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Many plants can produce essential oils (EOs), having various biological properties. This study evaluated the antioxidant, anti-enzymatic and antimicrobial effects of the EOs derived from leaves of Eucalyptus cladocalyx, E. angulosa, E. microcorys, E. ovata, E. diversicolor, E. saligna, E. sargentii and E. resinifera. The antioxidant activity of the EOs was carried out with three different methods (ABTS, DPPH and FRAP). In addition, their anti-colinesterases, anti α-amylase and anti α-glucosidase effects were assessed by spectrophotometric assays. The antimicrobial activities were tested against six phytopathogenic bacterial strains, including two G + ve (Bacillus mojavensis and Clavibacter michiganensis) and four G-ve (Pseudomonas fluorescence, P. syringae, Xanthomonas campestris and E. coli). The current study has also investigated the inhibition of biofilm formation and the possible effect on bacterial cells biofilm metabolism of three Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and two Gram-positive pathogenic bacteria (Staphylococcus aureus and Listeria monocytogenes). The ABTS and DPPH tests indicated that E. diversicolor and E. saligna EOs showed high antioxidant activities, whereas FRAP test suggested that E. diversicolor EO exhibited the better antioxidant activity. E. resinifera and E. ovata EOs were the most active against cholinesterases instead E. ovata and E. sargentii EOs were more active against enzymes involved in diabetes. Antibacterial assays revealed that E. ovata and E. saligna EOs possess significant activity closely to tetracycline. Whereas, the antifungal assay revealed that all EOs have effectively suppressed the tested fungal growth. E. saligna EO showed substantial efficacy inhibiting both the mature biofilm (85.40 %) and metabolic activities (89.80 %) of L. monocytogenes. These results demonstrate the wide range of possible uses for Eucalyptus EOs in both agriculture and medicine fields, suggesting potential uses as strong antibiofilm agents and for biocontrol of phytopathogens.

The Eucalyptus genus, characterized by its imposing stature and fragrant foliage, has been a source of fascination for humanity over the centuries. The focus of the present investigation was directed towards the essentials oils (EOs) of five Eucalyptus trees cultivated in Tunisia. The GC-MS analysis unveiled unique compositional profiles, a finding substantiated by both Hierarchical Clustering Analysis (HCA) and Principal Component Analysis (PCA) conducted on the leaves EOs. These analyses resulted in the formation of discrete HCA clades, delineating 23 significant components. Notably, the percentage of eucalyptol emerged as the pivotal factor demarcating the separation between three distinct groups. The statistical analysis revealed a dose-dependent relationship in both phytotoxicity evaluation and antibacterial activity. The EOs from Eucalyptus loxophleba and E. salubris exhibited the highest phytotoxicity, inhibiting radical elongation and germination of various seeds, especially Sinapis arvensis and Raphanus sativus. The antimicrobial assessment demonstrated significant inhibitory effects of the EOs on bacterial strains, with MIC values spanning from 14 to exceeding 50 mg/ml. The EOs also affected biofilm formation and cellular metabolism, displaying varied efficacy among different Eucalyptus species against some bacterial strains. The EOs exhibited selective inhibition against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-amylase, and α-glucosidase. E. campaspe EO showed the highest AChE activity, while E. loxophleba and E. salubris EOs were most potent toward α-amylase. E. loxophleba EO demonstrated notable activity against α-glucosidase. Overall, these findings provide important data about the diverse biological activities of Eucalyptus EOs, suggesting potential applications in agriculture, medicine, and pharmacy.

Our work investigated the antimicrobial and prebiotic properties of basil, mint, oregano, rosemary, savory, and thyme honey. The potential antimicrobial action, assessed against the pathogens Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus, evidenced the capacity of the honey to influence the pathogenic hydrophobicity and hemolytic activities. Honey inhibited pathogen biofilms, acting especially on the mature biofilms, with inhibition rates of up to 81.62% (caused by the presence of mint honey on L. monocytogenes). S. aureus biofilms were the most susceptible to the presence of honey, with inhibition rates up of to 67.38% in the immature form (caused by basil honey) and up to 80.32% in the mature form (caused by mint honey). In some cases, the amount of nuclear and proteic material, evaluated by spectrophotometric readings, if also related to the honey’s biofilm inhibitory activity, let us hypothesize a defective capacity of building the biofilm scaffold or bacterial membrane damage or an incapability of producing them for the biofilm scaffold. The prebiotic potentiality of the honey was assessed on Lacticaseibacillus casei Shirota, Lactobacillus gasseri, Lacticaseibacillus paracasei subsp. paracasei, and Lacticaseibacillus rhamnosus and indicated their capacity to affect the whole probiotic growth and in vitro adhesive capacity, as well as the antioxidant and cytotoxic abilities, and to inhibit, mainly in the test performed with the L. casei Shirota, L. gasseri, and L. paracasei supernatants, the immature biofilm of the pathogens mentioned above.

Honey can beneficially act against different human diseases, helping our body to improve its health. The aim of the present study was first to increase knowledge of some biochemical characteristics (amount and composition of polyphenols and volatile organic compounds, vitamin C content) of five Italian legume honeys (alfalfa, astragalus, carob, indigo, and sainfoin). Furthermore, we evaluated their potential health properties by studying their antioxidant and in vitro anti-inflammatory activities and in vitro inhibitory effects on three enzymes involved in neurodegenerative diseases (acetylcholinesterase, butyrylcholinesterase, and tyrosinase). Alfalfa honey showed the highest total polyphenol content (TPC) (408 μg g−1 of product). Indigo honey showed the lowest TPC (110 μg g−1 of product). The antioxidant activity was noteworthy, especially in the case of sainfoin honey (IC50 = 6.08 mg), which also exhibited excellent inhibitory action against butyrylcholinesterase (74%). Finally, the correlation between the biochemical and functional results allowed us to identify classes of molecules, or even single molecules, present in these five honeys, which are capable of influencing the properties indicated above.

Abstract We studied the total polyphenols, flavonoids, vitamin C, the antioxidant and anti-inflammatory activity of six Citrus monofloral honey, and the in vitro inhibitory effect against cholinesterases and tyrosinase. Finally, we assessed their effect against the biofilm of some pathogenic bacteria. Lime honey showed the best antioxidant activity and the highest content of polyphenols and vitamin C. Lemon and tangerine honey contained almost exclusively flavonoids. Lemon honey better preserved the bovine serum albumin against denaturation (IC50 = 48.47 mg). Honeys inhibited acetylcholinesterase, butyrylcholinesterase, and tyrosinase up to 12.04% (tangerine), 19.11% (bergamot), and 94.1% (lemon), respectively. Lime and clementine honey better inhibited the Listeria monocytogenes biofilm. Bergamot honey acted mainly against the Staphylococcus aureus and Acinetobacter baumannii biofilm; bergamot and tangerine honey inhibited the Pseudomonas aeruginosa biofilm particularly. Bergamot, clementine, and tangerine honey acted against Escherichia coli sessile cell metabolism. This Citrus honey exhibited in vitro prospective health benefits and is applicable for future in vivo studies.

