Caesalpinia palmeri: First Report on the Phenolic Compounds Profile, Antioxidant and Cytotoxicity Effect.

This study aimed to determine the phenolic compounds profile, antioxidant potential and cytotoxicity of extracts and fractions of Caesalpinia palmeri. Methanolic extracts were generated from C. palmeri berries, stems and flowers. The latter was subjected to liquid-liquid partition, obtaining hexane, ethyl acetate and residues fractions. Results showed that the flower extract and ethyl acetate fraction had a larger concentration of phenolic compounds (148.9 and 307.9 mg GAE/g, respectively), being ellagic acid (6233.57 and 19550.08 µg/g, respectively), quercetin-3-ß-glycoside (3023.85 and 8952.55 µg/g, respectively) and gallic acid (2212.98 and 8422.34 µg/g, respectively) the most abundant compounds. Flower extract and ethyl acetate fraction also presented the highest antioxidant capacity on all tested methods (DPPH, ABTS, ORAC and FRAP) and low cytotoxicity against ARPE-19 cells (IC50 >170 µg/mL). C. palmeri possessed high antioxidant potential, associated with the presence of phenolic compounds and low cytotoxicity, suggesting that they could represent an option to counter oxidative stress.

Avocado fruit and by-products as potential sources of bioactive compounds.

The increased demand for avocado, and therefore production and consumption, generate large quantities of by-products such as seeds, peel, and defatted pulp, which account for approximately 30% of fruit weight, and which are commonly discarded and wasted. The present review focuses on various compounds present in avocado fruit and its by-products, with particular interest to those that can be potentially used in different industrial forms, such as nutraceuticals, to add to or to formulate functional foods, among other uses. Main molecular families of bioactive compounds present in avocado include phenolic compounds (such as hydroxycinnamic acids, hydroxybenzoic acids, flavonoids and proanthocyanins), acetogenins, phytosterols, carotenoids and alkaloids. Types, contents, and possible functions of these bioactive compounds are described from a chemical, biological, and functional approach. The use of avocado and its by-products requires using processing methods that allow highest yield with the least amount of unusable residues, while also preserving the integrity of bioactive compounds of interest. Avocado cultivar, fruit development, ripening stage, and processing methods are some of the main factors that influence the type and amount of extractable molecules. The phytochemical diversity of avocado fruit and its by-products make them potential sources of nutraceutical compounds, from which functional foods can be obtained, as well as other applications in food, health, pigment, and material sectors, among others.

Quercetin repressed the stress response factor (sigB) and virulence genes (prfA, actA, inlA, and inlC), lower the adhesion, and biofilm development of L. monocytogenes.

The present study explored the effect of quercetin on the expression of virulence genes actA, inlA, inlC, and their regulatory components, sigB and prfA, in L. monocytogenes. Furthermore, the physicochemical changes on the surface, membrane permeability, and biofilm formation of quercetin-treated bacteria were evaluated. An inhibitory dose-dependent effect of quercetin (0.1-0.8 mM) was observed on the cell attachment on stainless steel at 2 and 6 h at 37 °C. Quercetin at 0.8 mM prevented the biofilm formation on stainless steel surfaces after 6 h of incubation at 37 °C, while the untreated bacteria formed biofilms with a cell density of 5.1 Log CFU/cm2. The microscopic analysis evidenced that quercetin at 0.2 mM decreased the biovolume and covered area of the attached micro-colonies. Also, sigB, prfA, inlA, inlC, and actA genes were downregulated by 7-29 times lower compared to untreated bacteria. In addition, quercetin decreased the superficial cell charge, increased the membrane permeability, and its surface hydrophobicity. These results demonstrated that quercetin prevented biofilm formation, repressed the genes of stress and virulence of L. monocytogenes and also altered the physicochemical cell properties.

Synergistic mode of action of catechin, vanillic and protocatechuic acids to inhibit the adhesion of uropathogenic Escherichia coli on silicone surfaces.

