Determination of the Total Polyphenols Content and Antioxidant Activity of Echinacea Purpurea Extracts Using Newly Manufactured Glassy Carbon Electrodes Modified with Carbon Nanotubes

Investigation of Health Effects of Major Phenolic Compounds in Foods: Extraction Processes, Analytical Approaches and Applications

The escalating costs of healthcare services and a growing awareness of personal health responsibilities have led individuals to explore natural methods alongside conventional medicines for health improvement and disease prevention. The aging global population is experiencing increased health needs, notably related to conditions like diabetes, heart disease, and hypertension. Lifestyle-related diseases, poor dietary habits, and sedentary lifestyles underscore the importance of foods containing nutrients that can aid in preventing and managing these diseases. Phenolic compounds, a fundamental group of phytochemicals, are prominent in the chemical diversity of the natural world and are abundant in functional foods. Widely distributed in various plant parts, these compounds exhibit important functional and sensory properties, including color, taste, and aroma. Their diverse functionalities, particularly antioxidant activity, play a crucial role in mitigating cellular oxidative stress, potentially reducing damage associated with serious health issues such as cardiovascular disease, neurodegenerative disea23ses, and cancer. Phenolic compounds exist in different forms, some combined with glycosides, impacting their biological effects and absorption. Approximately 8000 polyphenols isolated from plants offer significant potential for natural medicines and nutritional supplements. Therefore, their extraction process and selective and sensitive food determination are very important. This review focuses on the extraction processes, analytical methods, and health effects of major phenolic compounds in foods. The examination encompasses a comprehensive analysis of analytical approaches and their applications in elucidating the presence and impact of these compounds on human health.

Determination of the total antioxidant capacity of the Chinese tea based on a novel "peroxidase/zirconium phosphonate"composite electrochemical sensor

In this work, a novel zirconium phosphonate (ZrPR1R2) was prepared by decorating both the aminoethoxy- group (R1) and the carboxypropyl- group (R2) on the zirconium phosphate layers in order to manipulate further the immobilization of the peroxidase (POD), and an antioxidant biosensor with higher sensitivity was constructed by dropping the POD/ZrPR1R2 composite onto the glassy carbon electrode surface. The activity of the POD/ZrPR1R2 composite was detected by Uv-vis spectra. The direct electrochemical behavior, the electrocatalytic response to dissolved oxygen and hydrogen peroxide, as well as the ability to detect total antioxidant capacity in tea sample were investigated by the methods of cyclic voltammetry. The results indicated that the immobilization of POD in ZrPR1R2 nanosheets matrix enhanced the enzymatic activity, and achieved the fast and direct electron transfer between POD and glassy carbon electrode. Moreover, the POD/ZrPR1R2 composite modified electrode show the electrocatalytic response to hydrogen peroxide in the linear range of 8.8×10-8 to 8.8×10-7 mol L-1, with the detection limit of 3.3×10-8 mol L-1. Attributing to the sensitive response to dissolved oxygen, the total antioxidant capacity can be detected directly in the real tea water by this POD/ZrPR1R2 composite modified electrode.

Electrochemical Sensors for Detection of Phytomolecules: A Mechanistic Approach

High demand and ongoing technological advancements have created a market for sensors that is both varied and rapidly evolving. Bioactive compounds are separated systematically to conduct an in-depth investigation, allowing for the profiling or fingerprinting of different Plantae kingdoms. The profiling field is significant in elucidating the complex interplay of plant traits, attributes, and environmental factors. Flexible technology advancements have enabled the creation of highly sensitive sensors for the non-destructive detection of molecules. Additionally, very specialized integrated systems that will allow multiplexed detection by integrating many hybrid approaches have been developed, but these systems are highly laborious and expensive. Electrochemical sensors, on the other hand, are a viable option because of their ability to accomplish exact compound detection via efficient signal transduction. However, this has not been investigated because of some obstacles to learning minimum metabolites' fundamentals and nonredox properties. This article reviews the electrochemical basis of plants, contrasting it with more conventional techniques and offering both positive and negative perspectives on the topic. Because few studies have been devoted to the concept of merging the domains, we've expanded the scope of this work by including pertinent non-phytochemical reports for better report comparison.