IntroductionSeed oils are versatile in the food sector and for pharmaceutical purposes. In recent years, their biological properties aroused the interest of the scientific world.Materials and methodsWe studied the composition of fatty acids (FAs) and some in vitro potential therapeutic benefits of five cold-pressed commercial oils obtained from broccoli, coffee, green coffee, pumpkin, and watermelon seeds. In particular, we assayed the antioxidant activity (using diphenyl-1-picrylhydrazyl (DPPH) and azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays). In addition, through the fatty acid composition, we calculated the atherogenicity index (AI) and thrombogenicity index (TI) to evaluate the potential impact of such oils on cardiovascular diseases. Furthermore, we assessed the in vitro anti-inflammatory capacity of the oils (evaluated through their effectiveness in preventing protein degradation, using bovine serum albumin as protein standard) and the ability of the oils to inhibit in vitro activity of three among the essential enzymes, cholinesterases and tyrosinase, involved in the Alzheimer's and Parkinson's neurodegenerative diseases. Finally, we evaluated the capacity of the oils to inhibit the biofilm of some pathogenic bacteria.ResultsThe unsaturated fatty acids greatly predominated in broccoli seed oil (84.3%), with erucic acid as the main constituent (33.1%). Other unsaturated fatty acids were linolenic (20.6%) and linoleic (16.1%) acids. The saturated fatty acids fraction comprised the palmitic (6.8%) and stearic acids (0.2%). Broccoli seed oil showed the best AI (0.080) and TI (0.16) indexes. The oils expressed a good antioxidant ability. Except for the watermelon seed oil, the oils exhibited a generally good in vitro anti-inflammatory activity, with IC50 values not exceeding 8.73 micrograms. Broccoli seed oil and green coffee seed oil showed the best acetylcholinesterase inhibitory activity; coffee seed oil and broccoli seed oil were the most effective in inhibiting butyrylcholinesterase (IC50 = 15.7 μg and 20.7 μg, respectively). Pumpkin and green coffee seed oil showed the best inhibitory activity against tyrosinase (IC50 = 2 μg and 2.77 μg, respectively). In several cases, the seed oils inhibited the biofilm formation and the mature biofilm of some gram-positive and gram-negative bacteria, with Staphylococcus aureus resulting in the most sensitive strain. Such activity seemed related only in some cases to the capacity of the oils to act on the sessile bacterial cells' metabolism, as indicated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric method.

Abstract Background The potential of essential oils (EOs) and of their principal constituents for eradication of biofilm and at the same time the research of new potential acetylcholinesterase inhibitors is gaining increasing interest in last years. The aims of this study were to determine the chemical composition and to evaluate the antibacterial, cytotoxic, and anti-acetylcholinesterase properties of Myrtus communis leaves essential oil and its main constituents. Methods Essential oil was obtained by hydrodistillation of M. communis L. leaves and was analyzed by GC and GC–MS. The antimicrobial activity was carried out against both gram-negative and gram-positive bacteria. The microdilution method was used to estimate the minimum inhibitory concentrations (MICs). Then, the capacity of essential oil and its main constituent to inhibit biofilm growth, with the method of O’Toole and Kolterand, and the metabolic activity of biofilm cells through the MTT colorimetric method were evaluated at different times. Moreover, was studied the potential cytotoxic activity against SH-SY5Y cell line with MTT assay and the anti-acetylcholinesterase activity using Ellman’s assay. Results Myrtenyl-acetate, 1,8 cineole, α-pinene, and linalool were the main components in the EO. The myrtle EO, at the minimum tested dose (0.4 mg/ml), inhibited S. aureus biofilm by 42.1% and was capable of inhibiting the biofilm cell metabolism in all tested strains, except Staphylococcus aureus. Moreover, the EO showed good cytotoxic and anti-acetylcholinesterase activities IC50 of 209.1 and 32.8 μg/ml, respectively. Conclusions The results suggest that myrtle EO and its main constituents could be used as possible products that could act against the resistant pathogenic species E. coli, P. aeruginosa, L. monocytogenes and S. aureus, on the other hand, as possible coadjutants in the treatment of neurological diseases.

Several foods are used in both the nutraceutical and health sectors; vegetable oils, for example, can prevent the onset of numerous diseases. The properties of these oils are related to their chemical composition and primarily to the presence of fatty acids. The present work aimed to determine the chemical profiles of Argania spinosa, Pinus halepensis, and Pistacia altantica oils, used in traditional Tunisian foods, and to evaluate some biological properties. We evaluated their antioxidant, anti-enzymatic, antimicrobial, and anti-inflammatory properties. Linoleic acid was the main component of the three oils. P. atlantica oil showed more significant inhibitory activity against the enzymes studied than A. spinosa and P. halepensis. All three oils showed similar antioxidant and anti-inflammatory activity. Furthermore, A. spinosa and P. halepensis oils showed antibiofilm activity against P. aeruginosa, with 30–40% inhibition. These results focus on the possible use of these oils in the nutraceutical and healthcare sectors.

Satureja bachtiarica is an endemic plant from the Lamiaceae family, growing in the Zagros mountain range in Iran. Even if S. bachtiarica is reported to possess many biological activities, little is known about its chemical composition. For this reason, in the present research, a phytochemical investigation of this species was carried out. To have a preliminary metabolite profile of S. bachtiarica, the n-BuOH extract was analyzed using LC-ESI/LTQOrbitrap/MS/MS in negative ion mode, allowing the identification of specialized metabolites belonging to flavonoid, monoterpene, indol, phenylpropanoid, phenolic, lignan, coumarin, biphenyl, and triterpene classes. The LC-MS/MS analysis guided the isolation of compounds, and their structures were characterized using spectroscopic methods including 1D- and 2D-NMR experiments and HRMSn analysis. In this way, a compound never reported before belonging to the biphenyl class was identified. Total flavonoid content of the extract along with the antioxidant activity were assessed. Based on the traditional uses of S. bachtiarica suggesting potential antibacterial properties, an evaluation of the biofilm inhibitory activity of the extract and isolated compounds against mature biofilms of Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus, as well as their influence on the metabolism of sessile bacterial cells, was conducted. The results evidenced that some compounds including parmentin B, biphenyls, and 1-(1H-indole-3-carboxylate)-β-D-glucopyranoside might inhibit some changes occurring in the bacterial cells, which increases their virulence. In particular, biphenyl derivatives at a concentration of 80 μg/mL were capable of limiting remarkably the mature biofilms of A. baumannii and L. monocytogenes remarkably at a percentage ranging between 52.76% and 75.02%, and they reached an inhibition percentage of 69.28 % against E. coli. Biphenyl derivatives were also effective in exerting an inhibitory action against the mature biofilm of P. aeruginosa (inhibition ranging from 59.38% to 81.08%) and Staphylococcus aureus (inhibition percentage reached 82.94%). Of note, the biphenyl derivatives resulted in being capable of acting on the metabolism of the cells within the biofilm of all five pathogens.

