Antimicrobial and Antioxidant Properties of Total Polyphenols of Anchusa italica Retz

Anti-staphylococcal activity of a polyphenol-rich citrus extract: synergy with β-lactams and low proficiency to induce resistance

Introduction

Antibiotic resistance represents one of the most significant threats to public health in the 21st century. Polyphenols, natural molecules with antibacterial activity produced by plants, are being considered as alternative antimicrobial strategies to manage infections caused by drug-resistant bacteria. In this study, we investigated the antibacterial activity of a polyphenol mixture extracted from citrus fruits, against both antibiotic-susceptible and resistant strains of Staphylococcus aureus and Staphylococcus epidermidis.

Methods

Broth microdilution and time-kill curve experiments were used to test the extract anti-staphylococcal activity. Cytotoxicity was assessed by the hemolysis assay. The interaction between the mixture and antibiotics was investigated by the checkerboard assay. The effect of B alone and in combination with oxacillin on the membrane potential was investigated by the 3,3'-dipropylthiadicarbocyanine iodide assay. The ability of the extract to induce the development of resistance was verified by propagating S. aureus for 10 transfers in the presence of sub-inhibitory concentrations.

Results

The citrus extract was found to be active against all Staphylococcus strains at remarkably low concentrations (0.0031 and 0.0063%), displaying rapid bactericidal effects without being toxic on erythrocytes. In particular, B was found to rapidly cause membrane depolarization. When combined with methicillin, meropenem, and oxacillin, the mixture displayed synergistic activity exclusively against methicillin-resistant strains. We additionally show that the sequential exposure of S. aureus to sub-inhibitory concentrations did not induce the development of resistance against the extract.

Discussion

Overall, these findings support the potential use of the citrus extract as promising option to manage staphylococcal infections and suggest that it may counteract the mechanism behind methicillin-resistance.

In vitro and in silico evaluation of bioactivities and chemical composition of the aerial parts of Anchusa officinalis L. methanol extract

The main objective of the study is to evaluate the antioxidant, anticancer, and antimicrobial activities of Anchusa officinalis L. in vitro and in silico. The dried aerial parts of A. officinalis L. were extracted with methanol. Total phenolic and flavonoid content was analyzed. Antioxidant and antimicrobial effects were tested against both gram-positive and gram-negative bacteria. Gas chromatography-mass spectrometry analysis revealed the presence of 10 phytochemical compounds, and cyclobutane (26.07%) was identified as the major photochemical compound. The methanol extract exhibited the maximum amount of total phenolic content (118.24 ± 4.42 mg QE/g dry weight of the dry extract) (R2 = 0.994) and the total flavonoid content was 94 ± 2.34 mg QE/g dry weight of the dry extract (R2 = 0.999). The IC50 value for 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid was 107.12 ± 3.42 μg/mL, and it was high for 1,1-diphenyl-2-picryl hydrazyl (123.94 ± 2.31 μg/mL). The IC50 value was 72.49 ± 3.14 against HepG2 cell lines, and a decreased value was obtained (102.54 ± 4.17 g/mL) against MCF-7 cell lines. The methanol extract increased the expression of caspase mRNA and Bax mRNA levels when compared to the control experiment (p < .05). The conclusions, A. officinalis L. aerial parts extract exhibited antibacterial, antifungal, and antioxidant activities.

Recent Advances in the Inhibition of Membrane Lipid Peroxidation by Food-Borne Plant Polyphenols via the Nrf2/GPx4 Pathway

