Antioxidant and Antimicrobial Potential of Phenolic Metabolites from Traditionally Used Mediterranean Herbs and Spices

Inhibitory effects of garlic, cinnamon, and rosemary on viability, heat resistance, and biofilm formation of Bacillus cereus spores in the broth of a fermented soybean paste stew, Cheonggukjang jjigae

Foods prepared through heating, including broths, have the potential and risk of survival of Bacillus cereus, which has the ability to form spores and biofilms. This study evaluated the efficacy of various natural products (particularly spices) in mitigating B. cereus contamination in Cheonggukjang jjigae (CJ) broth. The following characteristics of B. cereus were examined: viability of vegetative cells (including other pathogenic bacteria) and planktonic spores, heat resistance of planktonic spores and spores in intact biofilms, and biofilm formation and persistence. In an antimicrobial test to evaluate the inhibitory effects of spice and cruciferous vegetable extracts on B. cereus CH3 vegetative cells, cinnamon, garlic, and rosemary extracts were selected as they have shown significant inhibitory effects, with inhibition zones of 20-29 mm in diameter at the highest concentration tested (160 mg/mL, unless otherwise stated). These spice extracts also exhibited antimicrobial activity against other foodborne pathogens, including Staphylococcus aureus, Listeria monocytogenes, Salmonella Typhimurium, and Escherichia coli O157:H7. Garlic extract showed the greatest inhibitory effect on the viability and heat resistance of planktonic spores of B. cereus CH3, and cinnamon and rosemary extracts exhibited similar effects. Garlic extract reduced B. cereus CH3 spore counts in phosphate buffer solution (PBS) and CJ broth by 20.22 % and 14.08 %, respectively, compared to control (treated with the same ethanol amount instead of the extract), and effectively weakened spore heat resistance, reducing the D100°C-values of planktonic spores of B. cereus CH3 in PBS and CJ broth by 32.89 % and 23.08 %, respectively, compared to control. As for the characteristics related to biofilm, garlic extract showed the highest inhibitory effect on biofilm formation and persistence and heat resistance of spores in intact biofilms, followed by rosemary and cinnamon extracts. All three spice extracts completely inhibited biofilm formation even at the lowest concentration (20 mg/mL) at the early stage of biofilm formation. They completely eradicated biofilm persistence formed in brain heart infusion (BHI) and CJ broth at the highest concentration. A high garlic extract concentration (80 mg/mL) also reduced the D100°C-values of spores in biofilms formed in BHI and CJ broth by 16.34 % and 9.00 %, respectively, compared to control. Taken together, garlic extract was most effective in mitigating B. cereus contamination in a concentration-dependent manner in in vitro-menstrua and CJ broth. This study may provide one of the promising strategies to reduce the risk of B. cereus in soybean stews such as CJ.

An Up-to-Date Review Regarding the Biological Activity of Geranium robertianum L

In this modern era, in which interest in natural compounds is gaining more ground, Geranium robertianum L. (Gr), a species with long use in traditional medicine, stands out for its promising potential in managing a multitude of health issues. In this context, the present review aims to explore the main phytocompounds detected in various types of extracts, as well as the biological activity of Gr species. This review was conducted by analyzing data published up to February 2025 from peer-reviewed journals and databases including PubMed, Web of Science, and Google Scholar, using key words combinations such as Geranium robertianum L. and the searched phytocompound and biological effect. According to the literature the main phytochemical classes identified in different types of extracts include tannins, flavonoids, phenolic acids, and essential oils. The most important biological actions described in the literature are antioxidant, anti-inflammatory, antimicrobial, antiulcerative, neuroprotective, anti-cancer, and antidiabetic effects. However, knowledge about Gr is still relatively limited, requiring more detailed study regarding its pharmacological proprieties and the molecular mechanisms behind them.

