A new colorimetric DPPH• scavenging activity method with no need for a spectrophotometer applied on synthetic and natural antioxidants and medicinal herbs

Evaluation of antioxidant and antibacterial properties of dehydrocostus lactone isolated from Echinops kebericho root

Background and Aim

Echinops kebericho, an endemic plant to Ethiopia, traditionally used to treat infectious as well as noninfectious diseases. The primary objective of this study was isolating dehydrocostus lactone (DHCL) from E. kebericho and evaluating antibacterial activities on selected human pathogenic bacteria.

Methods

Extraction method used in this study was maceration. Based on the bioassay information methanol extract of the root of E. kebericho was subjected to column chromatography on silica gel by increasing solvent gradients to isolate DHCL. Optimized amount isolation of DHCL was done by dissolving methanol crude extract by hexane followed by recrystallization at room temperature in the dark place. Different concentrations of the extract were subjected by disc diffusion method against tested bacterial species and antioxidant activity test.

Results

The phytochemical analysis of E. kebericho revealed a high presence of terpenoids, which are diverse natural compounds known for their antimicrobial and antioxidant properties. This suggests that terpenoids contribute significantly to the pharmacological effects of E. kebericho. In antibacterial testing, Escherichia coli was the most sensitive bacterium among all extracts and concentrations. The methanol extract displayed higher antioxidant activity compared to ethyl acetate and hexane extracts, indicating a higher concentration of antioxidant compounds. Notably, the isolated compound DHCL showed promising activity against tested pathogens and significant antioxidant activity. The higher activity of DHCL compared to the crude extracts suggests its responsibility for the observed effects, indicating that the isolation and purification process may have concentrated its beneficial properties. These findings highlight the potential of E. kebericho and DHCL as sources of bioactive compounds for therapeutic applications.

Conclusion

All tested extracts and pure compound showed higher inhibition than positive controls in both bioassay. DHCL the principal bioactive component in the root extract of the plant and it displayed potent antibacterial and antioxidant activity.

Discovery of dual-action phenolic 4-arylidene-isoquinolinones with antioxidant and α-glucosidase inhibition activities

A multicomponent-derived synthesis of arylidene isoquinolinones decorated with phenolic moieties is described. The series demonstrated good DPPH trapping and, in the case of sinapic acid-containing analogs, excellent activity against lipoperoxidation; EPR also demonstrated that one derivative scavenged hydroxyl radicals. In addition, some compounds showed excellent inhibition of α-glucosidase activity and, according to both Lineweaver-Burk plots and molecular docking, they act as non-competitive or mixed inhibitors. In vitro assay also demonstrated that two compounds significantly reduced the plasma glucose levels after sucrose administration. In summary, the studied isoquinolinones become novel compounds with dual action (antioxidant and α-glucosidase inhibition) against diabetes and related metabolic diseases, whose optimization would lead to more potent candidates.

Research-based Analytical Procedures to Evaluate Diabetic Biomarkers and Related Parameters: In Vitro and In Vivo Methods

BACKGROUND

The degenerative tendency of diabetes leads to micro- and macrovascular complications due to abnormal levels of biochemicals, particularly in patients with poor diabetic control. Diabetes is supposed to be treated by reducing blood glucose levels, scavenging free radicals, and maintaining other relevant parameters close to normal ranges. In preclinical studies, numerous in vivo trials on animals as well as in vitro tests are used to assess the antidiabetic and antioxidant effects of the test substances. Since a substance that performs poorly in vitro won't perform better in vivo, the outcomes of in vitro studies can be utilized as a direct indicator of in vivo activities.

OBJECTIVE

The objective of the present study is to provide research scholars with a comprehensive overview of laboratory methods and procedures for a few selected diabetic biomarkers and related parameters.

METHOD

The search was conducted on scientific database portals such as ScienceDirect, PubMed, Google Scholar, BASE, DOAJ, etc. Conclusion: The development of new biomarkers is greatly facilitated by modern technology such as cell culture research, lipidomics study, microRNA biomarkers, machine learning techniques, and improved electron microscopies. These biomarkers do, however, have some usage restrictions. There is a critical need to find more accurate and sensitive biomarkers. With a few modifications, these biomarkers can be used with or even replace conventional markers of diabetes.

Development and application of DPPH impregnated paper based color sensor disc to detect vegetable oils addition in cow ghee

Ghee is a premium product in Southeast Asia and is prone to adulteration with vegetable oils/ fats. The main aim of the study was to develop an easy-to-use paper-based sensor to detect this adulteration. Hence, a protocol involving hexane and acetonitrile for the extraction of synthetic antioxidants from adulterated ghee and its rapid detection using DPPH was standardized. Paper-based discs impregnated with 4 mM DPPH were developed. The developed paper-based disc sensors worked well and their response time was indirectly proportional to the antioxidant concentration (0.0025-0.02%). Using the developed disc sensors, the palm oil, and sunflower oil added to cow ghee @2.5% or more, and 1% or more, respectively could be detected. The shelf life of the developed sensors was 30 and 90 days at 30 °C and 4-6 °C, respectively. In stored cow ghee samples, the response time of the sensors increased as the storage period of ghee samples increased. The cutoff limit to declare the sample of cow ghee as unadulterated was fixed to 60 min. Based on the response time of the sensor, the level of detection of vegetable oils in stored cow ghee was found to be 2.5%.

In vitro antioxidant and free-radical scavenging activities of polar leaf extracts of Vernonia amygdalina

BACKGROUND

Plants are able to deliver a huge number of differing bioactive compounds which may supplement the requirements of the human body by acting as natural antioxidants. Antioxidants are mindful for the defense component of the life form against the pathologies related to the assault of free radicals. The main purpose of this study was to investigate the qualitative phytochemical composition of Vernonia amygdalina leaf extract and its antioxidant activity.

METHOD

The powdered plant sample was successively extracted with aqueous, methanol and ethanol solvents using Soxhlet apparatus. The antioxidant activities of the crude leaf extract were determined using 1, 1- diphenyl-2-picryl hydrazyl (DPPH) radical, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical, phosphomolybdate (PM) and hydrogen peroxide (H₂O₂) scavenging assay. All the examinations were drained triplicates and average values of each test were taken.

RESULTS

Phytochemical investigation of the plant revealed that the three solvent extracts contained numerous bioactive compounds namely alkaloids, tannins, saponins, phenols, terpenoids, steroids, glycosides and sugars. The result showed that, the leaf extracts of V. amygdalina obtained from methanol extract exhibit the maximum antioxidant activity compared ethanol and aqueous extracts. The IC50 values of DPPH assay for the H₂O, MeOH and EtOH extracts were 111.4, 94.92 and 94.83 μg/ml; of ABTS assay were 334.3, 179.8 and 256.9 μg/ml; of H₂O₂ assay were 141.6, 156 and 180.6 μg/ml, respectively. The maximum radical scavenging activity was obtained in DPPH assay while the lowest scavenging activity was obtained in ABTS assay method. The data obtained in the in vitro models clearly suggest that methanol extract has higher antioxidant activity due to a higher presence of phenolic constituents in the extract.

