Bilirubin oxidase expression and activity enhancement from Myrothecium verrucaria in Aspergillus species.

We constructed a new Aspergillus expression vector (pSENSU2512nid) under the control of the enolase promoter with 12 tandem repeats of cis-acting elements (region III) and the heat shock protein 12 (Hsp12) 5' untranslated region (UTR). Bilirubin oxidase (EC: 1.3.3.5) from Myrothecium verrucaria, which catalyzes the oxidation of bilirubin to biliverdin, was overexpressed in Aspergillus oryzae and A. niger. The productivity was estimated to be approximately 1.2 g/L in the culture broth, which was approximately 6-fold higher than that of recombinant bilirubin oxidase (BOD) expressed in Pichia pastoris (Komagataella phaffii). BOD was purified using hydrophobic interaction chromatography, followed by ion exchange chromatography. The specific activity of the purified BOD against 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) substrate was 57.6 U/mg and 66.4 U/mg for A. oryzae and A. niger, respectively. l-Ascorbic acid (4 mM) addition and storage under deoxygenated conditions for 3-7 d increased the specific activity of these Aspergillus-expressed BODs approximately 2.3-fold (154.1 U/mg). The BOD specific activity was enhanced by incubation at higher temperature (30-50 °C). Further characterization of the enzyme catalytic efficiency revealed that the Km value remained unchanged, whereas the kcat value improved 3-fold. In conclusion, this high-level of BOD expression meets the requirements for industrial-level production. Additionally, we identified an effective method to enhance the low specific activity during expression, making it advantageous for industrial applications.

A food color-based colorimetric assay for Cryptococcus neoformans laccase activity.

Cryptococcus neoformans is a fungal pathogen that causes cryptococcosis primarily in immunocompromised patients, such as those with HIV/AIDS. One survival mechanism of C. neoformans during infection is melanin production, which catalyzed by laccase and protects fungal cells against immune attack. Hence, the comparative assessment of laccase activity is useful for characterizing cryptococcal strains. We serendipitously observed that culturing C. neoformans with food coloring resulted in degradation of some dyes with phenolic structures. Consequently, we investigated the color changes for the food dyes metabolized by C. neoformans laccase and by using this effect explored the development of a colorimetric assay to measure laccase activity. We developed several versions of a food dye-based colorimetric laccase assay that can be used to compare the relative laccase activities between different C. neoformans strains. We found that phenolic color degradation was glucose-dependent, which may reflect changes in the reduction properties of the media. Our food color-based colorimetric assay has several advantages, including lower cost, irreversibility, and not requiring constant monitoring , over the commonly used 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay for determining laccase activity. This method has potential applications to bioremediation of water pollutants in addition to its use in determining laccase virulence factor expression.IMPORTANCECryptococcus neoformans is present in the environment, and while infection is common, disease occurs mostly in immunocompromised individuals. C. neoformans infection in the lungs results in symptoms like pneumonia, and consequently, cryptococcal meningitis occurs if the fungal infection spreads to the brain. The laccase enzyme catalyzes the melanization reaction that serves as a virulence factor for C. neoformans. Developing a simple and less costly assay to determine the laccase activity in C. neoformans strains can be useful for a variety of procedures ranging from studying the relative virulence of cryptococci to environmental pollution studies.

An insight into the antioxidant activities and the exploration of record high quantities of quercetin and luteolin in the plant parts of Myxopyrum smilacifolium (wall.) Blume.

This study attempts to reveal antioxidants in the plant parts of Myxopyrum smilacifolium (Wall.) Blume using antioxidant assays and LC-MS/MS analysis. Methanol is the most effective solvent for collecting antioxidants. The roots-derived methanol extract demonstrates the greatest antioxidant activity, corresponding to the extremely low IC50 values of 16.39 µg/mL and 19.80 µg/mL for DPPH and ABTS radicals, respectively. The high phenolic and flavonoid contents are the primary reason for outstanding total antioxidant capacity (TAC; i.e. 247.73 ± 1.62 mg GA/g or 163.93 ± 0.83 mg AS/g) of the root extract. LC-MS/MS quantification of five phenolic compounds reveals exceptionally high amounts of quercetin and luteolin in the root extract, ranging from 238.86 ± 5.74 to 310.99 ± 1.44 µg/g and from 201.49 ± 7.84 to 234.10 ± 2.54 µg/g, respectively, in the root-derived methanol extract. The achievement highlights M. smilacifolium as a promising source of natural antioxidants for large-scale medical applications.