Plants with medicinal benefits are a crucial source of compounds for developing drugs. This study was designed to determine the chemical composition, antibacterial, antibiofilm, antioxidant, and anti-enzymatic activities of Pulicaria incisa (Lam.) DC. We also reported the molecular interaction between identified molecules and several receptors associated with antimicrobial and antibiofilm activities. A total of seventeen and thirteen compounds were identified in aqueous and methanolic extracts of P. incisa, respectively. The methanolic extract yielded a higher total content of polyphenols and flavonoids of about 84.80 ± 2.8 mg GAE/g and 28.30 ± 1.2 mg QE/g, respectively. Significant antibacterial activity was recorded for both extracts, with minimum inhibitory concentration (MIC) values ranging from 30 to 36 µg/mL, and the result was comparable to the reference antibiotic control. Antibiofilm assays revealed that both extracts were able to reduce the attachment of bacterial cells to 96-well plates, but the highest antibiofilm activity was recorded against Staphylococcus aureus. The methanolic extract also showed anti-enzymatic potency and high antioxidant activity, as demonstrated by all assays used, including DPPH, FRAP, and ABTS. These results were further validated by in silico approaches, particularly the molecular interaction of the identified compounds with the targeted receptors. These findings present P. incisa as a significant source of antibacterial, antibiofilm, antioxidant, and anti-enzymatic molecules.

This study was conducted to examine the chemical composition of the essential oils (EOs) from six Tunisian Eucalyptus species and to evaluate their anti-enzymatic and antibiofilm activities. The EOs were obtained through hydro-distillation of dried leaves and subsequently analyzed using GC/MS. The main class of compounds was constituted by oxygenated monoterpenes, particularly prominent in E. brevifolia (75.7%), E. lehmannii (72.8%), and E. woollsiana (67%). Anti-enzymatic activities against cholinesterases, α-amylase, and α-glucosidase were evaluated using spectrophotometric methods. Notably, the E. brevifolia, E. extensa, E. leptophylla, E. patellaris, and E. woollsiana EOs displayed potent acetylcholinesterase (AChE) inhibition (IC50: 0.25–0.60 mg/mL), with E. lehmannii exhibiting lower activity (IC50: 1.2 mg/mL). E. leptophylla and E. brevifolia showed remarkable α-amylase inhibition (IC50: 0.88 mg/mL), while E. brevifolia and E. leptophylla significantly hindered α-glucosidase (IC50 < 30 mg/mL), distinguishing them from other EOs with limited effects. Additionally, the EOs were assessed for their anti-biofilm properties of Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative (Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli) bacterial strains. The E. extensa EO demonstrated the main antibiofilm effect against E. coli and L. monocytogenes with an inhibition > 80% at 10 mg/mL. These findings could represent a basis for possible further use of Eucalyptus EOs in the treatment of human microbial infections and/or as a coadjutant in preventing and treating Alzheimer’s disease and/or diabetes mellitus.

Honey is a natural remedy for various health conditions. It exhibits a prebiotic effect on the gut microbiome, including lactobacilli, essential for maintaining gut health and regulating the im-mune system. In addition, monofloral honey can show peculiar therapeutic properties. We in-vestigated some legumes honey’s prebiotic properties and potential antimicrobial action against different pathogens. We assessed the prebiotic potentiality of honey by evaluating the antioxidant activity, the growth, and the in vitro adhesion of Lacticaseibacillus casei, Lactobacillus gasseri, Lacticaseibacillus paracasei subsp. paracasei, Lactiplantibacillus plantarum, and Lacticaseibacillus rhamnosus intact cells. We also tested the honey’s capacity to inhibit or limit the biofilm produced by five pathogenic strains. Finally, we assessed the anti-biofilm activity of the growth medium of probiotics cultured with honey as an energy source. Most probiotics increased their growth or the in vitro adhesion ability to 84.13% and 48.67%, respectively. Overall, alfalfa honey best influenced the probiotic strains’ growth and in vitro adhesion properties. Their radical-scavenging activity arrived at 83.7%. All types of honey increased the antioxidant activity of the probiotic cells, except for the less sensitive L. plantarum. Except for a few cases, we observed a bio-film-inhibitory action of all legumes’ honey, with percentages up to 81.71%. Carob honey was the most effective in inhibiting the biofilm of Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus; it retained almost entirely the ability to act against the bio-film of E. coli, L. monocytogenes, and S. aureus also when added to the bacterial growth medium instead of glucose. On the other hand, alfalfa and astragalus honey exhibited greater efficacy in acting against the biofilm of Acinetobacter baumannii. Indigo honey, whose biofilm-inhibitory action was fragile per se, was very effective when we added it to the culture broth of L. casei, whose supernatant exhibited an anti-biofilm activity against all the pathogenic strains tested. Conclusions: the five kinds of honey in different ways can improve some prebiotic properties and have an inhibitory biofilm effect when consumed.

Eucalyptus species have been widely employed in the projects of reforestation in Tunisia. Although their ecological functions are controversial, these plants are indeed important to counteract soil erosion, and represent a fast-growing source of fuelwood and charcoal wood. In the present study, we considered five Eucalyptus species, namely Eucalyptus alba, E. eugenioides, E. fasciculosa, E. robusta, and E. stoatei cultivated in the Tunisian Arboreta. The aim was to carry out the micromorphological and anatomical characterization of the leaves, the extraction and phytochemical profile of the essential oils (EOs), and the evaluation of their biological properties. Four of the EOs showed the prevalence of eucalyptol (1,8-cineole) varying from 64.4 to 95.9%, whereas a-pinene predominated in E. alba EO (54.1%). These EOs showed in vitro antioxidant activity, and reduced the oxidative cellular stress as shown by their activity on reactive oxygen species (ROS) production, and modulation of the expression of antioxidant enzymes, such as glutamate-cysteine ligase (GCL) and heme oxygenase-1 (Hmox-1). Moreover, the EOs inhibited the production of nitric oxide (NO), showing anti-inflammatory activity. The data collected suggest that these EOs may be considered a promising therapeutic strategy for inflammation-based diseases and may represent an additional value for the economy of Tunisia.

