Free Radical Scavenging Method Research Articles

Microencapsulation of tomato oleoresin using tomato waste fibre and its application for orange juice fortification

SummaryFood waste by‐products contain many bioactive compounds, such as proteins, carbohydrates, polyphenols and carotenoids. The purposes of this study was to extract oleoresin from tomato waste, apply tomato pomace powder (TPP) as a new shell material for encapsulation of oleoresin and to fortify orange juice using the developed microcapsules. Microencapsulation was carried out based on different TPP (2% and 3%) and oleoresin (20% and 30%) concentrations by spray drying at two temperatures (130 and 140 °C). Different features of microcapsules such as the encapsulation load, encapsulation efficiency, moisture content, hygroscopicity, bulk and tapped densities and the Hausner ratio were analysed. Based on properties of microcapsules, samples containing 3% TPP and 30% oleoresin dried at 130 °C were selected as the best treatment and their characteristics such as morphology, chemical structure and thermal behaviour were investigated. Scanning electron microscopy indicated that spherical micron‐size particles were formed and their crack‐free fine surface showed their potential for encapsulation of anti‐oxidants to reduce oxygen diffusion. Microencapsulated oleoresin was then added to the orange juice and the samples' pH, acidity, total soluble solids and colour were evaluated and compared with pure orange juice. Free radical scavenging method was used to investigate the anti‐oxidant properties of orange juice during storage. The results indicated that at the end of the 30 days of storage the fortified orange juice had anti‐oxidant activity equal to pure fresh orange juice on day one. Sensory evaluation results showed no significant differences between appearance, colour, thickness and overall acceptance of fresh and the fortified juices (P < 0.05). The results of this study showed the potential application of food and agricultural waste in production of value‐added ingredients to be used as natural additives in food industries.

Synergistic activity of clove essential oil and thyme essential oil and their interaction against Malassezia furfur, Escherichia coli, Staphylococcusaureus

Plant essential oils have excellent antioxidant and antibacterial properties, which can greatly reduce microbial resistance. However, the odor and cost issues caused by their high concentration use remain the main bottlenecks in their application as antibacterial agents. The present study was conducted to evaluate inhibitory activity of essential oils (EOs) against Escherichia coli and Staphylococcus aureus, and focus on synergistic activity of EOs against Malassezia furfur. The minimum inhibitory concentrations and the active components of various EOs and their combination were determined using the agar dilution method and gas chromatography–mass spectrometry, respectively. The synergistic effect of EO combination on Malassezia furfur was evaluated by analyzing its growth, morphology, and cell membrane fluidity using growth curve analyses, scanning electron microscopy, and N-phenyl-1-naphthylamine method, respectively. Additionally, the antioxidant activity of the EOs combination was evaluated using the free radical scavenging method. The mixture of EOs exerted a synergistic effect on M. furfur, causing logarithmic growth phase lag, cell damage, decreased membrane fluidity, and the mixture of EOs also had synergistic effect on DPPH free radical scavenging. Conclusively, the combination of EOs investigated in this study exhibited good antibacterial ability against M. furfur, may have potential applications in seborrheic dermatitis.

Carbazole derivatives as antioxidant and anticorrosion materials

In this study, a series of new carbazole derivatives were studied using several reactions, including the Vilsmeier–Haack reaction. A cyclization reaction within bromoacetic acid was reported to synthesize thiazolidinone compounds, followed by the Mannich reaction by reacting the prepared compound with formaldehyde and secondary amines, that is, diphenylamine, morpholine, and phthalimide. All synthesized compounds were characterized by infrared spectroscopy, liquid chromatography–mass spectrometry, and 1H and 13C nuclear magnetic resonance spectroscopy. The antioxidant activities of all prepared compounds were studied using the free-radical scavenging method using 2,2-diphenyl-1-picrylhydrazyl, demonstrating their moderate activity compared with ascorbic acid as the standard substance. The effectiveness of the prepared compounds as corrosion inhibitors was studied in an acidic medium of sulfuric acid (0.25 mol/L) using the electrochemical method. Acceptable corrosion-inhibition efficiency was achieved, with the highest inhibition rate of 55.21 % for compound VII

Synthesis, characterisation, DFT and biological evaluation of 4-(1-ethylbenzimidazol-2-yl)-2-(arylamino)thiazoles