Lipid peroxidation (LP) leads to changes in the fluidity and permeability of cell membranes, affecting normal cellular function and potentially triggering apoptosis or necrosis. This process is closely correlated with the onset of many diseases. Evidence suggests that the phenolic hydroxyl groups in food-borne plant polyphenols (FPPs) make them effective antioxidants capable of preventing diseases triggered by cell membrane LP. Proper dietary intake of FPPs can attenuate cellular oxidative stress, especially damage to cell membrane phospholipids, by activating the Nrf2/GPx4 pathway. Nuclear factor E2-related factor 2 (Nrf2) is an oxidative stress antagonist. The signaling pathway regulated by Nrf2 is a defense transduction pathway of the organism against external stimuli such as reactive oxygen species and exogenous chemicals. Glutathione peroxidase 4 (GPx4), under the regulation of Nrf2, is the only enzyme that reduces cell membrane lipid peroxides with specificity, thus playing a pivotal role in regulating cellular ferroptosis and counteracting oxidative stress. This study explored the Nrf2/GPx4 pathway mechanism, antioxidant activity of FPPs, and mechanism of LP. It also highlighted the bioprotective properties of FPPs against LP and its associated mechanisms, including (i) activation of the Nrf2/GPx4 pathway, with GPx4 potentially serving as a central target protein, (ii) regulation of antioxidant enzyme activities, leading to a reduction in the production of ROS and other peroxides, and (iii) antioxidant effects on LP and downstream phospholipid structure. In conclusion, FPPs play a crucial role as natural antioxidants in preventing LP. However, further in-depth analysis of FPPs coregulation of multiple signaling pathways is required, and the combined effects of these mechanisms need further evaluation in experimental models. Human trials could provide valuable insights into new directions for research and application.

Development of a co-culture system for green production of caffeic acid from sugarcane bagasse hydrolysate

Caffeic acid (CA) is a phenolic acid compound widely used in pharmaceutical and food applications. However, the efficient synthesis of CA is usually limited by the resources of individual microbial platforms. Here, a cross-kingdom microbial consortium was developed to synthesize CA from sugarcane bagasse hydrolysate using Escherichia coli and Candida glycerinogenes as chassis. In the upstream E. coli module, shikimate accumulation was improved by intensifying the shikimate synthesis pathway and blocking shikimate metabolism to provide precursors for the downstream CA synthesis module. In the downstream C. glycerinogenes module, conversion of p-coumaric acid to CA was improved by increasing the supply of the cytoplasmic cofactor FAD(H2). Further, overexpression of ABC transporter-related genes promoted efflux of CA and enhanced strain resistance to CA, significantly increasing CA titer from 103.8 mg/L to 346.5 mg/L. Subsequently, optimization of the inoculation ratio of strains SA-Ec4 and CA-Cg27 in this cross-kingdom microbial consortium resulted in an increase in CA titer to 871.9 mg/L, which was 151.6% higher compared to the monoculture strain CA-Cg27. Ultimately, 2311.6 and 1943.2 mg/L of CA were obtained by optimization of the co-culture system in a 5 L bioreactor using mixed sugar and sugarcane bagasse hydrolysate, respectively, with 17.2-fold and 14.6-fold enhancement compared to the starting strain. The cross-kingdom microbial consortium developed in this study provides a reference for the production of other aromatic compounds from inexpensive raw materials.

Exploring the Biological and Phytochemical Potential of Jordan's Flora: A Review and Update of Eight Selected Genera from Mediterranean Region

Jordan's flora is known for its rich diversity, with a grand sum of 2978 plant species that span 142 families and 868 genera across four different zones. Eight genera belonging to four different plant families have been recognized for their potential natural medicinal properties within the Mediterranean region. These genera include Chrysanthemum L., Onopordum Vaill. Ex. L., Phagnalon Cass., and Senecio L. from the Asteraceae family, in addition to Clematis L. and Ranunculus L. from the Ranunculaceae family, Anchusa L. from the Boraginaceae family, and Eryngium L. from the Apiaceae family. The selected genera show a wide variety of secondary metabolites with encouraging pharmacological characteristics including antioxidant, antibacterial, cytotoxic, anti-inflammatory, antidiabetic, anti-ulcer, and neuroprotective actions. Further research on these genera and their extracts will potentially result in the formulation of novel and potent natural pharmaceuticals. Overall, Jordan's rich flora provides a valuable resource for exploring and discovering new plant-based medicines.