A pilot study on non-invasive in situ detection of phytochemicals and plant endogenous status using fiber optic infrared spectroscopy

Traditional methods for assessing plant health often lack the necessary attributes for continuous and non-destructive monitoring. In this pilot study, we present a novel technique utilizing a customized fiber optic probe based on attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) with a contact force control unit for non-invasive and continuous plant health monitoring. We also developed a normalized difference mid-infrared reflectance index through statistical analysis of spectral features, enabling differentiation of drought and age conditions in plants. Our research aims to characterize phytochemicals and plant endogenous status optically, addressing the need for improved analytical measurement methods for in situ plant health assessment. The probe configuration was optimized with a triple-loop tip and a 3 N contact force, allowing sensitive measurements while minimizing leaf damage. By combining polycrystalline and chalcogenide fiber probes, a comprehensive wavenumber range analysis (4000-900 cm-1) was achieved. Results revealed significant variations in phytochemical composition among plant species, for example, red spinach with the highest polyphenolic content and green kale with the highest lignin content. Petioles displayed higher lignin and cellulose absorbance values compared to veins. The technique effectively monitored drought stress on potted green bok choy plants in situ, facilitating the quantification of changes in water content, antioxidant activity, lignin, and cellulose levels. This research represents the first demonstration of the potential of fiber optic ATR-FTIR probes for non-invasive and rapid plant health measurements, providing insights into plant health and advancements in quantitative monitoring for indoor farming practices, bioanalytical chemistry, and environmental sciences.

Determination of the Bioactive Compounds from Echinacea purpurea (L.) Moench Leaves Extracts in Correlation with the Antimicrobial Activity and the In Vitro Wound Healing Potential

This study aimed at the relationship between antioxidant capacity, antimicrobial activity, and in vitro evaluation of the wound healing effect of the extract obtained from Echinaceae purpureae folium (EPF). This study's objective was to assess the bioactive components (total phenol and flavonoid content) and antioxidant activity of EPF extracts using the DPPH test method. The antioxidant capacity and the quantities of the compounds with antioxidant capacity were evaluated by spectrophotometric methods. Antimicrobial activity has been investigated against various pathogenic microorganisms. The minimum inhibitory concentration was determined by the microdilution method. Additionally, our work used a scratch test to examine the in vitro wound healing effects of EPF extract on NHDF cells. Statistical analysis was used to quantify the rate of migration and proliferation of fibroblast cells within the wound. Microscope pictures of fibroblast cells exposed to various EPF extract dosages were processed to estimate the width of the wound, area of the wound, and cell density inside the wound. The study proved that there was a relationship between the antioxidant, antimicrobial, and wound healing ability of EPF extracts.

In Vivo Acute Toxicity and Immunomodulation Assessment of a Novel Nutraceutical in Mice

Achieving and maintaining a well-balanced immune system has righteously become an insightful task for the general population and an even more fundamental goal for those affected by immune-related diseases. Since our immune functions are indispensable in defending the body against pathogens, diseases and other external attacks, while playing a vital role in maintaining health and modulating the immune response, we require an on-point grasp of their shortcoming as a foundation for the development of functional foods and novel nutraceuticals. Seeing that immunoceuticals are considered effective in improving immune functions and reducing the incidence of immunological disorders, the main focus of this study was to assess the immunomodulatory properties and possible acute toxicity of a novel nutraceutical with active substances of natural origin on C57BL/6 mice for 21 days. We evaluated the potential hazards (microbial contamination and heavy metals) of the novel nutraceutical and addressed the acute toxicity according to OECD guidelines of a 2000 mg/kg dose on mice for 21 days. The immunomodulatory effect was assessed at three concentrations (50 mg/kg, 100 mg/kg and 200 mg/kg) by determining body and organ indexes through a leukocyte analysis; flow cytometry immunophenotyping of lymphocytes populations and their subpopulations (T lymphocytes (LyCD3+), cytotoxic suppressor T lymphocytes (CD3+CD8+), helper T lymphocytes (CD3+CD4+), B lymphocytes (CD3-CD19+) and NK cells (CD3-NK1.1.+); and the expression of the CD69 activation marker. The results obtained for the novel nutraceutical referred to as ImunoBoost indicated no acute toxicity, an increased number of lymphocytes and the stimulation of lymphocyte activation and proliferation, demonstrating its immunomodulatory effect. The safe human consumption dose was established at 30 mg/day.