CONCLUSION

This study revealed that V. amygdalina leaf has a noteworthy antioxidant and free radical scavenging activity mitigating the traditional use of the plant for different aliments.

Synthesis of antioxidant and antimicrobial bioactive compounds based on the quinoline-hydrazone and benzimidazole structure

Quinoline and its derivatives are known to have various biological activities such as antibacterial and antioxidant. Therefore, this study aims to synthesize quinoline moiety from isatin and ethyl acetoacetate by Pfitzinger reaction under acidic conditions. The benzimidazole derivative was synthesized from quinoline and o-phenylenediamine by a solvent-less reaction, while the hydrazone derivative was formed by the reaction with hydrazine hydrate and aromatic aldehyde. In addition, 4-hydroxybenzaldehyde was used as an aromatic aldehyde. The four compounds formed were characterized by thin-layer chromatography (TLC), melting point measurement, Fourier-transform infrared, liquid chromatography-mass spectrometry, and ultraviolet-visible spectrophotometry. They were also evaluated for their antioxidant and antimicrobial activities using the 2,2-diphenyl-1-picrylhydrazyl assay and the disc diffusion method, respectively. All compounds showed weak antioxidant activity compared to ascorbic acid; the quinoline-hydrazone derivative showed the best antioxidant activity with IC50 = 843.52 ppm, while the IC50 value for quinoline-benzimidazole was 4784.66 ppm. All synthesized compounds have not been confirmed to be effective against Staphylococcus aureus and Escherichia coli bacteria in a concentration range of 75-1000 ppm. The bioactive compounds based on the quinoline-hydrazone and benzimidazole structures have been successfully synthesized and tested for their activity as antioxidant and antimicrobial agents.

Bioprospecting the Biological Effects of Cultivating Pleurotus ostreatus Mushrooms from Selected Agro-Wastes and Maize Flour Supplements

Pleurotus mushrooms are valuable food supplements with health and environmental restorative potential. In this paper, we sought to evaluate the biological activities and profile the bioactive compounds found in Pleurotus ostreatus cultivated from agro-waste supplemented with maize flour. We investigated carbon to nitrogen (C/N), antimicrobial, antioxidant, and antimalarial potential for the varying supplementation during mushroom cultivation. GCMS was utilized for screening bioactive compounds found in P. ostreatus. Changes in supplementation directly correlate with changes in compound profiling. Nonetheless, some compounds were found to be common amongst the tested mushrooms, including pentadecanoic acid; 9,12-octadecadienoic acid, methyl ester; pentadecanoic acid, methyl ester; octadecanoic acid; and diisooctyl phthalate. The highest antimicrobial potential against Gram-positive Staphylococcus aureus was observed when maize flour supplements were increased to 12% and 18%. Our data demonstrated that the observed antioxidant (DPPH, ABTS, and reducing power) and antimicrobial activity could emanate from various supplementation conditions. Furthermore, supplementation has an impact on the mushroom yield and phytochemical profiles of the produced mushroom.

Isolation and Chemical Characterization of Antifungal, Antioxidant, and Anti-Inflammatory Compounds from Centrosema coriaceum using GC/MS, UFLC-QTOF-MS, and FACE

In recent years, natural products with biological activities have been increasingly researched. The elucidation of phytoconstituents is necessary for the development of drugs as a natural alternative for the treatment of various diseases. The work aimed to evaluate in vitro and in silico bioactivities of hexane (CCHE) and methanol (CCME) fractions of ethanolic extract from Centrosema coriaceum Benth (Fabaceae) leaves and elucidate their phytoconstituents. CCHE and CCME showed antifungal activity for Candida glabrata (MIC of 1000 μg/mL) with fungistatic effect and action in cell envelope by sorbitol and ergosterol assays. CCHE and CCME presented promising antioxidant activity against the DPPH radical with IC₅₀ of 13.61±0.50 and 6.31±0.40 μg/mL, respectively, and relative antioxidant activity (RAA%) of 45.77±3.61/ 28.53±2.25 % for CCHE and 82.18±2.25/51.99±3.23 % for CCME when compared to rutin and quercetin, respectively. Moreover, these fractions demonstrated promising results for the inhibition of lipid peroxidation by β-carotene/linoleic acid assay. For anti-inflammatory and cytotoxicity activities, CCHE and CCME significantly inhibited the production of nitric oxide and TNF-α, without toxicity on murine intraperitoneal macrophages, respectively. Esters, alkanes, steroids, tocopherols, and terpenes were identified in CCHE by GC/MS. Flavonoids, phenolic acids, and disaccharides were detected in CCME by UFLC-QTOF-MS and FACE. Furthermore, rutin was purified from CCME. In silico predictions evidenced that compounds present in both fractions have high affinity to the fungal membrane besides antioxidant and anti-inflammatory activities. Based on these observations, CCHE and CCME have a noteworthy potential for the design of novel antifungal and anti-inflammatory agents that should be explored in future studies.

Nocellara Del Belice (Olea europaea L. Cultivar): Leaf Extract Concentrated in Phenolic Compounds and Its Anti-Inflammatory and Radical Scavenging Activity

Olea europaea L. is a plant belonging to the Oleaceae family, widely grown around the Mediterranean Basin and its leaves are a source of phenolic compounds with antioxidant and anti-inflammatory capacity. Among these, oleuropein and luteolin-7-O-glucoside represent two major polyphenolic compounds in olive-leaf extract. Herein, a polystyrene resin was used to recover the polyphenolic fraction from the acetone-water leaf extract from Nocellara del Belice cultivar, which showed the higher level of analysed bioactive compounds, compared to Carolea cultivar. The antioxidant activity of the extract concentrated in phenolic compounds (OLECp) was evaluated through a classical assay and electron paramagnetic resonance (EPR) for DPPH and hydroxyl radicals scavenging. Thus, the anti-inflammatory activity and the potential beneficial effects in reducing lipid accumulation in an in vitro model of NAFLD using McA-RH7777 cells exposed to oleic acid (OA) were evaluated. Nile Red and Oil Red O have been used to stain the lipid accumulation, while the inflammatory status was assessed by Cytokines Bioplex Assay. OLECp (TPC: 92.93 ± 9.35 mg GAE/g, TFC: 728.12 ± 16.04 mg RE/g; 1 g of extract contains 315.250 mg of oleuropein and 17.44 mg of luteolin-7-O-glucoside) exerted a good radical scavenging capability (IC₅₀: 2.30 ± 0.18 mg/mL) with a neutralizing power against DPPH and hydroxyl radicals, as confirmed by the decreased signal area of the EPR spectra. Moreover, OLECp at concentration of 25, 50 and 100 μg/mL counteracted the intracellular inflammatory status, as result of decreased intracellular lipid content. Our results highlighted the multiple properties and applications of an O. europaea extract concentrated in polyphenols, and the possibility to formulate novel nutraceuticals with antioxidant properties, destined to ameliorate human health.

