Grapefruit Seed Extract Research Articles

Efficacy of grapefruit seed extract and lactic acid bacteria in reducing Clostridioides difficile infection via gut microbiota modulation

Antibiotic-induced dysbiosis is a key factor that causes Clostridioides difficile infection (CDI). The current first-line drugs for initial CDI are antibiotics, and finding an alternate therapy to prevent recurrent CDI is essential. In this study, the anti-C. difficile activities of two isolated probiotic strains (Pediococcus pentosaceus CD5 and Lactobacillus salivarius CD4) and grapefruit seed extract (GSE) were investigated in vitro and in vivo. Specifically, GSE inhibited the growth of C. difficile at a minimal inhibitory concentration (MIC) of 40 ppm. Similarly, live cells of the two probiotics, as well as their cell-free culture supernatants, with or without pH adjustment, substantially suppressed C. difficile growth. In a CDI mouse model, C. difficile colonization in the cecum and colon inflammation were significantly reduced by GSE, followed by the probiotic treatments. A metagenomic analysis of cecal feces revealed that GSE and probiotic treatments modulated gut microbial compositions and enhanced the relative abundances of butyrate-producing bacteria. Therefore, GSE and the novel probiotics can potentially be administered as alternative therapies to alleviate CDI by modifying the gut microbiota.

Antimicrobial resistance induction potential of grapefruit seed extract on multi-species biofilm of E. coli in food industry

Biofilm formation in natural environments involving complex multi-structural arrangements hinders challenges in antimicrobial resistance. This study investigated the antimicrobial resistance potential of grapefruit seed extract (GSE) by examining the formation of mono-, dual-, and multi-species biofilms. We also explored the counterintuitive effect in response to GSE at various concentrations, including minimum inhibitory concentration (MIC) and sub-MIC (1/2 and 1/4 MIC). The results of the swimming and swarming motility tests revealed increased motility at the sub-MIC of GSE. The crystal violet assay demonstrated increased biofilm formation in multi-species biofilms, highlighting the synergistic effect of Escherichia coli, Salmonella Typhimurium, and Listeria monocytogenes. At the MIC concentration of GSE, field emission scanning electron microscopy (FE-SEM) revealed cell morphology damage, while sub-MIC increased biofilm formation and architectural complexity. Multi-species biofilms demonstrated greater biofilm-forming ability and antimicrobial resistance than mono-species biofilms, indicating synergistic interactions and enhanced resilience. These findings highlight the importance of understanding biofilm dynamics and antimicrobial resistance to ensure environmental safety.

Alginate-coated functional wrapping paper incorporated with sulfur quantum dots and grapefruit seed extract for preservation of potato hash browns

This study explores the impact of alginate-based functional coatings incorporating sulfur quantum dots (SQDs) and grapefruit seed extract (GFSE) on the antioxidant and antibacterial properties of kraft paper for food packaging. Applying these coatings effectively fills the porous interfibrillar spaces of the paper, significantly improving oil resistance and mechanical properties. However, the water vapor permeability and moisture absorption rate decreased slightly due to the hydrophilic nature of constituents. In particular, the addition of 5 wt% SQDs to the paper coating formulation resulted in remarkable antioxidant activity, with approximately 100% reduction in ABTS and 60% reduction in DPPH free radicals. The addition of SQDs significantly reduced the bacterial cell viability of E. coli and L. monocytogenes by ∼2 log CFU/mL and ∼4.5 log CFU/mL, respectively. Co-addition of SQDs and GFSE significantly improved antimicrobial activity with ∼3 log CFU/mL reduction of E. coli and complete (100%) eradication of L. monocytogenes even at lower concentrations (2.5 wt% each). The lipid oxidation in the hash brown potato patties wrapped in functional coated paper was reduced by nearly 50% compared to uncoated paper. This effect persisted even after an extended storage period of 15 days, demonstrating the superior ability of the coated paper to improve the shelf life of processed, ready-to-eat foods.

Antimicrobial Activity of Grapefruit Seed Extract on Edible Mushrooms Contaminations: Efficacy in Preventing Pseudomonas spp. in Pleurotus eryngii.