Comprehensive analysis of physical, chemical, and phenolic acid properties of powders derived from watermelon (Crimson Sweet) by-products

This study investigated the physical, chemical, and phenolic properties of watermelon peel powder (WPP), watermelon rind powder (WRP), and watermelon seed powder (WSP) derived from watermelon (Crimson sweet) by-products (WBP). As these by-products are typically discarded as waste, the aim was to enhance their added value and explore their potential as sustainable functional food additives. WSP has the largest particle size among the samples. The highest water holding capacity was observed in WRP (8.89%) and oil holding capacity in WPP (4.09%), while WSP had the lowest (6.69% and 2.06%). WRP exhibited better rehydration and solubility, whereas WSP had lower values. WSP contained higher protein and lipid levels (29.46% and 43.0%), while WPP and WRP had greater dietary fiber (78.55% and 48.66%). In terms of mineral matters, Mg and K were substantially greater in WBP than Fe and Na; furthermore, WRP had more K and Mg than the rest. The total phenolic content was determined to be 2855, 3330, and 4196.5 mg GAE/100 g for the WRP, WSP and WPP, respectively. The antioxidant activity as measured by IC50 values, varied between 44.42 (WPP) and 121.29 mg/mL (WRP). A total of 47 phenolic acids were characterised, with genistein being the most abundant compound identified at 10147.1 µg/kg throughout all three powders. In conclusion, these findings highlight the potential of WBP as a sustainable ingredient for the food industry, offering both high nutritional value and functional properties. By valorizing watermelon by-products, this study contributes to waste reduction and supports the development of eco-friendly, nutrient-rich food formulations.

Is Membrane Filtration Applicable for the Recovery of Biologically Active Substances from Spent Lavender?

This study explored the batch membrane filtration of 40% ethanol extracts from spent lavender, containing valuable compounds like rosmarinic acid, caffeic acid, and luteolin, using a polyamide-urea thin film composite X201 membrane. Conducted at room temperature and 20 bar transmembrane pressure, the process demonstrated high efficiency, with rejection rates exceeding 98% for global antioxidant activity and 93-100% for absolute concentrations of the target components. During concentration, the permeate flux declined from 2.43 to 1.24 L·m-2·h-1 as the permeate-to-retentate-volume ratio increased from 0 to 1. The process resistance, driven by osmotic pressure and concentration polarization, followed a power-law relationship with a power value of 1.20, consistent with prior nanofiltration studies of rosmarinic acid solutions. Notably, no membrane fouling occurred, confirming the method's scalability without compromising biological activity. The antioxidant activity, assessed via the DPPH method, revealed that the retentate exhibited double the activity of the feed. Antibacterial assays using broth microdilution showed that the retentate inhibited Escherichia coli by 73-96% and Bacillus subtilis by 97-98%, making it the most active fraction. These findings validate the effectiveness of the X201 membrane for concentrating natural antioxidants and antibacterial agents from lavender extract under sustainable operating conditions.

Natural Products in the Treatment of Lower Urinary Tract Dysfunction and Infection

The popularity of natural products for the treatment of lower urinary tract symptoms (LUTS) differs considerably between countries. Here we discuss the clinical evidence for efficacy in two indications, male LUTS suggestive of benign prostatic hyperplasia and urinary tract infections, and the mechanistic evidence from experimental studies. Most evidence for male LUTS is based on extracts from saw palmetto berries, stinging nettle roots, and pumpkin seeds, whereas most evidence for urinary tract infection is available for European golden rod and combined preparations although this field appears more fragmented with regard to extract sources. Based on differences in sample collection and extraction, extracts from the same plants are likely to exhibit at least quantitative differences in potential active ingredients, which makes extrapolation of findings with one extract to those of others potentially difficult. While only limited information is available for most individual extracts, some extracts have been compared to placebo and/or active controls in adequately powered trials.

Characterization of Sodium Alginate-Based Films Blended with Olive Leaf and Laurel Leaf Extracts Obtained by Ultrasound-Assisted Technology

Due to environmental concerns, there is an increasing need to reduce the use of synthetic and non-renewable packaging materials to reduce waste and increase sustainability. This study aimed to characterise sodium alginate edible-based films (SA) incorporated with laurel leaf extract (LLE) and olive leaf extract (OLE) obtained by ultrasound-assisted extraction. Determination of total phenolic content, antioxidant, and antimicrobial activity was performed for the extracts and films. Also, thickness, tensile strength, elongation at break, modulus of elasticity, opacity and colour, moisture content, water vapour permeability (WVP), Fourier-transform infrared spectroscopy (FTIR) spectra, and surface morphology by scanning electron microscope (SEM) analyses were performed for the films. LLE yielded better results in terms of phenolic content (195 mg GAE/g), antioxidant (2.1 TE/g extract) and antimicrobial activity (MIC at 1% for Listeria monocytogenes and Staphylococcus aureus, and 1.8% for Enterococcus faecalis). For the films, the simultaneous incorporation of LLE 1% (w/v) and OLE 1% (w/v) resulted in a significant reduction of approximately 2 log CFU/g against S. aureus. The addition of LLE and OLE extracts also proved to improve barrier properties (lower WVP for SA films with LLE 1% + OLE 1%, 3.49 × 10-11 g m-1 s-1 Pa-1) and promoted changes in resistance and flexibility. The results demonstrated that active alginate-based films can be valuable for enhancing food preservation.