AIMS: To study the individual and combined contribution of catechin, protocatechuic and vanillic acids to inhibit the adhesion of uropathogenic Escherichia coli (UPEC) on the surface of silicone catheters. METHODS AND RESULTS: The adhesion of UPEC to silicone catheters during the exposure to nonlethal concentrations of phenolic compounds was measured, as well as changes in motility, presence of fimbriae, extra-cellular polymeric substances, surface charge, hydrophobicity and membrane fluidity. The phenolic combination reduced 26-51% of motility, 1 log CFU per cm2 of adhered bacteria and 20-40% the carbohydrate and protein content in the biofilm matrix. Curli fimbriae, surface charge and cell hydrophobicity were affected to a greater extent by the phenolic combination. In the mixture, vanillic acid was the most effective for reducing bacterial adhesion, extra-polymeric substance production, motility, curli fimbriae and biofilm structure. Notwithstanding, protocatechuic acid caused major changes in the bacterial cell surface properties, whereas catechin affected the cell membrane functionality. CONCLUSION: Catechin, protocatechuic and vanillic acids have different bacterial cell targets, explaining the synergistic effect of their combination against uropathogenic E. coli. SIGNIFICANCE AND IMPACT OF STUDY: This study shows the contribution of catechin, protocatechuic and vanillic acids in producing a synergistic mixture against the adhesion of uropathogenic E. coli on silicone catheters. The action of catechin, vanillic and protocatechuic acids included specific contributions of each compound against the E. coli membrane's integrity, motility, surface properties and production of extracellular polymeric substances. Therefore, the studied mixture of phenolic compounds could be used as an antibiotic alternative to reduce urinary tract infections associated with silicone catheters.

Effect of phenolic compounds on the growth of selected probiotic and pathogenic bacteria.

Fruit extracts from different tissues (pulp, seed and peel) have shown antimicrobial and prebiotic activities related to their phenolic profile, although structure-specific evaluations have not been reported yet. The effect of five phenolic compounds (catechin and gallic, vanillic, ferulic and protocatechuic acids) identified in different fruits, particularly in mango, was evaluated on the growth of two probiotic (Lactobacillus rhamnosusGG ATCC 53103 and Lactobacillus acidophilusNRRLB 4495) and two pathogenic (Escherichia coli 0157:H7 ATCC 43890 and Salmonella enterica serovar Typhimurium ATCC 14028) bacteria. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of phenolic acids ranged from 15-20 mmol l-1 and 20-30 mmol l-1 against E. coli and S. Typhimurium, respectively. For catechin, the MIC and MBC were 35 mmol l-1 and >35 mmol l-1 against E. coli and S. Typhimurium, respectively. The presence of catechin and gallic, protocatechuic and vanillic acids in MRS broth without dextrose allowed the growth of lactobacilli. Catechin combined with protocatechuic or vanillic acid mildly allowed the growth of both probiotics. In conclusion, phenolic compounds can selectively inhibit the growth of pathogenic bacteria without affecting the viability of probiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides relevant information about the effects of phenolic compounds commonly present in fruit and vegetables on the growth of probiotic and pathogenic bacteria. The compounds selectively allowed the growth of probiotic lactobacilli (Lactobacillus rhamnosus GG and Lactobacillus acidophilus) and inhibited pathogenic bacteria (Escherichia coli and Salmonella Typhimurium) at the same concentration (20 mmol l-1 ). These findings can contribute to the formulation of nutraceutical products, such as synbiotics, that can restore or maintain an optimal composition of human microbiota, potentially improving the overall health of the consumer.

Antibacterial and antioxidant properties of grape stem extract applied as disinfectant in fresh leafy vegetables.

