Emerging Applications of Plant Antimicrobials in the Food Industry.

Food safety is a global concern with significant public health implications. Improper food handling can harbor a wide range of pathogenic organisms. Antimicrobial agents are crucial for controlling microbes and ensuring food safety and human health. The growing demand for natural, safe, and sustainable food preservation methods has driven research into using plant antimicrobials as alternatives to synthetic preservatives. The food industry is now exploring innovative approaches that combine various physical methods with multiple natural antimicrobials. This review aims to outline the evolving applications of plant antimicrobials in the food industry. It discusses strategies for managing bacteria and categorizes different plant antimicrobials, providing insights into their mechanisms of action and structures. This review offers a comprehensive overview of antimicrobial peptides (AMPs), detailing their structural characteristics, mechanisms of action, various types, and applications in food packaging fabrication and explaining how they contribute to food preservation. It highlights the synergistic and additive benefits of plant antimicrobials and their successful integration with food technologies like nanotechnology, which enhances the hurdle effect, improving food safety and extending shelf life. The review also emphasizes the importance of antimicrobial peptides and the need for further research in this area. Safety assessment and regulatory considerations are discussed as well. By addressing these gaps, plant antimicrobials have the potential to pave the way for more effective, safe, and sustainable food preservation strategies in the future.

Adipose-Derived Mesenchymal Stromal Cells: A Tool for Bone and Cartilage Repair.

The osteogenic and chondrogenic differentiation ability of adipose-derived mesenchymal stromal cells (ASCs) and their potential therapeutic applications in bone and cartilage defects are reported in this review. This becomes particularly important when these disorders can only be poorly treated by conventional therapeutic approaches, and tissue engineering may represent a valuable alternative. Being of mesodermal origin, ASCs can be easily induced to differentiate into chondrocyte-like and osteocyte-like elements and used to repair damaged tissues. Moreover, they can be easily harvested and used for autologous implantation. A plethora of ASC-based strategies are being developed worldwide: they include the transplantation of freshly harvested cells, in vitro expanded cells or predifferentiated cells. Moreover, improving their positive effects, ASCs can be implanted in combination with several types of scaffolds that ensure the correct cell positioning; support cell viability, proliferation and migration; and may contribute to their osteogenic or chondrogenic differentiation. Examples of these strategies are described here, showing the enormous therapeutic potential of ASCs in this field. For safety and regulatory issues, most investigations are still at the experimental stage and carried out in vitro and in animal models. Clinical applications have, however, been reported with promising results and no serious adverse effects.

Orobanche crenata Forssk. Extract Affects Human Breast Cancer Cell MCF-7 Survival and Viral Replication.

BACKGROUND: Breast cancer (BC) is the leading cause of death worldwide. The severity of BC strictly depends on the molecular subtype. The less aggressive hormone-positive subtype is treated with adjuvant endocrine therapy (AET), which causes both physical and psychological side effects. This condition strongly impacts the adherence and persistence of AET among oncologic patients. Moreover, viral infections also constitute a serious problem for public health. Despite their efficacy, antiviral agents present several therapeutic limits. Accordingly, in the present work, we investigated the antitumor and antiviral activities of Orobanche crenata Forssk. (O. crenata), a parasitic plant, endemic to the Mediterranean basin, traditionally known for its beneficial properties for human health. METHODS: The MTT assay was carried out to evaluate the cytotoxic effect of O. crenata leaf extract (OCLE) on human breast cancer cells (MCF-7 and MDA-MB-231) and the primary HFF-1 cell line. The lactic dehydrogenase (LDH) assay was performed on MCF-7 cells to analyze necrotic cell death. The antioxidant effect of OCLE was evaluated by intracellular determination of the reactive oxygen species and thiol groups, by DPPH and ABTS assays. The antiviral activity of OCLE was determined against Poliovirus 1, Echovirus 9, Human respiratory syncytial virus, Adenovirus type 2 and type 5, Coxsackievirus B1 (CoxB1) and B3 (CoxB3), Herpes simplex type 1 (HSV-1) and type 2 (HSV-2), and ß-Coronavirus by the plaque reduction assay. RESULTS: The extract, after 24 h of incubation, did not affect MDA-MB-231 and HFF-1 cell viability. However, at the same time point, it showed a dose-dependent inhibitory effect on MCF-7 cells, with an increase in LDH release. OCLE exhibited free radical scavenging activity and significantly increased non-protein thiol levels in MCF-7 cells. OCLE effectively inhibited HSV-1, HSV-2, CoxB1, and CoxB3 replication. CONCLUSIONS: The overall results showed an interesting inhibitory effect of OCLE on both MCF-7 cell survival and viral replication.