Development of a Chemically Modified Sensor Based on a Pentapeptide and Its Application for Sensitive Detection of Verbascoside in Extra Virgin Olive Oil

In addition to their antioxidant and antimicrobial action in functional foods, beverages, and in some dermato-cosmetic products, olive phenolic compounds are also recognized for their role in the prevention of diabetes and inflammation, treatment of heart disease and, consequently, of the numerous chronic diseases mediated by the free radicals. In recent years, attention has increased, in particular, regarding one of the most important compound in extra virgin olive oil (EVOO) having glycosidic structure, namely verbocoside, due to the existence in the literature of numerous studies demonstrating its remarkable contribution to the prophylaxis and treatment of various disorders of the human body. The purpose of this study was the qualitative and quantitative determination of verbascoside in commercial EVOOs from different regions by means of a newly developed sensor based on a screen-printed carbon electrode (SPCE) modified with graphene oxide (GPHOX), on the surface of which a pentapeptide was immobilized by means of glutaraldehyde as cross-linking agent. The modified electrode surface was investigated using both Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) methods. This newly developed sensor has shown a high sensibility compared to the unmodified electrode, a low detection limit (LOD) of up to 9.38 × 10^-8 M, and a wide linearity range between 0.1 µM and 10.55 µM. The applicability of the modified sensor was confirmed by detecting verbascoside in ten different EVOOs samples using the cyclic voltammetry (CV) method, with very good results. The validation of the electroanalytical method was performed by using the standard addition method with very good recoveries in the range of 97.48-103.77%.

Antioxidant Activity of 96% Ethanol Extract of Pepaya Jepang Leaves (Cnidoscolus aconitifolius (Mill.) I. M. Johnst) Using DPPH Method (1,1-diphenyl-2-picrylhydrazyl)

Free radicals in the human body can be helped neutralized by natural antioxidants derived from plants. Pepaya Jepang (Cnidoscolus aconitifolius (Mill.) I.M.Johnst) contains antioxidant compounds such as flavonoids and polyphenols. This study examined the antioxidant activity of 96% ethanol extract of C. aconitifolius leaves. Maceration of C. aconitifolius leaves using 96% ethanol solvent, phytochemical screening, and antioxidant activity assay was carried out with 1,1-Diphenyl-2-Picryl Hydrazil (DPPH) on 96% ethanol extract of C. aconitifolius. Extraction obtained a yield of 16.1834%, and phytochemical screening on the 96% ethanol extract of C. aconitifolius contained flavonoids, tannins, saponins, phenols, alkaloids, and steroids. The antioxidant activity assay on 96% ethanol extract of C. aconitifolius had an IC50 value of 145.3855 ppm and an IC50 value of vitamin C of 7.0806 ppm. The Antioxidant Activity Index (AAI) of 96% ethanol extract of C. aconitifolius was 0.4127, and the AAI of vitamin C was 8.4739. Based on the results obtained, although in a weak classification, a 96% ethanol extract of C. aconitifolius leaves has antioxidant activity.

The Formation of Self-Assembled Nanoparticles Loaded with Doxorubicin and d-Limonene for Cancer Therapy

Self-assembled nanoparticles present unique properties that have potential applications in the development of a successful drug delivery system. Doxorubicin (DOX) is an important anti-neoplastic anthracycline chemotherapeutic drug widely described. However, it suffers from serious dose-dependent cardiotoxicity. d-Limonene is a major constituent of numerous citrus oils that is considered a specific monoterpene against free radicals producing antioxidant activity. Herein, we aimed to design three types of self-assembled nanodelivery systems (nanoemulsion, niosomes, and polylactide nanoparticles) for loading both DOX and d-limonene to enhance the solubilization of d-limonene and provide antioxidant activity with excellent anticancer activity. As confirmed by dynamic light scattering and transmission electron microscopy, the nanoparticles were prepared successfully with diameter sizes of 52, 180, and 257 nm for the DOX-loaded nanoemulsion, niosomes, and polylactide nanoparticles, respectively. The zeta potential values were above -30 mV in all cases, which confirms the formation of stable nanoparticles. The loading efficiency of DOX was the highest in the case of the DOX-loaded nanoemulsion (75.8%), followed by niosomes (62.8%), and the least was in the case of polylactide nanoparticles with a percentage of 50.2%. The in vitro release study of the DOX-loaded nanoparticles showed a sustained release profile of doxorubicin with the highest release in the case of DOX-loaded PDLLA nanoparticles. The kinetic release model for all developed nanoparticles was the Peppas-Sahlin model, demonstrating DOX release through Fickian diffusion phenomena. Moreover, all developed nanoparticles maintain the antioxidant activity of d-limonene. The cytotoxicity study of the DOX-loaded nanoparticles showed concentration-dependent anticancer activity with excellent anticancer activity in the case of the DOX-loaded nanoemulsion and polylactide nanoparticles. These nanoparticles will be further studied in vivo to prove the cardioprotective effect of d-limonene in combination with DOX.

Development of a new paper-based voltage step electrocoagulation technique and application to wine classification

This study developed a novel voltage step electrocoagulation (VSEC) technique on paper for analysis and classification of red wine samples. The concept relies on the electrode system applying voltage steps along a strip of filter paper soaked with a wine sample. The system employed a cathode array system (CAS) for voltage step application and an aluminium anode undergoing corrosion to form the green sludges responsible for wine color bleaching along the paper. The VSEC technique led to the shade of colors along the paper which can be observed by the naked-eye or using image processing software. The system was applied to classify 15 wine samples into different groups and to perform dilution and adulteration tests. In addition, the approach could be applied to approximate antioxidant properties of the wine samples as observed via the correlation between the results from VSEC and IC₅₀ values obtained from the DPPH assay with an R² of 0.76.

An Overview on the Use of Extracts from Medicinal and Aromatic Plants to Improve Nutritional Value and Oxidative Stability of Vegetable Oils

Oil oxidation is the main factor limiting vegetable oils' quality during storage, as it leads to the deterioration of oil's nutritional quality and gives rise to disagreeable flavors. These changes make fat-containing foods less acceptable to consumers. To deal with this problem and to meet consumer demand for natural foods, vegetable oil fabricators and the food industry are looking for alternatives to synthetic antioxidants to protect oils from oxidation. In this context, natural antioxidant compounds extracted from different parts (leaves, roots, flowers, and seeds) of medicinal and aromatic plants (MAPs) could be used as a promising and sustainable solution to protect consumers' health. The objective of this review was to compile published literature regarding the extraction of bioactive compounds from MAPs as well as different methods of vegetable oils enrichment. In fact, this review uses a multidisciplinary approach and offers an updated overview of the technological, sustainability, chemical and safety aspects related to the protection of oils.

