Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation, Loss of Skin Density and UV Radiation-Deleterious Effects.

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O2•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O2•− scavenging, (IC50 = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC25 = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC50 = 863 µg/mL; elastase, IC50 = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O2•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.

Phytochemical Content and Antioxidant Activity of Malus domestica Borkh Peel Extracts.

Apple is an important dietary source of carotenoids and phenolic compounds, and its regular consumption is associated with several health benefits. The aim of this study was to evaluate the phytochemical composition of fresh peels of four red-skinned ("Champion", "Generos", "Idared", "Florina") and two yellow-skinned ("Golden Delicious", "Reinette Simirenko") apple varieties. Antioxidant activity of apple peel extracts was determined by ferric reducing antioxidant power (FRAP) and ABTS radical scavenging capacity assays. Total carotenoid and polyphenolic contents were determined spectrophotometrically, while the profile of individual carotenoids and anthocyanins (in red-skinned varieties) was analyzed using high-performance liquid chromatography coupled to a photodiode array detector (HPLC-PDA). Carotenoid composition was specific for each variety, and total carotenoid content was slightly higher in yellow-skinned apple peels compared to red-skinned varieties. In contrast, total phenolic content was higher in the peels of red-skinned cultivars. Anthocyanin profile was predominated by cyanidin-3-O-galactoside. Antioxidant potential followed the trend of the total polyphenolic content, being highest in "Florina", as measured by both FRAP and ABTS assays. Our results demonstrated apple peels have high phytochemical content with diverse compositions, and their regular consumption can be an excellent source of antioxidants.

Identifying Chemical Composition, Safety and Bioactivity of Thai Rice Grass Extract Drink in Cells and Animals.

Rice grass has been reported to contain bioactive compounds that possess antioxidant and free-radical scavenging activities. We aimed to assess rice grass extract (RGE) drink by determining catechin content, free-radical scavenging and iron-binding properties, as well as toxicity in cells and animals. Young rice grass (Sukhothai-1 strain) was dried, extracted with hot water and lyophilized in a vacuum chamber. The resulting extract was reconstituted with deionized water (260 mg/40 mL) and served as Sukhothai-1 rice grass extract drink (ST1-RGE). HPLC results revealed at least eight phenolic compounds, for which the major catechins were catechin, epicatechin and epigallocatechin-3-gallate (EGCG) (2.71-3.57, 0.98-1.85 and 25.47-27.55 mg/40 mL serving, respectively). Elements (As, Cu, Pb, Sn and Zn) and aflatoxin (B1, B2, G1 and G2) contents did not exceed the relevant limits when compared with WHO guideline values. Importantly, ST1-RGE drink exerted radical-scavenging, iron-chelating and anti-lipid peroxidation properties in aqueous and biological environments in a concentration-dependent manner. The drink was not toxic to cells and animals. Thus, Sukhothai-1 rice grass product is an edible drink that is rich in catechins, particularly EGCG, and exhibited antioxidant, free radical scavenging and iron-binding/chelating properties. The product represents a functional drink that is capable of alleviating conditions of oxidative stress and iron overload.

Physicochemical, antioxidant and enzymes activities of grape fruit peel and pomace enriched functional drinks.