The witnesses of the millenary history of Campania felix in southern Italy highlighted that several fruit and vegetables cultivated in such territory could potentially be a treasure trove of important health elements. Our work evaluated the content of β-carotene, ascorbic acid, and total phenolics and the antioxidant activity of ten typical varieties of apricots cultivated in the Vesuvius area in the Campania region. The total polyphenols varied between 10.24 and 34.04 mg/100 g of a fresh sample. The amount of ascorbic acid also varied greatly, ranging from 2.65 to 10.65 mg/100 g of a fresh product. B-Carotene reached values up to 0.522 mg/100 g of the fresh sample. The correlation analysis performed, accounting for these parameters, showed that the antioxidant activity, calculated by 2,2-diphenyl-1-picrylhydrazyl (DPPH assay) and azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) tests, was influenced mainly by the content of total polyphenols, with ρ = −0.762 and ρ = 0.875 when we considered DPPH and ABTS tests, respectively, slightly less by the content of ascorbic acid, and not by β-carotene. The dendrogram clustered eight varieties into two main groups; on the other hand, two varieties (“Vitillo” and “Preveta bella”) seemed hierarchically distant. The gas chromatography–mass spectrometry (GC–MS) analysis of volatile organic compounds (VOCs), herein performed for the first time, demonstrated the influence of the varieties on the VOC profiles, both from a qualitative and semiquantitative perspective, discriminating the varieties in different clusters, each of which was characterized by specific notes. α-Terpinolene was the only terpene identified by GC–MS that appeared to affect the antioxidant activity.

Background/Aim: Sweet almond (Prunus amygdalus dulcis) oil is one of the most famous cold-pressed seed oils. However, other species of Prunus can provide oils with healthy properties. We analyzed the fatty acid (FA) composition, as well as the antioxidant, the in vitro anti-inflammatory properties, and the antibiofilm activity of five commercial vegetable cold-pressed seed oils of apricot, peach, plum, cherry, and black cherry.Methods: Gas Chromatography-Mass Spectrometry was performed for the analysis of FAs The antioxidant property of the oils was carried using different tests [2, 2-diphenyl-1-picrylhydrazyl (DPPH assay)], Ferric Reducing Antioxidant Power (FRAP), and the 2, 20 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+). The denaturation assay performed on bovine serum albumin (BSA) was used to evaluate the in vitro anti-inflammatory activity. The anti-biofilm activity was assessed using five pathogenic strains, namely, Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus, through the crystal violet test and the 3-(4,5-dimethylthiazol-2-yl)−2,5-diphenyltetrazolium bromide (MTT), used to evaluate the metabolism of the microbial cells present within the biofilm.Results: Oleic acid and linoleic acids were the most abundant FAs. Black cherry seed oil exhibited the best antioxidant activity, but in general, the amount of oil needed to inhibit the activity of 1 ml of DPPH assay at 50% did not exceed 10 μg. The extract concentration for the 50% inhibition of the denaturation of the protein (IC50) did not exceed 4.4 μg. Linoleic and stearic acids affected the antioxidant activity of the oils; oleic acid, linolenic, and palmitoleic acids exhibited beneficial effects in preserving the BSA denaturation, as shown by the correlation data. The oils were able to inhibit the biofilm formation of the pathogens (up to 71.40% of inhibition) as well as act against their mature biofilm, although with different strengths, with values up to 61.54%. Concurrently, they also acted on the pathogen metabolism.Conclusion: The oils represent a valuable source of some healthy FAs. They showed potential antioxidant and anti-inflammatory in vitro activity, in addition, their potential effect on the biofilm can offer important ideas for research and reflection on their use as functional foods and/or ingredients.

This study was carried out to characterize the chemical composition of the essential oils from seven Eucalyptus species (E. griffithsii, E. hemiphloia, E. lesouefii, E. longicornis, E. pyriformis, E. viminalis, and E. wandoo), as well as their phytotoxic and antibacterial activities. The essential oils were analyzed by GC/MS and the potential in vitro phytotoxicity was evaluated against germination and radical elongation of Raphanus sativus, Lolium multiflorum, and Sinapis arvensis seeds. The antibiofilm activity was studied against both Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and Gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria. The inhibition of biofilm formation and its metabolism was determined at different times. Eucalyptol was the most abundant component in all essential oils studied (ranging from 40.8% for E. lesouefii EO to 73.6% for E. wandoo) except for that of E. pyriformis where it was present but at 15.1%. E. pyriformis was the most active against both germination and radical elongation of S. arvensis. The action of all essential oils proved to be highly effective in inhibiting the bacterial adhesion process of the five strains considered. In light of these results, these essential oils could have potential applications both in the agricultural and health fields.

Eucalyptus species are characterized by their richness in essential oils (EOs) with a great diversity of biological activities. This study reports the chemical composition and the phytotoxic and antibiofilm activities of the EOs of six Eucalyptus species growing in Tunisia: E. bicostata, E. gigantea, E. intertexta, E. obliqua, E. pauciflora and E. tereticornis. Four EOs were rich above all in oxygenated monoterpenes (25.3–91.4%), with eucalyptol as the main constituent. However, in the EOs of E. pauciflora and E. tereticornis, sesquiterpene hydrocarbons (28.8–54.0%) were the main class of constituents; piperitone was the main constituent of both EOs. The phytotoxicity of the EOs was tested against germination and radicle elongation of the weeds Sinapis arvensis and Lolium multiflorum and the crop Raphanus sativus, resulting in the different inhibition of seed germination and radicle elongation depending on both chemical composition and the seed tested, with remarkable phytotoxicity towards S. arvensis and R. sativus. Furthermore, almost all EOs showed antibacterial potential, resulting in significant inhibition of bacterial biofilm formation and the metabolism of Gram-positive (Staphylococcus aureus subsp. aureus and Listeria monocytogenes) and Gram-negative (Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli) bacterial strains, in addition to acting on mature biofilms. The EOs were inhibitory against all bacterial strains tested and usually reluctant to undergo the action of conventional antibiotics. Therefore, these EOs may be considered for applications both as herbicides and in food and health fields.