The Novel Potentiometric Approach to Antioxidant Capacity Assay Based on the Reaction with Stable Radical 2,2'-diphenyl-1-picrylhydrazyl

For the first time, new possibilities of using the DPPH^• as a signal-forming oxidant molecule with potentiometric detection are shown. The CV method confirmed the presence of a quasi-reversible potential-determining system DPPH^•/DPPH-H under experimental conditions. This fact makes it possible to use DPPH^• as the model of the oxidizing agent for obtaining an analytical signal by the potentiometry method. The potentiometric approach makes it possible to obtain the value of the Nernst slope and the antioxidant capacity in one experiment. It consists of an antioxidant supplement and two consecutive DPPH^• supplements. In this case, the calculation of the Nernst slope is carried out by introducing the second addition of the oxidizing agent and constructing a calibration curve against the reaction background with an antioxidant. Solutions of individual antioxidants α-tocopherol, quercetin, (±)-catechin hydrate, and α-lipoic acid were studied by the developed approach. A high correlation with the results of spectrophotometric measurements is shown. At the same time, the potentiometry method is devoid of the concentration limitations of the spectrophotometric method, which was confirmed. In the study of plant materials extracts, a high correlation of antioxidant capacity, obtained by potentiometric and spectrophotometric methods, was shown only for objects whose color did not contribute to the DPPH^• absorption. The versatility of the potentiometric method for studying objects of any color was shown.

Chemical and Pharmacological Profiling of Wrightia coccinea (Roxb. Ex Hornem.) Sims Focusing Antioxidant, Cytotoxic, Antidiarrheal, Hypoglycemic, and Analgesic Properties

The aim of the study was to conduct phytochemical and pharmacological investigations of Wrightia coccinea (Roxb. ex Hornem.) Sims via several in vitro, in vivo, and in silico models. A total of four compounds were identified and isolated from the methanol extract of the bark and the methanol extract of the seed pulp of W. coccinea through successive chromatographic techniques and were characterized as 3β-acetyloxy-olean-12-en-28-ol (1), wrightiadione (2), 22β-hydroxylupeol (3), and β-sitosterol (4) by spectroscopic analysis. The aqueous fraction of the bark and chloroform fraction of the fruits provided the most potent antioxidant capacity (IC50 = 7.22 and 4.5 µg/mL, respectively) in DPPH free radical scavenging assay compared with the standard ascorbic acid (IC50 = 17.45 µg/mL). The methanol bark extract and the methanol fruit coat extract exerted anti-diarrheal activity by inhibiting 74.55 ± 0.67% and 77.78 ± 1.5% (mean ± SEM) of the diarrheal episode in mice, respectively, after four hours of loading the samples. In the hypoglycemic test, the methanol bark extract and the methanol fruit coat extract (400 mg/kg) produced a significant (p < 0.05) reduction in the blood glucose level in mice. Both doses of the plant extracts (200 mg/kg and 400 mg/kg) used in the study induced a significant (p < 0.05) increase in pain reaction time. The in vitro and in vivo findings were supported by the computational studies. The isolated compounds exhibited higher binding affinity compared with the standard drugs towards the active binding sites of glutathione reductase, epidermal growth factor receptor (EGFR), kappa opioid receptor, glucose transporter 3 (GLUT 3), Mu opioid receptor, and cyclooxygenase 2 (COX-2) proteins due to their potent antioxidant, cytotoxic, anti-diarrheal, hypoglycemic, and central and peripheral analgesic properties, respectively. The current findings concluded that W. coccinea might be a potential natural source for managing oxidative stress, diarrhea, hyperglycemia, and pain. Further studies are warranted for extensively phytochemical screening and establishing exact mechanisms of action.

Ceylon cinnamon and clove essential oils as promising free radical scavengers for skin care products

Due to adverse effects of free radicals on human skin and increasing consumer demand for natural ingredients, essential oils from basil, Ceylon cinnamon bark, clove, juniper, lavender, oregano, rosemary, tea tree, thyme, and ylang-ylang were assessed for their antiradical activity. The oils were evaluated in the concentration range of 5—0.1 mg·mL−1, in which the three reference synthetic antioxidants are most often added to mass-produced cosmetics. Among all examined samples, C. cinnamon oil at a concentration of 5 mg·mL−1 showed the strongest DPPH radical scavenging activity (0.41 mg·mL−1 IC50), followed by clove oil, BHA, α-tocopherol, and BHT (0.82, 0.84, 0.88 and 0.93 mg·mL−1 IC50), respectively. At the same concentration, the reduction power of C. cinnamon oil was higher (1.64 mg·mL−1 Trolox Eq.) than that of α-tocopherol and BHT (1.42 and 0.80 mmol·L−1 Trolox Eq., respectively) but lower than that of BHA (1.81 mmol·L–1 Trolox Eq.). Antiradical activity of the other eight essential oils was low or negligible. C. cinnamon oil and clove oil are promising antiradical agents for skin care but according to our GC-MS analysis, these oils contain 0.29 % of cinnamaldehyde, 0.03 % of linalool, 0.02 % of D-limonene, and 0.02 % of eugenol or 0.41 % of eugenol and 0.002 % of linalool, respectively, which are monitored contact allergens in cosmetics. Such a product is not be suitable for consumers allergic to these substances but for the vast majority of consumers it does not pose a risk in terms of allergic manifestations.

Molecular insights into binding mechanism of rutin to bovine serum albumin - Levothyroxine complex: Spectroscopic and molecular docking approaches

Bovine serum albumin (BSA) has been used as a transporter protein for levothyroxine (LT4) and rutin, due to its property of binding to various ligands. Rutin binding to the BSA-LT4 complex can bring many benefits due to its proven pharmacological properties. Using Fourier-Transform Infrared Spectroscopy (FT-IR) the changes induced by rutin in the structure of BSA-LT4 complex were determined. Fluorescence studies allowed us to determine the quenching mechanism and affinity of rutin to the BSA-LT4 complex. The thermodynamic parameters suggest the binding of rutin to BSA-LT4 is a spontaneous process, driven by enthalpy and electrostatic forces. Also, the second derivative of the emission spectra suggests the Trp's of BSA are located in two different microenvironments. Thermal and chemical denaturation of BSA-LT4-rutin complex presents similar behavior but with better stability of the complex in case of chemical denaturation. Molecular docking studies show the binding of the two ligands to the same BSA site, suggesting that rutin may influence the bond of LT4 with the protein. Studies on the antioxidant activity of the BSA-LT4-rutin complex suggest that the presence of LT4 decreases the antioxidant activity of the rutin, but even so this antioxidant activity can be used to bring benefits for medical purposes.