Modulation of the bacterial virulence and resistance by well-known European medicinal herbs

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia officinalis L., Sambucus nigra L., Matricaria chamomilla L., Agrimonia eupatoria L., Fragaria vesca L. and Malva sylvestris L. are plants that have a long tradition in European folk medicine. To this day, they are part of medicinal teas or creams that help with the healing of skin wounds and the treatment of respiratory or intestinal infections. However, so far these plants have not been investigated more deeply than in their direct antibacterial effect.

AIM OF THE STUDY

Our research is focused on adjuvants that inhibit the mechanism of antibiotic resistance or modulate bacterial virulence. Based on a preliminary screening of 52 European herbs, which commonly appear as part of tea blends or poultice. Six of them were selected for their ability to revert the resistant phenotype of nosocomial bacterial strains.

METHODS

Herbs selected for this study were obtained from commercially available sources. For the extraction of active compounds ethanol was used. Modulation of virulence was observed as an ability to inhibit bacterial cell-to-cell communication using two mutant sensor strains of Vibrio campbellii. Biofilm formation, and planktonic cell adhesion was measured using a static antibiofilm test. Ethidium bromide assay was used to checked the potential of inhibition bacterial efflux pumps. The antibacterial activities of the herbs were evaluated against resistant bacterial strains using macro dilution methods.

RESULTS

Alcohol extracts had antibacterial properties mainly against Gram-positive bacteria. Of all of them, the highest antimicrobial activity demonstrated Malva sylvestris, killing both antibiotic resistant bacteria; Staphylococcus aureus with MIC of 0.8 g/L and Pseudomonas aeruginosa 0.7 g/L, respectively. Fragaria vesca extract (0.08 g/L) demonstrated strong synergism with colistin (4 mg/L) in modulating the resistant phenotype to colistin of Pseudomonas aeruginosa. Similarly, the extract of S. officinalis (0.21 g/L) reverted resistance to gentamicin (1 mg/L) in S. aureus. However, Sambucus nigra and Matricaria chamomilla seem to be a very promising source of bacterial efflux pump inhibitors.

CONCLUSION

The extract of F. vesca was the most active. It was able to reduce biofilm formation probably due to the ability to decrease bacterial quorum sensing. On the other hand, the activity of S. nigra or M. chamomilla in reducing bacterial virulence may be explained by the ability to inhibit bacterial efflux systems. All these plants have potential as an adjuvant for the antibiotic treatment.

Evaluation of physicochemical, antioxidant, antibacterial activity, and sensory properties of watermelon rind candy

Watermelon (Citrullus lanatus) is consumed all over the world that contains a large number of seeds and rind, which is discarded. These by-products contain phytochemical compounds with great nutritional potential. This study aims to evaluate physicochemical properties and sensory values of watermelon rind candy. In this study in order to make the waste of watermelon a more sustainable and value-added food product, the watermelon rind was dried using an osmotic dehydration technique which comprises gradual impregnation of syrup (50 and 70% w/w - 1 to 5 h) before drying at 40 and 60 °C in 8 and 10 h. Various variables such as moisture content, chemical composition, water loss, solid gain, rehydration water, acidity, pH, antioxidant activity, antibacterial activity, residual toxins, phenolic and flavonoid contents during osmotic dehydration of watermelon were investigated. Results showed by rising temperatures, dehydration becomes more severe. Increasing the temperature in both osmotic samples in a concentrated solution (70%) and in osmotic samples with a dilute solution (50%) can enhance the mass transfer, water loss, solid absorption, as well as dehydration intensity. However, antioxidant activity, phenolic and flavonoid content significantly decreased after osmotic dehydration. TPC decreased from 35.83 mg/100 g to 27.45 mg/100 g and TFC of the watermelon rind (8.71 ± 0.01 mg/100 g) decreased to 2.63 ± 0.02 mg/100 g and also antioxidant activity after the osmotic process decreased from 61% to 40%. Also, osmotic dehydration had no significant impact on acidity and pH. The watermelon rind dehydrated sample (osmosis temperature: 40 °C, osmotic solution concentration: 70%, immersion duration: 5 h) was the best choice of panelists due to the highest score in the sensory evaluation including taste, texture, and overall acceptability. By determining the hardness of the watermelon rind candy and comparing it with the results of texture analysis of other dried products, it can be concluded that this product can be used as a healthy snack with longer shelf life properties.