Anthracene detoxification by Laccases from indigenous fungal strains Trichoderma lixii FLU1 and Talaromyces pinophilus FLU12.

The persistence and ubiquity of polycyclic aromatic hydrocarbons (PAHs) in the environment necessitate effective remediation strategies. Hence, this study investigated the potential of purified Laccases, TlFLU1L and TpFLU12L, from two indigenous fungi Trichoderma lixii FLU1 (TlFLU1) and Talaromyces pinophilus FLU12 (TpFLU12), respectively for the oxidation and detoxification of anthracene. Anthracene was degraded with vmax values of 3.51 ± 0.06 mg/L/h and 3.44 ± 0.06 mg/L/h, and Km values of 173.2 ± 0.06 mg/L and 73.3 ± 0.07 mg/L by TlFLU1L and TpFLU12L, respectively. The addition of a mediator compound 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) to the reaction system significantly increased the degradation of anthracene, with up to a 2.9-fold increase in vmax value and up to threefold decrease in Km values of TlFLU1L and TpFLU12L. The GC-MS analysis of the metabolites suggests that anthracene degradation follows one new pathway unique to the ABTS system-hydroxylation and carboxylation of C-1 and C-2 position of anthracene to form 3-hydroxy-2-naphthoic acid, before undergoing dioxygenation and side chain removal to form chromone which was later converted into benzoic acid and CO2. This pathway contrasts with the common dioxygenation route observed in the free Laccase system, which is observed in the second degradation pathways. Furthermore, toxicity tests using V. parahaemolyticus and HT-22 cells, respectively, demonstrated the non-toxic nature of Laccase-ABTS-mediated metabolites. Intriguingly, analysis of the expression level of Alzheimer's related genes in HT-22 cells exposed to degradation products revealed no induction of neurotoxicity unlike untreated cells. These findings propose a paradigm shift for bioremediation by highlighting the Laccase-ABTS system as a promising green technology due to its efficiency with the discovery of a potentially less harmful degradation pathway, and the production of non-toxic metabolites.

Nutritional and bioactive properties and antioxidant potential of Amaranthus tricolor, A. lividus, A viridis, and A. spinosus leafy vegetables.

Climate change results in continuous warming of the planet, threatening sustainable crop production around the world. Amaranth is an abiotic stress-tolerant, climate-resilient, C4 leafy orphan vegetable that has grown rapidly with great divergence and potential usage. The C4 photosynthesis allows amaranth to be grown as a sustainable future food crop across the world. Most amaranth species grow as weeds in many parts of the world, however, a few amaranth species can be also found in cultivated form. Weed species can be used as a folk medicine to relieve pain or reduce fever thanks to their antipyretic and analgesic properties. In this study, nutritional value, bioactive pigments, bioactive compounds content, and radical scavenging potential (RSP) of four weedy and cultivated (WC) amaranth species were evaluated. The highest dry matter, carbohydrate content, ash, content of iron, copper, sodium, boron, molybdenum, zinc, ß-carotene and carotenoids, vitamin C, total polyphenols (TP), RSP (DPPH), and RSP (ABTS+) was determined in Amaranthus viridis (AV). On the other hand, A. spinosus (AS) was found to have the highest content of protein, fat, dietary fiber, manganese, molybdenum, and total flavonoids (TF). In A. tricolor (AT) species the highest total chlorophyll, chlorophyll a and b, betaxanthin, betacyanin, and betalain content was determined. A. lividus (AL) was evaluated as the highest source of energy. AV and AT accessions are underutilized but promising vegetables due to their bioactive phytochemicals and antioxidants.

[A comparative study of antioxidant active components in different parts of Artemisia argyi by UPLC-ABTS-Q-TOF-MS].