Chemical characterization, anti-struvite crystal, anti-inflammatory, analgesic, and antidepressant activities of Papaver rhoeas L. root and leaf extracts

ETHNOPHARMACOLOGICAL RELEVANCE

Papaver rhoeas L. (P. rhoeas) is used to treat a wide range of pathologies. But there is no data on the anti-struvite, anti-inflammatory, analgesic, and anti-depressant effects of root and leaf extracts from this medicinal plant.

AIM OF THE STUDY

This study aimed to chemically characterize and determine the antidepressant, analgesic, anti-inflammatory, and anti-struvite activities of the root extract (RE) and leaf extract (LE) of P. rhoeas, a wild plant.

MATERIALS AND METHODS

The extraction of secondary metabolites and phytochemical screening were carried out using standard methods. The anti-struvite effect of our samples was assessed by Fourier transform infrared spectroscopy (FT-IR) and microscopic observation. For the anti-inflammatory impact, we used the carrageenan-induced paw edema technique in rats. To assess the analgesic effect of the extracts, we recorded the resulting abdominal contraction after intraperitoneal (IP) acetic acid injection. Finally, we assessed the antidepressant effect by conducting the Forced Swimming Test (FST).

RESULTS

Phytochemical screening results revealed the presence of phenols, flavonoids, saponins, tannins, coumarins, terpenoids, and alkaloids. Extraction results confirmed that our extracts were rich in secondary metabolites. Both P. rhoeas extracts limited struvite crystal development by reducing the size and number of crystals, as indicated by FT-IR analysis and microscopic observation. Additionally, the anti-struvite effects of the LE sample were greater than those of the RE sample. The results of the anti-inflammatory capacity of our extracts demonstrate the maximum inhibition of carrageenan-induced edema following 6 h (T6) of injection, ranging from 72.73 ± 7.7% for LE (400 mg/kg) to 95.45 ± 6.42% for the RE sample (400 mg/kg). On the other hand, the results for analgesic activity showed that the number of abdominal contractions in rats treated with RE and LE ranged from 11 ± 1.73 for RE (400 mg/kg) to 18 ± 1.50 for LE (200 mg/kg), while that of aspirin was 10.33 ± 0.57. Furthermore, the FST results show that the immobility time in rats treated with RE and LE varied from 91.98 ± 4.24 s for LE-treated rats (300 mg/kg) to 123.54 ± 7.83 s for RE-treated rats (150 mg/kg).

CONCLUSION

Based on these results, the roots and leaves of the studied plant can be considered a significant source of biologically active molecules for use in the pharmaceutical industry.

Papaver rhoeas L. stem and flower extracts: Anti-struvite, anti-inflammatory, analgesic, and antidepressant activities

The Papaver rhoeas L. (P. rhoeas) plant, which belongs to the Papaveraceae family, is also used as food and is exploited to treat several health problems. The purpose of this research is to determine the anti-struvite, anti-inflammatory, analgesic, and antidepressant effects of the stem extract (SE) and flower extract (FE) of the plant P. rhoeas. We used polarizing microscopy and Fourier transform infrared spectrometry (FT-IR) to evaluate the anti-struvite effect of our plant. The edema approach induced by the carrageenan molecule was used to study the anti-inflammatory impact of our extracts. The analgesic test was determined by calculating the number of abdominal contractions induced by the intraperitoneal (IP) administration of acetic acid. To evaluate the antidepressant effect of our extracts, we used the forced swimming test (FST). According to the results of the secondary metabolite extraction, both extracts contained high contents of secondary metabolites, while the results of the screening test showed that flavonoids, alkaloids, phenols, tannins, coumarins, saponins, and terpenoids were present. The result of struvite crystallization inhibition observed by polarizing microscopy and FT-IR shows the inhibition of struvite crystal aggregation by SE by decreasing the amount and size of crystals in a manner similar to cystone. The results of anti-inflammatory activity show maximum inhibition of edema after six hours of carrageenan injection in rats (T₆) for all extracts, with a maximum value of 86.36% for SE at the dose of 200 mg/kg. Regarding the analgesic effect of our plant, the lowest number of abdominal contractions was observed in rats treated with SE at a dose of 400 mg/kg. The FST results show that the lowest immobilization time was observed in rats treated with FE at a dose of 400 mg/kg. The results obtained show that the flowers and stems of P. rhoeas can constitute a rich source of bioactive molecules with potential pharmaceutical applications.