In the present study total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity and antimicrobial properties of grape (Vitis vinifera var. Red Globe) stem extract is reported. Also, the identification of main phenolic compounds was carried out by UPLC-PAD analysis. TPC and TFC of extract were 37.25 g GAE kg-1 and 98.07 g QE kg-1, respectively. Extract showed an antioxidant capacity of 132.60 and 317 g TE kg-1 for DPPH and ABTS radical scavenging capacity, respectively. The main phenolic compounds identified were rutin, gallic acid, chlorogenic acid, caffeic acid, catechin and ferulic acid. Extract inhibited the growth of Listeria monocytogenes, Staphylococcus aureus, Salmonella enterica subsp. enterica serovar Typhimurium, and Escherichia coli O157: H7 at MIC range 16-18 g L-1. Extract affected the different phases of bacterial growth. In addition, application of Extract (25 g L-1) as a sanitizer was effective to reduce the populations of all bacteria inoculated in lettuce (0.859-1.884 log reduction) and spinach (0.843-2.605 log reduction). This study emphasizes the potential of grape processing byproducts as an emergent and attractive source of bioactive compounds with antioxidant properties and antimicrobial activity against important foodborne pathogens. The study demonstrated that stem extract could be used to control the presence of human pathogenic bacteria in fresh leafy vegetables.

Oregano Essential Oil as an Antimicrobial and Antioxidant Additive in Food Products.

Food consumers and industries urged the need of natural alternatives to assure food safety and quality. As a response, the use of natural compounds from herbs and spices is an alternative to synthetic additives associated with toxic problems. This review discusses the antimicrobial and antioxidant activity of oregano essential oil (OEO) and its potential as a food additive. Oregano is a plant that has been used as a food seasoning since ancient times. The common name of oregano is given to several species: Origanum (family: Lamiaceae) and Lippia (family: Verbenaceae), amongst others. The main compounds identified in the different OEOs are carvacrol and thymol, which are responsible for the characteristic odor, antimicrobial, and antioxidant activity; however, their content may vary according to the species, harvesting season, and geographical sources. These substances as antibacterial agents make the cell membrane permeable due to its impregnation in the hydrophobic domains, this effect is higher against gram positive bacteria. In addition, the OEO has antioxidant properties effective in retarding the process of lipid peroxidation in fatty foods, and scavenging free radicals. In this perspective, the present review analyzes and discusses the state of the art about the actual and potential uses of OEO as an antimicrobial and antioxidant food additives.

Expression and enzymatic activity of phenylalanine ammonia-lyase and p-coumarate 3-hydroxylase in mango (Mangifera indica 'Ataulfo') during ripening.

Phenylalanine ammonia lyase (PAL) and p-coumarate 3-hydroxylase (C3H) are key enzymes in the phenylpropanoid pathway. The relative expression of PAL and C3H was evaluated in mango fruit cultivar 'Ataulfo' in four ripening stages (RS1, RS2, RS3, and RS4) by quantitative polymerase chain reaction. In addition, enzyme activity of PAL and C3H was determined in mango fruits during ripening. The PAL levels were downregulated at the RS2 and RS3 stages, while C3H levels were upregulated in fruits only at RS3. The enzyme activity of PAL followed a pattern that was different from that of the PAL expression, thus suggesting regulation at several levels. For C3H, a regulation at the transcriptional level is suggested because a similar pattern was revealed by its activity and transcript level. In this study, the complexity of secondary metabolite biosynthesis regulation is emphasized because PAL and C3H enzymes are involved in the biosynthesis of several secondary metabolites that are active during all mango ripening stages.

Dietary fiber and phenolic compounds as functional ingredients: interaction and possible effect after ingestion.

Dietary fiber and phenolic compounds are two recognized dietary factors responsible for potential effects on human health; therefore, they have been widely used to increase functionality of some foods. This paper focuses on showing the use of both substances as functional ingredients for enriching foods, and at the same time, describes the use of a single material that combines the properties of the two types of substances. The last part of the work describes some facts related to the interaction between dietary fiber and phenolic compounds, which could affect the bioaccessibility and absorption of phenolics in the gut. In this sense, the purpose of the present review is to compile and analyze evidence relating to the use of dietary fiber and phenolic compounds to enhance technological and nutritional properties of foods and hypothesize some of the possible effects in the gut after their ingestion.

Phenolic compounds: their journey after intake.