Pleurotus eryngii is an edible mushroom that suffers significant losses due to fungal contamination and bacteriosis. The Pseudomonadaceae family represents one of the most frequent etiologic agents. Grapefruit seed extract (GSE) is a plant extract that contains different bioactive components, such as naringin, and exhibits a strong antibacterial and antioxidant activity. Over the last decade, GSE use as an alternative to chemical treatments in the food sector has been tested. However, to our knowledge, its application on mushroom crops has never been investigated. This study focuses on evaluating GSE efficacy in preventing P. eryngii yellowing. GSE antibiotic activity, inhibitory and bactericidal concentrations, and antibiofilm activity against several microorganisms were tested with the Kirby-Bauer disk diffusion assay, the broth microdilution susceptibility test, and the Crystal violet assay, respectively. In vitro, the extract exhibited antimicrobial and antibiofilm activity against Staphylococcus aureus 6538 and MRSA (wild type), Escherichia coli ATCC 8739, and Pseudomonas spp. (Pseudomonas aeruginosa 9027, P. fluorescens (wild type)). GSE application in vivo, in pre- and post-sprouting stages, effectively prevented bacterial infections and subsequent degradation in the mushroom crops: none of the P. eryngii treated manifested bacteriosis. Our findings support the use of GSE as an eco-friendly and sustainable alternative to chemical treatments for protecting P. eryngii crops from bacterial contamination, consequently ensuring food safety and preventing financial losses due to spoilage. Furthermore, GSE's potential health benefits due to its content in naringin and other bioactive components present new possibilities for its use as a nutraceutical in food fortification and supplementation.

Study of coating effectiveness of grape fruit seed extract incorporated Chitosan/cornstarch based active packaging film on grapes

The aim of the present study was to optimize the manufacturing process of grapefruit seed extract (GFSE) incorporated Chitosan (0.75 %, 2 % w/w) and various corn starch concentration of CHCS film of ratio 2:1, 1:1, 1:2 respectively using sorbitol as plasticizer. Optimization of chitosan concentration in chitosan corn starch film was done on the basis of physicochemical properties e.g. moisture content, film thickness, solubility, water vapour permeability and characterization of the films were done. It was reported that the films with CH: CS ratio 2:1 had tensile strength values comparable to that of other films with CH: CS ratio 1:1 and 1:2. Hence, films with 2 % (w/w) chitosan and CH: CS ratio 2:1 was found best among all the film samples shelf life extended to 20 days. GFSE incorporated film was found to have better anti-microbial properties as compared to commercial polypropylene (PP) and low density polyethylene (LDPE) films. GFSE incorporated CHCS film of ratio 2:1 was applied on Grape fruits. The antimicrobial effect of coating formulation on grape was mathematically calculated by predictive kinetic models and digital imaging. Sensory evaluation of applied coating formulation was found very efficient and confirmed the shelf life enhancement of 20 days.

Alginate Microbeads Containing Halloysite and Layered Double Hydroxide as Efficient Carriers of Natural Antimicrobials.

The present paper describes the preparation and characterization of novel microbeads from alginate filled with nanoclay such as halloysite nanotubes (HNTs). HNTs were used as support for the growth of layered double hydroxide (LDH) crystals producing a flower-like structure (HNT@LDH). Such nanofiller was loaded with grapefruit seed oil (GO), an active compound with antimicrobial activity, up to 50% wt. For comparison, the beads were also loaded with HNT and LDH separately, and filled with the same amount of GO. The characterization of the filler was performed using XRD and ATR spectroscopy. The beads were analyzed through XRD, TGA, ATR and SEM. The functional properties of the beads, as nanocarriers of the active compound, were investigated using UV-vis spectroscopy. The release kinetics were recorded and modelled as a function of the structural characteristics of the nanofiller.

Propylene Glycol Potentiates the Inhibitory Action of CTZ Paste on Antibiotic-Resistant Enterococcus faecalis Isolated from the Root Canal: An In Vitro Study.