Mesoporous silica stabilized Cu-Fe bimetallic nanozymes for total antioxidant capacity assay of fruit foods

Total antioxidant capacity (TAC) is currently considered as a vital indicator of food quality in antioxidant ability and attracts much attention for human healthcare. It is thus of great significance to realize the accurate and rapid detection of TAC in foods. Herein, we have constructed a preferable hybrid nanozyme based on the mesoporous silica-stabilized CuO composited Fe₃O₄ nanoparticles (Fe₃O₄@MSNs@CuO, FMC NPs), which possess the enhanced peroxidase (POD)-like activity via cascade response for specific and sensitive determination of TAC in fruit foods. The results showed the hybrid nanozyme displayed a remarkable POD-like activity, excellent selectivity and sensitivity, and the limit of detection (LOD) of the colorimetric sensor was 6.13 mM with the concentration range from 10 to 45 mM. Therefore, the fabricated hybrid nanozyme can be regarded as an effective biosensor for the evaluation of antioxidant quality in fruit foods in future. KEY POINTS: • The stabilized bimetallic nanozyme was constructed for TAC analysis in fruits. • The hybrid nanozyme possessed the enhanced POD-like activity by cascading effects. • The nanozyme was an effective biosensor for antioxidant quality evaluation in fruits.

Effect of In Vitro Digestion on the Phenolic Content of Herbs Collected from Eastern Anatolia

Phenolic compounds in herbs have high antioxidant activities, and their consumption as functional foods may impact human health positively. The main objective of this study was to investigate the total phenolic (TPC) and total flavonoid (TFC) contents as well as total antioxidant capacities (TAC) of bioactive compounds in various infusions prepared by herbs collected from the Bingöl region of Turkey during in vitro gastrointestinal digestion. According to the results, while the highest TPC (5836 ± 373 mg GAE/100 g dw), TFC (2301 ± 158 CE/100 g, dw), and TAC (1347 mg TE/100 g dw) were obtained with Anchusa azurea Mill. species, Crataegus orientalis exhibited the lowest values (863 ± 24 mg GAE/100 g dw, 242 ± 23 CE/100 g dw, 735 ± 47 mg TE/100 g dw, respectively). Gallic acid and chlorogenic acid were the most common phenolic compounds in the infusions. In detail, the highest gallic acid was found in E. spectabilis M. Bieb (27.3 ± 0.9 mg/100 g of dw) and the highest chlorogenic acid was observed in F. elaeochytris (919.2 ± 35.7 mg/100 g of dw). After in vitro gastrointestinal digestion, the highest bioaccessibility values of TPC and TFC were determined as 0.6- and 3-fold of the values observed in undigested C. orientalis, respectively. Besides, C. orientalis Pall. had the highest bioaccessibility of TAC according to the DPPH (6.7-fold increase) and CUPRAC (9.7-fold increase) assays. It can be concluded that the use of these medicinal herbs in human dietary intake due to their high bioactive compounds even after digestion can improve nutritional value and contribute to human health.