Plectranthus ecklonii Benth: A Comprehensive Review Into its Phytochemistry and Exerted Biological Activities

Ethnopharmacological Relevance: Plectranthus genus (Lamiaceae family) contain several species with acknowledged ethnopharmacological uses, such as, for gastrointestinal and respiratory-related problems, due to their anti-inflammatory, antibacterial and antifungal properties. The bioactivity of isolated medicinal compounds from this genus justifies the increased interest in recent times for species of Plectranthus, placing them in the spotlight for natural product drug development. Aim of the study: To the best of our knowledge, this is the first review on the biological activities of Plectranthus ecklonii Benth. As such, the aim of this review was three-fold: 1) to summarize the chemical compounds isolated from P. ecklonii; 2) to collate the biological activities and mechanisms of action of these compounds from in vitro studies; and 3) to evaluate the documented uses and potential applications of this species, in order to postulate on the direction of pharmaceutical uses of this species. Materials and methods: An extensive database retrieval was performed using the electronic databases Web of Science, PubMed, Google Scholar and ScienceDirect. The search criteria consisted of the keywords "Plectranthus ecklonii", "Plectranthus ecklonii + review", "Plectranthus ecklonii + diterpenes" or "Plectranthus ecklonii + abietanes", "ecklonii + parviflorone D", searched individually and as combinations. Eligibility criteria were set out and titles in English, Portuguese and Spanish were reviewed, with all references included dating from 1970 to 2021. A total of 169 papers were selected and included. Chemical structures were drawn using ChemDraw 20.0, CID numbers were searched in PubChem and the PRISMA diagram was created using PowerPoint 2012. Results: To date, a total of 28 compounds have been isolated from P. ecklonii, including diterpenes, triterpenes, flavonoids, and hydroxycinnamic acids. Most focused on the antimicrobial action of its constituents, although compounds have demonstrated other bioactivities, namely antioxidant, anti-inflammatory and antitumor. The most recent studies emphasize the diterpenoids, particularly parviflorone D, with the help of nanotechnology. Conclusions: The widespread ethnobotanical and traditional uses of P. ecklonii can be scientifically justified by a range of biological activities, demonstrated by isolated secondary metabolites. These bioactivities showcase the potential of this species in the development of economically important active pharmaceutical ingredients, particularly in anticancer therapy.

Formulation of Genistein-HP β Cyclodextrin-Poloxamer 188 Ternary Inclusion Complex: Solubility to Cytotoxicity Assessment

The current study was designed to prepare the inclusion complex Genistein (GS) using Hydroxypropyl β cyclodextrin (HP β CD) and poloxamer 188 (PL 188). The binary inclusion complex (GS BC) and ternary inclusion complex (GS TC) were developed by microwave irradiation technique and evaluated for a comparative dissolution study. Further, the samples were assessed for FTIR, DSC, XRD, and NMR for the confirmation of complex formation. Finally, antioxidant and antimicrobial studies and cytotoxicity studies on a breast cancer (MCF-7) cell line were conducted. The dissolution study result showed a marked increment in GS dissolution/release after incorporation in binary (GS: HP β CD, 1:1) and ternary (GS: HP β CD: PL 188; 1:1:0.5) inclusion complexes. Moreover, the ternary complex exhibited a significant enhancement (p < 0.05) in dissolution than did the binary complexes. This might be due to the presence of PL 188, which helps in solubility enhancement of GS. DSC, XRD and SEM evaluation confirmed the modification in the structure of GS. FTIR and NMR results indicated the formation of an inclusion complex. The antioxidant and antimicrobial activity results revealed that GS TC has shown significant (p < 0.05) higher activity than pure GS. The cytotoxicity study results also depicted concentration-dependent cytotoxicity. GS TC exhibited significantly (p < 0.05) high cytotoxicity to cancer cells (IC₅₀ = 225 µg/mL) than pure GS (IC₅₀ = 480 µg/mL). Finally, it was concluded that a remarkable enhancement in the dissolution was observed after the inclusion of GS in the ternary complex and it therefore has significant potential for the treatment of breast cancer.

Correlational nutritional relationships and interactions between expansive holoparasite Orobanche laxissima and woody hosts on metal-rich soils

Plant parasitism by other plants, combined with abiotic environmental stress, offers a unique opportunity to study correlational nutritional relationships in terms of parasite-host interactions and their functional roles in nutrient cycling in ecosystems. Our study analysed the transfer of selected mineral elements, including heavy metals, from soil to different organs in hosts (Punica granatum and Fraxinus angustifolia) and from hosts to the expansive holoparasite (Orobanche laxissima) in cinnamonic soil habitats in Georgia (Caucasus). We also identified other correlated trophic and bioactive effects in the parasite-host relationship. O. laxissima was characterized by a high accumulation tendency for micro- and macroelements, such as K and Ca, and heavy metals, such as Zn, Ni, and Cd. Parasites can reduce the concentration of heavy metals in host tissues owing to this high accumulation tendency. In total, 85 compounds were identified in the examined parasite and its hosts. Despite the distinct phytochemical content of species of the infected host, the parasite produced specific metabolites with dominant phenylethanoid glycosides (PhGs), with acteoside and crenatoside being the primary dominant compounds - ca. 98% of all polyphenols. Polyphenols in parasite specimens that are correlated with Cu and Zn are antagonistic to polyphenols correlated with Fe, Pb, Cr, and Ni. The profile of polyphenols in the host species was both qualitatively and quantitatively distinct from the profile of the compounds in the parasite and between hosts (only acteoside in group PhGs was common between the parasite and Fraxinus host), which indicates the existence of a unique compound biosynthesis pathway in the parasite. Our results demonstrated that the parasite, particularly in its flowers, exhibited higher polyphenol content, antioxidative effects (ABTS-+, DPPH, and FRAP), and inhibitory effects.

Effect of glucose substitution by low-molecular weight chitosan-derivatives on functional, structural and antioxidant properties of maillard reaction-crosslinked chitosan-based films

In this study, the effects of different temperatures, incubation times and types of reducing sugars, including glucose and different low molecular weight (Mw) chito-oligosaccharides (COS) with varying acetylation degree (AD), on the extent of Maillard reaction (MR) on chitosan-based films were studied. Interestingly, an improvement of structural and functional properties of all MR-crosslinked films was noted, which is more pronounced by heating at higher temperature and exposure time. These findings were proved through Fourier-transform infrared and X-ray diffraction analyses. In addition, color change and Ultraviolet spectra demonstrate that glucose addition provides the high extent of MR, followed by COS1 (Mw < 4.4 kDa; AD, 18.20%) and COS2 (Mw < 4.4 kDa; AD, 10.63%). These results were confirmed by enhanced water resistance and thermal properties. Moreover, MR-chitosan/COS films showed the highest mechanical properties, whereas, glucose-loaded films were brittle, as demonstrated by scanning electron microscopy micrographs. Furthermore, MR-chitosan/COS1 films exhibited the better antioxidant behavior followed by chitosan/glucose and chitosan/COS2 films, mainly at higher heating-conditions. Thereby, MR-crosslinked chitosan/COS based films were attractive to be applied as functional and active coating-materials in various fields.

A Novel Stoichio-Kinetic Model for the DPPH• Assay: The Importance of the Side Reaction and Application to Complex Mixtures

The 2,2-diphenyl-1-picrylhydrazyl (DPPH•) assay is widely used to determine the antioxidant activity of food products and extracts. However, the common DPPH• protocol uses a two-point measurement and does not give information about the kinetics of the reaction. A novel stoichio-kinetic model applied in this study monitors the consumption of DPPH• by common antioxidants following the second order reaction. The fitting of such decay yields the rate constant k₁, which describes the main reaction between antioxidants and DPPH•, and the rate constant k₂, which is attributed to a slower side reaction considering the products generated between the transient radicals (AO•) and another molecule of DPPH•. The model was first applied to antioxidant standards. Sinapic acid, Trolox and ascorbic and chlorogenic acids did not show any side reaction. Instead gallic, ferulic and caffeic acids achieved the best fitting with k₂. The products of the side reaction for these compounds were confirmed and identified with high-resolution mass spectrometry. Finally, the kinetic model was applied to evaluate the antioxidant activity of eight herbal extracts. This study suggests a new kinetic approach to standardize the common DPPH• assay for the determination of antioxidant activity.