Experiment was conducted to determine the proximate, minerals, antioxidant capacities and enzymes activities of grape fruit peel and grape fruit pomace along with sensorial evaluation of functional drinks. In this milieu, values of grapefruit peel and pomace powder for moisture, fat, crude protein, carbohydrate, crude fiber, ash, and NFE were recorded as 10.85±1.34,8.9±0.08 , 9.27±0.03, 7.69±0.02, 60.22±2.32, 50.33±2.1, 6.13±0.02, 6.13±0.01, 2.97±0.01 ,2.16±0.01 ,10.56±1.97, 24.97±2.4, respectively whilst in time intervals highest TPC for peel (118.66±8.9) mg/g was observed in 60 min followed by (102.33±7.6) mg/g at 90 min and (82.02±5.5) mg/g at 30 min respectively Whereas, the recorded TPC for pomace at 30, 60 and 90 minute were (112.73±9.1) mg/g has observed in 60 min followed by (97.21±7.9) mg/g at 90 min and (84.55±5.8) mg/g at 30 min respectively. Among the time intervals highest flavonoids contents of peel were at 60 min 52.3±1.9% followed by 52.51±1.7% at 90 min and minimum 50.72±1.4% at 30 min. The highest ABTS value was observed for peel content 248.33±5.6 λg/ml in ethanol extract followed by methanolic extract 212.11±4.4 λg/ml least in water extract 152.5±3.2 λg/ml. The means reviewed FRAP activity highest value for ethanol in peel and pomace were (92.66±5.3 µg/ml Fe2+/g) & (82.47±4.2 µg/ml Fe2+/g) followed by methanol (86.33±4.1 µg/ml Fe2+/g) & (76.83±3.4 µg/ml Fe2+/g) and least in water (66.46±2.2 µg ml Fe2+/g) &(54.24±2.1 µg/ml Fe2+/g) respectively. The color acceptability varied significant effect between 7.49 to 7.55 in T0 to T3. Likewise, storage imparted more significant decline from 7.72 to 7.30 at 0th to 60th days, respectively. The flavor scores were 7.59, 7.41, 7.26 and 7.53 in T0, T1, T2 and T3 respectively. The overall acceptability of drink was significantly increase from initiation (0th) day to termination (60th) day as 7.68 to 6.9.

Chemical profiling, HPLC characterization and in-vitro antioxidant potential of Pakistani propolis collected from peripheral region of Faisalabad.

Propolis is a highly adhesive and resinous product of honey bee (Apis mellifera L.) which is produced from the exudations of plants. Bee propolis being a source of bioactive compounds like polyphenols and flavonoids imparts numerous biological properties including, antioxidant, anti-inflammatory, antimicrobial and anticancer activities. Present study was designed to elucidate the composition and antioxidant status of locally available propolis using in-vitro conditions. Propolis collected from locally found apiaries and its hydroalcoholic extract of propolis was prepared using different concentrations of ethanol and methanol. The results regarding proximate composition of propolis showed a higher proportion of ether extract (85.59±0.87%) and lowest contents of crude fiber (0.31±0.08%). Among the mineral's sodium, potassium and calcium was found in a concentration of 11.33±0.91, 52.10±2.9 and 10.53±0.83.59±0.23mg/Kg respectively whilst zinc was noticed as 3.59±0.23mg/Kg. HPLC characterization indicates a highest concentration of Chlorogenic acid 31.80±2.56mg/Kg whereas gallic acid (0.21±0.01mg/Kg) was found in lowest concentration among the polyphenols. Ethanol extract represents more phenolic contents, DPPH activity and antioxidant status as 327.30±14.89mg/gGAE, 73.18±4.43% and 60.59±4.38% accordingly in comparison to methanol and water extract. Bee propolis found an effective source of natural antioxidants which retards the production of free radicals and reactive oxygen species thus help to cope oxidative stress.

Effects of Long-Term Storage on Radical Scavenging Properties and Phenolic Content of Kombucha from Black Tea.

Kombucha is a fermented beverage. Its consumption has significantly increased during the last decades due to its perceived beneficial effects. For this reason, it has become a highly commercialized drink that is produced industrially. However, kombucha is still also a homemade beverage, and the parameters which, besides its organoleptic characteristics, define the duration of its potential beneficial properties over time, are poorly known. Therefore, this study aimed to determine the effect of 9-month storage at 4 °C with 30-day sampling on the pH, total phenolic, and flavonoid contents, free radical scavenging properties of kombucha fermented from black tea. Our results highlighted that, after four months, the phenolic content decreased significantly from the initial value of 234.1 ± 1.4 µg GAE mL-1 to 202.9 ± 2.1 µg GAE mL-1, as well its antioxidant capacity tested by two in vitro models, DPPH, and ABTS assays. Concomitantly, the pH value increased from 2.82 to 3.16. The novel findings of this pilot study revealed that kombucha from sugared black tea can be stored at refrigerator temperature for four months. After this period the antioxidant properties of kombucha are no longer retained.