The compounds 4-(1-ethylbenzimidazol-2-yl)-2-(arylamino)thiazoles were expected to have many biological activities and were synthesized from 1,2-diaminobenzene and lactic acid. The synthesized compounds are characterised by FT-IR, 1H NMR and mass spectroscopy. Thiazole moiety present in the compounds was found to possess anticancer, anti-HIV activities. Theoretical information on the optimized geometry, vibrational frequencies and atomic charges in the ground state were determined by means of density functional theory (DFT) using standard B3LYP/6-31G basis set with Gaussian ’09 software. Mulliken population analysis was performed on the atomic charges and the HOMO-LUMO energies were calculated. From the HOMO-LUMO energy gap, we know that the charge transfer occurs within the molecule. Docking studies are also done by using PyRx and are visualized by PyMoL software. By 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method, anti-oxidant activity of the synthesized compounds was evaluated. In vitro cytotoxic activity of the compounds against A549 cell lines was evaluated by MTT assay.

Health Benefits of Antioxidant Bioactive Compounds in Ginger (Zingiber officinale) Leaves by Network Pharmacology Analysis Combined with Experimental Validation.

Network pharmacology is an ideal tool to explore the effects of therapeutic components derived from plants on human metabolic diseases that are linked to inflammation. This study investigated the antioxidant effects of ginger leaves (GLs) and predicted targets for antioxidant activity. Quantitative and free radical scavenging analyses were performed to detect the main bioactive compounds of GLs and evaluate their antioxidant activities. Chemical diversity and network pharmacology approaches were used to predict key antioxidant components of GLs and their molecular targets. Nine major bioactive compounds of GLs were quantified using an internal standard method, and the antioxidant activity was evaluated using the DPPH and ABTS free radical scavenging methods. We first built the compound-gene-pathways and protein-protein interaction networks of GLs-related antioxidant targets and then conducted gene ontology and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway enrichment analyses. Molecular docking results show that astragalin, a compound isolated from GLs, had the highest level of connectivity in the compound-target network and was involved in inflammation-related biosynthesis by directly impacting cytokine gene expression and PTGS2 inhibition markers. These findings not only suggest that the compounds isolated from GLs can be developed as potential antioxidants, but also demonstrate the applicability of network pharmacology to assess the potential of foods for disease treatment.

Stigmas and Petals of Crocus sativus L. (Taliouine, Morocco): Comparative Evaluation of Their Phenolic Compounds, Antioxidant, and Antibacterial Activities.

The dried stigmas of Crocus sativus L. produce saffron, a precious spice used for its culinary and medicinal properties since ancient times, while its petals are considered the main by-product of saffron production. The present study aimed to comparatively evaluate the phenolic content, antioxidant capacity, and antibacterial activity of methanolic extracts of stigmas and petals of Crocus sativus L. from Taliouine. The polyphenol content was measured using the Folin-Ciocalteu method, the antioxidant activity was determined using the DPPH free radical scavenging method, and the well-diffusion method was used to assess antibacterial activity against seven pathogenic bacterial strains (Bacillus subtilis, Escherichia coli, Listeria monocytogenes, Proteus vulgaris, Pseudomonas aeruginosa, Salmonella enterica, and Staphylococcus aureus). Furthermore, the minimum inhibitory concentration (MIC) of the extracts was determined using the microdilution broth test. Our findings revealed that stigmas and petals contained phenolic compounds at the rate of 56.11 ± 4.70 and 64.73 ± 3.42 mg GAE/g, as well as DPPH radical scavenging capacity with IC50 of 1700 µg/ml and 430 µg/ml, respectively. Petal extract showed more effective antibacterial activity, with inhibition diameters ranging from 10.66 ± 0.57 to 22.00 ± 1.00 mm and MIC values ranging from 2.81 to 5.62 mg/ml, compared to the stigma extract, which displayed inhibition diameters from 10.00 ± 0.00 to 18.67 ± 0.76 mm and MIC from 2.81 to 11.25 mg/ml, against five of the seven bacterial strains tested, including S. aureus, E. coli, P. vulgaris, P. aeruginosa, and S. enterica. Statistical analyses were performed to determine the significance of these results. Thus, stigmas and petals of Crocus sativus L. might serve as a suitable source of natural antioxidant and antimicrobial agents for application in the food and pharmaceutical industries.