In vitroanti-oxidant and cytotoxic activities of gold nanoparticles synthesized from an aqueous extract of theXylopia aethiopicafruit

The development of gold nanoparticles (AuNPs) using a green approach has drawn considerable interest in the field of nanomedicine. Its wide application in clinical diagnosis, imaging and therapeutics portrays its importance for human existence. In this study, we reported on the biogenic synthesis of AuNPs using the aqueous extract of theXylopia aethiopicafruit (AEXAf), which acts as both a reducing and stabilizing agent. The characterization of AEXAf-AuNPs was performed using ultraviolet-visible spectroscopy, dynamic light scattering and zeta potential measurements, high-resolution transmission electron microscopy and Fourier transform-infrared spectroscopy. Thein vitroanti-oxidant activities of the AEXAf-AuNPs and AEXAf were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing anti-oxidant power. Thein vitrocytotoxic activities of the AEXAf-AuNPs and AEXAf against breast and colorectal cancer cells were evaluated using 3,-(4,5 dimethylthiazol)-2,5 diphenyl tetrazolium bromide (MTT) viability and annexin V/PI assays. The AEXAf-AuNPs exhibited surface plasmon absorption maximum at 522 nm and were stable for 4 weeks. The average size of the AEXAf-AuNPs was 10.61 ± 3.33 nm on the high-resolution transmission electron microscopy images. Thein vitroanti-oxidant activities of the AEXAf-AuNPs and AEXAf were concentration dependent. The AEXAf-AuNPs were cytotoxic to the cancer cells and non-toxic to the non-cancerous human fibroblast cells (KMST-6) (up to 200μg ml^-1). From these results, the AEXAf-AuNPs showed good anti-oxidant and anti-cancer activities, and can be suggested as a possible therapeutic agent for breast and colorectal cancer.

Antioxidant HPTLC-DPPH Fingerprinting of Honeys and Tracking of Antioxidant Constituents Upon Thermal Exposure

The use of High-Performance Thin-Layer Chromatography (HPTLC) coupled with the use of DPPH* (2,2-diphenyl-1-picrylhydrazyl) as a derivatisation reagent is a novel approach to the analysis of antioxidant activity of honeys. The method facilitates the visualisation of individual constituents that contribute to the overall antioxidant activity of the honey, even if they are not yet chemically identified, and allows for the quantification of their antioxidant activity as gallic acid equivalents. The method supports a more in-depth study of the antioxidant activity of honey as it allows for a comparative analysis of the antioxidant fingerprints of honeys of different floral origin and is able to capture differences in their individual bioactive constituents. Further, it supports the tracking of changes in antioxidant activity of individual honey constituents over time upon exposure to different temperature conditions, which demonstrates the potential value of the method for in-process quality control.

Spermidine promotes melanin production through an MITF signalling pathway

Melanin plays an important role in determining skin colour. Apoptosis of melanocytes and defect in melanin production cause vitiligo. Various studies have been conducted to treat the disease, but its treatment is still difficult. Therefore, this study aimed to investigate the effect of spermidine, which is known as an inhibitor of ageing-related oxidized proteins, on melanogenesis. Even though spermidine above 50 μM had no effect on antioxidant activity and DOPA oxidation, it displayed tyrosinase activity. However, spermidine at 2000 μM was cytotoxic in B16F1 cells using MTT assay. Spermidine above 125 μM decreased the amount of intracellular hydrogen peroxide in a concentration-dependent manner in DCFH-DA analysis. It was also found that spermidine above 2000 μM increased melanin synthesis in living cells. However, spermidine above 1000 μM increased melanin synthesis in a concentration-dependent manner in H₂ O₂ -treated B16F1 cells. Furthermore, spermidine enhanced the expression of tyrosine hydroxylase via MITF transcription factor involved in melanogenesis in H₂ O₂ -treated B16F1 cells. Therefore, these results suggest that spermidine could be applied as a potential stimulator of melanin synthesis for the prevention of hair greying.

(-)-Epicatechin-An Important Contributor to the Antioxidant Activity of Japanese Knotweed Rhizome Bark Extract as Determined by Antioxidant Activity-Guided Fractionation

The antioxidant activities of Japanese knotweed rhizome bark extracts, prepared with eight different solvents or solvent mixtures (water, methanol, 80% methanol_(aq), acetone, 70% acetone_(aq), ethanol, 70% ethanol_(aq), and 90% ethyl acetate_(aq)), were determined using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay. Low half maximal inhibitory concentration (IC₅₀) values (2.632–3.720 µg mL⁻¹) for all the extracts were in the range of the IC₅₀ value of the known antioxidant ascorbic acid at t₀ (3.115 µg mL⁻¹). Due to the highest extraction yield (~44%), 70% ethanol_(aq) was selected for the preparation of the extract for further investigations. The IC₅₀ value calculated for its antioxidant activity remained stable for at least 14 days, while the IC₅₀ of ascorbic acid increased over time. The stability study showed that the container material was of great importance for the light-protected storage of the ascorbic acid_(aq) solution in a refrigerator. Size exclusion–high-performance liquid chromatography (SEC-HPLC)–UV and reversed phase (RP)-HPLC-UV coupled with multistage mass spectrometry (MSⁿ) were developed for fractionation of the 70% ethanol_(aq) extract and for further compound identification, respectively. In the most potent antioxidant SEC fraction, determined using an on-line post-column SEC-HPLC-DPPH assay, epicatechin, resveratrol malonyl hexoside, and its in-source fragments (resveratrol and resveratrol acetyl hexoside) were tentatively identified by RP-HPLC-MSⁿ. Moreover, epicatechin was additionally confirmed by two orthogonal methods, SEC-HPLC-UV and high-performance thin-layer chromatography (HPTLC) coupled with densitometry. Finally, the latter technique enabled the identification of (−)-epicatechin. (−)-Epicatechin demonstrated potent and stable time-dependent antioxidant activity (IC₅₀ value ~1.5 µg mL⁻¹) for at least 14 days.

In vitro and in vivo evaluation of pharmacological potential of Begonia barbata Wall

Background

Begonia barbata Wall is an important medicinal plant in Bangladesh used to treat several human diseases. The intention of the existing work was to determine in vitro and in vivo pharmacological properties of petroleum-ether, dichloromethane, and ethyl acetate soluble fractions of methanol extract of B. barbata whole plant (MEBB). The total phenolic content (TPC) was determined by Folin-Ciocalteu test while antioxidant activity assay was performed by DPPH radical quenching process. Tail immersion and acetic acid-induced writhing methods were utilized to evaluate analgesic effect in albino mice. To evaluate the hypoglycemic potential, glucose tolerance test is used. Castor oil-induced diarrhea method is utilized to figure out the anti-diarrheal action in mice. Thiopental-sodium-induced sleeping time test was exploited for the appraisal of CNS antidepressant action.