Plant-Based Antioxidants for Prevention and Treatment of Neurodegenerative Diseases: Phytotherapeutic Potential of Laurus nobilis, Aronia melanocarpa, and Celastrol

With the progress of medicine, especially in the last century, life expectancy increased considerably. As a result, age-related diseases also increased, especially malignancies and degenerative diseases of the central nervous system. The incidence and prevalence of neurodegenerative diseases steadily increased over the years, but despite efforts to uncover the pathophysiological processes behind these conditions, they remain elusive. Among the many theories, oxidative stress was proposed to be involved in neurodegenerative processes and to play an important role in the morbidity and progression of various neurodegenerative disorders. Accordingly, a number of studies discovered the potential of natural plant constituents to have significant antioxidant activity. This review focused on several plant-based antioxidants that showed promising results in the prevention and treatment of neurodegenerative diseases. Laurus nobilis, Aronia melanocarpa, and celastrol, a chemical compound isolated from the root extracts of Tripterygium wilfordii and T. regelii, are all known to be rich in antioxidant polyphenols.

Current Understanding of the Molecular Basis of Spices for the Development of Potential Antimicrobial Medicine

Antimicrobial resistance increases day by day around the world. To overcome this situation new antimicrobial agents are needed. Spices such as clove, ginger, coriander, garlic, and turmeric have the potential to fight resistant microbes. Due to their therapeutic properties, medicinal herbs and spices have been utilized as herbal medicines since antiquity. They are important sources of organic antibacterial substances that are employed in treating infectious disorders caused by pathogens such as bacteria. The main focus of the study is the bioactivity of the active ingredients present in different kinds of naturally available spices. We conducted a thorough search of PubMed, Google Scholar, and Research Gate for this review. We have read many kinds of available literature, and in this paper, we conclude that many different kinds of naturally available spices perform some form of bioactivity. After reading several papers, we found that some spices have good antimicrobial and antifungal properties, which may help in controlling the emerging antimicrobial resistance and improving human health. Spices have many phytochemicals, which show good antimicrobial and antifungal effects. This review of the literature concludes that the natural bioactivate compounds present in spices can be used as a drug to overcome antimicrobial resistance in human beings.

Antibacterial and Antiproliferative Activities of Azadirachta indica Leaf Extract and Its Effect on Oil-in-Water Food Emulsion Stability

The present study aims to identify and quantify the phenolic compounds of Azadirachta indica leaf extract using HPLC-MS and to evaluate the antioxidant, antibacterial (against different Gram-positive and negative bacteria) and in vitro anti-proliferative activities of this extract (against breast, human liver and cervix adenocarcinoma-derived cells). The application of this extract as a natural antioxidant for food preservation was also tested on oil-in-water food emulsions for the first time in the present work in order to determine the use of Azadirachta indica leaves as a natural additive to preserve the food against lipid oxidation and rancidity. The results obtained revealed that 50%-aqueous ethanol leaf extract showed the best extraction yield (25.14%), which was characterized by a high content in phenolic compounds and strong antioxidant activity. Moreover, this leaf extract inhibited the growth of the bacterial strains tested (Staphylococcus aureus, Escherichia coli, Salmonella paratyphi and Micrococcus luteus) and showed better anti-proliferative activity against breast and cervix adenocarcinoma-derived cells than human liver cancer cells after 48 h of treatment. Additionally, Azadirachta indica leaf extract showed almost similar effects as gallic acid solutions (0.25% and 0.5%) in preserving the oxidation of oil-in-water food emulsions and prevented the formation of secondary oxidation products (malondialdehyde) as well. The results obtained suggested that extracts of Azadirachta indica leaves are a potential source of antioxidant and antibacterial compounds and pointed to the potential of these natural extracts as therapeutic agents.