Effect of thermal processing on the molecular, structural, and antioxidant characteristics of highland barley ß-glucan.

This present work evaluated the effect of heat fluidization, microwave roasting and baking treatment of highland barley (HB) on the molecular, structural, thermal and antioxidant characteristics of ß-glucan. Fluorescence microscopy results showed that heat fluidization exhibited the greatest disruption effect on endosperm cell walls, resulting in the highest extractability (3.35 ± 0.06 g/100 g flour) and purity (92.67 ± 0.73%) of ß-glucan. After HB thermal processing, the molecular weight and polydispersity index of ß-glucan were respectively reduced by 3.68%-90.35% and 26.45%-39.83%, and its microscopic molecular morphology transformed from large sphere aggregate to alveolate gel network structure. Meanwhile, the structural elucidation by X-ray diffraction and infrared spectroscopy revealed that thermal processing induced the scission of polymeric chain and formation of lattice-type microgels without changing the primary functional groups of ß-glucan. Furthermore, thermogravimetry and antioxidant results indicated the thermal stability and antioxidant activity of ß-glucan were enhanced by thermal processing.

Chemical Analysis, Toxicity Study, and Free-Radical Scavenging and Iron-Binding Assays Involving Coffee (Coffea arabica) Extracts.

We aimed to analyze the chemical compositions in Arabica coffee bean extracts, assess the relevant antioxidant and iron-chelating activities in coffee extracts and instant coffee, and evaluate the toxicity in roasted coffee. Coffee beans were extracted using boiling, drip-filtered and espresso brewing methods. Certain phenolics were investigated including trigonelline, caffeic acid and their derivatives, gallic acid, epicatechin, chlorogenic acid (CGA) and their derivatives, p-coumaroylquinic acid, p-coumaroyl glucoside, the rutin and syringic acid that exist in green and roasted coffee extracts, along with dimethoxycinnamic acid, caffeoylarbutin and cymaroside that may be present in green coffee bean extracts. Different phytochemicals were also detected in all of the coffee extracts. Roasted coffee extracts and instant coffees exhibited free-radical scavenging properties in a dose-dependent manner, for which drip coffee was observed to be the most effective (p < 0.05). All coffee extracts, instant coffee varieties and CGA could effectively bind ferric ion in a concentration-dependent manner resulting in an iron-bound complex. Roasted coffee extracts were neither toxic to normal mononuclear cells nor breast cancer cells. The findings indicate that phenolics, particularly CGA, could effectively contribute to the iron-chelating and free-radical scavenging properties observed in coffee brews. Thus, coffee may possess high pharmacological value and could be utilized as a health beverage.

Total Polyphenol and Flavonoid Content and Antioxidant Capacity of Some Varieties of Persea americana Peels Consumed in Cameroon.

Fruit peels are increasingly being used as functional foods nowadays. Peelings of twelve varieties of Persea americana fruits consumed in Cameroon were investigated for their phenolic compounds (polyphenols and flavonoids) using three solvents systems, water, ethanol: water (50 : 50 v/v), and ethanol, and antioxidant activity using total antioxidant capacity (TAC), ferric reducing antioxidant power (FRAP), and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging methods. Total polyphenol, flavonoids, and antioxidant potential of the peels significantly varied with P. americana variety and also with the extraction solvents in the order ethanol > ethanol: water > water. Total phenolic content varied from 2407 (Fuerte florid) to 673 (Semil) mg GAE/g DM, respectively, while flavonoids varied from 986 to 119 mg QE/g DM for Fuerte florid and Hickson varieties, respectively. TAC, respectively, varied between 132.87 and 126.85 mg AAE/g DM with Hass and Semil varieties, respectively. The highest DPPH scavenging capacity was recorded for the ethanolic extract with Lula (86.33%) and the least for the aqueous extract with the Semil (30.11%) variety. With FRAP, the highest capacity was obtained with hydroethanolic extract of Fuerte florid (0.43 mg AAE/g DM) and the least for aqueous extract with the Semil (0.269 mg AAE/g DM) variety. In conclusion, varieties of avocado peels are a good source of antioxidants. Solvent extraction significantly affected the concentration of bioactive compounds but not the potency of the antioxidants. A weakly positive correlation but not significant between the quantity of polyphenol, flavonoid, and antioxidant capacity of avocado peelings was obtained in this study.