In order to characterize and identify the chemical components in different parts of Artemisia argyi(roots, stems, leaves, and seeds), compounds with antioxidant activity were screened. In this study, ultra-performance liquid chromatography-2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt-quadrupole time-of-flight-tandem mass spectrometry(UPLC-ABTS-Q-TOF-MS) was used as an online combination technique. Poroshell 120 SB-Aq(3.0 mm×150 mm, 2.7 µm) was used as the column, and acetonitrile(A)-0.2% formic acid water(B) was adopted as the mobile phase to perform gradient elution and was scanned in positive and negative ion modes. MassLynx software was utilized, and combined with reference substances and related literature, the chemical components of different parts of A. argyi were identified and compared. The antioxidant active components were detected by using the online detection system, and the antioxidant activities of active components of different parts of A. argyi were compared and evaluated by scavenging efficiency. As a result, a total of 87 compounds were identified from extracts of different parts of A. argyi, and 38, 72, 85, and 33 components were identified from roots, stems, leaves, and seeds. 22 compounds with antioxidant activity were screened, and 14, 17, 20, and 11 compounds with antioxidant activity were identified from roots, stems, leaves, and seeds. The results show that there are certain differences in chemical components and antioxidant components of different parts of A. argyi, which provides data support for the resource utilization and further research and development of A. argyi.

Ultrarobust stable ABTS radical cation prepared using Spore@Cu-TMA biocomposites for antioxidant capacity assay.

Herein, spore@Cu-trimesic acid (TMA) biocomposites were prepared by self-assembling Cu-based metal-organic framework on the surface of Bacillus velezensis spores. The laccase-like activity of spore@Cu-TMA biocomposites was enhanced by 14.9 times compared with that of pure spores due to the reaction of Cu2+ ions with laccase on the spore surface and the microporous structure of Cu-TMA shell promoting material transport and increasing substrate accessibility. Spore@Cu-TMA rapidly oxidized and transformed 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) into ABTS●+ without using H2O2. Under optimum conditions, the ABTS●+ could be stored for 21 days at 4 °C and 7 days at 37 °C without the addition of any stabilizers, allowing for the large-scale preparation and long-term storage of ABTS●+. The ultrarobust stable ABTS●+ obtained with the use of Cu-TMA could effectively reduce the "back reaction" by preventing the leaching of the metabolites released by the spores. On the basis of these findings, a rapid, low-cost, and eco-friendly colorimetric platform was successfully developed for the detection of antioxidant capacity. Determination of antioxidant capacity for several antioxidants such as caffeic acid, glutathione, and Trolox revealed their corresponding limits of detection at 4.83, 8.89, and 7.39 nM, respectively, with linear ranges of 0.01-130, 0.01-140, and 0.01-180 µM, respectively. This study provides a facile way to prepare ultrarobust stable ABTS●+ and presents a potential application of spore@Cu-TMA biocomposites in food detection and bioanalysis.

Antioxidant Activity and Fatty Acid Profile of Sous-Vide Beef Marinated with Kiwiberry Fruit Pulp: Effects of Level Addition and Refrigerated Storage.

The purpose of the study was to determine the antioxidant activity (AA) and fatty acid (FA) profile of sous-vide beef previously marinated in brine with a 10, 20 and 30% addition of kiwiberry (Actinidia arguta cv. 'Ananasnaya') fruit pulp, as well as changes in the parameters studied after 0, 1, 2 and 3 weeks of refrigerated storage in a vacuum package. The FA profile, FRAP (ferric-reducing antioxidant power assay), ABTS (2,2'-azinobis (3-ethylbenzthiazoline-6-acid)), total polyphenols, chlorophylls and carotenoids were also determined in the fruit pulp. Lipid indices for meat were calculated based on the obtained FA profile. The values of FRAP and ABTS of experimental meat products were significantly (p ≤ 0.05) higher than those of control samples but decreased with storage time. The proportion of unsaturated FA in the lipids of sous-vide meat was higher in samples with pulp than in control samples and insignificantly decreased with storage time. Meat marinated with kiwiberry pulp was characterized by a significantly (p ≤ 0.05) higher proportion of ALA (α-linolenic acid) and LA (linoleic acid), considerably affecting the more favorable value of polyunsaturated FA/saturated FA ratio. A troubling finding was the heightened level of palmitic acid (C16:0) in the lipids of beef subjected to 30% kiwiberry pulp, a factor recognized to play a significant role in the development of various diseases. Beef marinated with 20% kiwiberry pulp addition provides greater nutritional and health benefits than other sample variants because of optimal AA and FA profile changes during refrigerated storage.

Chemodiversity of Arctic Plant Dryas oxyodonta: LC-MS Profile and Antioxidant Activity.