Phenolic Profile, EPR Determination, and Antiproliferative Activity against Human Cancer Cell Lines of Anthyllis vulneraria Extracts

In the current work, the leaf and flower extracts of Anthyllis vulneraria were evaluated for their chemical characterization using HPLC-MS and for their radical scavenging capacity toward methoxy radicals produced by a Fenton-type reaction using an electron paramagnetic resonance (EPR) spectroscopy assay. The in vitro antiproliferative activity of these extracts against several human-derived cancer cells (breast: MCF-7; cervical: HeLa; hepatocellular: HepG2) was also evaluated. The results showed that the Anthyllis vulneraria leaf extract was characterized by 17 different phenolic compounds, among which phenolic acids were the most abundant, while its flower extract exhibited higher contents of flavonoids. Furthermore, Anthyllis vulneraria extracts demonstrated a potent radical scavenging activity against methoxy radicals. Both extracts also significantly reduced the viability of the different cancer cell lines. The results of the current study suggested that Anthyllis vulneraria extracts are a promising source of antioxidant compounds with health benefits and pointed to their potential use for treating cancer and developing novel therapeutic agents.

Identification of Phytogenic Compounds with Antioxidant Action That Protect Porcine Intestinal Epithelial Cells from Hydrogen Peroxide Induced Oxidative Damage

Oxidative stress contributes to intestinal dysfunction. Plant extracts can have antioxidant action; however, the specific phytogenic active ingredients and their potential mechanisms are not well known. We screened 845 phytogenic compounds using a porcine epithelial cell (IPEC-J2) oxidative stress model to identify oxidative-stress-alleviating compounds. Calycosin and deoxyshikonin were evaluated for their ability to alleviate H2O2-induced oxidative stress by measuring their effects on malondialdehyde (MDA) accumulation, reactive oxygen species (ROS) generation, apoptosis, mitochondrial membrane potential (MMP), and antioxidant defense. Nrf2 pathway activation and the effect of Nrf2 knockdown on the antioxidative effects of hit compounds were investigated. Calycosin protected IPEC-J2 cells against H2O2-induced oxidative damage, likely by improving the cellular redox state and upregulating antioxidant defense via the Nrf2-Keap1 pathway. Deoxyshikonin alleviated the H2O2-induced decrease in cell viability, ROS production, and MMP reduction, but had no significant effect on MDA accumulation and apoptosis. Nrf2 knockdown did not weaken the effect of deoxyshikonin in improving cell viability, but it weakened its effect in suppressing ROS production. These results indicate that the mechanisms of action of natural compounds differ. The newly identified phytogenic compounds can be developed as novel antioxidant agents to alleviate intestinal oxidative stress in animals.

Computational Insights and In Vitro Validation of Antibacterial Potential of Shikimate Pathway-Derived Phenolic Acids as NorA Efflux Pump Inhibitors

The expression of the efflux pump systems is the most important mechanism of antibiotic resistance in bacteria, as it contributes to reduced concentration and the subsequent inactivity of administered antibiotics. NorA is one of the most studied antibacterial targets used as a model for efflux-mediated resistance. The present study evaluated shikimate pathway-derived phenolic acids against NorA (PDB ID: 1PW4) as a druggable target in antibacterial therapy using in silico modelling and in vitro methods. Of the 22 compounds evaluated, sinapic acid (−9.0 kcal/mol) and p-coumaric acid (−6.3 kcal/mol) had the best and most prominent affinity for NorA relative to ciprofloxacin, a reference standard (−4.9 kcal/mol). A further probe into the structural stability and flexibility of the resulting NorA-phenolic acids complexes through molecular dynamic simulations over a 100 ns period revealed p-coumaric acid as the best inhibitor of NorA relative to the reference standard. In addition, both phenolic acids formed H-bonds with TYR 76, a crucial residue implicated in NorA efflux pump inhibition. Furthermore, the phenolic acids demonstrated favourable drug likeliness and conformed to Lipinski’s rule of five for ADME properties. For the in vitro evaluation, the phenolic acids had MIC values in the range 31.2 to 62.5 μg/mL against S. aureus, and E. coli, and there was an overall reduction in MIC following their combination with ciprofloxacin. Taken together, the findings from both the in silico and in vitro evaluations in this study have demonstrated high affinity of p-coumaric acid towards NorA and could be suggestive of its exploration as a novel NorA efflux pump inhibitor.