Results

Antioxidant activities of the test materials followed the order: dichloromethane fraction (DCMF) > ethyl acetate fraction (EAF) > petroleum-ether fraction (PEF). The EAF yielded maximum amount of phenolic compounds (12.47 mg of GAE/g of sample). The DMF was most effective in terms of thrombolytic activity while the EAF protected the membrane integrity of erythrocyte by 63.47% inhibition of hemolysis induced by heat. Among all fractions, the PEF (400 mg/kg body weight) demonstrated highest analgesic activity in both tail immersion test (maximum elongations as 262.053%) and acetic acid-induced writhing method (66.02% writhing inhibition). During anti-diarrheal test, the plant samples significantly diminished the frequency of diarrheal episodes in mice. Similarly, the plant samples decreased the sleeping duration induced by thiopental sodium.

Conclusion

The above outcome exposed that B. barbata possesses significant pharmacological potential, which validates its use in Bangladesh folk medicinal practices.

Phenolic profile and antioxidant capacity of Pithecellobium dulce (Roxb) Benth: a review

Pithecellobium dulce (Roxb) Benth (P. dulce), known as "guamúchil", is a tree native to the American continent. Various parts of the tree are used in traditional medicine, primarily for treating gastrointestinal disorders. The phenolic compounds and antioxidant capacity of this plant are largely responsible for the beneficial health effects attributed to it. A number of authors have studied the antioxidant capacity and phenolic compounds of the aril, seed, leaf and root of P. dulce using various methodologies, which can differ considerably in variables such as environmental factors, type of drying, temperature, the way the sample is stored, and the use of different solvents in the various extraction methods. Even methods of quantification by HPLC vary tremendously. This paper summarizes the existing research carried out to date on determining the phenolic profile and antioxidant capacity of P. dulce.

Oxidative Degradation of High-Molar-Mass Hyaluronan: Effects of Some Indole Derivatives to Hyaluronan Decay

Indole derivatives such as isatin (a natural compound), cemtirestat, stobadine, and its derivatives (synthetic compounds) are known to have numerous positive effects on human health due to regulation of oxidative status. The aim of the study was to assess radical scavenging capacities of these compounds and explore their potential protective effects against reactive oxygen species formed during Cu(II) ions and ascorbate-induced degradation of high-molar-mass hyaluronan. Based on the IC₅₀ values determined by the ABTS assay, the most effective compound was SM1M3EC2·HCl reaching the value ≈ 11 µmol/L. The lowest IC₅₀ value reached in the DPPH assay was reported for cemtirestat ≈ 3 µmol/L. Great potency of inhibition of hyaluronan degradation was shown by cemtirestat, followed by isatin even at low concentration 10 µmol/L. On the other hand, stobadine·2HCl had also a protective effect on hyaluronan degradation, however at greater concentrations compared to cemtirestat or isatin. SME1i-ProC2·HCl reported to be a less effective compound and SM1M3EC2·HCl can be considered almost ineffective compared to stobadine·2HCl. In conclusion, our results showed that both isatin and cemtirestat were capable of attenuating the degradation of high-molar-mass hyaluronan due to their ability to complex/sequester cupric ions.

Synthesis of Novel 3-(4-tert-Butylphenyl)-5-Cylopropyl-4H-1,2,4-Triazole Derivatives with Antioxidative and Antimicrobial Activities

Background:

In this work, new heterocyclic compounds containing 3-(4-tertbutylphenyl)- 5-cyclopropyl-4H-1,2,4-triazole ring were synthesized, starting from iminoester hydrochlorides and 4-tert-butylbenzhyrazide.

Methods:

Ethyl N-[(4-tert-butylphenyl)carbonyl]cyclopropanecarbohydrazonoate was used to synthesize 4-amino-3-(4-tert-butylphenyl)-5-cyclopropyl-4H-1,2,4-triazole, 3-(4-tert-butylphenyl)-5- cyclopropyl-4-(arylmethyleneamino)-4H-1,2,4-triazole, 3-(4-tert-butylphenyl)-5-cyclopropyl-4- (arylmethylamino)-4H-1,2,4-triazole and their phthalonitrile derivatives sequentially.

Results:

Seventeen new 3-(4-tert-butylphenyl)-5-cyclopropyl-4H-1,2,4-triazole derivatives were synthesized and their antioxidant and antimicrobial activities were determined.

Conclusion:

Imine and amine derivatives were better antioxidants than phthalonitrile derivatives. Doubly fluorination compounds appeared to result in higher activity. The compounds tested with five microorganisms showed better activity against B. subtilis with the antimicrobial activity of two far exceeding that of ampicillin. Imine and amine derivatives were better antimicrobials than phthalonitrile derivatives.

State of the Art of Anthocyanins: Antioxidant Activity, Sources, Bioavailability, and Therapeutic Effect in Human Health

The antioxidant activity of anthocyanins in food is well known. Numerous antioxidant assays have been proposed to measure the capacity of anthocyanins to prevent the oxidation process that naturally occurs. Different solvents, temperatures, and pH levels are applied in each assay, and these factors should be taken into account in order to obtain useful and reproducible results. The concentration and the structure of these compounds are directly related to their antioxidant capacity and their environment. However, the effectiveness of the anthocyanin ingestion against diseases is also influenced by its bioavailability. Novel methodologies that simulate the digestion process have been developed in order to facilitate the current knowledge of anthocyanins bioavailability. Studies highlight the potential synergy effect between parent compounds and their derivatives (metabolites, conjugated products, and microbe-generated metabolites). The aim of this review is to provide an overview of advantages and disadvantages of the most common methods to determine the antioxidant activity of anthocyanins, chemical structure, and concentration of these compounds in different edible fruits, vegetables, and plants; their bioavailability after intake; as well as the main therapeutic effect described in the scientific literature.