Identification of Potent Bioassay Guided Terpenoid and Glycoside Root Fractions of Astragalus candolleanus against Clinically Significant Bacterial Strains.

Antibiotic resistance represents one of the biggest challenges, and there is an urgent need for plant-based antimicrobial agents that enable managing this crisis effectively. In this work, we aimed to investigate the antibacterial activity of Astragalus candolleanus (A. candolleanus) hydromethanolic root extract against Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli, Salmonella typhimurium, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Kocuria rhizophila) strains by the cup-plate method. The root was powdered and extracted with 70% methanol by cold maceration for 5 days. Preliminary phytochemical screening was performed with different solvents in the order of increasing polarity. Pure compounds were isolated by column chromatography and were characterized through liquid chromatography-mass spectrometry. Targeted predictions of the isolated compounds were also studied using Swiss Target prediction software and prediction of activity spectra for substances. The extract showed a broad zone of inhibition against pathogenic bacteria. Four pure compounds were isolated, of which a novel terpenoid compound has been identified as stemmadenine along with scillirosidin, cephalotaxine, and myxoxanthophyll. The structures of the isolated phytoconstituents were elucidated by spectral analysis. The four pure components isolated from the roots of A. candolleanus are suggested to be effective against tested pathogens. Overall results of drug design suggest that myxoxanthophyll is a promising bioactive compound endowed with antibacterial activity.

Anti-Candidal Activity of the Parasitic Plant Orobanche crenata Forssk.

Candida albicans (C. albicans) and Candida glabrata (C. glabrata) are part of the human microbiome. However, they possess numerous virulence factors, which confer them the ability to cause both local and systemic infections. Candidiasis can involve multiple organs, including the eye. In the present study, we investigated the anti-candidal activity and the re-epithelizing effect of Orobanche crenata leaf extract (OCLE). By the microdilution method, we demonstrated an inhibitory effect of OCLE on both C. albicans and C. glabrata growth. By crystal violet and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, we showed the ability of OCLE to inhibit the biofilm formation and the viability of yeast cells, respectively. By germ tube and adhesion assays, we proved the capacity of OCLE to affect the morphological transition of C. albicans and the adhesion of both pathogens to human retinal pigment epithelial cells (ARPE-19), respectively. Besides, by MTT and wound healing assay, we evaluated the cytotoxic and re-epithelizing effects of OCLE on ARPE-19. Finally, the Folin-Ciocalteu and the ultra-performance liquid chromatography-tandem mass spectrometry revealed a high content of phenols and the presence of several bioactive molecules in the extract. Our results highlighted new properties of O. crenata, useful in the control of Candida infections.

Correction: Genovese et al. In Vitro Antibacterial, Anti-Adhesive and Anti-Biofilm Activities of Krameria lappacea (Dombey) Burdet & B.B. Simpson Root Extract against Methicillin-Resistant Staphylococcus aureus Strains. Antibiotics 2021, 10, 428.

The authors would like to make the following corrections to the published paper [...].

In Vitro Antibacterial, Anti-Adhesive and Anti-Biofilm Activities of Krameria lappacea (Dombey) Burdet & B.B. Simpson Root Extract against Methicillin-Resistant Staphylococcus aureus Strains.