An assessment of the evidence for antibacterial activity of stinging nettle (Urtica dioica) extracts

Stinging nettles (Urtica spp.) have been used in a diverse range of traditional and historical medicines from around the world for the treatment of skin diseases, wounds, urinary disorders, respiratory diseases, bone and joint pain, anaemia and other circulatory problems, as well as in cosmetic preparations for skin and haircare. As part of an interdisciplinary exploration of nettle-based remedies, we performed a systematic review of published evidence for the antimicrobial activity of Urtica spp. extracts against bacteria and fungi that commonly cause skin, soft tissue and respiratory infections. We focussed on studies in which minimum inhibitory concentration (MIC) assays of U. dioica were conducted on the common bacterial opportunistic pathogens Escherichia coli , Pseudomonas aeruginosa , Klebsiella pneumoniae and Staphylococcus aureus . No studies used fresh leaves (all were dried prior to use), and no studies prepared nettles in weak acid (corresponding to vinegar) or in fats/oils, which are common combinations in historical and traditional preparations. We addressed this gap by conducting new antibacterial tests of extracts of fresh U. dioica leaves prepared in vinegar, butter or olive oil against P. aeruginosa and S. aureus . Our systematic review and additional experimental data leads us to conclude that there is no strong evidence for nettles containing molecules with clinically useful antimicrobial activity. It seems most likely that the utility of nettles in traditional topical preparations for wounds may simply be as a 'safe' absorbent medium for keeping antibacterial (vinegar) or emollient (oils) ingredients at the treatment site.

Natural Polyphenols for the Preservation of Meat and Dairy Products

Food spoilage makes foods undesirable and unacceptable for human use. The preservation of food is essential for human survival, and different techniques were initially used to limit the growth of spoiling microbes, e.g., drying, heating, salting, or fermentation. Water activity, temperature, redox potential, preservatives, and competitive microorganisms are the most important approaches used in the preservation of food products. Preservative agents are generally classified into antimicrobial, antioxidant, and anti-browning agents. On the other hand, artificial preservatives (sorbate, sulfite, or nitrite) may cause serious health hazards such as hypersensitivity, asthma, neurological damage, hyperactivity, and cancer. Thus, consumers prefer natural food preservatives to synthetic ones, as they are considered safer. Polyphenols have potential uses as biopreservatives in the food industry, because their antimicrobial and antioxidant activities can increase the storage life of food products. The antioxidant capacity of polyphenols is mainly due to the inhibition of free radical formation. Moreover, the antimicrobial activity of plants and herbs is mainly attributed to the presence of phenolic compounds. Thus, incorporation of botanical extracts rich in polyphenols in perishable foods can be considered since no pure polyphenolic compounds are authorized as food preservatives. However, individual polyphenols can be screened in this regard. In conclusion, this review highlights the use of phenolic compounds or botanical extracts rich in polyphenols as preservative agents with special reference to meat and dairy products.

Isolation of Laurus nobilis Leaf Polyphenols: A Review on Current Techniques and Future Perspectives

In recent years, the market demand for products enhanced with ingredients derived from natural products, such as polyphenols, is rapidly increasing. Laurus nobilis L., known as bay, sweet bay, bay laurel, Roman laurel or daphne is an evergreen Mediterranean shrub whose leaves have traditionally been used in cuisines and folk medicine due to their beneficial health effects, which can nowadays be scientifically explained by various biological activities of the leaf extracts. Many of these activities can be attributed to phenolic compounds present in L. nobilis leaves which include flavonoids, phenolic acids, tannins (proanthocyanidins) and lignans. In order to enable efficient industrial utilization of these valuable compounds, it is crucial to establish optimal extraction procedures resulting in the highest yields and quality of the extracts. This paper offers the first systematic review of current literature on the influence of conventional and advanced extraction techniques, including microwave-assisted, ultrasound-assisted, enzyme-assisted, supercritical-CO2 and mechanochemical-assisted extraction on the phenolic content of L. nobilis leaf extracts, allowing more efficient planning of further research and simplifying the steps towards industrial utilization of this plant.