Evaluation of antioxidant potential of crude extract of metabolites from endophytic fungi isolated from <i>Annona senegalensis</i> Pers

Degenerative diseases resulting from free radicals can be prevented through the use of natural antioxidants. This study aimed to assess the free radical scavenging potential of the underexplored endophytic fungal metabolites from Annona senegalensis Pers (wild custard apple). Freshly collected root, midrib, and leaf tissues were planted on malt extract agar following surface sterilization with 70% ethanol for 3 minutes, washed twice with distilled water, immersed in a sodium hypochlorite solution (4%) for 5 minutes, and subsequently rinsed with sterile water. Seven endophytic fungi were isolated, and the antioxidant activity of their metabolites was evaluated using the 2,2- diphenyl-1-picrylhydrazyl free radical scavenging method, with ascorbic acid serving as a reference antioxidant. The crude extract from the seven endophytic fungal isolates demonstrated concentration- dependent antioxidant activities. LB2 exhibited a strong antioxidant activity with an IC50 value of 38.15 μg/ml. Extracts from RT1 and LB1 showed antioxidant activities, with the highest inhibition of 60% and 65%, respectively, observed at a concentration of 1000 μg/ml. This was compared favorably to ascorbic acid, which exhibited 94% inhibition. This indicates that the crude extract from endophytic fungi isolated from A. senegalensis possesses free radical scavenging properties. Further purification and elucidation of the crude extract will reveal the bioactive compounds responsible for the antioxidant activities.

Extraction of Antioxidants from Brown Macroalgae Fucus spiralis.

In this study, different extraction methods and conditions were used for the extraction of antioxidants from brown macroalgae Fucus spiralis. The extraction methodologies used were ultrasound-assisted extraction (ultrasonic bath and ultrasonic probe), extraction with a vortex, extraction with an Ultra-Turrax® homogenizer, and high-pressure-assisted extraction. The extracts were analyzed for their total phenolic content (TPC) and their antioxidant activity, and evaluated through the 2,2-difenil-1-picrilhidrazil (DPPH) free radical scavenging method and ferric reducing antioxidant power (FRAP) assay. Ultrasonic probe-assisted extraction yielded the highest values of TPC (94.78-474.16 mg gallic acid equivalents/g extract). Regarding the antioxidant activity, vortex-assisted extraction gave the best DPPH results (IC50 1.89-16 µg/mL), while the highest FRAP results were obtained using the Ultra-Turrax® homogenizer (502.16-1188.81 μmol ascorbic acid equivalents/g extract). For each extraction method, response surface methodology was used to analyze the influence of the experimental conditions "extraction time" (t), "biomass/solvent ratio" (R), "solvent" (S, water % in water/ethanol mixture), and "pressure" (P) on TPC, DPPH, and FRAP of the F. spiralis extracts. In general, higher TPC content and higher antioxidant capacity (lower IC50 and higher FRAP) were obtained with higher R, t, and P, and lower S (higher ethanol %). The model regarding the combined effects of independent variables t, R, and S on the FRAP response values for vortex-assisted extractions best fitted the experimental data (R2 0.957), with optimal extraction conditions of t = 300 s, R = 50 g, and S = 25%.

ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF ETHYL ACETATE EXTRACT OF ACTINOMYCETES ISOLATED FROM TERMITE NESTS

Actinomycetes are an important source for the discovery of bioactive secondary metabolite compounds. Over 10,000 bioactive metabolite compounds have been isolated from terrestrial actinomycetes with various biological activities, such as antibiotic, antiviral, anti-inflammatory, antitumor, anticancer, and antioxidant. One source of origin for actinomycetes is soil, including termite nests. Utilization of natural sources such as actinomycetes from termite nests as antioxidants and antibacterials can be an alternative source of production of new secondary metabolite compounds. This research aims to evaluate the antioxidant and antibacterial activities of actinomycete extracts from termite nests. Antioxidant activity using the DPPH free radical scavenging method, and antibacterial activity against S. aureus. Antioxidant and antibacterial activity were performed by using the TLC dot-blot, TLC bioautography, and microdilution methods to determine the inhibitory concentration of 50% (IC50), antioxidant activity index (AAI), and minimum inhibitory concentration (MIC). From the 33 extracts tested, 16 extracts showed antioxidant activity with IC50 values range of 76.64-126.22 µg/mL or AAI value > 0.05 (moderate), and 8 extracts had moderate antibacterial activity against S. aureus (MIC values range of 256-512 µg/mL). Future research for scaling-up of actinomycete culture, isolating of active compounds, determining of the chemical structure of active compounds, and further testing as antioxidants and antibacterials still need to be carried out.