This study aimed to evaluate if the change of vehicle for CTZ (Chloramphenicol, Tetracycline, zinc oxide, and Eugenol) paste improves the inhibition of Enterococcus faecalis in vitro. The vehicles evaluated alone and mixed with CTZ were Eugenol, propylene glycol (PG), super-oxidized solution (SOS), grapefruit-seed extract (GSE), and 0.9% saline solution as a negative control. A clinical isolate of E. faecalis was morphologically and biochemically characterized, and its antimicrobial susceptibility was tested using 20 antimicrobial agents. Once characterized, the clinical isolate was cultivated to perform the Kirby-Bauer disc diffusion method with paper discs embedded with the different vehicles mixed or used alone, and incubated at 37 °C for 24 h. Data were analyzed using one-way ANOVA, and the means were compared using Tukey test with a significance level of p < 0.05. For vehicles used alone, GSE presented the greatest inhibition showing a statistically significant difference with the rest of the vehicles. When vehicles were mixed with the CTZ paste, PG showed a greater inhibition with a statistically significant difference from the rest of the vehicles. In conclusion, the vehicle used to mix the CTZ paste plays an important role in the inhibition of E. faecalis in vitro; therefore, we consider that this can be an important factor to achieve success in the use of this technique.

Alginate/carboxymethyl cellulose/starch-based active coating with grapefruit seed extract to extend the shelf life of green chilli

The present study investigates a functional packaging film made of alginate (SA), carboxymethyl cellulose (CMC), and starch from potato (PS) with grapefruit seed extract (GSE) by solvent casting method. The surface morphology of the prepared films was analysed by SEM, and results revealed that the GSE was homogeneously mixed with the polymer matrix and maintained uniformity in thickness, creating a continuous structure without any cracks or pores. Incorporating GSE enhanced the UV barrier properties (>99.9%) without compromising much of the transparency of the film. All the prepared films with grapefruit seed extract offered high antioxidant and antimicrobial (Escherichia coli and Staphylococcus aureus) properties. Also, the inclusion of GSE reduced the TS and water vapour permeability properties. In comparison, the inclusion of GSE enhanced the flexibility and thermal stability of the film. The prepared blend solution with 0.5 g of GSE effectively enhanced the shelf life of green chilli by 25 days.

The Specific Effect of Grapefruit Seed, Sea-Buckthorn Leaves, and Chaga Extracts on the Properties of Model Lipid Membranes

The Specific Effect of Grapefruit Seed, Sea-Buckthorn Leaves, and Chaga Extracts on the Properties of Model Lipid Membranes

Gelatin/poly(vinyl alcohol)-based functional films integrated with spent coffee ground-derived carbon dots and grapefruit seed extract for active packaging application

Nanoparticles are attractive, functional additives with great potential to be applied in biomaterial and food packaging. However, these particles are not soluble in water, thus limiting their widespread application. Here, we report a facile fabrication of carbon dots (CDs) using the spent coffee ground as the carbon source through a hydrothermal method. The CD was added to the gelatin/poly(vinyl alcohol) (Gel/PVA) film and grapefruit seed extract (GSE) to prepare multifunctional packaging films. The functional films' physiochemical and functional properties and packaging application were investigated. The composite film showed good UV protection properties with a slight decrease in transparency. The composite film containing CD/GSE showed strong antioxidant activity, scavenging >38 % DPPH and 100 % ABTS radicals. The film also exhibited significant antibacterial activity against the foodborne pathogens Listeria monocytogenes and Escherichia coli, completely eradicating the growth of these bacteria within 9 h of exposure. The CD/GSE-incorporated Gel/PVA films were used for pork packaging. The films were able to enhance the pork shelf life by reducing the L. monocytogenes bacterial growth in meat by 2 Log CFU/mL lower than the control wrapping film. The multifunctional Gel/PVA films are expected to be used for the active packaging of meat products.

Grapefruit Seed Extract-Added Functional Films and Coating for Active Packaging Applications: A Review.