Evaluation of the Antidiarrheal and Antioxidant Effects of Some Chewing Sticks Commonly Used for Oral Hygiene in Ghana

Microbial etiology of diarrhea is a significant cause of death, especially in children in developing countries. The presence of microbes that are resistant to current treatment options for diarrhea suggests the need to find newer antimicrobial agents for treatment. Therefore, this study focused on investigating the antimicrobial effect of some Ghanaian chewing sticks commonly used for oral hygiene, Azadirachta indica, Garcinia afzelii, and Garcinia kola, against selected diarrhea-causing organisms. From the stem and bark of each plant, 70% methanolic extract was experimented on Salmonella and Shigella species, namely, Shigella sonnei, Shigella flexeneri, Salmonella typhinirium enterica, Salmonella typhi attenuated, and Klebsiella oxytoca for microbial susceptibility using the agar well diffusion method. Additionally, the antioxidant profile of the methanolic extracts were investigated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic) acid (ABTS) scavenging activities, and ferric-reducing antioxidant potential (FRAP) assays, while the total polyphenolic content was determined using the Folin–Ciocalteau reagent. G. afzelii and A. indica stem demonstrated the highest antimicrobial effect, inhibiting the growth of all test organisms. Additionally, the extracts demonstrated high antioxidant potential and were found to possess significant amounts of phenolic compounds. Therefore, methanolic extracts of G. afzelii and A. indica stem are promising candidates for the identification of safe novel compounds to mitigate diarrheal diseases.

Phenolic compounds in Nordic berry species and their application as potential natural food preservatives

An increasing demand for natural food preservatives is raised by consumers. For Nordic berry species, abundance of phenolic compounds and potent activities of anti-oxidation and anti-bacteria enables a great potential as food preservatives. This review provides a systematic examination of current literature on phenolic profiles, anti-oxidative and anti-bacterial activities of various extracts of Nordic berry species, as well as the impact of various structure features of phenolics on the bioactivities. Special attention is placed on exploitation of leaves of berry species and pomaces after juice-pressing as side-streams of berry production and processing. The current progress and challenges in application of Nordic berry species as food preservatives are discussed. To fully explore the potential application of Nordic berry species in food industry and especially to valorize the side-streams of berry cultivation (leaves) and juice-pressing industry (pomaces), it is crucial to obtain extracts and fractions with targeted phenolic composition, which have high food preserving efficacy and minimal impact on sensory qualities of food products.

Chitosan Films Functionalized with Different Hydroxycinnamic Acids: Preparation, Characterization and Application for Pork Preservation

Hydroxycinnamic acids are one category of bioactive phenolic acids that are widely distributed in plants. In this study, chitosan (CS) was functionalized with three kinds of hydroxycinnamic acids (p-coumaric acid, caffeic acid and ferulic acid) through the carbodiimide-mediated grafting method. The obtained hydroxycinnamic-acid-grafted CSs (hydroxycinnamic acid-g-CSs) were further fabricated into food packaging films through solvent casting. For the first time, the functionalities of the different hydroxycinnamic acid-g-CS films were compared. Results showed the grafting ratio of p-coumaric acid-g-CS, caffeic acid-g-CS and ferulic acid-g-CS was 73.68, 129.42 and 91.75 mg/g, respectively. Instrumental analyses confirmed hydroxycinnamic acids conjugated with CS through amide and ester bonds. The functionalization of CS film with hydroxycinnamic acids produced a more compact microstructure and higher UV light barrier ability, mechanical strength, water vapor barrier ability, thermal stability and antioxidant and antimicrobial activities. Among the different hydroxycinnamic acid-g-CS films, caffeic acid-g-CS film presented the strongest barrier, mechanical, antioxidant and antimicrobial properties. Moreover, caffeic acid-g-CS film packaging effectively extended the shelf life of pork to 10 days at 4 °C. Our results suggest caffeic acid-g-CS film can be used in the active food packaging field.

Comparative stability of arbutin in Arctostaphylos uva-ursi by a new comprehensive stability-indicating HPLC method

INTRODUCTION

Arbutin is a phenol glucoside found in high concentrations in bearberry leaves and associated with the antimicrobial activity of the plant. Hydroquinone can also be found in leaves or be formed by degradation of arbutin. Lengthy exposure to free hydroquinone is associated with induction of toxicity in different organs.

OBJECTIVE

To develop and validate a stability-indicating method by high-performance liquid chromatography diode array detector (HPLC-DAD) for simultaneous quantification of arbutin and hydroquinone in bearberry leaves and perform a comprehensive forced degradation study comparing synthetic arbutin and the arbutin in bearberry leaves.

METHODS

Separation was performed using a C18 column, mobile phase with water-methanol (95:5), flow rate 1.0 mL/min and detection at 280 nm. Bearberry leaves were assayed and a forced degradation study of arbutin was performed in different conditions.