Anticancer, antioxidant, and antibacterial activity of chemically fingerprinted extract from Cyclamen persicum Mill.

In the last few decades, researchers have thoroughly studied the use of plants in Palestine, one of them is Cyclamen persicum Mill. (C. persicum). Cyclamen persicum has been historically cultivated since the 1700s due to its tuber. The tuber is known to stimulate the nasal receptors, thus triggering the sensory neurons. Cyclamen persicum has anti-inflammatory effects, reduces cholesterol levels, treats diabetes, and inhibits tumor growth. In this respect, in-vitro examination of antibacterial and anticancer activities and antioxidative potency of C. persicum ethanolic extract were evaluated. The antioxidative potency of the extracted plant material was determined spectrophotometrically using the DPPH free radical scavenging method and the HPLC–PDA method to evaluate its total phenolic content (TPC) and total flavonoid content (TFC). The experimental results demonstrated limited antibacterial activity of C. persicum extract against both gram negative (E. coli) and gram positive (Streptococcus and S. aureus) bacterial strains, with the observed zones of inhibition measuring less than 8 mm. On the other hand, powerful activity against MCF7 breast cancer as well as HT29 colon cancer cell lines was obtained. The findings also revealed potent inhibition of free radicals and the presence of maximal levels of natural products such as phenolic compounds and flavonoids, which supportits biological activities and powerful ability to scavenge free radicals. HPLC results showed the presence of numerous flavonoid and phenolic compounds such as rutin, chlorogenic acid, kaempferol, trans-cinnamic acid, quercetin, sinapic acid, and p-coumaric acid.

Antimicrobial secondary metabolites and antioxidant activities of fungal endophytes associated with Ziziphus spina-christi (L.) Desf. (Nabq) leaves

A total of 20 endophytic fungi were isolated (ZSEFL1-ZSEFL20) from Ziziphus spina-christi (L.) Desf. (Nabq) leaves. Four isolates A2/ZSEFL2, Alternaria alternata, D/ZSEFL14, Aspergillus niger, E/ZSEFL15, Epicoccum nigrum, and S/ZSEFL19, Penicillium crustosum were found to show the most promising antimicrobial activities either in plug or disc diffusion screening assays against Gram-positive, Gram-negative bacteria and pathogenic fungi. Antimicrobial activity was tested against Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213, Serratia marcescens ATCC 14764, Klebsiella pneumoniae ATCC 700603, Candida albicans ATCC 10231, and Fusarium oxysporum ATCC417. In vitro antioxidant activity assay was conducted using the ABTS [2,2′-Azino-bis (3-Ethylbenzthiazoline-6-Sulfonic Acid)] free radical scavenging method. EtOAc extracts of all isolated endophytic fungi showed antioxidant activities. This study would be one of the first reports to measure the antioxidant activity of Z. spina-christi (L.) Desf. endophytic fungi. Therefore, these isolated endophytic fungi can provide additional information for medicinal sources of natural antioxidants and antimicrobial agents.

Assessment of Antioxidant Activity, Total Phenolic and Flavonoid Contents of Albizia saponaria L. Bark Extract

Langir (Albizia saponaria L.), belonging to the family of the Fabaceae, is a medicinal endemic plant of South Sulawesi, Indonesia. The Albizia genus shows antioxidant, antibacterial, anthelmintic, antidandruff, and anti-inflammatory properties. In this study, total phenolic (TP) and total flavonoid (TF) extracts from the bark of A. saponaria were screened for robust antioxidant activity in order to identify potential sources of new compounds for use in pharmaceutical formulations in the future. TP and TF of the 96% ethanol extract and fractions (hexane, ethyl acetate, butanol, and water) were calculated by the Folin–Ciocalteu and aluminum chloride procedures, respectively. Furthermore, the antioxidant activity was determined by DPPH free radical scavenging method and ABTS assay. Generally, both extract and fractions showed significant radical scavenging activities. Ethyl acetate fraction exhibited more potent radical scavenging activity in the DPPH method (IC50 35.27 ± 2.85 µg/mL) and ABTS assay (IC50 60.04 ± 0.98 µg/mL), followed by 96% ethanol extract, and hexane, butanol, and water fractions. Furthermore, the highest TP (4.50 ± 0.01 mg/g GAE) and TF (3.55 ± 0.04 mg/g QE) were obtained from ethyl acetate fraction. There was a strong correlation between antioxidant activity with TP (DPPH, R2 = 0.6436; ABTS, R2 = 0.7676) and TF content (DPPH, R2 = 0.5533; ABTS, R2 = 0.5961). The extract’s antioxidant properties may be attributable to its higher phenolic and flavonoid content. In summary, the phenolic and flavonoid content of the ethyl acetate fraction indicates its potential utility as a source of antioxidants.