Recently, consumers have been increasingly inclined towards natural antimicrobials and antioxidants in food processing and packaging. Several bioactive compounds have originated from natural sources, and among them, grapefruit seed extract (GSE) is widely accepted and generally safe to use in food. GSE is a very commonly used antimicrobial in food; lately, it has also been found very effective as a coating material or in edible packaging films. A lot of recent work reports the use of GSE in food packaging applications to ensure food quality and safety; therefore, this work intended to provide an up-to-date review of GSE-based packaging. This review discusses GSE, its extraction methods, and their use in manufacturing food packaging film/coatings. Various physical and functional properties of GSE-added film were also discussed. This review also provides the food preservation application of GSE-incorporated film and coating. Lastly, the opportunities, challenges, and perspectives in the GSE-added packaging film/coating are also debated.

Functional Properties of Grapefruit Seed Extract Embedded Blend Membranes of Poly(vinyl alcohol)/Starch: Potential Application for Antiviral Activity in Food Safety to Fight Against COVID-19.

The poly(vinyl alcohol) (PVA) and starch-based polymeric films with a ratio of 2:8 were prepared using solution casting followed by a solvent evaporation method. Four types of membranes with varied concentrations of grapefruit seed extract (GSE) i.e., 2.5-10 wt% was incorporated in the films. The prepared membranes were assessed for transparency test, mechanical properties, surface morphology, permeability test for O2, and antimicrobial properties. The PVA/starch-10% GSE loaded film showed excellent mechanical properties showing highest 1344 ± 0.7% elongation at break but poor optical transparency with 53.8% to 68.61%. The Scanning Electron Microscopic study reveals the good compatibility between the PVA, Starch, and GSE. The gas permeability test reveals that the prepared films have shown good resistance to the O2 permeability 0.0326-0.316 Barrer at 20kg/cm2 feed pressure for the prepared membranes showing excellent performance. By adding the little amount of GSE into the PVA/starch blend membranes showed promising antimicrobial efficacy against MNV-1. For 4h. incubation, PVA/starch blend membranes containing 2.5%, 5%, and 10% GSE caused MNV-1 reductions of 0.92, 1.89, and 2.27 log PFU/ml, respectively. Similarly, after 24h, the 5% and 10% GSE membranes reduced MNV-1 titers by 1.90 and 3.26 log PFU/ml, respectively. Antimicrobial tests have shown excellent performance to resist microorganisms. The water uptake capacity of the membrane is found 72% for the PVA/starch pristine membrane and is reduced to 32% for the 10% GSE embedded membrane. Since the current pandemic situation due to COVID-19 occurred by SARSCOV2, the prepared GSE incorporated polymeric blend films are the rays of hope in the packaging of food stuff.

Effects of molecular weight of chitosan in a blend with polycaprolactone and grapefruit seed extract for active packaging and biodegradation

Packaging films was developed by melt blending polycaprolactone (PCL) with chitosan as carrier for grapefruit seed extract (GSE). The influence of molecular weight (MW) of chitosan on the biodegradability and antimicrobial efficacy of the blend was investigated. Lower MW chitosan accelerated the release of GSE leading to significant improvement in plasticization, hydrophilicity and inhibition of the growth of Escherichia coli. Albeit it did not change the film morphology as PCL and chitosan remained in immiscible phases. Biodegradation in soil compost over 16 weeks had films with lower MW chitosan demonstrated faster rates of biodegradation with dry weight loss reaching 27 %. This was due to earlier onset of bulk degradation. Interestingly, it was not accompanied by accelerated depolymerisation as all blended films shared similar rates of decline in molecular weight. The formulation of PCL/GSE using lower MW chitosan offers a promising avenue to strengthen biodegradation and antimicrobial efficacy of packaging films.