Plant foods are rich in phenolic compounds (PCs) that display multifaceted bioactions in health promotion and disease prevention. To exert their bioactivity, they must be delivered to and absorbed in the gastrointestinal (GI) tract, transported in circulation, and reach the target tissues. During the journey from ingestion to target tissues and final excretion, PCs are subjected to modifications by many factors during their absorption, deposition, metabolism and excretion (ADME) and consequently their bioefficacy may be modified. Consistent with all nutrients in foods, PCs must first be released from the food matrix through mechanical, chemical, and enzymatic forces to facilitate absorption along the GI tract, particularly in the upper small intestine section. Further, glycosylation of PCs directs the route of their absorption with glycones being transported through active transportation and aglycones through passive diffusion. After enteral absorption, the majority of PCs are extensively transformed by the detoxification system in enterocytes and liver for excretion in bile, feces, and urine. The journey of PCs from consumption to excretion appears to be comparable to many synthetic medications, but with some dissimilarities in their fate and bioactivity after phase I and II metabolism. The overall bioavailability of PCs is determined mainly by chemical characteristics, bioaccessibility, and ADME. In this review, factors accounting for variation in PCs bioavailability are discussed because this information is crucial for validation of the health benefits of PCs and their mechanism of action.

Cloning and expression of ethylene receptor ERS1 at various developmental and ripening stages of mango fruit.

Ethylene induces characteristic ripening reactions in climacteric fruits through its binding to histidine-kinase (HK) receptors, activating the expression of ripening genes. Ethylene receptors have been found in Arabidopsis thaliana (Brassicaceae) and some fruits; number and expression patterns differ among species. In mango, only ethylene receptor ETR1 was known. We cloned ERS1 cDNA from mango, and evaluated the expression of Mi-ERS1 and Mi-ETR1 by qPCR in developmental and ripening stages of this fruit. The Mi-ERS1 coding sequence is 1890 bp long and encodes 629 amino acids, similar to ERS1 from other fruits. Also, the amino acid sequence of ERS1 C-terminal HK domain shows the cognate fold after molecular modeling. Mi-ERS1 expression levels increased as mangoes ripened, showing the highest levels at the climacteric stage, while Mi-ETR1 levels did not change during development and ripening. We conclude that the patterns of expression of Mi-ERS1 and Mi-ETR1 differ in mango fruit.

Antioxidant enrichment and antimicrobial protection of fresh-cut fruits using their own byproducts: looking for integral exploitation.

Fresh-cut fruit consumption is increasing due to the rising public demand for convenience and awareness of fresh-cut fruit's health benefits. The entire tissue of fruits and vegetables is rich in bioactive compounds, such as phenolic compounds, carotenoids, and vitamins. The fresh-cut fruit industry deals with the perishable character of its products and the large percentage of byproducts, such as peels, seeds, and unused flesh that are generated by different steps of the industrial process. In most cases, the wasted byproducts can present similar or even higher contents of antioxidant and antimicrobial compounds than the final produce can. In this context, this hypothesis article finds that the antioxidant enrichment and antimicrobial protection of fresh-cut fruits, provided by the fruit's own byproducts, could be possible.

Quality index, consumer acceptability, bioactive compounds, and antioxidant activity of fresh-cut "ataulfo" mangoes (mangifera indica L.) as affected by low-temperature storage.

To measure bioactive compound losses due to minimal processing, mature green fresh-cut mangoes (Mangifera indica L.) cv. "Ataulfo" were subjected to an antioxidant treatment and stored at 5 degrees C during 15 d. Quality index, total phenols, flavonoids, beta-carotene, ascorbic acid, vitamin E, and antioxidant activity were measured during the storage period of fruits. Antioxidant capacity was estimated using ORAC(FL), TEAC, and DPPH assays. The dipping treatments with ascorbic acid (AA) + citric acid (CA) + CaCl2 affected positively quality delaying deterioration of fresh-cut mango as compared with whole fruit. However, dipping treatment affected the consumer preferences of fresh-cut mangoes. The highest vitamin C, beta-carotene, and vitamin E losses were observed after 10 d, being similar in whole and fresh-cut mangoes. The antioxidant activity was not significantly affected by storage time. We conclude that fresh-cut mangoes retained their bioactive compound content during storage and their antioxidant and nutritional properties make them a good source of these compounds.

