g flour), and minerals (potassium, calcium, and magnesium). Apigenin C glycosides and phenylpropanoid acids were identified in free and bound phenolic enriched extracts, respectively. Polyphenols (especially free polyphenols) were able to inhibit enzymes associated with the metabolic syndrome, including α-amylase (IC50 30.1 µg GAE/mL), α-glucosidase (IC50 22.5 µg GAE/mL), while bound phenolics may control lipase activity (IC50 33.5 µg GAE/mL) and exhibit antioxidant activity by different action mechanisms (SC50 between 16 and 93 µg GAE/mL). Both extracts were more effective to inhibit cyclooxygenase-2 than phospholipase A2 and lipoxygenase, proinflammatory enzymes. Polyphenolic extracts did not show any mutagenic effect. Our studies add value to this non-conventional flour as a promising food resource that could be used as a functional food or functional ingredient in formulations to reduce the risk of the development of obesity. These studies revalue our native resources by promoting their conservation, their use and their propagation. PRACTICAL APPLICATION: Pods of P. nigra are traditional food resources in South America. The non-conventional flour obtained from them is a food that inhibits enzymes linked to carbohydrates metabolism and lipids metabolism, show antioxidant activity and anti-inflamatory activity, principally on COX-2. This natural product is a promising resource that could be used as a functional food or as functional ingredient in food formulations for reduce the risk of the development of obesity. Our studies are relevant to stimulate a sustainable management of this specie and for its development as potential new crops.

Effect of structurally related flavonoids from Zuccagnia punctata Cav. on Caenorhabditis elegans.

Zuccagnia punctata Cav. (Fabaceae), commonly called jarilla macho or pus-pus, is being used in traditional medicine as an antiseptic, anti-inflammatory and to relieve muscle and bone pain. The aim of this work was to study the anthelmintic effects of three structurally related flavonoids present in aerial parts of Z. punctata Cav. The biological activity of the flavonoids 7-hydroxyflavanone (HF), 3,7-dihydroxyflavone (DHF) and 2´,4´-dihydroxychalcone (DHC) was examined in the free-living nematode Caenorhabditis elegans. Our results showed that among the assayed flavonoids, only DHC showed an anthelmintic effect and alteration of egg hatching and larval development processes in C. elegans. DHC was able to kill 50% of adult nematodes at a concentration of 17 µg/mL. The effect on larval development was observed after 48 h in the presence of 25 and 50 µg/mL DHC, where 33.4 and 73.4% of nematodes remained in the L3 stage or younger. New therapeutic drugs with good efficacy against drug-resistant nematodes are urgently needed. Therefore, DHC, a natural compound present in Z. punctata, is proposed as a potential anthelmintic drug.

Wine composition plays an important role in the control of carcinogenic precursor formation by Lactobacillus hilgardii X1B.

BACKGROUND: Lactobacillus hilgardii, a wine lactic acid bacterium, is able to use arginine, through the arginine deiminase pathway with the formation of citrulline, a precursor of the carcinogen ethyl carbamate. The influence of different Argentine wine varieties (Merlot, Cabernet Sauvignon and Malbec), on bacterial growth and arginine metabolism was examined. Furthermore, the effect of different components normally present in wines on the enzyme activities of the arginine deiminase system was determined. RESULTS: Malbec wine under all conditions assayed (33, 50 and 100% supplemented wine:basal media) showed higher arginine consumption and citrulline production than the other wines, as well as the highest bacterial growth and survival of Lactobacillus hilgardii X1B. Glucose and L-malic inhibited both arginine deiminase enzymes while fructose and citric acid only inhibited arginine deiminase. The red wines assayed in this study had different composition, and this is an explanation for the different behavior of the bacterium. CONCLUSION: The highest citrulline production in Malbec wine could be correlated with its lower concentrations of glucose, fructose, citric and phenolic acid than the other wines. Therefore, a wine with lower concentration of these sugars and acids could be dangerous due to the formation of ethyl carbamate precursors.

Inhibition of arachidonic acid metabolism by the Andean crude drug Parastrephia lucida (Meyen) Cabrera.