Detection of Bacillus cereus and Pseudomonas fluorescens in dual-species biofilm via real-time PCR and eradication using grapefruit seed extract

Foodborne outbreaks are closely associated with the formation of biofilms. However, due to their complexity of the formation and structure, studies of dual-species biofilms are still required. The aim of this study was to analyse the dual-species biofilm of Bacillus cereus and Pseudomonas fluorescens by investigating the interactions between the two species. The results showed that the dual-species biofilm had a higher amount of protein than the mono-species biofilms of the two bacterial species. In addition, in mono-species and dual-species biofilms, the number of B. cereus and P. fluorescens was shown to increase and decrease, respectively, over time. With respect to antimicrobial resistance, the dual-species biofilm required a higher amount of grapefruit seed extract (GSE) than the mono-species biofilms, indicating that the resistance of dual-species biofilm was higher. As only a limited number of studies have investigated the interactions between B. cereus and P. fluorescens using real-time PCR and adopting GSE as an antimicrobial agent, this study may assist the food industries in controlling dual-species biofilms that contain these two bacterial species.

Antimicrobial, antioxidant, and pH-sensitive polyvinyl alcohol/chitosan-based composite films with aronia extract, cellulose nanocrystals, and grapefruit seed extract

Aronia or black chokeberry (Aronia melanocarpa), cellulose nanocrystals (CNCs), and grapefruit seed extract (GSE) were used for the preparation of multifunctional polyvinyl alcohol/chitosan (PVA/CS) composite films with pH-sensitivity, antimicrobial, antioxidant, and UV-barrier properties. Aronia extract showed total phenolic content of 297 ± 0.5 μg GAE/mg aronia extract, potent antioxidant activity, and high color-response efficiency. Isolated CNCs showed a needle-like structure with a length of 470 nm and a width of 35 nm. The tensile strength of the PVA/CS composite film increased by 74% after the incorporation of CNCs, whereas the film flexibility was enhanced by 75% after adding GSE. The PVA/CS-A (aronia extract) composite film showed a significant color change at different pHs and potent antioxidant activity. At the same time, the PVA/CS-G (GSE) showed the highest antimicrobial activity against Escherichia coli (Gram-negative) and Listeria monocytogenes (Gram-positive) bacteria. The PVA/CS-CGA composite film, reinforced with CNCs/GSE/Aronia extract, showed the highest UV-barrier (95.5%), highest antioxidant activity (95%), potent antimicrobial activity, pH-sensitivity, lowest water vapor permeability (WVP), and desirable mechanical properties. The multifunctional properties of the produced composite films encourage their use as active and intelligent food packaging films to extend shelf life and monitor food quality.

Synergistic effect of UV-C LED irradiation and PLA/PBAT-based antimicrobial packaging film on fresh-cut vegetables

The combined use of ultraviolet-C light-emitting diodes (UV–C LED) irradiation and antimicrobial packaging film was used to secure the safety of fresh-cut vegetables. The antimicrobial packaging film was prepared by adding grapefruit seed extract (GSE) and zinc oxide nanoparticles (ZnO) to a blend film of poly(lactide) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT). The GSE and ZnO added film (PLA/PBAT/GSE/ZnO film) showed moderate antioxidant activity of about 36.3% and 21.9% in the ABTS and DPPH methods, respectively, and exhibited strong antibacterial activity against Enterohemorrhagic Escherichia coli (EHEC) and Staphylococcus aureus. The UV-C LED treatment reduced EHEC by 0.47, 0.55, and 0.61 Log CFU/g and S. aureus by 0.46, 0.39, and 0.33 Log CFU/g of fresh-cut onion, cabbage, and carrot, respectively. The combined UV-C LED irradiation and antimicrobial packaging showed a significant synergistic effect in reducing the bacteria during storage. After 7 days of storage at 10 °C, it showed 2.02, 2.82, and 2.06 log CFU/g lower E. coli, and 1.59, 1.77, and 1.47 log CFU/g lower S. aureus in onion, cabbage, and carrot, respectively, than the control group. The combined use of UV-C LED and antimicrobial packaging has a high potential to extend the shelf life of fresh-cut vegetables without heat treatment or the addition of chemical preservatives.

Fabrication and Characterization of Bio-Nanocomposites Based on Halloysite-Encapsulating Grapefruit Seed Oil in a Pectin Matrix as a Novel Bio-Coating for Strawberry Protection.