The complex taxonomy of Eucalyptus genus, the renewed interest in natural compounds able to combat microbial strains, the overuse of synthetic pesticides, the consequent request for alternative control methods were the reasons for this research. The essential oils (Eos) of Eucalyptus bosistoana, Eucalyptus melliodora, Eucalyptus odorata, Eucalyptus paniculata, Eucalyptus salmonopholia, and Eucalyptus transcontinentalis were analyzed by GC/MS and their potential phytotoxic activity was evaluated against the germination and radicle elongation of Sinapis arvensis, Raphanus sativus and Lolium multiflorum. The antibiofilm activity was assayed against both Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative (Pseudomonas aeruginosa, Escherichia coli, and Acinetobacter baumannii) bacteria. Monoterpenoids were the most representative constituents in all EOs and eucalyptol was the dominant component except in E. melliodora EO, in which p-cymene was the most abundant. In phytotoxic assays, the EOs from E. odorata and E. paniculata were the most active against germination and radical elongation of the tested seeds. Finally, the Eucalyptus EOs proved their capacity to effectively inhibit the adhesion process of all five pathogen strains, with percentages often reaching and exceeding 90%. These Eucalytpus EOs could have possible employments in the food, health and agricultural fields.

The Eucalyptus genus (Myrtaceae) is characterized by a richness in essential oils (EO) with multiple biological activities. This study reports the chemical composition and the phytotoxic and antimicrobial activities of the EOs from Tunisian E.occidentalis, E.striaticalyx and E.stricklandii. The EOs were analyzed using GC/MS and their phytotoxicities were assessed against the germination and seedling growth of Sinapis arvensis, Trifolium campestre and Lolium rigidum. Antimicrobial activity was investigated against both Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and Gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria. The inhibition of biofilm formation and its metabolism was determined at different times. All EOs were rich in oxygenated monoterpenes (36.3–84.8%); the EO of E.occidentalis was rich in sesquiterpenes, both oxygenated and hydrocarbon (40.0% and 15.0%, respectively). Eucalyptol was the main constituent in all samples. The EOs showed phytotoxic activity on seed germination and seedling growth, depending both on chemical composition and weed. The EOs show a remarkable antibacterial potential resulting in a significant inhibition of the formation of bacterial biofilm and its metabolism, depending on the EO and the strain, with activity on the mature biofilm as well. Therefore, these Eucalyptus EOs could have potential applications both in the food and health fields.

Aqueous and ethanolic pomegranate peel extracts (PPE) were studied as a source of phenolic compounds with antimicrobial, anti-quorum sensing, and antioxidant properties. The aqueous extract showed higher total phenolic and flavonoid content (153.43 mg GAE/g and 45.74, respectively) and antioxidant capacity (DPPH radical inhibition: 86.12%, ABTS radical scavenging capacity: 958.21 mg TE/dw) compared to the ethanolic extract. The main phenolic compounds identified by UPLC-DAD were chlorogenic and gallic acids. The aqueous PPE extract showed antimicrobial activity against Listeria monocytogenes, Salmonella Typhimurium, Candida tropicalis (MICs 19–30 mg/mL), and anti-quorum sensing activity expressed as inhibition of Chromobacterium violaceum violacein production (%). The aqueous PPE extracts at 25 mg/mL applied on alfalfa sprouts reduced psychrophilic bacteria (1.12 Log CFU/100 g) and total coliforms (1.23 Log CFU/100 g) and increased the antioxidant capacity of the treated sprouts (55.13 µmol TE/100 g (DPPH) and 126.56 µmol TE/100 g (ABTS)) compared to untreated alfalfa. This study emphasizes PPE’s antioxidant and antimicrobial activities in alfalfa sprouts preservation.

This work aimed to evaluate the chemical composition of the essential oils (EOs) of two cultivars of Allium sativum and their antibiofilm activity against the food pathogens Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus. The crystal violet assay ascertained the susceptibility of the bacterial biofilms, while the MTT assay let to evaluations of the metabolic changes occurring in the bacterial cells within biofilms. Their chemical composition indicated some sulfuric compounds (i.e., allicin, diallyl disulfide, and allyl propyl disulfide), and decene as some of the main components of the EOs. The aerial parts and bulbs’ EOs from the two cultivars showed chemical differences, which seemed to affect the antibiofilm activity. The EOs from aerial parts of ‘Bianco del Veneto’ inhibited the biofilm formation of L. monocytogenes and E. coli (60.55% and 40.33%, respectively). In comparison, the ‘Staravec’ EO inhibited the cellular metabolism of E. coli (62.44%) and S. aureus (51.52%) sessile cells. These results indicate their possible use as preserving agents in the food industry and suggest their potential exploitation in the development of new formulations to avoid or limit nosocomial infections.

The aim of this study was to characterize the chemical composition and to evaluate the antimicrobial and phytotoxic properties of the essential oils (EOs) obtained from leaves of Leptospermum petersonii chemotype “Variety B” and Eucalyptus gunnii, native to Australia. Geranyl acetate, γ-terpinene, geraniol, terpinolene, α-pinene, p-cimene, and linalool were the main components in L. petersonii EO, confirming also the existence of several chemotypes in such taxa; on the other hand, 1,8-cineole, trans-sabinene hydrate acetate, globulol, longicyclene, terpinolene, and camphene were present in major amounts in the E. gunnii EO. Chemical analysis of L. petersonii revealed that it belongs to the variety “B.” E. gunnii EO showed good antibacterial activity, with an MIC of 0.5 and 2 μg/mL against Staphylococcus aureus, and Pectobacterium carotovorum, respectively. The activity of E. gunnii EO was stronger than L. petersonii EO, whose maximum MIC reached 5 μg/mL. E. gunnii and L. petersonii EOs were particularly effective in inhibiting the biofilm formation by S. aureus, already at a concentration of 0.01 μg/mL. The other strains were resistant to both EOs up to a dose of 0.05 μg/mL. The maximum inhibition on biofilm formed by P. carotovorum was recorded for E. gunnii EO, reaching a value of 93.12% at 1.0 μg/mL. This is the first manuscript which studies the biofilm inhibition by EOs and evaluates their effects on biofilm metabolism. Both EOs were more effective against P. carotovorum. In addition, even though L. petersonii EO 0.1 μg/mL was unable to inhibit biofilm formation by Escherichia coli, it decreased the metabolic activity of the biofilm to 78.55% compared to control; furthermore, despite it inducing a relatively low inhibition (66.67%) on biofilm formation, it markedly affected metabolic activity, which decreased to 16.09% with respect to the control. On the contrary, L. petersonii EO 0.5 μg/mL induced a 79.88% inhibition of S. aureus biofilm, maintaining a high metabolic activity (90.89%) compared to the control. Moreover, this EO showed inhibitory activity against radical elongation of Solanum lycopersicum and the germination of radish. On the contrary, E. gunnii EO showed no phytotoxic activity.