Puerarin improves graft bone defect through microRNA‑155‑3p‑mediated p53/TNF‑α/STAT1 signaling pathway

Bone graft defects may lead to dysfunction of bone regeneration and metabolic disorders of bone mesenchymal stem cells (BMSCs). Puerarin has demonstrated pharmacological activities in the treatment of human metabolic diseases. The purpose of the present study was to investigate the role of puerarin and to explore its possible protective mechanism of action in rats with bone grafts. A bone graft rat model was established using bone grafting surgery and the rats received puerarin or PBS. Reverse transcription-quantitative PCR, western blot, TUNEL, immunofluorescence and immunohistochemistry assays were used to analyze the beneficial effects of puerarin on bone repair. The results demonstrated that puer-arin effectively ameliorated pathological graft bone defects, decreased bone loss and apoptosis of BMSCs, promoted BMSC proliferation and differentiation, and increased bone mass and the parameters of bone formation in rats with bone grafts. Puerarin decreased the levels of pro-inflammatory cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-17A, IL-6 and transforming growth factor (TGF)-β1] and increased the levels of anti-inflammatory cytokines (IL-2 and IL-10) in the serum compared with the PBS group. Puerarin treatment was associated with lower serum alanine transaminase, glutamic oxaloacetic transaminase, γ-glutamyl transferase, alkaline phosphatase, direct bilirubin and total bilirubin levels compared with those in the PBS group in experimental rats. The expression of microRNA-155-3p (miR-155-3p) was upregulated, whereas that of p53, TNF-α and signal transducer and activator of transcription (STAT)1 was downregulated in BMSC cultures of puerarin-treated rats. In vitro assay demonstrated that knockdown of miR-155-3p increased p53, TNF-α and STAT1 expression in BMSCs, and blocked puerarin-regulated p53/TNF-α/STAT1 signaling. Most importantly, miR-155-3p knockdown inhibited puer-arin-regulated apoptosis, proliferation and differentiation of BMSCs. Moreover, the results demonstrated that puerarin regulated vascular endothelial growth factor expression via the miR-155-3p signaling pathway. In conclusion, the results of the present study demonstrated that the upregulation of miR-155-3p induced by puerarin promoted BMSC differentiation and bone formation and increased bone mass in rats with bone grafts, thereby supporting the potential application of puerarin in the prevention of bone graft defects.

Conception of novel blue crab chitosan films crosslinked with different saccharides via the Maillard reaction with improved functional and biological properties

This work aimed to modify blue crab chitosan-based films through the Maillard reaction (MR) as a novel alternative to improve their functional and biological properties. To this end, different saccharides (glucose (aldohexose), fructose (ketohexose), xylose (aldopentose) and arabinose (aldopentose)), at different weight ratios 0.5, 1.0 and 2.0 % (g/100 g polymer), were studied, and films were heated at 90 °C for 24 h. Based on color changes and browning index measurements, the extent of MR was the highest with aldopentoses, whereas hexoses and particularly ketohexoses, exhibited a relative crosslinking rate. These findings were further reflected with an improvement in treated films mechanical properties and thermal degradation temperatures, and advantageously, barrier properties against UV light and water. In addition, the MR-modified Cs-based films antioxidant activity was interestingly enhanced with mainly aldopentoses. Consequently, MR crosslinked chitosan-based films are promising alternative for active and functional packaging able of food oxidation hindering, especially using aldopentoses.

Test on the Antioxidant Activities of Methanol Extract of Bidara Leaves (Ziziphus spina-christi L.) using the DPPH Radical Immersion Method

Bidara (Ziziphus spina-christi L.) is a tropical tree originating from Sudan in which it is commonly known as "Nebeq" in Saudi Arabia. It is of a bioactive compound - a flavonoid compound, which is the potential to be used as an antioxidant. It is capable of inhibiting any cell damages caused by free radicals. This study aimed to measure the activities of the free radicals in methanol extracts of Z. spina-christi leaves. The process of extracting the Z. spina-christi leaves was carried out through the maceration method using methanol as a solvent. The qualitative analysis of chemical compounds with certain eluents using thin-layer chromatography (TLC) was purposely to determine the groups of active compounds in extracts. The measurement of antioxidant activities was carried out using the 1,1-Diphenyl-2-picryl Hidrazyl (DPPH) immersion method in which absorption was measured at a maximum wavelength of 513 nm. The results showed that the methanol extract of Z. spina-christi leaves had a very weak antioxidant activity with the IC50 value of 466.804 �g/ml. The results of the bioautographic profile showed the presence of flavonoid compounds, phenols, saponins, and tannins.

Application of Deep Eutectic Solvents for the Extraction of Rutin and Rosmarinic Acid from Satureja montana L. and Evaluation of the Extracts Antiradical Activity

Satureja montana L. was used in the current research as the plant exhibits numerous health-promoting benefits due to its specific chemical composition. The extraction method based on deep eutectic solvents (DESs) was used for the extraction of rutin and rosmarinic acid from this plant. Five different choline chloride-based DESs with different volumes of water (10%, 30%, and 50% (v/v)) were used for the extraction at different temperatures (30, 50, and 70 °C) to investigate the influence on rosmarinic acid and rutin content obtained by high-performance liquid chromatography with diode-array detector (HPLC-DAD) in the obtained extracts. A principal component analysis was employed to explore and visualize the influence of applied parameters on the efficiency of the extraction procedure of rutin and rosmarinic acid. Among the tested DESs, choline chloride:lactic acid (mole ratio 1:2) and choline chloride:levulinic acid (mole ratio 1:2) were the most suitable for the extraction of rutin, while for rosmarinic acid choline chloride:urea (mole ratio 1:2) was the most effective solvent. The extract showing the best antiradical activity was obtained with choline chloride:urea (mole ratio 1:1) at 30 °C and 50% H₂O (v/v).

Correlation between Antibacterial Activity and Free-Radical Scavenging: In-Vitro Evaluation of Polar/Non-Polar Extracts from 25 Plants

Objectives: The current study aimed to measure the antioxidant and antibacterial activities of 25 wild Palestinian edible plants, which were subjected to extraction by polar and non-polar solvents. Correlations between free radical scavenging activity and antibacterial activity of the extracts were assessed for both polar and non-polar fractions. Materials: Twenty-five wild edible plant species that are frequently consumed by people in Palestine (mainly in a rural area) were examined. Among them, 10 plant species were among those with the highest mean cultural importance values, according to an ethnobotanical survey that was conducted in the West Bank, Palestine, a few years ago. Method: The protocol of the DPPH assay for testing free-radical scavenging was utilized for determining EC50 values, while microdilution tests were conducted to determine the 50% inhibitory concentration (IC50) of the extracts for the microorganism Staphylococcus mutans. Results and Discussion: Eight extracts (non-polar fractions) were found to possess an antibacterial IC50 of less than 20 ppm, such as Foeniculum vulgare, Salvia palaestinafruticose, Micromeria fruticose, Trigonella foenum-graecum, Cichorium pumilum jacq, Salvia hierosolymitana boiss, Ruta chalepensis, and Chrysanthemum coronarium. The polar fractions possess higher antioxidant activity, while non-polar fraction possess higher antibacterial activity. Looking at all the results together can deceive and lead to the conclusion that there is no correlation between antibacterial activity against S. mutans and free radical scavenging (R2 equals 0.0538). However, in-depth analysis revealed that non-polar plant extracts with an EC50 of free radical scavenging ≤100 ppm have a four-fold order of enrichment toward more activity against S. mutans. These findings are of high importance for screening projects. A four-fold order of enrichment could save plenty of time and many in screening projects. The antibacterial active extracts marked by low-medium free radical scavenging might act through a mechanism of action other than that of highly active, free radical scavenging extracts. Conclusion: The screening of antioxidant and antimicrobial activity performed on 25 selected wild plant extracts revealed a satisfactory free radical scavenging and antimicrobial potential that could be of value in the management of oxidative stress. Further studies are recommended to explore novel and highly active natural antibacterial products.