Electrochemical Characterization of the Antioxidant Properties of Medicinal Plants and Products: A Review

Medicinal plants are an important source of bioactive compounds with a wide spectrum of practically useful properties. Various types of antioxidants synthesized in plants are the reasons for their application in medicine, phytotherapy, and aromatherapy. Therefore, reliable, simple, cost-effective, eco-friendly, and rapid methods for the evaluation of antioxidant properties of medicinal plants and products on their basis are required. Electrochemical methods based on electron transfer reactions are promising tools to solve this problem. Total antioxidant parameters and individual antioxidant quantification can be achieved using suitable electrochemical techniques. The analytical capabilities of constant-current coulometry, potentiometry, various types of voltammetry, and chrono methods in the evaluation of total antioxidant parameters of medicinal plants and plant-derived products are presented. The advantages and limitations of methods in comparison to each other and traditional spectroscopic methods are discussed. The possibility to use electrochemical detection of the antioxidants via reactions with oxidants or radicals (N- and O-centered) in solution, with stable radicals immobilized on the electrode surface, via oxidation of antioxidants on a suitable electrode, allows the study of various mechanisms of antioxidant actions occurring in living systems. Attention is also paid to the individual or simultaneous electrochemical determination of antioxidants in medicinal plants using chemically modified electrodes.

Investigation on wound healing effect of Mediterranean medicinal plants and some related phenolic compounds: A review

ETHNOPHARMACOLOGICAL RELEVANCE

The human skin constitutes a biological barrier against external stress and wounds can reduce the role of its physiological structure. In medical sciences, wounds are considered a major problem that requires urgent intervention. For centuries, medicinal plants have been used in the Mediterranean countries for many purposes and against wounds.

AIM OF THIS REVIEW

Provides an outlook on the Mediterranean medicinal plants used in wound healing. Furthermore, the wound healing effect of polyphenolic compounds and their chemical structures are also summarized. Moreover, we discussed the wound healing process, the structure of the skin, and the current therapies in wound healing.

MATERIALS AND METHODS

The search was performed in several databases such as ScienceDirect, PubMed, Google Scholar, Scopus, and Web of Science. The following Keywords were used individually and/or in combination: the Mediterranean, wound healing, medicinal plants, phenolic compounds, composition, flavonoid, tannin.

RESULTS

The wound healing process is distinguished by four phases, which are respectively, hemostasis, inflammation, proliferation, and remodeling. The Mediterranean medicinal plants are widely used in the treatment of wounds. The finding showed that eighty-nine species belonging to forty families were evaluated for their wound-healing effect in this area. The Asteraceae family was the most reported family with 12 species followed by Lamiaceae (11 species). Tunisia, Egypt, Morocco, and Algeria were the countries where these plants are frequently used in wound healing. In addition to medicinal plants, results showed that nineteen phenolic compounds from different classes are used in wound treatment. Tyrosol, hydroxytyrosol, curcumin, luteolin, chrysin, rutin, kaempferol, quercetin, icariin, morin, epigallocatechin gallate, taxifolin, silymarin, hesperidin, naringin, isoliquiritin, puerarin, genistein, and daidzein were the main compounds that showed wound-healing effect.

CONCLUSION

In conclusion, medicinal plants and polyphenolic compounds provide therapeutic evidence in wound healing and for the development of new drugs in this field.

Phytosynthesis of Biological Active Silver Nanoparticles Using Echinacea purpurea L. Extracts

With their phytoconstituents acting as reducing and capping agents, natural extracts can be considered a viable alternative for the obtaining of metallic nanoparticles. The properties of phytosynthesized nanoparticles are dependent upon size and morphology, which, in turn, can be tailored by adjusting different parameters of the phytosynthesis process (such as the extracts' composition). In the present study, we aimed to evaluate, for the first time in the literature, the influence of the extraction method and extract concentration on the morphological and biological properties (antioxidant and antibacterial activity) of silver nanoparticles phytosynthesized using Echinacea pupurea L. extracts. The obtained results revealed that the use of the low-concentration Echinacea hydro-alcoholic extract obtained via classical temperature extraction led to the development of nanoparticles with the smallest dimensions (less than 10 nm), compared with the use of extracts obtained with higher concentrations and the extract obtained via the microwave method. The developed nanomaterials exhibited enhanced antioxidant effects (determined via the DPPH assay) and antimicrobial properties (against Escherichia coli and Candida albicans), compared with the parent extracts.