In this work, we aimed to study the chemical composition of the essential oils from bulbs and leaves of two cultivars of Allium sativum L. and two of A. ampeloprasum L. var. holmense. Moreover, we investigated their activity against four common bacterial strains responsible for food contamination (Listeria monocytogenes, Escherichia coli, Acinetobacter baumannii, and Staphylococcus aureus) by formation of biofilms. The susceptibility of bacterial biofilms was evaluated by crystal violet assay, whereas the metabolic changes occurring in the bacterial cells were ascertained through the MTT test. The essential oils were characterized by the presence of most characteristic components, although with different composition between the species and the cultivars. The essential oils inhibited the capacity of the pathogenic bacteria to form biofilms (up to 79.85 against L. monocytogenes) and/or acted on their cell metabolism (with inhibition of 68.57% and 68.89% against L. monocytogenes and S. aureus, respectively). The capacity of the essential oils to act against these foodborne bacteria could suggests further ideas for industrial applications and confirms the versatility of these essential oils as food preservatives.

The extraction method is critical for the recovery of phenolic compounds. The main goal was to evaluate the effect of an extraction process from mango seed on their phenolic profile, antioxidant and antimicrobial capacities. Phenolic extraction was performed in different steps: maceration, alkaline hydrolysis, acid/alkaline hydrolysis, polar and non-polar fraction of an ethyl acetate separation.The macerated extract showed a higher variety of polyphenols from mango seed:gallic (138.36 µg/g dry weight), coumaric (65.36 µg/g), ferulic (1376.67 µg/g) , chlorogenic (57.75 µg/g) anddicaffeoylquinic (219.29 µg/g) acids, catechin (16.78 µg/g) and rutin (6678.62µg/g). In alkaline hydrolyzed extract most of these compounds were lost, ferulic acid decreased 1356.77 µg/g dw and gallic acid increased 1383.89 µg/g dw. Gallic and chlorogenic acids increased 165 and 969. 45 µg/g dw respectively in acid/alkaline hydrolyzed, 109.57 and 841.38 µg/g dw respectively in non-polar and 277.15 and 77.88 µg/g dw respectively in polar extracts related to the macerated extract. Rutin was found only in acid/hydrolyzed and non-polar extract in lesser amount (87.62 and 78.51 µg/g dw) compared to macerated extract. The content of phenolic compounds was higher for the macerated extract (phenols=484.42 mg GAE/g and flavonoids=86.59 mg QE/g) than for the other steps. Acid/alkaline hydrolysis increased the antioxidant activity (1787.67 μmol TE/g for DPPH and 3692.86 μmol TE/g for TEAC); while the alkaline hydrolysis increased the antimicrobial effectivity (MIC=2.5 mg/mL for bacteria and 0.5 mg/mL for yeast). Results indicate that the acid or alkaline hydrolysis yields a stronger antioxidant and antimicrobial extract.

Campania is the most important region of Italy in the apricot cultivation, present mostly in the Vesuvio area. At least to the best of our knowledge, no studies are reporting the biochemical characterization of the considerable number of traditional apricot varieties present on this territory, including the qualitative and quantitative profile of the polyphenols present. Our work evaluated the content of β-carotene, total phenolics, phenolic profiles, ascorbic acid and antioxidant activity of 23 traditional varieties of apricots of the Campania region. Principal component analysis (PCA) highlighted that, in the two main groups, the antioxidant activity was strongly affected by the content of ascorbic acid (−0.89), or slightly affected by the content of total polyphenols (−0.67), respect to the content of ascorbic acid (−0.55), never by β-carotene. Chlorogenic acid (up to 55.07 μg g−1) and catechin (up to 96.15 μg g−1) resulted the most abundant polyphenols recognized through the chromatographic analysis. PCA, extended to the polyphenol profile, confirmed the distribution of the varieties in two large groups, evidencing once again the hierarchical distance of four varieties (“Panzona”, “Paolona” “Baracca” and “Boccucia Eboli”) compared to the others.

We evaluated the polyphenol content and the α-glucosidase activity exhibited by different monofloral honeys of Italian origin. Their capacity to act on different pathogenic (Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus) as well as probiotic bacteria (Lacticaseibacillus casei, Lactobacillus acidophilus, Lactiplantibacillus plantarum, Lactobacillus gasseri, and Lacticaseibacillus rhamnosus) was also assessed. Total polyphenols varied between 110.46 μg/g of fresh product (rhododendron honey) and 552.29 μg/g of fresh product (strawberry tree honey). Such result did not correspond to a parallel inhibitory α-glycosidase activity that, in each case was never higher than 33 μg/mL. Honeys were differently capable to fight the biofilm formation of the pathogens (inhibition up to 93.27%); they inhibited the in vitro adhesive process (inhibition up to 84.27%), and acted on mature biofilm (with values up to 76.64%). Their effect on bacterial metabolism was different too. Honeys were ineffective to inhibit E. coli mature biofilm nor to act on its metabolism. The action of the honey on probiotic strains seemed almost always stimulate their growth. Thus, these monofloral honeys might exhibit effects on human health and act positively as prebiotics.

This study identified the lactic acid bacteria (LAB) biota and the volatilome profile of 28 typical sourdoughs of Irpinia—a large area of the Campania region of Southern Italy where numerous breads are produced, even today, following the ancient procedures of sourdough fermentation and for which information on the microbiological and sensory profile is lacking in literature. For this purpose, microbial quality, LAB biodiversity, chemical, and technological characteristics, as well as aroma profile by solid-phase microextraction technique (SPME)–gas chromatography/mass spectrometry (GC/MS) of Irpinian sourdoughs were investigated. The dominant LAB microbiota was examined by both culture-dependent and culture-independent methods Polymerase Chain Reaction/Denaturing Gradient Gel Electrophoresis (PCR-DGGE). Results showed a high biodiversity in LAB community whereas the most frequent lactobacilli species recognized were Lactobacillus plantarum (ca. 22% of total LAB isolates), Lactobacillus sanfranciscensis (11%), Lactobacillus paralimentarius (8%), and Lactobacillus rossiae (6.5%), whereas LAB cocci could be mainly referred to Pediococcus pentosaceus (9.5% of total LAB isolates), Leuconostoc spp. (7.8%), and Weissella cibaria (7.7%). Sourdoughs were characterized by the dominance of one or two LAB species, thus proving that the environment influences the selection and the establishment of few key LAB species and that no specific correlation can be traced between microbial composition and geographical origin of the samples. Furthermore, although sourdoughs were characterized by different qualitative and quantitative volatile organic compound (VOC) compositions, no noticeable correlation between volatilome profile and geographical origin was found. However, it emerged that for more isolated locations, it was possible to find the existence of microbial biotypes and sensory profiles with a strong identity, thus revealing the existence of highly traditional and evocative bread recipes in those geographical contexts.