Dryas oxyodonta Yuz. is a perennial evergreen shrub from the Rosaceae family. D. oxyodonta thrives in subalpine and subarctic regions, as well as in highlands spanning from Central Asia to Siberia and Mongolia. Owing to a lack of information on its chemical composition, we conducted qualitative and quantitative chromatographic analyses on extracts from the leaves and flowers of D. oxyodonta sourced from various Siberian habitats. Employing high-performance liquid chromatography with photodiode-array detection and electrospray ionization triple-quadrupole mass spectrometric detection, we identified 40 compounds, encompassing gallotannins, hydroxycinnamates, procyanidins, catechins, flavonoids, and triterpenes. All Siberian populations of D. oxyodonta exhibited a notable abundance of phenolic compounds. Furthermore, we identified rare glycosides, such as sexangularetin and corniculatusin, as potential markers of the chemodiversity within the Dryas genus. Extracts from the flowers and leaves were effective scavengers of free radicals, including DPPH•, ABTS•+-, O2•-, and •OH radicals. Our findings unequivocally establish D. oxyodonta as a rich source of phenolic compounds with potent antioxidant activity, suggesting its potential utility in developing novel functional products.

Variation in Nutritional Components and Antioxidant Capacity of Different Cultivars and Organs of Basella alba.

Basella alba is a frequently consumed leafy vegetable. However, research on its nutritional components is limited. This study aimed to explore the variation in the nutritional components and antioxidant capacity of different cultivars and organs of Basella alba. Here, we primarily chose classical spectrophotometry and high-performance liquid chromatography (HPLC) to characterize the variation in nutritional components and antioxidant capacity among different organs (inflorescences, green fruits, black fruits, leaves, and stems) of eight typical cultivars of Basella alba. The determination indices (and methods) included the total soluble sugar (anthrone colorimetry), total soluble protein (the Bradford method), total chlorophyll (the ethanol-extracting method), total carotenoids (the ethanol-extracting method), total ascorbic acid (the HPLC method), total proanthocyanidins (the p-dimethylaminocinnamaldehyde method), total flavonoids (AlCl3 colorimetry), total phenolics (the Folin method), and antioxidant capacity (the FRAP and ABTS methods). The results indicated that M5 and M6 exhibited advantages in their nutrient contents and antioxidant capacities. Additionally, the inflorescences demonstrated the highest total ascorbic acid and total phenolic contents, while the green and black fruits exhibited relatively high levels of total proanthocyanidins and antioxidant capacity. In a comparison between the green and black fruits, the green fruits showed higher levels of total chlorophyll (0.77-1.85 mg g-1 DW), total proanthocyanidins (0.62-2.34 mg g-1 DW), total phenolics (15.28-27.35 mg g-1 DW), and ABTS (43.39-59.16%), while the black fruits exhibited higher levels of total soluble protein (65.45-89.48 mg g-1 DW) and total soluble sugar (56.40-207.62 mg g-1 DW) in most cultivars. Chlorophyll, carotenoids, and flavonoids were predominantly found in the leaves of most cultivars, whereas the total soluble sugar contents were highest in the stems of most cultivars. Overall, our findings underscore the significant influence of the cultivars on the nutritional composition of Basella alba. Moreover, we observed notable variations in the nutrient contents among the different organs of the eight cultivars, and proanthocyanidins may contribute significantly to the antioxidant activity of the fruits. On the whole, this study provides a theoretical basis for the genetic breeding of Basella alba and dietary nutrition and serves as a reference for the comprehensive utilization of this vegetable.

Exploring the Chemical Profile, In Vitro Antioxidant and Anti-Inflammatory Activities of Santolina rosmarinifolia Extracts.