ETHNOPHARMACOLOGICAL RELEVANCE: Parastrephia lucida (Meyen) Cabrera is used in the traditional medicine of Argentinean highlands as an antiseptic and anti-inflammatory medicinal plant. To give scientific support to the ethnopharmacological claim of Parastrephia lucida as an anti-inflammatory crude drug the effect of Parastrephia lucida extracts and fractions was assessed on key enzymes of the biosynthesis of pro-inflammatory eicosanoids mediators from arachidonic acid (AA). MATERIALS AND METHODS: A bio-guided fractionation of the plant extract was carried out to find out the compounds or mixtures responsible for the anti-inflammatory effect. The extracts and fractions were tested in vitro for their ability to inhibit the enzymes cyclooxygenase (COX)-1 and COX-2, lipoxygenase (LOX) and phospholipase (sPLA2). Fractions were analyzed by HPLC-MS, HPLC-ESI-MS/MS and NMR to relate the effect with groups of secondary metabolites. RESULTS: Parastrephia lucida was more effective inhibiting COX and sPLA2 than LOX. Assay-guided isolation led to the active fractions C and F which showed different effect on the selected enzymes. The fraction C was more effective inhibiting LOX while fraction F showed better activity against sPLA2 and COX-2. Both fractions were further worked-up following the isolation of the anti-inflammatory agents with the selected enzyme assays. The main compounds identified in the most active fractions were 5,4'-dihydroxi-7-methoxyflavanone, apigenin, apigenin methyl ether and apigenin trimethyl ether, methyl and dimethyl ethers from quercetin, kaempferol and luteolin methyl ether, ferulic acid esters, cinnamic acid and vanillin. CONCLUSIONS: Parastrephia lucida extract inhibit AA metabolism via several enzymes. The results give support to the traditional use of this plant for the treatment of inflammatory disorders.

Antimicrobial phenylpropanoids from the Argentinean highland plant Parastrephia lucida (Meyen) Cabrera.

ETHNOPHARMACOLOGICAL RELEVANCE: The Argentinean highland plant Parastrephia lucida (Meyen) Cabrera is used in traditional medicine as an antiseptic and anti-inflammatory crude drug. AIM OF THE STUDY: To relate the antimicrobial effect of the crude drug with the constituents of the active fractions and traditional use. MATERIALS AND METHODS: Assay-guided isolation of the methanol (MeOH) plant extract was carried out using bacteria and yeasts as target organisms. Both ATCC and local strains were included in the study. The antimicrobial fractions and compounds were detected by bioautographic assays. Minimum inhibitory concentrations (MIC) of each extract and fraction were determined and compared with reference antibiotics. Fractions were analyzed by HPLC-DAD, GC-MS, (1)H NMR and (13)C NMR. RESULTS: From the MeOH extract of the plant, assay-guided isolation of the antimicrobial constituents led to 12 phenylpropanoids and two simple phenolics. Most of the compounds occurring in the active fractions were E-caffeoyl or E-cinnamoyl esters including prenyl and phenethyl derivatives. The MIC values of the most active fractions ranged between 12.5 and 200 µg/mL against reference strains and local isolates of Staphylococcus aureus and Enterococcus faecalis. CONCLUSIONS: The antimicrobial effect found in the crude drug was associated with mixtures of phenylpropanoids, including prenyl and phenethyl esters of caffeic and cinnamic acids. The results support at least in part the traditional use of the plant as local antiseptic.

Antioxidant/antibacterial activities of a topical phytopharmaceutical formulation containing a standardized extract of Baccharis incarum, an extremophile plant species from Argentine Puna.

The antimicrobial and antioxidant activities of standardized extracts of Baccharis incarum in 60° and 80° ethanol and of a phytopharmaceutical formulation obtained from them were measured. Baccharis tinctures showed antimicrobial activity against clinically isolated antibiotic resistant Staphylococcus aureus and Enterococcus faecalis, with MIC values of 40-80 µg GAE/mL. Both tinctures exhibited ABTS(●+) scavenging activity with SC(50) values between 1.6 and 4.0 µg GAE/mL. The tinctures were not genotoxic in the Salmonella assay. For this reason, the tincture in 60° ethanol was incorporated into a topical pharmaceutical formulation (Hydrogel/ Carbopol® 934). The phytopharmaceutical formulation also showed antibacterial and antioxidant activities in the in vitro assays. The hydrogel showed microbiological, chemical, physical and functional stability during storage at room temperature. Studies that measure drug release as a determination of bioavailability were also carried out using the Franz diffusion cell (FC). The results demonstrated the release of two bioactive compounds (chlorogenic acid and 4',5-dihydroxy-3',3,6,7,8-pentamethoxyflavone) from the phytotherapic preparation in HPLC studies of FC receptor solution. In consequence, the phytopreparation applied topically could be used to treat skin and soft tissue infection produced by methicillin-resistant Staphylococcus aureus (MRSA) or Enterococcus faecalis and opens new opportunities for the use of active natural ingredients in the cosmeceutical field as antiacne and antioxidant.

Influence of phenolic compounds on the growth and arginine deiminase system in a wine lactic acid bacterium

The influence of seven phenolic compounds, normally present in wine, on the growth and arginine deiminase system (ADI) of Lactobacillus hilgardii X1B, a wine lactic acid bacterium, was established. This system provides energy for bacterial growth and produces citrulline that reacts with ethanol forming the carcinogen ethyl carbamate (EC), found in some wines. The influence of phenolic compounds on bacterial growth was compound dependent. Growth and final pH values increased in presence of arginine. Arginine consumption decreased in presence of protocatechuic and gallic acids (31 and 17%, respectively) and increased in presence of quercetin, rutin, catechin and the caffeic and vanillic phenolic acids (between 10 and 13%, respectively). ADI enzyme activities varied in presence of phenolic compounds. Rutin, quercetin and caffeic and vanillic acids stimulated the enzyme arginine deiminase about 37-40%. Amounts of 200 mg/L gallic and protocatechuic acids inhibited the arginine deiminase enzyme between 53 and 100%, respectively. Ornithine transcarbamylase activity was not modified at all concentrations of phenolic compounds. As gallic and protocatechuic acids inhibited the arginine deiminase enzyme that produces citrulline, precursor of EC, these results are important considering the formation of toxic compounds.