Polyphenols, L-Ascorbic Acid, and Antioxidant Activity in Wines from Rose Fruits (Rosa rugosa).

The aim of the present study was to determine the influence of the winemaking process on the antioxidant potential and content of phenolic compounds and L-ascorbic acid in wines from the fruits of Rosa rugosa. The results obtained in this study clearly indicate that the fruits of the Rosa rugosa are a desirable raw material for the production of fruit wine. The parameters of the technological process of producing wines from rose fruits had a diversified influence on the tested quality characteristics. Aged wines contained phenolics levels of 473-958 mg/100 mL GAE. The final concentrations of ascorbic acid ranged from 61 to 155 mg/100 mL for the different variants of the wine. Wines revealed high antioxidant activity in assay with DPPH. On the basis of the obtained results, it can be assumed that all the applied variants of the winemaking process are suitable for rose fruit wine. Each variant ensured at least the stability of the antioxidant capacity.

Enhancing Effect of a Roasting Treatment on the Radical Scavenging Activity of a Marine Brown Alga Polysaccharide (Alginic acid).

We found an effective roasting method that enhances the effects on various radical scavenging activities of polysaccharide (alginic acid) derived from the marine brown alga Lessonia trabeculata. These enhancing effects were observed by a roasting treatment under relatively high temperature conditions (160ºC and 180ºC), which were measured by (i) a stable radical compound diphenylpicrylhydrazyl (DPPH), (ii) a hydroperoxide generating system of linoleic acid autooxidation, and (iii) an opsonized zymosan (Opz)-induced oxygen radical generating system in human blood neutrophils. Although a significant enhancing effect of the roasting treatment on the radical scavenging activity of the alginic acid itself was not detected under relatively low temperature conditions (100ºC and 130ºC), the roasting treatment of a mixture of alginic acid and several specific amino acids caused considerable radical scavenging activities under the same roasting conditions. When alginic acid was roasted at relatively high temperatures (160ºC or 180ºC), the mixture of the alginic acid and specific amino acids exhibited much higher radical scavenging activities than did the alginic acid alone. The significance of this finding is discussed from the viewpoint of healthy food science.

Preparative Isolation and Purification of Calycosin and Formononetin from Astragali Radix using Hydrolytic Extraction Combined with High Speed Countercurrent Chromatography.

Calycosin and formononetin were efficiently extracted from Astragali Radix and purified by high-speed countercurrent chromatography. Calycosin and formononetin could be hydrolyzed from calycosin-7-glucoside and ononin, respectively. The best extraction conditions were realized by single factor and orthogonal experiments, which were 100% ethanol, 2.5 mol/L hydrochloric acid, 1:40 ratio of solid to liquid, extracted 2 h and one time. The two-phase solvent system of n-hexane-ethyl acetate-ethanol-water (3:5:3:5, v/v) was selected for the purification of calycosin, and 1.3 mg calycosin (the purity was 95.8% and the recovery was 85.9%) was obtained from 264.9-mg crude extraction. The two-phase solvent system of n-hexane-ethyl acetate-ethanol-water (4:5:4:5, v/v) was selected for the purification of formononetin, and 2.0 mg formononetin (the purity was 98.9% and the recovery was 84.4%) was obtained from 248.9-mg crude extraction. Their structures were identified by HPLC, melting points, UV, FTIR, ESI-MS, 1H NMR and 13C NMR spectrum. According to the antioxidant activity assay, the scavenging abilities of calycosin to 1,1-diphenyl-2-picrylhydrazyl and hydroxyl free radicals (·OH) were stronger. The scavenging effect of formononetin was not demonstrated.

Identification and characterization of potential antioxidant components in Isodon amethystoides (Benth.) Hara tea leaves by UPLC-LTQ-Orbitrap-MS.