In this study, the phytochemical composition, in vitro antioxidant, and anti-inflammatory effects of the aqueous and 60% ethanolic (EtOH) extracts of Santolina rosmarinifolia leaf, flower, and root were examined. The antioxidant activity of S. rosmarinifolia extracts was determined by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays. The total phenolic content (TPC) of the extracts was measured by the Folin-Ciocalteu assay. The anti-inflammatory effect of the extracts was monitored by the Griess assay. The chemical composition of S. rosmarinifolia extracts was analysed using the LC-MS technique. According to our findings, 60% EtOH leaf extracts showed the highest Trolox equivalent antioxidant capacity (TEAC) values in both ABTS (8.39 ± 0.43 µM) and DPPH (6.71 ± 0.03 µM) antioxidant activity assays. The TPC values of the samples were in good correspondence with the antioxidant activity measurements and showed the highest gallic acid equivalent value (130.17 ± 0.01 µg/mL) in 60% EtOH leaf extracts. In addition, the 60% EtOH extracts of the leaves were revealed to possess the highest anti-inflammatory effect. The LC-MS analysis of S. rosmarinifolia extracts proved the presence of ascorbic acid, catalpol, chrysin, epigallocatechin, geraniol, isoquercitrin, and theanine, among others, for the first time. However, additional studies are needed to investigate the direct relationship between the chemical composition and physiological effects of the herb. The 60% EtOH extracts of S. rosmarinifolia leaves are potential new sources of natural antioxidants and anti-inflammatory molecules in the production of novel nutraceutical products.

Essential oil of Eugenia stictopetala Mart. ex DC. has antioxidant, antibacterial, and gastrointestinal protective effect.

This work aimed to investigate the chemical composition, antioxidant capacity, antibacterial activity, and intestinal and gastric protective effects, in addition to the acute toxicity of the essential oil of E. stictopetala (EOEs). (E)-caryophyllene (18.01%), ß-pinene (8.84%), and (E)-nerolidol (8.24%), were the components found in higher content in the essential oil. The EOEs showed antioxidant capacity with IC50 values ranging from 220.28 to 283.67 µg/mL, in addition to presenting antibacterial activity against Escherichia coli, Enterobacter aerogenes, Vibrio cholerae, Salmonella enterica, and Listeria monocytogenes. The essential oil showed a gastroprotective effect, with a reduction in the levels of TNF-α, IL-1ß, and IL-6, having multiple pharmacological mechanisms of action. An antidiarrheal effect of EOEs was observed in the castor oil-induced diarrheal model, with reduced intestinal motility. Our findings demonstrate that essential oil can be beneficial in pharmaceutical and therapeutic applications for treating gastrointestinal diseases.

Relationship between Flavonoid Chemical Structures and Their Antioxidant Capacity in Preventing Polycyclic Aromatic Hydrocarbons Formation in Heated Meat Model System.

The relationship between the chemical structures of six flavonoids and their abilities to inhibit the formation of polycyclic aromatic hydrocarbons (PAHs) in a heated meat model system was investigated. The PAH8 forming in samples was analyzed by using QuEChERS coupled GC-MS. Inhibitory effects of PAHs were myricetin (72.1%) > morin (55.7%) > quercetin (57.3%) > kaempferol (49.9%) > rutin (32.7%) > taxifolin (30.2%). The antioxidant activities of these flavonoids, assessed through (1, 1-diphenyl-2-picrylhydrazyl) free radical scavenging activity assay (DPPH), [2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonic acid)] free radical scavenging activity assay (ABTS) and ferric ion reducing antioxidant power assay (FRAP) assays, exhibited a significant negative correlation with PAH reduction. Notably, myricetin that contained three hydroxyl groups on the B-ring, along with a 2,3-double bond in conjugation with a 4-keto moiety on the C-ring, demonstrated strong antioxidant properties and free radical scavenging abilities, which significantly contributed to their ability to inhibit PAH formation. However, rutin and taxifolin, substituted at the C-3 position of the C-ring, decreased the PAH inhibitory activity. The ABTS assay proved the most effective in demonstrating the correlation between flavonoid antioxidant properties and their capacity to inhibit PAH formation in heated meat model systems. Thus, the inhibition of PAHs can be achieved by dietary flavonoids according to their chemical structures.

Design of three-component essential oil extract mixture from Cymbopogon flexuosus, Carum carvi, and Acorus calamus with enhanced antioxidant activity.