The effect of different ammonium to nitrate ratios on antioxidant activity, morpho-physiological and phytochemical traits of Moldavian balm (Dracocephalum moldavica)

Improving yield and secondary metabolites production of medicinal plants through nutrition management recently has been considered. The present study was done to determine the effects of different ammonium (NH₄⁺) to nitrate (NO₃^-) ratios (100:0, 75:25, 50:50, 25:75, 0:100) on morphophysiological, nutrient contents (N, P, K, Ca, and Mg), phenolic compounds (Total phenolics (TPC) and flavonoid (TFC) contents and individual phenolics including chlorogenic acid, rosmarinic acid, gallic acid, cinnamic acid, caffeic acid, rutin, p-Coumaric acid, apigenin, and quercetin by HPLC-DAD), essential oil composition (by GC and GC-MS), and antioxidant capacity (by DPPH and FRAP assays) of Moldavian balm (Dracocephalum moldavica L.) in deep water culture (DWC) system. The highest biomass and morphological traits values of D. moldavica observed in 0:100 ratio of NH₄⁺:NO₃^-. Also, the highest TPC and TFC was earned in plants that supplied with 0:100 ratio of NH₄⁺:NO₃^-. Using the 25:75 ratio of NH₄⁺:NO₃^- caused the highest nutrient contents (N, Ca and Mg) in the leaves. p-Coumaric acid was detected as the major abundant phenolic compound in extracts and the application of 75:25 ratio of NH₄⁺:NO₃ resulted in the highest amounts of p-Coumaric acid, gallic acid, rosmarinic acid, caffeic acid, quercetin, and rutin. The highest antioxidant capacity by both FRAP and DPPH assays was obtained in 75:25 ratio of NH₄⁺:NO₃^-. Also, the highest geranial and geranyl acetate, geraniol, and neral were obtained in 75:25, 25:75, and 50:50 ratios of NH₄⁺:NO₃^-, respectively. Plants supplied with the 0:100 ratio of NH₄⁺:NO₃^-, had the highest total carotenoids, while the highest chlorophyll a and b content gained with 75:25 ratio of NH₄⁺:NO₃^-. These results suggest that the management of N source in nutrient recipe could contribute to enhance of morphophysiological traits, antioxidant activity and phytochemical compounds in Moldavian balm.

Extracts Rich in Nutrients as Novel Food Ingredients to Be Used in Food Supplements: A Proposal Classification

Consumers’ commitment to healthy lifestyles and a varied diet has experienced rapid growth in recent decades, causing an increase in the demand of better food quality and variety. The food industry has opted for innovation and the search for new sources of food, and these trends led to the need to develop a European regulatory framework. Novel foods are under Regulation (EU) 2015/2283 (formerly Regulation (EC) No 258/97), and this concept includes all food not used in an important measure for human consumption in the EU before 15 May 1997, and which is included in any of the food categories established. Currently, there are 26 extracts authorized as novel foods or ingredients, being one of the most numerous groups. These extracts are concentrated sources of nutrients, and 23 of them can be used in food supplements. Given their heterogeneous composition and the perceptive risk assessments performed, sometimes, the authorizations are limited to certain population groups. The present work is a comprehensive review of the extracts rich in nutrients authorized as novel ingredients to be used in food supplements within the EU. A classification is proposed according to their source of origin, resulting in four main groups: extracts of plant, animal, algae, and fungal origins. A description of each extract as well as the evaluation of the potential use restriction and health benefits are also addressed.