Our aim was to evaluate the susceptibility of bacterial biofilm formation and the metabolic changes occurring in the bacterial cells by the action of ivy, strawberry tree, lavender, sulla and tree of heaven monofloral honeys. Listeria monocytogenes was the most sensitive bacteria with percentages of biofilm inhibition up to 72.20%. Pseudomonas aeruginosa was less sensitive, but tree of heaven and sulla honey caused an inhibition of biofilm up to 40.41% and 35.85%, respectively. The tree of heaven honey acted on the P. aeruginosa metabolism (75.24%). Staphylococcus aureus, majorly resistant to the biofilm-inhibitory action of the honey, was more sensitive at the metabolic level (61.63% inhibition in the presence of the tree of heaven honey).

Prickly pear [Opuntia ficus-indica (L.) Mill.] is a succulent plant that is globally diffused. The oil obtained from its seeds has antimicrobial and antioxidant properties. We evaluated the antibiofilm of the oil and its capacity to block the metabolic changes taking place in the microbial cells included in the biofilm. The oil was capable to inhibit at 38.75% the biofilm of Escherichia coli, Pseudomonas aeruginosa, and Pectobacterium carotovorum (38.75%, 71.84%, and 63.06% inhibition, respectively). The metabolic activity of the microbial cells within the biofilm was also strongly inhibited. The action of the prickly pear seeds oil was effective also in blocking at 64.97% the metabolism of Listeria monocytogenes cells.

Extracts of the bulbs of Italian ecotypes of Allium sativum were analysed to determine their phenolic profiles, antioxidant activities, ascorbic acid and allicin content, and in vitro antibacterial and anti-proliferative activities. Ultra performance liquid chromatography with diode array detector (UPLC-DAD) was used to detect and quantify gallic acid, chlorogenic acid, caffeic acid, epicatechin, hyperoside, ferulic acid, apigenin, p-coumaric acid and allyl isothiocyanate. All extracts exhibited antioxidant activity with concentrations necessary to inhibit the activity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical by 50% (EC50) ranging from 60 to 114 mg. Ascorbic acid and allicin ranged between 0.268 and 0.658 mg/g, and between 0.411 and 1.105%, respectively. Extracts exhibited antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa more so than against Bacillus cereus. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays demonstrated that the extracts inhibited the proliferation of the human epithelial colorectal adenocarcinoma (Caco-2) cells in time- and dose-dependent manners.

The present study was carried out to determine some biochemical characteristics, in particular the total polyphenol content and the free radical scavenging activity, of the extracts recovered from bulbs and aerial parts (these last often considered as by-products) of two landraces of A. ampeloprasum var. holmense cultivated in Southern Italy. For the first time, the capacity of the extracts of these landraces to inhibit the formation of biofilm of different Gram-negative and Gram-positive bacteria and to affect the metabolism of the cells present within the bacterial biofilm was evaluated. All extracts exhibited an amount of total polyphenols not lower than 2.86 mg/g of dried product and revealed a noteworthy antioxidant activity, with EC50 values not exceeding 4.95 mg. In both cases, the aerial parts extracts were more effective than the bulb extracts, which also showed a minor amount of total polyphenols. The extracts inhibited mainly the adhesive capability of Pseudomonas aeruginosa and Staphylococcus aureus, by 95.78% and 85.01%, respectively. The extracts demonstrated to inhibit also the metabolism of the bacterial cells reaching levels up to 90%. Finally, as assessed by the assays performed on the 24-h preformed biofilms, all the extracts were also capable to cause a reduction in bacterial biomass and to affect their metabolism.

Our study aimed to analyze some qualitative aspects of five landraces of the tomato “Piennolo,” typical of the Vesuvian area, Italy, and determine the in vitro antioxidant activity. All samples showed a high °Brix value and acidity, as well as a discrete amount of reducing sugars, indicating their good quality as fresh products. They showed a high content of lycopene (up to 218 μg g−1 of fresh product) and ascorbic acid (up to 238 μg g−1 of fresh product). The content of total polyphenols was never less than 278 μg g−1 of fresh product. Hyperoside, chlorogenic and gallic acids were the most abundant polyphenols. The interrelationships between the parameters analyzed and the different landraces showed that total polyphenols could have mostly affected (ρ = 0.76) the antioxidant activity more than lycopene (ρ = −0.96). The interrelationships between the most abundant polyphenols and antioxidant activity showed that hyperoside, although the most abundant, negatively affected (ρ = −0.93) the antioxidant activity. Due to the high content of lycopene, ascorbic acid, and hyperoside, the five landraces of the tomato “Piennolo” could be considered promising in terms of their potential healthy characteristics.

Bioactive compounds of different Campania native sweet pepper varieties were evaluated. Polyphenols ranged between 1.37 mmol g−1 and 3.42 mmol g−1, β-carotene was abundant in the red variety “Cazzone” (7.05 μg g−1). Yellow and red varieties showed a content of ascorbic acid not inferior to 0.82 mg g−1, while in some green varieties the presence of ascorbic acid was almost inconsistent. Interrelationships between the parameters analyzed and the varieties showed that ascorbic acid could represent the factor mostly influencing the antioxidant activity. Polyphenol profile was different among the varieties, with a general prevalence of acidic phenols in yellow varieties and of flavonoids in red varieties. Principal Component Analysis, applied to ascorbic acid, total polyphenols and β-carotene, revealed that two of the green varieties (“Friariello napoletano” and “Friariello Sigaretta”) were well clustered and that the yellow variety “Corno di capra” showed similarity with the green varieties, in particular with “Friariello Nocerese”. This was confirmed by the interrelationships applied to polyphenol composition, which let us to light on a clustering of several red and yellow varieties, and that mainly the yellow ”Corno di capra” was closer to the green varieties of “Friariello”.