The development of novel antioxidant compounds with high efficacy and low toxicity is of utmost importance in the medicine and food industries. Moreover, with increasing concerns about the safety of synthetic components, scientists are beginning to search for natural sources of antioxidants, especially essential oils (EOs). The combination of EOs may produce a higher scavenging profile than a single oil due to better chemical diversity in the mixture. Therefore, this exploratory study aims to assess the antioxidant activity of three EOs extracted from Cymbopogon flexuosus, Carum carvi, and Acorus calamus in individual and combined forms using the augmented-simplex design methodology. The in vitro antioxidant assays were performed using DPPH and ABTS radical scavenging approaches. The results of the Chromatography Gas-Mass spectrometry (CG-MS) characterization showed that citral (29.62%) and niral (27.32%) are the main components for C. flexuosus, while D-carvone (62.09%) and D-limonene (29.58%) are the most dominant substances in C. carvi. By contrast, ß-asarone (69.11%) was identified as the principal component of A. calamus (30.2%). The individual EO exhibits variable scavenging activities against ABTS and DPPH radicals. These effects were enhanced through the mixture of the three EOs. The optimal antioxidant formulation consisted of 20% C. flexuosus, 53% C. carvi, and 27% A. calamus for DPPHIC50. Whereas 17% C. flexuosus, 43% C. carvi, and 40% A. calamus is the best combination leading to the highest scavenging activity against ABTS radical. These findings suggest a new research avenue for EOs combinations to be developed as novel natural formulations useful in food and biopharmaceutical products.

Exploring the antioxidant potential of endophytic fungi: a review on methods for extraction and quantification of total antioxidant capacity (TAC).

Endophytic fungi have emerged as a significant source of natural products with remarkable bioactivities. Recent research has identified numerous antioxidant molecules among the secondary metabolites of endophytic fungi. These organisms, whether unicellular or micro-multicellular, offer the potential for genetic manipulation to enhance the production of these valuable antioxidant compounds, which hold promise for promoting health, vitality, and various biotechnological applications. In this study, we provide a critical review of methods for extracting, purifying, characterizing, and estimating the total antioxidant capacity (TAC) of endophytic fungi metabolites. While many endophytes produce metabolites similar to those found in plants with established symbiotic associations, we also highlight the existence of novel metabolites with potential scientific interest. Additionally, we discuss how advancements in nanotechnology have opened new avenues for exploring nanoformulations of endophytic metabolites in future studies, offering opportunities for diverse biological and industrial applications.

The effects of ultrasonic processing on the antioxidant activity of Geotrichum candidum LG-8 and its cell wall extracts.

Introduction: Extraction techniques that influence cell wall polysaccharides (EPS) is crucial for maximizing their bioactivity. This study evaluates ultrasound technology for extracting antioxidant polysaccharides from Geotrichum candidum LG-8, assessing its impacton antioxidant activity. Methods: Ultrasound extraction of EPS from G. candidum LG-8 was optimized (18 min, pH 7.0, 40 W/cm2, 0.75 M NaCl). ABTS scavenging efficiency and monosaccharide composition of LG-EPS1 and LG-EPS3 were analyzed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Results: The Results showed that ultrasonic treatment markedly increased the ABTS radical scavenging efficiency of LG-8 cells by 47%. At a concentration of 1 mg/mL, the ultrasonically extracted LG-EPS1 and LG-EPS3 polysaccharides exhibited significant ABTS radical scavenging efficiencies of 26% and 51%, respectively. Monosaccharide composition analysis identified mannose and glucose in LG-EPS1, while LG-EPS3 was primarily composed of mannose. FTIR spectra verified the polysaccharides' presence, and SEM provided visual confirmation of the nanoparticle structures characteristic of LG-EPS1 and LG-EPS3. Discussion: This research not only underscores the technological merits of ultrasound in polysaccharide extraction but also highlights the potential of G. candidum LG-8 derived polysaccharides as valuable bioactive compounds for antioxidant utilization.

Rhodanine-benzamides as potential hits for α-amylase enzyme inhibitors and radical (DPPH and ABTS) scavengers.

A series of 3-substituted and 3,5-disubstituted rhodanine-based derivatives were synthesized from 3-aminorhodanine and examined for α-amylase inhibitory, DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities in vitro. These derivatives displayed significant α-amylase inhibitory potential with IC50 values of 11.01-56.04 µM in comparison to standard acarbose (IC50 = 9.08 ± 0.07 µM). Especially, compounds 7 (IC50 = 11.01 ± 0.07 µM) and 8 (IC50 = 12.01 ± 0.07 µM) showed highest α-amylase inhibitory activities among the whole series. In addition to α-amylase inhibitory activity, all compounds also demonstrated significant scavenging activities against DPPH and ABTS radicals, with IC50 values ranging from 12.24 to 57.33 and 13.29-59.09 µM, respectively, as compared to the standard ascorbic acid (IC50 = 15.08 ± 0.03 µM for DPPH; IC50 = 16.09 ± 0.17 µM for ABTS). These findings reveal that the nature and position of the substituents on the phenyl ring(s) are crucial for variation in the activities. The structure-activity relationship (SAR) revealed that the compounds bearing an electron-withdrawing group (EWG) at para substitution possessed the highest activity. In kinetic studies, only the km value was changed, with no observed changes in Vmax, indicating a competitive inhibition. Molecular docking studies revealed important interactions between compounds and the α-amylase active pocket. Further advanced research needs to perform on the identified compounds in order to obtain potential antidiabetic agents.