Influence of phenolic compounds on the growth and arginine deiminase system in a wine lactic acid bacterium.

The influence of seven phenolic compounds, normally present in wine, on the growth and arginine deiminase system (ADI) of Lactobacillus hilgardii X1B, a wine lactic acid bacterium, was established. This system provides energy for bacterial growth and produces citrulline that reacts with ethanol forming the carcinogen ethyl carbamate (EC), found in some wines. The influence of phenolic compounds on bacterial growth was compound dependent. Growth and final pH values increased in presence of arginine. Arginine consumption decreased in presence of protocatechuic and gallic acids (31 and 17%, respectively) and increased in presence of quercetin, rutin, catechin and the caffeic and vanillic phenolic acids (between 10 and 13%, respectively). ADI enzyme activities varied in presence of phenolic compounds. Rutin, quercetin and caffeic and vanillic acids stimulated the enzyme arginine deiminase about 37-40%. Amounts of 200 mg/L gallic and protocatechuic acids inhibited the arginine deiminase enzyme between 53 and 100%, respectively. Ornithine transcarbamylase activity was not modified at all concentrations of phenolic compounds. As gallic and protocatechuic acids inhibited the arginine deiminase enzyme that produces citrulline, precursor of EC, these results are important considering the formation of toxic compounds.

Metabolism of gallic acid and catechin by Lactobacillus hilgardii from wine.

The ability of Lactobacillus hilgardii 5w to metabolize gallic acid and catechin was evaluated. It was grown in a complex medium containing gallic acid or catechin. The metabolites were analyzed by high-performance liquid chromatography and identified by comparing the retention times and spectral data with the standards of a database. In gallic acid-grown cultures, gallic acid, pyrogallol, catechol, protocatechuic acid, p-hydroxybenzoic acid, p-hydroxybenzaldehyde, and p-hydroxybenzyl alcohol were detected. In catechin-grown cultures, catechin, gallic acid, pyrogallol, catechol, p-hydroxybenzoic acid, acetovanillone, and homovanillic acid were detected. This work presents evidence of gallic acid and catechin degradation by L. hilgardii from wine.

Differences between biogenic amine detection by HPLC methods using OPA and dansyl derivates.

Biogenic amines can be formed and degraded as a result of normal metabolic activity in animals, plants, and microorganisms and are usually produced by the decarboxylation of amino acids. Recent trends in food security are promoting an increasing search for trace compounds that can affect human health. Although they are present in fermented foods and beverages in low quantities, they exhibit interactions with normal human metabolism (e.g., having vasoactive or psychoactive properties) that justify the research on their presence in foods and the possible related toxicological effects that they may cause. Estimation of the biogenic amines histamine, tyramine, agmatine, putrescine, and cadaverine is important not only from the point of view of their toxicity, but also because they can be used as indicators of the degree of freshness or spoilage of food. Until recently, because of the difficulty in detecting and quantifying amines reliably we have had insufficient information about their occurrence in different types of foods and beverages. These problems are related to matrix interference (e.g., the presence of free amino acids) and the low levels at which the amines are found. Early techniques for the determination of biogenic amines in foods were based on thin-layer chromatography. More modern analytical techniques have since been developed that allow the acquisition of reliable quantitative data and better separation/resolution of various amines. The quantitative determination of biogenic amines is generally accomplished by overpressure-layer chromatography, high-performance liquid chromatography (HPLC), and gas chromatography. The use of reverse-phase column and precolumn derivatization was more efficient and faster than the conventional ion-exchange techniques. This study was conducted to evaluate two HPLC derivatization methods for quantitative determination of biogenic amines: the method described by Gonzales de Llano et al. for amino acid analysis and the method described by Eerola et al.

Effect of wine phenolic compounds on Lactobacillus hilgardii 5w viability.

After 6 days of Lactobacillus hilgardii 5w incubation at 4 degrees C, the viable cell counts diminish 31.9, 45.6, and 89.0% when suspended in control wine (2,600 mg/liter gallic acid equivalents [GAE]), three-fold concentrated wine (6,150 mg/liter GAE), and six-fold concentrated wine (13,000 mg/liter GAE), respectively. At 20 degrees C in the same conditions, the cell viabilities decrease 74.2, 80.5, and 100.0%, respectively. In decolorized wines, which result in tannin losses, the viable cell counts increase. There is a relationship between L. hilgardii 5w tannin binding and its viability loss.