Isodon amethystoides (Benth.) Hara (IA) tea is a commonly used dietetic Chinese herb and employed for the treatments of tumor and lung abscess. To assess chemical composition and antioxidant capacity of IA leaves extract, a UPLC-LTQ-Orbitrap-MS method and antioxidant tests were used, respectively. 17 compounds were identified including Vinyl caffeate (1), 3,4-dimethoxyphenyl-ß-D-glucopyranoside (2), Rutin (3), Quercetin (4), Loliolide (5), Caffeic acid (6), Rubesanolide D (7), Isorhamnetin (8), Lambertic acid (9), 6, 7-Dehydroroyleanone (10), Dihydrorabdokunmin C (11), Nervosin (12), Quercitrin (13), Vitexin (14), ß-sitosterol (15), Wangzaozin A (16), Amethystonoic acid (17). Among these, 1-14 compounds were novel and have not been reported ever before in IA while component 10 was a novel finding within this genus. Flavonoid components showed better free radical scavenging ability and profound correlation was observed between diterpenoid compounds content and flavonoids activity. Our results provide experimental basis for extraction and separation of chemical constituents of IA which are antioxidant in nature.

Effect of extraction temperature and solvent type on the bioactive potential of Ocimum gratissimum L. extracts.

Ocimum gratissimum is a shrub that belongs to the Lamiaceae family of plants. Despite the known biological activities and ethnomedicinal applications, comparative evaluation of the effects of different extraction techniques on the chemical and bioactive properties of O. gratissimum extracts has not yet been performed. This study adopted different analytical techniques to determine the effect of extraction temperature and solvent type on the phytochemical and bioactive properties of O. gratissimum extracts. Chemical profiling showed increased concentrations of compounds for both the ethanolic and methanolic extracts compared to the water extracts. The results also revealed that the extraction temperature had an effect on the total phenolic content and radical-scavenging properties of the different extracts. The antioxidant kinetic modeling achieved the best fit when using the second-order kinetic model. Methanolic extracts had the highest levels of antibacterial activity against Escherichia coli, Bacillus cereus, Staphylococcus aureus, and Salmonella typhimurium. At high concentrations, all extracts lowered the viability of the breast cancer cell line MDA-MB-231. In conclusion, the chemical and bioactive properties of all extracts showed significant dependence on the extraction temperature and solvent type. With proper extraction methods, they boast a wide range of promising applications in the medical, pharmaceutical, and food industries.

Polyphenol and flavonoid profiles and radical scavenging activity in leafy vegetable Amaranthus gangeticus.

BACKGROUND: Red amaranth (Amaranthus gangeticus L.) has great diversity in Bangladesh, India, and South East Asia with multipurpose uses. The bright red-violet colored A. gangeticus is a popular and low-cost leafy vegetable in the Asian continent including Bangladesh and India because of attractive leaf color, taste, adequate nutraceuticals, phenolic compounds, and sole source of betalains. The natural colors and phenolic compounds of this species have a significant role in promoting the health-benefit including the scavenging capacity of radicals, the colorant of food products, and play a vital role in the industry of foods. However, phenolic profiles and radical scavenging activity of this species have not been evaluated. Hence, for the first time, four selected advance lines of A. gangeticus were characterized for phenolic profiles, antioxidant constituents, and antioxidant potentiality. RESULTS: A. gangeticus genotypes are abundant sources of phenolic profiles and antioxidant constituents with good radical quenching capacity that differed across the genotypes. Twenty-five phenolic acids and flavonoids, such as protocatechuic acid, salicylic acid, gentisic acid, gallic acid, ß-resorcylic acid, vanillic acid, p-hydroxybenzoic acid, chlorogenic acid, ellagic acid, syringic acid, ferulic acid, kaempferol, m-coumaric acid, trans-cinnamic acid, quercetin, p-coumaric acid, apigenin, caffeic acid, rutin, sinapic acid, isoquercetin, naringenin, myricetin, catechin, and hyperoside were identified in A. gangeticus accessions. A. gangeticus accessions LS7 and LS9 demonstrated ample phenolic acids, flavonoids, antioxidant constituents, and antioxidant potentiality. It revealed from the correlation study that antioxidant components of A. gangeticus genotypes exhibited good radical scavenging activities. The genotypes LS7 and LS9 could be directly used as phenolic profiles, antioxidant constituents, and antioxidant activity enrich cultivars. CONCLUSIONS: The identified compounds of phenolic acids and flavonoids in A. gangeticus privilege the comprehensive study of pharmacology. The basic information on phenolic profiles and antioxidant constituents achieved in the present study will provide the scientist's forum for the scientific assessment of these compounds in A. gangeticus.