Methicillin-resistant Staphylococcus aureus (MRSA) represents a serious threat to public health, due to its large variety of pathogenetic mechanisms. Accordingly, the present study aimed to investigate the anti-MRSA activities of Krameria lappacea, a medicinal plant native to South America. Through Ultra-High-Performance Liquid Chromatography coupled with High-Resolution Mass spectrometry, we analyzed the chemical composition of Krameria lappacea root extract (KLRE). The antibacterial activity of KLRE was determined by the broth microdilution method, also including the minimum biofilm inhibitory concentration and minimum biofilm eradication concentration. Besides, we evaluated the effect on adhesion and invasion of human lung carcinoma A549 cell line by MRSA strains. The obtained results revealed an interesting antimicrobial action of this extract, which efficiently inhibit the growth, biofilm formation, adhesion and invasion of MRSA strains. Furthermore, the chemical analysis revealed the presence in the extract of several flavonoid compounds and type-A and type-B proanthocyanidins, which are known for their anti-adhesive effects. Taken together, our findings showed an interesting antimicrobial activity of KLRE, giving an important contribution to the current knowledge on the biological activities of this plant.

Antimicrobial, Antioxidant, and Cytotoxic Activities of Juglans regia L. Pellicle Extract.

The difficulty to treat resistant strains-related hospital-acquired infections (HAIs) promoted the study of phytoextracts, known sources of bioactive molecules. Accordingly, in the present study, the pharmacological activities of Juglans regia (L.) pellicle extract (WPE) were investigated. The antiviral effect was tested against Herpes simplex virus type 1 and 2, Poliovirus 1, Adenovirus 2, Echovirus 9, Coxsackievirus B1 through the plaque reduction assay. The antibacterial and antifungal activities were evaluated against medically important strains, by the microdilution method. DPPH and superoxide dismutase (SOD)s-like activity assays were used to determine the antioxidant effect. Besides, the extract was screened for cytotoxicity on Caco-2, MCF-7, and HFF1 cell lines by the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. The total phenolic and flavonoid contents were also evaluated. Interestingly, WPE inhibited Herpes simplex viruses (HSVs) replication, bacterial and fungal growth. WPE showed free radical scavenging capacity and inhibited superoxide anion formation in a dose-dependent manner. These effects could be attributed to the high content of phenols and flavonoids, which were 0.377 ± 0.01 mg GE/g and 0.292 ± 0.08 mg CE/g, respectively. Moreover, WPE was able to reduce Caco-2 cell viability, at both 48 h and 72 h. The promising results encourage further studies aimed to better elucidate the role of WPE in the prevention of human infectious diseases.

Antibacterial and anti-biofilm activities of walnut pellicle extract (Juglans regia L.) against coagulase-negative staphylococci.

Juglans regia L. (common walnut) is a deciduous tree belonging to Juglandaceae family. Since ancient time, walnut was widely used in traditional medicine for its antioxidant, antidiabetic, antimicrobial, anti-inflammatory, anti-atherogenic and liver-protective effects. In this work, the antibacterial and anti-biofilm activities of walnuts pellicle extract against coagulase-negative staphylococci were evaluated. Qualitative chemical analysis was performed by the thin layer chromatography. UPLC-Ms/Ms was used to identify the chemical composition of J. regia extract. The total flavonoid and phenolic contents were determined by the Aluminium chloride and Folin-Ciocalteu methods, respectively. The extract showed antibacterial activity with MIC ranging from 3.60 to 461.75 µg/ml and MBC ranging from 461.75 to >461.75 µg/ml. Furthermore, it significantly reduced biofilm biomass and cell viability in a dose-dependent manner. Biological activities of J. regia extract may be due to its high flavonoid and phenolic contents. The obtained results are promising and they deserve further scientific investigations.

Phytochemical composition and biological activities of Orobanche crenata Forssk.: a review.

The genus Orobanche includes about 100 different species. Among them, Orobanche crenata Forssk. (Orobanchaceae family), commonly known as broomrape, is a holoparasitic plant, noxious to legume crops that inhabits mainly in the Mediterranean basin. The aim of this review is to evaluate and organise the available reports on O. crenata. Our research revealed that the plant is edible, relatively safe to ingest, historically used for the treatment of skin infections, ulcers and bowel disorders. In addition, it represents a rich source of nutrients, antioxidant, antitumor and antimicrobial compounds. Phytochemical studies revealed the presence of twenty-two molecules, identified from different parts of the plant. The Prediction of Activity Spectra for Substances (PASS) analysis allowed predicting the biological activity of each compound. Furthermore, biological properties of O. crenata extracts were reported. Therefore, here we elucidate the botanic, phytochemical and biological profile of O. crenata, shedding light on a little characterised plant.