Optimization of Ultrasonic-Assisted Extraction Conditions for Bioactive Components and Antioxidant Activity of Poria cocos (Schw.) Wolf by an RSM-ANN-GA Hybrid Approach

In this study, a response surface methodology and an artificial neural network coupled with a genetic algorithm (RSM-ANN-GA) was used to predict and estimate the optimized ultrasonic-assisted extraction conditions of Poria cocos. The ingredient yield and antioxidant potential were determined with different independent variables of ethanol concentration (X₁; 25-75%), extraction time (X₂; 30-50 min), and extraction solution volume (mL) (X₃; 20-60 mL). The optimal conditions were predicted by the RSM-ANN-GA model to be 55.53% ethanol concentration for 48.64 min in 60.00 mL solvent for four triterpenoid acids, and 40.49% ethanol concentration for 30.25 min in 20.00 mL solvent for antioxidant activity and total polysaccharide and phenolic contents. The evaluation of the two modeling strategies showed that RSM-ANN-GA provided better predictability and greater accuracy than the response surface methodology for ultrasonic-assisted extraction of P. cocos. These findings provided guidance on efficient extraction of P. cocos and a feasible analysis/modeling optimization process for the extraction of natural products.

In Vitro Studies on the Antimicrobial and Antioxidant Activities of Total Polyphenol Content of Cynara humilis from Moulay Yacoub Area (Morocco)

In Morocco, Cynara humilis L. is used in traditional medicine. The objective of this research was to research the antioxidant and antimicrobial properties of hydroethanolic extracts from the C. humilis plant's leaves and roots. The content of polyphenols and flavonoids was evaluated using Folin-Ciocalteu's and aluminum chloride assays. Two techniques were used to evaluate antioxidant properties: antioxidant capacity in total (TAC) and 2,2-diphenyl-1-picrylhdrazyl (DPPH). In antimicrobial assays, five pathogenic microbial strains were studied including two Escherichia coli, one coagulase-negative Staphylococcus and Klebsiella pneumoniae, and one Candida albicans, by two techniques: agar disk diffusion and microdilution. Leaves had a greater content of flavonoids 27.07 mg QE/g of extract and the polyphenols 38.84 mg GAE/g of extract than root 24.39 mg QE/g of extract and 29.39 mg GAE/g of extract, respectively. The TAC test value of the 0.77 mg AAE/g extract in the leaf extract was found to be significantly greater than that of the 0.60 mg EAA/g extract in the root extract. The DPPH antioxidant assay IC₅₀ values of the root and leaf extract were 0.23 and 0.93 µg/mL, respectively. C. humilis extracts showed an antimicrobial effect against all tested strains, the inhibitory zone (DIZ) have values in the range between 12 and 15 mm. Moreover, the root extract showed the lowest minimum inhibitory concentration (MIC) against coagulase-negative Staphylococcus with an IC₅₀ value of 6.25 mg/mL. The higher content of flavonoids and polyphenols in the hydroethanolic extracts of C. humilis leaves and roots demonstrates that they have a significant antimicrobial and antioxidant effect, as found in this study.

Characterization and Valorization of the Agricultural Waste Obtained from Lavandula Steam Distillation for Its Reuse in the Food and Pharmaceutical Fields

The main focus of the current research was the characterization of the by-products from the steam distillation of Lavandula angustifolia Mill. (LA) and Lavandula x intermedia Emeric ex Loisel (LI) aerial parts, as they are important sources of bioactive compounds suitable for several applications in the food, cosmetic, and pharmaceutical industries. The oil-exhausted biomasses were extracted and the total polyphenol and flavonoid contents were, respectively, 19.22 ± 4.16 and 1.56 ± 0.21 mg/g for LA extract and 17.06 ± 3.31 and 1.41 ± 0.10 mg/g for LI extract. The qualitative analysis by liquid chromatography-electrospray tandem mass spectrometry (HPLC-ESI-MS) revealed that both the extracts were rich in phenolic acids and glycosylated flavonoids. The extracts exhibited radical scavenging, chelating, reducing activities, and inhibitory capacities on acetylcholinesterase and tyrosinase. The IC50 values against acetylcholinesterase and tyrosinase were, respectively, 5.35 ± 0.47 and 5.26 ± 0.02 mg/mL for LA, and 6.67 ± 0.12 and 6.56 ± 0.16 mg/mL for LI extracts. In conclusion, the oil-exhausted biomasses demonstrated to represent important sources of bioactive compounds, suitable for several applications in the food, cosmetic, and pharmaceutical industries.