Mechanism insights into the transformation of carbosulfan during apple drying processes.

The transformation of carbosulfan (CSN) in apples was investigated during oven-drying, microwave drying, and sun-drying. CSN transformed primarily into carbofuran (COA) during these drying processes. The conversion kinetics of CSN and COA was fitted by curve regression and mainly conformed to quadratic models (R2 = 0.70-0.97). Oven-drying promoted the transformation of CSN into COA. Microwave drying resulted in the highest scavenging capacity against CSN and COA (41%-100%). Moreover, a transformation mechanism was proposed on the basis of density functional theory (DFT) calculation. The COA originated from a series of chemical reactions involving hydroxyl substitution, cleavage, and oxidation; this result was further confirmed on the basis of molecular electrostatic potential (MEP) and molecular orbital theory. Furthermore, the toxicity and stability of CSN and COA were evaluated with the T.E.S.T. program. COA was less toxic than CSN to aquatic organisms but more toxic than CSN to rats. Therefore, COA production should be avoided during drying. Microwave drying was found to be the optimum choice for drying apples.

Colorimetric determination of polyphenols via a gold nanoseeds-decorated polydopamine film.

A polystyrene ELISA plate (EP) modified with a thin film based on gold nanoseeds (AuSDs) assembled onto polydopamine (PDA) is proposed. The nanodecorated film (PDA@AuSD) allows to evaluate the polyphenols antioxidant capacity (AOC) through a colorimetric approach based on a seed-mediated growth strategy. Polyphenols, in the presence of the nanodecorated (PDA@AuSD) surfaces are able to drive an increase in size of the AuSDs according to their AOC; this produces an increase of the localized surface plasmon resonance (LSPR; maximum at λ ~ 550 nm) that is taken as analytical signal. The PDA@AuSD EP manufacturing shows good intraplates repeatability (RSD ≤ 6.6%, n = 96 wells) and interplates reproducibility (RSD ≤ 7.4%, n = 748 wells), resulting stable for 1 year. The AuSDs growth kinetic has been studied using 11 polyphenols belonging to different chemical classes and 4 different food samples. The PDA@AuSD film is able to return quantitative information on the AOC of food polyphenols. Good repeatability (RSD ≤ 5.7%, n = 12 EP wells) and reproducibility (RSD ≤ 8.1%, n = 12 EP wells) was achieved, with acceptable linear correlation coefficients (R2 ≥ 0.990) and useful limits of detection (LODs ≤ 2.5 10-5 mol L-1). The samples analyzed with the PDA@AuSD device have been successfully ordered according to their AOC in agreement with conventional optical methods. The PDA@AuSD plate allows multiple measurements (96 wells per EP) with a one-step strategy, overcoming the limitations related to the use of colloidal nanoparticles; in addition, since absorbance is measured after washing, it is not affected by sample color or turbidity. Graphical abstract Schematic representation of ELISA plate (EP) modified with polydopamine (PDA) film decorated with gold nanoseeds (AuSD). The colorimetric assay, to evaluate the antioxidant capacity, is based on the AuSD growth mediated by polyphenols, resulting in absorbance increase at 550 nm (ΔAbs550), which is employed as analytical signal.

Rapid screening and evaluation of XOD inhibitors and O2 •- scavenger from total flavonoids of Ginkgo biloba leaves by LC-MS and multimode microplate reader.