Streptococcus agalactiae in pregnant women: serotype and antimicrobial susceptibility patterns over five years in Eastern Sicily (Italy).

Streptococcus agalactiae (also known Group B Streptococcus or GBS) represents the main pathogen responsible for early- and late-onset infections in newborns. The present study aimed to determine the antimicrobial susceptibility pattern and the capsular serotypes of GBS isolated in Eastern Sicily over 5 years, from January 2015 to December 2019. A total of 3494 GBS were isolated from vaginal swabs of pregnant women (37-39 weeks), as recommended by the Centers for Disease Control and Prevention. Capsular polysaccharide's typing of GBS was determined by a commercial latex agglutination test containing reagents to serotypes I-IX. The antimicrobial resistance pattern of GBS was determined through the disk diffusion method (Kirby-Bauer) and the double-disk diffusion test on Mueller-Hinton agar plates supplemented with 5% defibrinated sheep blood, according to the guidelines of the Clinical and Laboratory Standards Institute. Serotypes III (1218, 34.9%) and V (1069, 30.6%) were the prevalent colonizers, followed by not typable (570, 16.3%) and serotypes Ia (548, 15.7%), Ib (47, 1.3%), II (40, 1.1%), and IV (2, 0.1%). All 3494 clinical isolates were susceptible to cefditoren and vancomycin. Resistance to penicillin, ampicillin, levofloxacin, clindamycin, and erythromycin was observed in 6 (0.2%), 5 (0.1%), 161 (4.6%), 1090 (31.2%), and 1402 (40.1%) of the strains, respectively. Most of erythromycin-resistant GBS (1090/1402) showed the cMLSB phenotype, 276 the M phenotype, and 36 the iMLSB phenotype. Our findings revealed a higher prevalence of serotype III and a relevant resistance rate, among GBS strains, to the most frequently used antibiotics in antenatal screening.

Comparison of Cell Culture with Three Conventional Polymerase Chain Reactions for Detecting Chlamydophila pneumoniae in Adult's Pharyngotonsillitis.

Chlamydophila pneumoniae is an intracellular pathogen responsible for respiratory tract infections. The isolation of the microorganism from clinical specimens is essential for a diagnosis. However, the identification of C. pneumoniae by cell cultures is very difficult besides strongly depending on the sample conditions. The study aimed to investigate, in adult patients with pharyngotonsillitis, the frequency of Chlamydophila pneumoniae detection by cell cultures and three conventional PCRs (a conventional PCR targeting the 16S rRNA gene and two nested PCRs, targeting the 16S rRNA gene and the ompA gene, respectively). The presence of chlamydial inclusion in cell cultures was observed in 11/94 samples (11.70%) by IFA. C. pneumoniae DNA was detected in 12/94 (12.76%) specimens by the 16S rRNA gene nested PCR, 4/94 (4.26%) by ompA gene nested PCR, and in 2/94 (2.13%) by 16S rRNA single-step PCR. Our data show poor agreement between the three applied DNA-amplification methods; in fact, only 16S rRNA gene nested PCR showed a statistically significant difference. Moreover, this result allowed us to achieve a definitive confirmation of the previous finding and to avoid the risk of an overestimation of the C. pneumoniae as a pathogen in pharyngotonsillitis.

Optimization of ZnO Nanorods Growth on Polyetheresulfone Electrospun Mats to Promote Antibacterial Properties.

Zinc oxide (ZnO) nanorods grown by chemical bath deposition (CBD) on the surface of polyetheresulfone (PES) electrospun fibers confer antimicrobial properties to the obtained hybrid inorganic-polymeric PES/ZnO mats. In particular, a decrement of bacteria colony forming units (CFU) is observed for both negative (Escherichia coli) and positive (Staphylococcus aureus and Staphylococcus epidermidis) Grams. Since antimicrobial action is strictly related to the quantity of ZnO present on surface, a CBD process optimization is performed to achieve the best results in terms of coverage uniformity and reproducibility. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) provide morphological and compositional analysis of PES/ZnO mats while thermogravimetric analysis (TGA) is useful to assess the best process conditions to guarantee the higher amount of ZnO with respect to PES scaffold. Biocidal action is associated to Zn2+ ion leaching in solution, easily indicated by UV-Vis measurement of metallation of free porphyrin layers deposited on glass.