The phenolic contents and antioxidant activities of grass pea (Lathyrus sativus), lentil (Lens culinaris), and chickpea (Cicer arietinum) cultivars from the Campania region of Southern Italy were investigated. Lentils (cv Colliano and San Gerardo) demonstrated the highest antioxidant activity, (EC50 not higher than 2.3 mg/g), confirming that lentils are an excellent antioxidant food. Grass peas (cv San Gerardo and san Rufo) tested exhibited lower content of total polyphenols, as well as a minor amount of hydrolysable and condensed tannins compared to other grass pea cultivars; their low levels of the two types of tannins suggest that they are more nutritional and should not negatively affect humans and monogastric animals. Chickpeas (cv Castelcivita and Sassano) exhibited the lowest content of total polyphenols (147.13 and 183.78 μg/g of raw product, respectively), although their values were higher than those of the other European cultivars. UPLC analysis revealed differences in the quality and quantity of polyphenols, which are important due to their healthful properties. Therefore, these legumes can be considered therapeutic functional foods due to their significant content of functional proteins and carbohydrates and their extraordinary reserve of secondary metabolites and bioactive constituents that are beneficial for managing and preventing several chronic illnesses in humans.

Production of extra virgin olive oil (EVOO) represents an important element for the economy of Southern Italy. Therefore, EVOO is recognized as a food with noticeable biological effects. Our study aimed to evaluate the antimicrobial activity exhibited by the polyphenolic extracts of EVOOs, obtained from three varieties of Olea europea L. (Ruvea antica, Ravece, and Ogliarola) cultivated in the village of Montella, Avellino, Southern Italy. The study evaluated the inhibiting effect of the extracts against some Gram-positive and Gram-negative bacteria. Statistical analysis, used to relate values of antimicrobial activity to total polyphenols and phenolic composition, revealed a different behavior among the three EVOO polyphenol extracts. The method applied could be useful to predict the influence of singular metabolites on the antimicrobial activity.

The increasing resistance of microorganisms to conventional chemicals and drugs is a serious and evident worldwide problem that has prompted research into the identification of new biocides with broad activity. Plants and their derivatives, such as essential oils, are often used in folk medicine. In nature, essential oils play an important role in the protection of plants. Essential oils contain a wide variety of secondary metabolites that are capable of inhibiting or slowing the growth of bacteria, yeasts and moulds. Essential oils and their components have activity against a variety of targets, particularly the membrane and cytoplasm, and in some cases, they completely change the morphology of the cells. This brief review describes the activity of essential oils against pathogenic bacteria.

The antioxidant capacity and antimicrobial activity of the essential oil of Moringa oleifera (Moringaceae) grown in Mozambique was investigated. The chemical composition was studied by means of GC and GC-MS analysis. Hexacosane (13.9%), pentacosane (13.3%) and heptacosane (11.4%) were the main components. Ultra High Performance Chromatography-DAD analysis detected the flavonoids quercetin (126 μg/g) and luteolin (6.2 μg/g). The essential oil exhibited a relatively low free radical scavenging capacity. The antimicrobial activity of the essential oil was assayed against two Gram-positive strains (Bacillus cereus, Staphylococcus aureus), two Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa), and five fungal strains of agro-food interest (Penicillium aurantiogriseum, Penicillium expansum, Penicillium citrinum, Penicillium digitatum, and Aspergillus niger spp.). B. cereus and P. aeruginosa, as well as the fungal strains were sensitive to the essential oil.

The viability of the probiotic strain Lactobacillus plantarum subsp. plantarum, after its passage through simulated gastric and pancreatic juices, was evaluated as function of its pre-growth in a medium containing the known prebiotics pectin or inulin, and was compared to glucose used as control. The presence of pectin or inulin did not markedly affect the growth (10.07 log10 colony forming units/mL and 10.28 log10 colony forming units/mL for pectin and inulin respectively versus 10.42 log10 colony forming units/mL obtained for glucose). Pectin and inulin, in contrast to glucose, induced cell stress resistance against gastrointestinal juices (D log101.5 and 2.4 colony forming units/mL respectively, versus D log10 4.0 for glucose). The data were corroborated by the analysis of the protein pattern following stress treatments which, in the case of microbial cells grown with glucose, revealed a more marked protein degradation after the double passage through simulated gastric and intestinal juices. Inulin stimulated the production of the relevant healthy bio-molecule butyrate, which amount was 30% higher respect of growth in the presence of glucose. Inulin and pectin improved cell DPPH scavenging activity, and an impressive hydrophobicity (35.28% and 34.81%, respectively) was observed with respect to the microbial growth in presence of glucose (3.39%).

Plant extracts have the potential to be used as food additives; however, their use have been limited by causing undesirable changes in the sensory attributes of foods. We characterized the mango seed extract as a preserving agent for fresh-cut mangoes. We established the maximum concentration of extract that, while increasing the antioxidant activity, and limiting microbial contamination of the fruit, did not negatively affect fruit sensory acceptability. The extract contained 277.4 g gallic acid equivalent (GAE)/kg dw (dry weight) of polyphenols and 143.7 g quercetin equivalent (QE)/kg dw of flavonoids. Antioxidant capacity values were 2034.1 and 4205.7 μmol Trolox equivalent (TE)/g against 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radicals, respectively. Chromatographic analysis revealed the presence of gallic and chlorogenic acids. The extract (16 g/L) inhibited the growth of Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus and Listeria monocytogenes. The highest concentration with sensory acceptability was 6.25 g/L. At such concentration, the extract preserved fresh-cut fruits, increasing polyphenols (0.427 g GAE/kg fw (fresh weight)), flavonoid content (0.234 g QE/kg fw) and antioxidant activity (DPPH = 2.814 and ABTS = 0.551 mol TE/kg fw). It also reduced inoculated bacteria (range: 5.50 × 103 to 1.44 × 105 colony forming units (CFU)/g). These results showed the importance of considering consumer acceptability to determine the effective concentration of plant extracts as additives.

Lactobacillus acidophilus was encapsulated in alginate-inulin-xanthan gum and its ability to grow in carrot juice and survive 8 weeks of storage at 4 °C and subsequent exposure to artificial gastrointestinal conditions were assessed. Encapsulation significantly enhanced cell viability after fermentation and storage (6 × 1012 and 4 × 1010 cells/ml versus 4 × 1010 and 2 × 108 for free cells, respectively). Encapsulation protected L. acidophilus from exposure to simulated gastric conditions; minor alterations in viability and the protein profile occurred after incubation in pancreatic juice. For free cells, viability decreased significantly and the expression of numerous proteins was lost after incubation in gastric and pancreatic juice. Thus, encapsulation preserved probiotic bacterial viability and activity; the addition of inulin as a prebiotic component could enhance the functional properties of food products containing this formulation.