Novel 1,3,4-thiadiazol derivatives including α-lipoic acid: Synthesis, characterization, and antioxidant properties

In this study, new 1,3,4-thiadiazole-2-amine derivatives containing different substitution groups were synthesized in order to increase the free radical quenching ability of α-lipoic acid. The target thiadiazole amines were derived from thiosemicarbazide reagent. Structural analysis for the synthesized compounds (1–8) was carried out using modern spectroscopic techniques including FTIR, NMR, EIMS spectral analyses. The antioxidant properties of each molecule were elucidated by calculating% inhibition as well as significant IC50 values using the 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging method. The antioxidant activities of the compounds were compared against ascorbic acid, a water-soluble antioxidant, and against α-lipoic acid, the starting molecule of the synthesis step, which actually showed a low DPPH quenching activity. While lipoic acid had a reference standard value of 15,625.02±0.96 µM, compound 8 was the compound with the highest antioxidant activity with an IC50 value of 433.69±0.04 µM. The obtained data suggested that the (NH) proton in the thiadiazole structure bound to lipoic acid plays an important role in binding to the DPPH radical. This study may provide a source for the synthesis of α-lipoic acid-based thiadiazole derivatives, new compounds with antioxidant properties that can be used in medicine and pharmacy.

Electrospun Materials Based on Cellulose Acetate Loaded with Rosmarinic Acid with Antioxidant and Antifungal Properties.

Fibrous cellulose acetate (CA) materials loaded with rosmarinic acid (RA) were successfully created by one-pot electrospinning. In order to improve the water solubility of the polyphenolic acid and to facilitate its release from the fibrous materials, the non-ionic water-soluble polyethylene glycol (PEG) was added. Detailed characterization of the fabricated fibrous CA/RA and CA/PEG/RA materials was performed using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), UV-Vis spectroscopy and water contact angle analysis. The optimal ratio between CA, RA and PEG for preparation of defect-free and uniform fibers was accomplished by varying their concentrations. Furthermore, the incorporation of the PEG improved the hydrophilicity and wettability of the fibrous CA materials. Moreover, PEG facilitated the RA release and over 360 min, the amount released from fibrous CA/PEG/RA fibers was 91%, while that released from CA/RA materials was 53%. Both of the RA-containing fibrous materials, with and without PEG, manifested high antioxidant activity as determined by the DPPH free radical-scavenging method. In addition, the electrospun CA/PEG/RA materials displayed good antifungal activity against C. albicans. These features make the fibrous CA/PEG/RA materials promising candidates for treatment of wound infections.

In vitro evaluation of the osteogenic and antimicrobial potential of porous wollastonite scaffolds impregnated with ethanolic extracts of propolis.

Context: The development of porous devices using materials modified with various natural agents has become a priority for bone healing processes in the oral and maxillofacial field. There must be a balance between the proliferation of eukaryotic and the inhibition of prokaryotic cells to achieve proper bone health. Infections might inhibit the formation of new alveolar bone during bone graft augmentation. Objective: This study aimed to evaluate the in vitro osteogenic behavior of human bone marrow stem cells and assess the antimicrobial response to 3D-printed porous scaffolds using propolis-modified wollastonite. Methodology: A fractional factorial design of experiments was used to obtain a 3D printing paste for developing scaffolds with a triply periodic minimal surface (TPMS) gyroid geometry based on wollastonite and modified with an ethanolic propolis extract. The antioxidant activity of the extracts was characterized using free radical scavenging methods (DPPH and ABTS). Cell proliferation and osteogenic potential using Human Bone Marrow Stem Cells (bmMSCs) were assessed at different culture time points up to 28days. MIC and inhibition zones were studied from single strain cultures, and biofilm formation was evaluated on the scaffolds under co-culture conditions. The mechanical strength of the scaffolds was evaluated. Results: Through statistical design of experiments, a paste suitable for printing scaffolds with the desired geometry was obtained. Propolis extracts modifying the TPMS gyroid scaffolds showed favorable cell proliferation and metabolic activity with osteogenic potential after 21days. Additionally, propolis exhibited antioxidant activity, which may be related to the antimicrobial effectiveness of the scaffolds against S. aureus and S. epidermidis cultures. The mechanical properties of the scaffolds were not affected by propolis impregnation. Conclusion: These results demonstrate that propolis-impregnated porous wollastonite scaffolds might have the potential to stimulate bone repair in maxillofacial tissue engineering applications.