Preliminary in Vitro Studies on Corynebacterium urealyticum Pathogenetic Mechanisms, a Possible Candidate for Chronic Idiopathic Prostatitis?

Corynebacterium urealyticum is a well-known opportunistic uropathogen that can occur with cystitis, pyelonephritis, and urinary sepsis. Although a wide variety of coryneform bacteria have been found from the male genital tract of prostatitis patients, only one clinical case of prostatitis caused by C. urealyticum has been reported. The aim of this study was to evaluate the in vitro tropism of C. urealyticum towards LNCaP (lymph node carcinoma of the prostate) human cells line and the influence of acetohydroxamic acid as an irreversible urease inhibitor on different aspects of its pathogenicity by means of several in vitro tests, such as the determination and analysis of growth curves, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, the production of biofilms, and adhesion to LNCaP and HeLa cell lines. Results have brought new pieces of evidence on the in vitro tropism of C. urealyticum for the human prostate cell line LNCaP and the therapeutic use of the irreversible urease inhibitors such as acetohydroxamic acid (AHA), not only as enzyme blockers to facilitate the removal of encrustations but also as modulators of some pathogenic mechanisms. These interesting preliminary data allow us to assert that there is a real possibility that C. urealyticum is a new candidate for chronic idiopathic prostatitis.

The double effect of walnut septum extract (Juglans regia L.) counteracts A172 glioblastoma cell survival and bacterial growth.

Walnut (Juglans regia L.) is considered to be a 'superfood' for its multiple protective actions on human health. Walnut extracts have proven antitumor activity in different cancer cell lines. However, the efficacy of septum extract against glioblastoma has still not been investigated. Glioblastoma is the most difficult type of brain cancer to treat. The standard therapy, based on temozolomide, causes several side effects, including neutropenia and lymphocytopenia, which often favor the onset of opportunistic infections. In the present study, the chemical profile of the Sicilian walnut septum ethanolic extract was analyzed using high­performance liquid chromatography (HPLC)­diode array detection and HPLC­electrospray ionization tandem mass spectrometry. The potential cytostatic activity of the extract against the human A172 glioblastoma cell line was investigated and the results showed that the extract could decrease cancer cell proliferation and migration. Using cytofluorimetric analyses and caspase­3 assays, the pro­apoptotic action of walnut extract was demonstrated. Furthermore, the evaluation of the antibacterial activity highlighted the efficacy of the extract in reducing Gram­positive and Gram­negative bacterial growth, most of which were resistant to the antibiotic, ciprofloxacin. Finally, Prediction of Activity Spectra for Substances analysis showed the predicted antitumor and antibacterial activity of HPLC detected compounds. The promising results could provide novel perspective in the field of chemotherapeutic co­adjuvants.

In vitro evaluation of biological activities of Orobanche crenata Forssk. leaves extract.

Orobanche crenata Forssk. (Orobanchaceae) is a holoparasitic plant noxious to legumes. Orobanchaceae are well known in traditional medicine for their hypotensive, antihyperglycemic, antispasmodic, analgesic and antimicrobial effects. In this work, the biological activities of the acetonic leaves extract were evaluated. Qualitative chemical analysis was determined through thin layer chromatography. Total phenols and flavonoids content was obtained by the Folin-Ciocalteu and the Aluminium chloride colorimetric methods, respectively. The antimicrobial activity was performed by the broth microdilution method. The extract showed antibacterial activity, particularly against Gram-positive strains, with MIC ranging from 376.00 to 3011.00 µg/ml. Besides, it exhibited antifungal effects on Candida spp. with MIC ranging from 94.10 to 3011.00 µg/ml. In addition, O. crenata inhibited superoxide anion formation and showed a DPPH quenching capacity, particularly at 80 µg/ml. Interestingly, our results are promising thus indicating the importance of O. crenata as a significant source of biologically active natural compounds.