High relative humidity in-package of fresh-cut fruits and vegetables: advantage or disadvantage considering microbiological problems and antimicrobial delivering systems?

This hypothesis article states that the high relative humidity (RH) of packaged fresh-cut fruits or vegetables that is associated with spoilage can be used as an advantageous way to deliver antimicrobial compounds using cyclodextrins (CDs) as carriers. CDs can function as antimicrobial delivery systems as they can release antioxidant and antimicrobial compounds (guest molecules) as the humidity levels increase in the headspace. Hydrophobic antimicrobial guests can be complexed with CDs due to the amphiphatic nature of the host. Then, at high RH values, due to the water-CDs interaction, host-guest interactions are weakened; consequently, the antimicrobial molecule is released and should protect the product against the microbial growth. Potential antimicrobial compounds capable of forming complexes with CDs are discussed, as well as possible applications to preserve fresh-cut produce and future research in this area.

Methyl jasmonate treatments reduce chilling injury and activate the defense response of guava fruits.

Tropical fruits cannot be stored at low temperatures due to the chilling injury phenomena. With the goal of reducing the chilling injury, we tested 10(-4) and 10(-5) M of methyl jasmonate (MJ) treatment before the storage of red and white cultivars of guava fruits at 5 degrees C for up to 15 days plus two days at 20 degrees C. Every five days, we evaluated chilling injury index, ion leakage percentage, vitamin C, sugars, total phenols, and the activity of the enzymes lipoxygenase (LOX) and phenylalanine-ammonia lyase (PAL). We found that methyl jasmonate treatments reduce the chilling injury index and the ion leakage percentage. Furthermore, MJ did not affect vitamin C, chlorophyll, and total phenols. MJ increased sugar content, PAL, and LOX activities. We concluded that MJ reduces chilling injury and activates the fruit defense response as indicated by the behavior of total phenols and the increase in sugar content, PAL, and LOX activities.

Maintaining quality of fresh-cut mangoes using antibrowning agents and modified atmosphere packaging.

Treatments to inhibit browning and decay and prolong shelf life of fresh-cut mangoes were investigated. Combinations of antibrowning agents and modified atmosphere packaging (MAP) resulted in a reduction of browning and deterioration of fresh-cut mangoes stored at 10 degrees C. Combinations of several browning inhibitors were more effective than those applied individually. Among these treatments, solutions containing 4-hexylresorcinol (0.001 M) (HR) plus potassium sorbate (0.05 M) (KS) and HR plus KS plus D-isoascorbic acid (0.5 M) (ER) reduced changes in color (L, a, and b) and microbial growth and did not affect sensory characteristics of fresh-cut mangoes. In general, these treatments did not affect significantly the changes in organic acids and sugar content of slices during the 14 days of storage at 10 degrees C. High humidity created in the in-package atmosphere alleviated tissue dryness and was an important factor in the ability of the antibrowning solutions to prevent browning and decay. It appears that the maintenance of quality of fresh-cut mangoes is more related to particular combinations of the antibrowning agents used rather than the modified atmosphere created inside the package. HR + ER + KS treatment in combination with MAP could be used to inhibit browning, decay, and deterioration of fresh-cut mangoes.

Methyl jasmonate reduces chilling injury and maintains postharvest quality of mango fruit.

Exposure of mango (Mangifera indica cv. Tommy Atkins) fruit to methyl jasmonate (MJ) vapors (10(-)(4) M) for 24 h at 25 degrees C reduced chilling injury during subsequent storage for 21 days at 7 degrees C and after 5 days of shelf life at 20 degrees C. The chilling tolerance induced by MJ was positively correlated with the reduction in the percent ion leakage of mango tissue. The overall quality of MJ-treated fruit was also better than that of control fruit. MJ treatment increased the total soluble solids but did not affect titratable acidity or pH. MJ also did not change the normal climacteric rise in respiration, water loss, and softening rates. The efficacy of MJ to reduce chilling injury and decay of mango could be related to the tolerance induced at low temperature. It was concluded that MJ treatment may prevent chilling injury symptoms of mango without altering the ripening process.