Profiling the Phytochemicals of Orostachys margaritifolia: Biological Activities, LC-ESI/MS, and HPLC Analyses.

Orostachys margaritifolia Y. N. Lee (OMY) is an endemic Korean plant in the family Crassulaceae that is known to contain a variety of bioactive compounds. To assess the physiological activities of an OMY ethanol extract, ABTS+ and DPPH radical scavenging assays and a nitric oxide (NO) inhibition assay were conducted. The phytochemical makeup of the extract was profiled via liquid chromatography-mass spectrometry (LC-ESI/MS) and high-performance liquid chromatography with a photodiode array detector (HPLC/PDA). The OMY extract was found to have weaker ABTS+ and DPPH radical scavenging activities than the control group (green tea). In the NO inhibition assay, the OMY extract induced a significant increase in macrophage cell viability but showed a lower NO inhibitory activity than l-NAME, producing an IC50 value of 202.6 µg/mL. The LC-ESI/MS and HPLC/PDA analyses identified isoquercitrin and astragalin in the OMY extract, quantifying their contents at 3.74 mg/g and 3.19 mg/g, respectively. The study revealed possibilities for the utilization of OMY as a future source of drugs for alleviating inflammation and diseases related to reactive oxygen species.

Comparison of Milk Kefirs Obtained from Cow's, Ewe's and Goat's Milk: Antioxidant Role of Microbial-Derived Exopolysaccharides.

Different types of milk are used in the production of milk kefir, but little information is available on the release of potentially antioxidant exopolysaccharides (EPS). The aim of this study was to investigate whether the microbial dynamics and EPS release are dependent on the milk substrate. In our study, the inoculated microbial consortium was driven differently by each type of milk (cow, ewe, and goat). This was evident in the sugar consumption, organic acid production, free amino release, and EPS production. The amount and the composition of the secreted EPS varied depending on the milk type, with implications for the structure and functional properties of the EPS. The low EPS yield in ewe's milk was associated with a higher lactic acid production and thus with the use of carbon sources oriented towards energy production. Depending on the milk used as substrate, the EPS showed different monosaccharide and FT-IR profiles, microstructures, and surface morphologies. These differences affected the antiradical properties and reducing power of the EPS. In particular, EPS extracted from cow's milk had a higher antioxidant activity than other milk types, and the antioxidant activity was concentration dependent.

Stability, Content of Bioactive Compounds and Antioxidant Activity of Emulsions with Propolis Extracts during Simulated In Vitro Digestion.

The objective in this work was the evaluation of the stability and content of bioactive compounds (total phenols and total flavonoids) and antioxidant activity of emulsions of ethanolic extracts of propolis obtained by ultrasound, during simulated in vitro digestion. The emulsions prepared with propolis extracts were evaluated on certain properties: their emulsion efficiency, stability (zeta potential, particle size, electrical conductivity), content of bioactive compound (total phenolics and total flavonoids), antioxidant activity and their behavior during simulated in vitro digestion. Based on the total phenol content, an emulsification efficiency of 87.8 ± 1.9% to 97.8 ± 3.8% was obtained. The particle size of the emulsions was 322.5 ± 15.33 nm to 463.9 ± 33.65 nm, with a zeta potential of -31.5 ± 0.66 mV to -28.2 ± 1.0 mV and electrical conductivity of 22.7 ± 1.96 µS/cm to 30.6 ± 0.91 µS/cm. These results indicate good emulsion stability. During simulated in vitro digestion, the content of bioactive compounds (total phenolics, total flavonoids) and antioxidant activity were affected during 77 days of storage at 4 °C. It was concluded that the emulsion process fulfills the function of protecting the bioactive compounds and therefore their biological activity.