Synthesis, chemical characterization, and biological investigation of naturally isolated hesperidin and its metal complexes

This study was conducted to investigate the ability of hesperidin (HES) to form metal-complexes (HES-M) by chelation with transition metals such iron(III), copper(II), zinc(II), and silver(I), in addition to screen the antioxidant activity (DPPH free radical scavenging and phosphomolybdenum reduction potential methods PRP), anti-Alzheimer activity [(acetylcholinesterase (AChE)] inhibition assay) and coagulant activity (prothrombin time PT assay). The results indicated that HES could form a 1:1 complex with the studied metals in methanolic solution. The complex has been synthesized and characterized by physicochemical methods. Complexing of hesperidin with metals leads to increase in the antioxidant activity by 15.4-33%. Also, the total antioxidant capacities of HES-M complexes were increased by 13.8-251%. Cu-complex revealed the most increasing antioxidant activity by 33% for DPPH scavenging activity and 251% for PRP activity. The inhibition capacity of the HES, as well as of the HES-M complexes on the enzyme AChE, was revealed that only HES-Zn complex has higher anti-Alzheimer activity (IC50 1.18 mg/mL). HES and HES-M complexes led to accelerate the clotting time by 28.9-67.3%, where HES-Zn complex was the most accelerating clotting time by 67.3%. The high increase in total antioxidant activity of hesperidin after chelating with copper (251%) opens the door for further research.
 KEY WORDS: Hesperidin, Metal ions, Complexation, Antioxidant, Anti-Alzheimer, Coagulant activity
 Bull. Chem. Soc. Ethiop. 2024, 38(2), 385-395. 
 DOI: https://dx.doi.org/10.4314/bcse.v38i2.8

Antioxidant, antidiabetic effects and polyphenolic contents of propolis from Siirt, Turkey.

Propolis, a natural product collected by honeybees from various plant sources, has gained significant attention due to its diverse bioactive compounds and potential therapeutic properties. To further explore its contents and biological activities, this study aimed to analyze the phenolic compounds in Siirt propolis extracts obtained using different solvents, namely ethanol, water, and ethanol-water mixtures. The primary objective of this research was to investigate the phenolic profile, as well as the antidiabetic and antioxidant activities of the propolis extracts. Chemical profiling of extracts was performed using LC-MS/MS. The antioxidant potential of the propolis extracts was evaluated through free radical scavenging methods, including DPPH and ABTS assays. As a result of these analyses, propolis extracts showed moderate radical scavenging potential with 13.86%-35.72% for DPPH and 33.62%-62.50% for ABTS at a concentration of 30 μg mL-1, respectively. This radical scavenging potential of the extracts sheds light on its ability to combat oxidative stress, which is implicated in the development of diabetes, and its potential effects on cellular health. Additionally, the study assessed the antidiabetic properties of the propolis extracts by examining their inhibition effects on α-amylase and α-glycosidase enzymes. Extracts with high phenolic content showed a high inhibitory effect against α-glucosidase with an IC50 of 5.72 ± 0.83 μg mL-1. This research provided significant findings regarding the potential use of propolis in the treatment of diabetes and related metabolic disorders.

Evaluation of antioxidant activity of steviol glucoside commercial powder in neutral and acidic pH