METHODICAL APPROACH TO THE DETERMINATION OF THE ANTIOXIDANT ACTIVITY OF THE ECHINACEA PURPUREA AND MONARDA FISTULOSA TINCTURES AS A QUALITY CRITERION OF THE DEVELOPMENT OF THEIR COMPOSITION AND LABORATORY TECHNOLOGY

Aim. The aim of the study was to develop the methodical approach to determine the antioxidant activity of the tinctures of Monarda fistulosa herb and flowers and roots of Echinacea purpurea, as well as to develop their technology in  laboratory conditions. Materials and Methods. The following methods were used: analysis, synthesis, systematization, and comparison for processing of published scientific data on antioxidant activity; method for measuring the particle size of raw herbal materials; maceration and remaceration methods for obtaining the tested tinctures; DPPH test for the valuation of the antioxidant activity of the developed tinctures. Results and Discussion. The methodical approach to determining the antioxidant activity of the tinctures of Monarda fistulosa herb and flowers and roots of Echinacea purpurea was elaborated, the essence of which consisted in the selection of the appropriate dilution of the tinctures. Tinctures were prepared with the help of maceration or/and remaceration in laboratory conditions. The ratios of herbal raw materials (HRM) to the final tincture were close to ratios that are widely employed in the pharmaceutical industry, namely 1 to 5 and 1 to 10. The coefficients of alcohol absorption for the roots of Echinacea purpurea (size 2-5 mm), flowers of Echinacea purpurea (size 1-3 mm), herb of Monarda fistulosa (size 0.5-3 mm) were measured. They were measured as 1.2, 2.25, and 5.0 ml/g, respectively, for 70% ethanol. The studies revealed that Echinacea purpurea tinctures are a valuable source of antioxidant compounds. The antioxidant activity of these tinctures was 254.8-815.8 mg rutin-equivalents in 1 L of the tinctures or 1.12-4.43 mg rutin-equivalents in 1 g of the HRM depending on the part of the plant, particle size and extraction type. The antioxidant activity of the tinctures of the Monarda fistulosa herb was equal to 2203.6 mg eq-rutin/L and 20.3 mg eq-rutin/g for the tincture and HRM at a ratio of 1 to 9.5 and 2119.4 mg eq-rutin/L and 9.7 mg eq-rutin/g for the tincture at a ratio of 1 to 4.5. Conclusions. The approach to the determination of the antioxidant activity of the tested tinctures was elaborated, namely the dilutions of the tinctures were established for the analytical procedure of the determination of the antioxidant activity. Our studies demonstrated that tinctures of Echinacea purpurea contained compounds with antioxidant activity. The tinctures of Monarda fistulosa herb are very rich in compounds with antioxidant properties. The laboratory technology of six tinctures was elaborated. Further studies will be directed at laboratory studies on microorganisms and animals.

Echinacea purpurea (L.) Moench: Biological and Pharmacological Properties. A Review

Echinacea purpurea (L.) Moench (EP)is a perennial herbaceous flowering plant, commonly known as purple coneflower and it belongs to the Asteraceae family. The Echinacea genus is originally from North America, in the United States, and its species are widely distributed throughout. There are nine different species of Echinacea, but only three of them are used as medicinal plants with wide therapeutic uses: Echinacea purpurea (L.) Moench, Echinacea pallida (Nutt.) Nutt. and Echinacea angustifolia DC. Several significant groups of bioactive compounds with pharmacological activities have been isolated from Echinacea species. Numerous beneficial effects have been demonstrated about these compounds. The immunomodulatory effect was initially demonstrated, but over time other effects have also been highlighted. The present review gives a comprehensive summary of the chemical constituents, bioactive compounds, biological effects and therapeutical uses of purple coneflower. Research shows that such a well-known and recognized species needs to be further studied to obtain efficient products with a guarantee of the safety.

A novel flow injection amperometric method for sensitive determination of total antioxidant capacity at cupric-neocuproine complex modified MWCNT glassy carbon electrode