Bioinspired benzoxanthene lignans as a new class of antimycotic agents: synthesis and Candida spp. growth inhibition.

In this work we synthetized the bioinspired benzoxanthene lignans (BXLs) 3, 14-22, and the phenazine derivative 23 as potential antimycotic agents. MICs and MFCs against Candida strains were determined. In a preliminary screening, compounds 3, 15, 20, 21, 22 were substantially inactive. Compounds 14 and 17 showed antifungal activity, being able to inhibit the growth of the majority of Candida strains with MIC values in the range 4.6-19.2 µM (14) and 26.0-104.3 µM (17); for three strains, the MICs were lower than those obtained using the antimycotic drug fluconazole. The three BXLs 18, 19 and 23 showed some MIC values lower than that of fluconazole; 18 was also active against two non-albicans Candida strains resistant to fluconazole. Phenazine 23, although active only against one strain (MIC = 1.3 µM), was one order of magnitude more potent than fluconazole. All the BXLs were fungicidal.

Antimicrobial efficacy of cordless sonic or ultrasonic devices on Enterococcus faecalis-infected root canals.

AIM: The aim of the present study was to evaluate the immediate and residual antimicrobial activity of cordless sonic or ultrasonic devices on Enterococcus faecalis (E faecalis)-infected teeth. METHODS: A total of 140 single-rooted extracted teeth with E faecalis were grouped as follows (N = 15): conventional syringe irrigation with 3% sodium hypochlorite activated by ultrasonic device (group 1) or cordless ultrasonic device (group 2), EndoActivator (group 3) or without activation (group 4), conventional syringe irrigation with sterile bi-distilled water and ultrasonic device (group 5), EndoUltra (group 6), EndoActivator (group 7), or without activation (group 8). The remaining 20 teeth were used for positive and negative controls. Colony-forming units (CFU) and turbidity were recorded from bacteriological samples taken before and after irrigation and after 24 hours of re-incubation. Data were statistically analyzed using Student's t test, Mann-Whitney test, Kruskal-Wallis test, and Dunn's multiple comparison tests (P < .05). RESULTS: Groups 1 and 2 showed higher antimicrobial efficacy than groups 3 and 4 (P < .05). No bacteria reduction was found in groups 5-8 (P > .05). After 24 hours, regrowth of bacteria was not significantly different for all groups (P > .05). CONCLUSIONS: Ultrasound produced lower CFU and turbidity after treatment and after re-incubation of 24 hours than sonic or no activation.

Betula etnensis Raf. (Betulaceae) Extract Induced HO-1 Expression and Ferroptosis Cell Death in Human Colon Cancer Cells.

Betula etnensis Raf. (Birch Etna) belonging to the Betulaceae family grows on the eastern slope of Etna. Many bioactive compounds present in Betula species are considered promising anticancer agents. In this study, we evaluated the effects of B. etnensis Raf. bark methanolic extract on a human colon cancer cell line (CaCo2). In order to elucidate the mechanisms of action of the extract, cellular redox status, cell cycle, and heme oxygenase-1 (HO-1) expression in ferroptosis induction were evaluated. Cell viability and proliferation were tested by tetrazolium (MTT) assayand cell cycle analysis, while cell death was evaluated by annexin V test and lactic dehydrogenase (LDH) release. Cellular redox status was assessed by measuring thiol groups (RSH) content, reactive oxygen species (ROS) production, lipid hydroperoxide (LOOH) levels and (γ-glutamylcysteine synthetase) γ-GCS and HO-1 expressions. The extract significantly reduced cell viability of CaCo2, inducing necrotic cell death in a concentration-depending manner. In addition, an increase in ROS levels and a decrease of RSH content without modulation in γ-GCS expression were detected, with an augmentation in LOOH levels and drastic increase in HO-1 expression. These results suggest that the B. etnensis Raf. extract promotes an oxidative cellular microenvironment resulting in CaCo2 cell death by ferroptosis mediated by HO-1 hyper-expression.