RESULTS

The method complied with all required validation parameters. Contents varied from 1.19 to 4.15% (w/w) of arbutin and from 0.022 to 0.604% (w/w) of hydroquinone. Synthetic arbutin was susceptible to acid hydrolysis and oxidative degradation, forming hydroquinone as the main degradation product. The same study using bearberry leaves showed that constituents of the plant matrix may act as antioxidants, reducing the oxidative degradation of arbutin, however acid hydrolysis of arbutin occurred in higher intensity.

CONCLUSION

Analysis of bearberry leaves evidenced high variation in arbutin and hydroquinone levels, demonstrating the need for standardisation and control. The stability profiles of synthetic arbutin and the arbutin in bearberry leaves were considerably different and the results may be useful for determining the most appropriate conditions for extraction and production of bearberry-based formulations.

Phenolic Compounds Content and Genetic Diversity at Population Level across the Natural Distribution Range of Bearberry (Arctostaphylos uva-ursi, Ericaceae) in the Iberian Peninsula

Bearberry (Arctostaphylos uva-ursi) is a medicinal plant traditionally employed for the treatment of urinary tract infections due to high contents of arbutin (hydroquinone β-D-glucoside), which is now mainly used as a natural skin-whitening agent in cosmetics. Bearberry has also been proposed as a natural antioxidant additive due to the high contents of phenolic compounds in leaves. We studied the variation on phenolic compounds in 42 wild populations of bearberry, aiming to elucidate if intrinsic biological, climatic, and/or geographic factors affect phenolic contents across its natural distribution in the Iberian Peninsula. Bearberry leaves were collected during autumn over a three-year period (2014-2016) in populations across a latitude and altitude gradient. Methanolic extracts showed a wide range of variation in total phenols content, and different phenolic profiles regarding arbutin (levels of this major constituent varied from 87 to 232 mg/g dr wt), but also catechin and myricetin contents, which were affected by geographic and climatic factors. Moderate levels of variation on genome size-assessed by flow cytometry-and on two plastid DNA regions were also detected among populations. Genetic and cytogenetic differentiation of populations was weakly but significantly associated to phytochemical diversity. Elite bearberry genotypes with higher antioxidant capacity were subsequently identified.

The Impact of Dietary Supplementation of Whole Foods and Polyphenols on Atherosclerosis

The purpose of this review is to highlight current research on the benefits of supplementation with foods with a diverse polyphenol composition, including fruits, vegetables, nuts, grains, oils, spices, and teas in blunting atherosclerosis. We searched PubMed for publications utilizing whole food or polyphenols prepared from whole foods in Apolipoprotein E (ApoE) or Low-Density Lipoprotein Receptor (LDLR) knockout mice, and identified 73 studies in which plaque was measured. The majority of the studies reported a reduction in plaque. Nine interventions showed no effect, while three using Agaricus blazei mushroom, HYJA-ri-4 rice variety, and safrole-2', 3'-oxide (SFO) increased plaque. The mechanisms by which atherosclerosis was reduced include improved lipid profile, antioxidant status, and cholesterol clearance, and reduced inflammation. Importantly, not all dietary interventions that reduce plaque showed an improvement in lipid profile. Additionally, we found that, out of 73 studies, only 9 used female mice and only 6 compared both sexes. Only one study compared the two models (LDLR vs. ApoE), showing that the treatment worked in one but not the other. Not all supplementations work in both male and female animals, suggesting that increasing the variety of foods with different polyphenol compositions may be more effective in mitigating atherosclerosis.

Plant Phenolics and Phenolic-Enriched Extracts as Antimicrobial Agents against Food-Contaminating Microorganisms

Phenolic compounds and extracts with bioactive properties can be obtained from many kinds of plant materials. These natural substances have gained attention in the food research as possible growth inhibitors of foodborne pathogenic and spoilage bacteria. Many phenolic-enriched plant extracts and individual phenolics have promising anti-quorum sensing potential as well and can suppress the biofilm formation and toxin production of food-related pathogens. Various studies have shown that plant phenolics can substitute or support the activity of synthetic food preservatives and disinfectants, which, by the way, can provoke serious concerns in consumers. In this review, we will provide a brief insight into the bioactive properties, i.e., the antimicrobial, anti-quorum sensing, anti-biofilm and anti-enterotoxin activities, of plant phenolic extracts and compounds, with special attention to pathogen microorganisms that have food relation. Carbohydrase aided applications to improve the antimicrobial properties of phenolic extracts are also discussed.