A novel amperometric method is presented for the determination of total antioxidant capacity in flow injection analysis (FIA) system using copper(II)-neocuproine complex modified on Nafion-functionalized multi-walled carbon nanotube-glassy carbon electrode ([Cu(Ncp)₂²⁺]/Nf@f-MWCNT/GCE). Cyclic voltammetric studies showed that the modified electrode exhibits a very well-formed reversible redox couple for Cu(II)-/Cu(I)-complex. In addition, the [Cu(Ncp)₂²⁺]/[Cu(Ncp)₂⁺] redox pair shows very good electrocatalytic activity towards the oxidation of polyphenolic compounds (PPhCs) such as trolox, catechin, and quercetin due to the enhancement of the anodic peak current of the redox couple in the presence of these analytes. This electrocatalytic oxidation current at the [Cu(Ncp)₂²⁺]/Nf@f-MWCNT/GCE was used for flow injection (FI) amperometric determination of PPhCs. FI amperometric-time curves recorded under optimized conditions (applied potential: + 0.6 V vs. Ag/AgCl/KCl_(0.10 M), flow rate: 2 mL/min) showed that the proposed electrode had a wide linear range (LR) with a very low detection limit (LOD) for PPhCs. LR and LOD were 0.5-800 and 0.2 µM for trolox, respectively and 0.50-250 and 0.14 µM, respectively, for both quercetin and catechin. This sensitive method was successfully applied to the amperometric measurement of total antioxidant capacity (TAC) of some herbal teas, giving compatible results with the spectrophotometric CUPRAC method. The proposed method gave higher rank to fast-reacting antioxidants; it was equally precise but had a wider linear range and lower LOD than the spectrophotometric CUPRAC assay (e.g., LOD for ascorbic acid and gallic acid were 0.07 and 0.08 μM, respectively), and similar electroanalytical methods using the CUPRAC reagent.

Nano-Drug Delivery Systems Entrapping Natural Bioactive Compounds for Cancer: Recent Progress and Future Challenges

Cancer is a prominent cause of mortality globally, and it becomes fatal and incurable if it is delayed in diagnosis. Chemotherapy is a type of treatment that is used to eliminate, diminish, or restrict tumor progression. Chemotherapeutic medicines are available in various formulations. Some tumors require just one type of chemotherapy medication, while others may require a combination of surgery and/or radiotherapy. Treatments might last from a few minutes to many hours to several days. Each medication has potential adverse effects associated with it. Researchers have recently become interested in the use of natural bioactive compounds in anticancer therapy. Some phytochemicals have effects on cellular processes and signaling pathways with potential antitumor properties. Beneficial anticancer effects of phytochemicals were observed in both in vivo and in vitro investigations. Encapsulating natural bioactive compounds in different drug delivery methods may improve their anticancer efficacy. Greater in vivo stability and bioavailability, as well as a reduction in undesirable effects and an enhancement in target-specific activity, will increase the effectiveness of bioactive compounds. This review work focuses on a novel drug delivery system that entraps natural bioactive substances. It also provides an idea of the bioavailability of phytochemicals, challenges and limitations of standard cancer therapy. It also encompasses recent patents on nanoparticle formulations containing a natural anti-cancer molecule.

A Review on Electrochemical Sensors and Biosensors Used in Assessing Antioxidant Activity

Currently, there is growing interest in screening and quantifying antioxidants from biological samples in the quest for natural and effective antioxidants to combat free radical-related pathological complications. Antioxidants play an important role in human health and provide a defense against many diseases. Due to the valuable dietary role of these compounds, the analysis and determination of their amount in food is of particular importance. In recent years, many attempts have been made to provide simple, fast, and economical analytical approaches for the on-site detection and determination of antioxidant activity in food antioxidants. In this regard, electrochemical sensors and biosensors are considered promising tools for antioxidant research due to their high sensitivity, fast response time, and ease of miniaturization; thus, they are used in a variety of fields, including food analysis, drug screening, and toxicity research. Herein, we review the recent advances in sensors and biosensors for the detection of antioxidants, underlying principles, and emphasizing advantages, along with limitations regarding the ability to discriminate between the specific antioxidant or quantifying total antioxidant content. In this work, both direct and indirect methods for antioxidants detecting with electrochemical sensors and biosensors are analyzed in detail. This review aims to prove how electrochemical sensors and biosensors represent reliable alternatives to conventional methods for antioxidant analysis.

Traditional Medicinal Plants—A Possible Source of Antibacterial Activity on Respiratory Diseases Induced by Chlamydia pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae and Moraxella catarrhalis

Background. Nowadays, phytotherapy offers viable solutions in managing respiratory infections, disorders known for considerable incidence in both children and adults. In a context in which more and more people are turning to phytotherapy, finding new remedies is a topical goal of researchers in health and related fields. This paper aims to identify those traditional medicinal plants that show potentially antibacterial effects against four Gram-negative germs (Chlamydia pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae, and Moraxella catarrhalis), which are considered to have high involvement in respiratory infections. Furthermore, a comparison with Romanian folk medicines was performed. Methods. An extensive review of books and databases was undertaken to identify vegetal species of interest in the context of the topic. Results. Some traditional Romanian species (such as Mentha × piperita, Thymus vulgaris, Pinus sylvestris, Allium sativum, Allium cepa, Ocimum basilicum, and Lavandulaangustifolia) were identified and compared with the plants and preparations confirmed as having antibacterial effects against specific germs. Conclusions. The antibacterial effects of some traditionally used Romanian medicinal plants are poorly investigated, and deserve further attention.