Introduction. Current trends on new food products aim to incorporate biopolymers to improve their physicochemical stability, such as Stevia rebaudiana. Furthermore, due to its high sweetening potential, commercial steviol glucoside (CSP) powder has been recently incorporated into food formulation for its antioxidant capacity. Objective. This study focused on the evaluation of antioxidant capacity of commercial steviol glucoside powder, under both neutral and acidic pH conditions (3.5-7) at concentrations ranging from 100-500 µg/mL. Material and Methods. Tests were assessed in triplicate for a sample of CSP, available in Algeria, by using 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging method (DPPH). Total phenolic compounds were measured in 100µg with Folin-Ciocalteu. Results. Commercial powder of steviol glucoside presented a total polyphenols content of 2.500±0.0150 mg/g of CSP dry weight, and exhibited a significant inhibitory percentage of DPPH. Values were ranged of 35.89±0.16% to 62.32±0.45% in neutral pH, and were between 40.21±0.04% to 65.00±0.26% in acidic pH. Data showed that inhibitory concentration IC50 against DPPH was ranged of 208.204 µg/mL in neutral pH, and 269.547 µg/mL in acidic pH. Conclusion. Commercial stevioside powder can be used not only as sweetener, but also as poly-phenols source with antioxidant activity in the preparation of neutral and acidic low calorie functional foods.

Comprehensive In Silico Analysis of Uncaria Tomentosa Extract: Chemical Profiling, Antioxidant Assessment, and CLASP Protein Interaction for Drug Design in Neurodegenerative Diseases.

Uncaria tomentosa is a traditional medicinal herb renowned for its anti-inflammatory, antioxidant, and immune-enhancing properties. In the realm of neurodegenerative diseases (NDDS), CLASP proteins, responsible for regulating microtubule dynamics in neurons, have emerged as critical players. Dysregulation of CLASP proteins is associated with NDDS, such as Alzheimer's, Parkinson's, and Huntington's diseases. Consequently, comprehending the role of CLASP proteins in NDDS holds promise for the development of innovative therapeutic interventions. The objectives of the research were to identify phytoconstituents in the hydroalcoholic extract of Uncaria tomentosa (HEUT), to evaluate its antioxidant potential through in vitro free radical scavenging assays and to explore its potential interaction with CLASP using in silico molecular docking studies. HPLC and LC-MS techniques were used to identify and quantify phytochemicals in HEUT. The antioxidant potential was assessed through DPPH, ferric reducing antioxidant power (FRAP), nitric oxide (NO) and superoxide (SO) free radical scavenging methods. Interactions between conventional quinovic acid, chlorogenic acid, epicatechin, corynoxeine, rhynchophylline and syringic acid and CLASP were studied through in silico molecular docking using Auto Dock 4.2. The HEUT extract demonstrated the highest concentration of quinovic acid derivatives. HEUT exhibited strong free radical-scavenging activity with IC50 values of 0.113 μg/ml (DPPH) and 9.51 μM (FRAP). It also suppressed NO production by 47.1 ± 0.37% at 40 μg/ml and inhibited 77.3 ± 0.69% of SO generation. Additionally, molecular docking revealed the potential interaction of quinovic acid with CLASP for NDDS. The strong antioxidant potential of HEUT and the interaction of quinovic acid with CLASP protein suggest a promising role in treating NDDS linked to CLASP protein dysregulation.

Mixture-efficient identification of high-order herbal essential oil synergy using a normalized DiaMOND design

In this study, the effect of high-order combinations of Rosmarinus officinalis L. (R) EO with other essential oils obtained from selected Moroccan medicinal and aromatic plants, namely, Thymus satureioides Coss. (T), Origanum compactum Benth. (O), Pelargonium roseum L. (P), Artemisia herba-alba Asso. (A), and Salvia officinalis L. (S), was evaluated. The chemical composition of EOs was determined by GC/MS. Their antibacterial effect was determined using the microdilution method, whereas their antioxidant activity was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing antioxidant power (FRAP) methods. The type of interaction between EOs was evaluated by the diagonal measurement of n-way drug interactions (DiaMOND). Antioxidant and antibacterial activity results demonstrate that O. compactum, T. satureioides, and P. roseum EOs tested alone showed significant efficacy. Using Principal Component Analysis (PCA) and hierarchical clustering analysis (HCA) modeling, one three-way combination (RST) was found with particularly strong synergistic DPPH radical scavenging (FIC3 = 0.50) and Fe3+ reducing (FIC3 = 0.48) properties. This combination also produced the highest activity against four bacteria strains (FIC3 = 0.38 for S. aureus, FIC3 = 0.38 for E. faecalis, FIC3 = 0.44 for E. coli, and FIC3 = 0.79 for P. aeruginosa). This mixture was, therefore, combined with conventional antibiotics. The results of all combinations showed a synergistic effect against four bacteria strains, which were tested with FIC2 ranging between 0.11 and 0.97. Our findings showed that a three-way combination of RST EOs constitutes a promising approach for possible application in the food and pharmaceutical industries.