In the framework of designing a novel bio-coating for the preservation of fresh fruits, this paper reports the design, preparation, and characterization of novel bio-nanocomposites based on pectin loaded with grapefruit seed oil (GO), a natural compound with antimicrobial properties, encapsulated into halloysite nanotubes (HNTs). The vacuum-based methodology was used for the encapsulation of the oil into the hollow area of the nanotubes, obtaining nano-hybrids (HNT-GO) with oil concentrations equal to 20, 30, and 50 wt%. Physical properties (thermal, mechanical, barrier, optical) were analyzed. Thermal properties were not significantly (p < 0.05) affected by the filler, while an improvement in mechanical performance (increase in elastic modulus, stress at breaking, and deformation at breaking up to 200%, 48%, and 39%, respectively, compared to pure pectin film) and barrier properties (increase in water permeability up to 480% with respect to pure pectin film) was observed. A slight increase in opacity was detected without significantly compromising the transparency of the films. The release of linoleic acid, the main component of GO, was followed for 21 days and was correlated with the amount of the hybrid filler, demonstrating the possibility of tailoring the release kinetic of active molecules. In order to evaluate the effectiveness of the prepared bio-composites as an active coating, fresh strawberries were coated and compared to uncoated fruit. Qualitative results showed that the fabricated novel bio-coating efficiently extended the preservation of fresh fruit.

Grapefruit Seed Extracts’ Antibacterial and Antiviral Activity: Anti-Severe Acute Respiratory Syndrome Coronavirus 2 Impact

The Corona pandemic has affected the entire world. It caused a fatal respiratory illness and threatened public safety and human health. Scientists scrambled to detect an operative drug to counter the SARS-CoV-2 (severe acute respiratory syndrome Coronavirus 2). The hunt for a nutritional supplement to treat the Coronavirus has occupied a large area of scientific inquiry. Grapefruit (GF) (Rutaceae family) is a subtropical fruit, it has potent bioactive properties. Natural grapefruit seed extract

Preparation of nanoemulsion of grapefruit seed extract and evaluation of its antibacterial activity

To improve the stability of grapefruit seed extract (GSE) and prolong its antibacterial effect, a GSE nanoemulsion (GNE) was prepared by a high-energy emulsifying method. The particle size and PDI of fresh GNE were 173.9 nm and 0.105, respectively. TEM images showed that uniform and closely distributed GNE droplets. The minimum inhibitory concentration (MIC) of GNE against Staphylococcus aureus and Escherichia coli were 0.6 wt% and 1.2 wt%, respectively, 25% and 14% improved compared to GSE. Besides, the GNE was proved to be more effective to destroy the cell wall of E. coli than that of S. aureus by measuring the concentration of alkaline phosphatase after treatment. The increase of conductivity, nucleic acid, and protein released from the cells indicated that the bacteria cell membrane has been severely damaged after GNE treatment. TEM results further illustrated that the internal microstructure of bacteria cells was significantly changed with GNE treatment. Novelty impact statement In the present study, the grapefruit seed extract nanoemulsion (GNE) with more surface-volume ratio, higher biological activity, and stronger bioavailability was successfully prepared using the high energy method. GNE has an inhibitory effect on S. aureus and E. coli by destroying the cell wall and cell membrane of the bacteria. This work provides support for expanding the application of grapefruit seed extract.

Antioxidant Activity of Citrus Limonoids and Investigation of Their Virucidal Potential against SARS-CoV-2 in Cellular Models.

The COVID-19 pandemic represents an unprecedented global emergency. Despite all efforts, COVID-19 remains a threat to public health, due to the complexity of mass vaccination programs, the lack of effective drugs, and the emergence of new variants. A link has recently been found between the risk of developing a severe COVID-19 infection and a high level of oxidative stress. In this context, we have focused our attention on natural compounds with the aim of finding molecules capable of acting through a dual virucidal–antioxidant mechanism. In particular, we studied the potential of grapefruit seed extracts (GSE) and their main components, belonging to the class of limonoids. Using chemical and biological approaches including isolation and purification of GSE, antioxidant and virucidal assays, we have shown that grapefruit seed constituents, belonging to the class of limonoids, are endowed with remarkable virucidal, antioxidant and mitoprotective activity.