Special Issue on “Phenolic Compounds: Extraction, Optimization, Identification and Applications in Food Industry”

Interest has grown regarding natural plant extracts in food and beverage applications, their vital role in food quality and technology, and their therapeutic use in inhibiting several diseases [...]

Evaluation of In Vitro Wound-Healing Potential, Antioxidant Capacity, and Antimicrobial Activity of Stellaria media (L.) Vill

The healing of skin wounds remains an important concern in medicine, especially in chronic wounds caused by various diseases such as diabetes. Using herbs or herbal products to heal skin wounds is a therapeutic challenge for traditional medicine. In this context, the main aim of our work was to highlight the in vitro healing potential of Stellaria media (L.) Vill. (SM) extract using the scratch assay on normal human dermal fibroblasts (NHDF). The ability to stimulate cell migration and proliferation under the influence of different concentrations of SM extract (range between 12.5 and 200 µg/mL) was determined compared to the control (untreated in vitro-simulated wound) and positive control (allantoin 50 µg/mL). Our results showed that the concentration of 100 µg/mL SM extract applied on the simulated wound recorded the strongest and fastest (24 h) migration (with wound closure) and proliferation of NHDF compared with the control. In addition, the SM extract was characterized in terms of bioactive compounds (total phenols and flavonoids content), antioxidant capacity (FRAP (The Ferric-Reducing Antioxidant Power) assay and electrochemical method), and antimicrobial activity. The results show that the SM extract contains a considerable amount of polyphenols (17.19 ± 1.32 mg GAE/g dw and 7.28 ± 1.18 mg QE/g dw for total phenol and flavonoid content, respectively) with antioxidant capacity. Antimicrobial activity against Gram-positive bacteria (S. aureus) is higher than E. coli at a dose of 15 µg/mL. This study showed that Stellaria media is a source of polyphenols compounds with antioxidant capacity, and for the first time, its wound healing potential was emphasized.

Metal Nanoparticles and Carbon-Based Nanomaterials for Improved Performances of Electrochemical (Bio)Sensors with Biomedical Applications

Monitoring human health for early detection of disease conditions or health disorders is of major clinical importance for maintaining a healthy life. Sensors are small devices employed for qualitative and quantitative determination of various analytes by monitoring their properties using a certain transduction method. A "real-time" biosensor includes a biological recognition receptor (such as an antibody, enzyme, nucleic acid or whole cell) and a transducer to convert the biological binding event to a detectable signal, which is read out indicating both the presence and concentration of the analyte molecule. A wide range of specific analytes with biomedical significance at ultralow concentration can be sensitively detected. In nano(bio)sensors, nanoparticles (NPs) are incorporated into the (bio)sensor design by attachment to the suitably modified platforms. For this purpose, metal nanoparticles have many advantageous properties making them useful in the transducer component of the (bio)sensors. Gold, silver and platinum NPs have been the most popular ones, each form of these metallic NPs exhibiting special surface and interface features, which significantly improve the biocompatibility and transduction of the (bio)sensor compared to the same process in the absence of these NPs. This comprehensive review is focused on the main types of NPs used for electrochemical (bio)sensors design, especially screen-printed electrodes, with their specific medical application due to their improved analytical performances and miniaturized form. Other advantages such as supporting real-time decision and rapid manipulation are pointed out. A special attention is paid to carbon-based nanomaterials (especially carbon nanotubes and graphene), used by themselves or decorated with metal nanoparticles, with excellent features such as high surface area, excellent conductivity, effective catalytic properties and biocompatibility, which confer to these hybrid nanocomposites a wide biomedical applicability.