Superoxide anion radical scavenger and xanthine oxidase inhibitor play an important role in the treatment of several relevant human diseases. In the present study, ultrafiltration liquid chromatography-mass spectrometry coupled to microplate reader was applied to screen and identify superoxide anion radical scavengers and xanthine oxidase inhibitors from total flavonoids of Ginkgo biloba leaves. As a result, four compounds (quercetin, apigenin, kaempferol and isorhamnetin) were screened as xanthine oxidase inhibitors by ultrafiltration LC-MS, and the 50% scavenging concentration values of the screened flavonoids were lower than those for allopurinol. Lineweaver-Burk plot results indicated that kaempferol was a competitive xanthine oxidase inhibitor; the other flavonoids were all anticompetitive inhibitors. Four flavonoids-rutin, quercetin, kaempferol and isorhamnetin-were screened as superoxide anion radical scavengers by LC-MS. The results demonstrate that the method for screening and evaluation of superoxide anion radical scavenger and xanthine oxidase inhibitor from a complex mixture system is feasible and efficient.

Phenolic composition and biological activities of geographically different type of propolis and black cottonwood resins against oral streptococci, vaginal microbiota and phytopathogenic Fusarium species.

AIMS: A multidisciplinary approach was used to compare phenolic composition, radical scavenging and antimicrobial activity of propolis samples from different geographical localities, and plant resin against various microorganisms. METHODS AND RESULTS: Using UHPLC-qqqMS quantitative analysis, 28 phenolic compounds were determined. Caffeic and p-coumaric acids were identified as main phenolic acids in poplar propolis samples, except samples from Russia (P6) and China (P7). Radical scavenging activity (applying DPPH spectrophotometric assay) showed the highest activity of Serbian (40·51%) and Chinese (53·21%) propolis samples. Broth microdilution method was used for the oral cavity, fungal phytopathogenic and human vaginal isolates which have been identified at a molecular level. The most sensitive bacterial isolates were Lactobacillus acidophilus (MIC of 0·03-0·13 mg ml-1 ) and the oral streptococci isolates (MIC values of 0·19-0·13 mg ml-1 ). The most sensitive fungal phytopathogenic isolate was Fusarium oxysporum (MIC 0·003 mg ml-1 ). All samples, except propolis from Serbia (P4) and Turkey (P5), showed a strong antifungal activity against Fusarium sporotrichioides, Fusarium subglutinans and Fusarium proliferatum. CONCLUSION: The results of various tests indicate good radical scavenging and antimicrobial activity against important human and plant pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: A detailed propolis analysis is important when proposing a preparation of new biological antimicrobial products which have a positive impact on human health and reduce antibacterial resistance.

Preparative isolation of highly polar free radical inhibitor from Floccularia luteovirens using hydrophilic interaction chromatography directed by on-line HPLC-DPPH assay.

Wild edible macro fungi Floccularia luteovirens proved to be a valuable source for the identification of novel lead molecules with therapeutic potential. Nevertheless, the chemical constituents of Floccularia luteovirens are rarely reported due to absence of efficient purification methods. In this study, a hydrophilic interaction chromatography directed by on-line HPLC-DPPH assay has been developed and successfully applied for the isolation of free radical inhibitor from the methanolic extract of Floccularia luteovirens. Using a hydrophilic interaction chromatographic column coupled with the HPLC-DPPH assay for screening the potential radical scavengers, the mid-pressure hydrophilic interaction chromatography (HILIC) proved to be more efficient in the pretreatment stage, yielding the fraction rich in free radical scavengers in good yield (5.9% recovery from 130.0 g of fresh F. luteovirens). From highly potent fraction, the target compound was isolated using the Click XION preparative chromatography with 17.2% recovery. The isolated compound was L-(+)-ergothioneine, where the purity (>95%) and antioxidant activity of were confirmed by chromatography and HPLC-DPPH assay, while the structure of this compound was elucidated from HR ESI-MS and NMR data. This method proved to be very efficient for the recognition and isolation of highly polar free radical inhibitors from fungi extracts, and is also applicable for the purification of highly polar compounds from other sources.