Increasing medicinal and phytochemical compounds of coneflower (Echinacea purpurea L.) as affected by NO3-/NH4+ ratio and perlite particle size in hydroponics

Medicinal plants are considered as one of the most important sources of chemical compounds, so preparing a suitable culture media for medicinal plant growth is a critical factor. The present study is aimed to improve the caffeic acid derivatives and alkylamides percentages of Echinacea purpurea root extract in hydroponic culture media with different perlite particle size and NO₃^-/NH₄⁺ ratios. Perlite particle size in the growing media was varied as very coarse perlite (more than 2 mm), coarse perlite (1.5-2 mm), medium perlite (1-1.5 mm), fine perlite (0.5-1 mm), and very fine perlite (less than 0.5 mm) in different ratios to peat moss (including pure perlite, 50:50 v/v, 30:70 v/v, and pure peat moss). Two NO₃^-/NH₄⁺ ratios (90:10 and 70:30) were tested in each growing media. All phytochemical analyses were performed according to standard methods using high performance liquid chromatography (HPLC). It was found that the E. purpurea grown in the medium containing very fine-grade perlite with 50:50 v/v perlite to peat moss ratio had the maximum caffeic acid derivatives, including chicoric acid (17 mg g^-1 DW), caftaric acid (6.3 mg g^-1 DW), chlorogenic acid (0.93 mg g^-1 DW), cynarin (0.84 mg g^-1 DW), and echinacoside (0.73 mg g^-1 DW), as well as, alkylamides (54.21%). The percentages of these phytochemical compounds increased by decreasing perlite particle size and increasing of NO₃^-/NH₄⁺ ratio. The major alkylamide in the E. purpurea root extract was dodeca-2E, 4E, 8Z-10 (E/Z)-tetraenoic acid isobutylamide in all treatments, ranging from 31.12 to 54.21% of total dry weight. It can be concluded that optimizing hydroponic culture media and nutrient solution has significant effects on E. purpurea chemical compounds.

Cytotoxicity assessment of antibiotics on Ctenopharyngodon idellus kidney cells by a sensitive electrochemical method

As emerging pollutants, antibiotics are ubiquitous in the environment and pose a threat to human health, giving rise to an urgent need to assess their biological toxicity. In the present study, a cell electrochemical method based on the bromocresol violet/carbon nanotubes/glassy carbon electrode (BCP/MWCNTs/GCE) was established to evaluate the cytotoxicities of sulfamethoxazole (SMZ), ciprofloxacin (CIP), and tetracycline (TC). BCP/MWCNTs/GCE has advantages due to its excellent electrocatalytic activity for the oxidation of electroactive species of the Ctenopharyngodon idellus kidney (CIK) cells. The half-maximal inhibitory concentration (IC₅₀) values of SMZ, CIP, and TC obtained by the electrochemical method were 831.51 μM, 354.98 μM, and 184.51 μM, which were lower than those of the traditional methyl-thiazolyl-tetrazolium (MTT) assay (907.47 μM, 414.87 μM, and 208.11 μM). These results indicate the higher sensitivity of the electrochemical method. This study provided a sensitive tool for the cytotoxicity evaluation of antibiotics in the environmental toxicology field.

Antioxidant Determination with the Use of Carbon-Based Electrodes

Antioxidants are compounds that prevent or delay the oxidation process, acting at a much smaller concentration, in comparison to that of the preserved substrate. Primary antioxidants act as scavenging or chain breaking antioxidants, delaying initiation or interrupting propagation step. Secondary antioxidants quench singlet oxygen, decompose peroxides in non-radical species, chelate prooxidative metal ions, inhibit oxidative enzymes. Based on antioxidants’ reactivity, four lines of defense have been described: Preventative antioxidants, radical scavengers, repair antioxidants, and antioxidants relying on adaptation mechanisms. Carbon-based electrodes are largely employed in electroanalysis given their special features, that encompass large surface area, high electroconductivity, chemical stability, nanostructuring possibilities, facility of manufacturing at low cost, and easiness of surface modification. Largely employed methods encompass voltammetry, amperometry, biamperometry and potentiometry. Determination of key endogenous and exogenous individual antioxidants, as well as of antioxidant activity and its main contributors relied on unmodified or modified carbon electrodes, whose analytical parameters are detailed. Recent advances based on modifications with carbon-nanotubes or the use of hybrid nanocomposite materials are described. Large effective surface area, increased mass transport, electrocatalytical effects, improved sensitivity, and low detection limits in the nanomolar range were reported, with applications validated in complex media such as foodstuffs and biological samples.