Azinobis-3-ethylbenzothiazoline-6-sulphonate Research Articles

The effect of herbal Lippia javanica extracts on the bioactive content, functional properties, and sensorial profile of biofortified-orange maize based fermented maheu

Lippia javanica is commonly used to treat respiratory ailments because of its rich phytochemical profile, however its importance as a food additive in maheu production is not known. The study was aimed at determining the effect of herbal Lippia javanica extract (L.J.E) on the bioactive content, functional properties, and sensorial profile of biofortified-orange maize based fermented maheu. The prepared orange maize gruels were mixed with 5%, 10%, and 15% v/w L.J.E and fermented spontaneously for 24 h. Total polyphenols (TP), antioxidant activity (AOA), β-carotene, vitamin A and vitamin C content were analysed using Folin-Ciocalteu reagent, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, ABTS (2,2′-azinobis-3-ethyl-benzothiazoline-6-sulphonate), HPLC, retinol activity equivalent (RAE) conversion, and dichlorophenolindophenol titration method respectively. Physiochemical properties, mineral content and product acceptability were analysed using standard AOAC methods. The β-carotene, vitamin A, and vitamin C range was 0.8-1.1 µg/g, 3.55-3.90 µREA/100g and 6.3-11.1 mg/100g respectively. TP, AOA, total antioxidant activity range was 8.2-19.4 mg GAE/g, 28.1-41 EC50mg/L and 31.3-48.3AE/100g respectively. The pH, total soluble sugars, and titratable acidity was 3.6-3.9, 4-4.5% and 0.08-0.16%. Minerals present in maheu were zinc (0.8-1.1mg), iron (2.6-3.1mg), magnesium (93.2-97.1mg), calcium (80.1-89.4mg), and potassium (72.5-82mg). Maheu with 15% v/w L.J.E had better improved bioactive content, functional properties and sensorial profile.

Investigation of Antistress and Antidepressant Activities of Synthetic Curcumin Analogues: Behavioral and Biomarker Approach.

Depression is a serious psychiatric disorder that affects millions of individuals all over the world, thus demanding special attention from researchers in order to investigate its effective remedies. Curcumin, along with its synthetic derivatives, is recognized for its incredible pharmacological activities. In this study, methyl, methoxy and chloro-substituent synthetic curcumin analogues C1–C3 were respectively tested for free radical-scavenging activity. Behavioral studies were performed using chemical-induced and swimming endurance tests as stress models, and forced swim tests (FSTs) and tail suspension tests (TSTs) as depression mice models. Biochemical examinations were performed after a scopolamine-induced stress model by decapitating the mice, and brain tissues were isolated for biochemical assessment of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA). The curcumin analogue C2 exhibited higher DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis-3-ethylbenzothiazo-line-6-sulphonate) free radical-scavenging potential, having IC50 values of 45.18 µg/mL and 62.31 µg/mL, respectively, in comparison with reference curcumin and tocopherol. In the chemical-induced test, C2 (80.17%), C3 (72.79%) and C1 (51.85%) revealed higher antistress responses by significantly reducing the number of writhes, whereas the immobility time was significantly reduced by C2 and C3 in the swimming endurance test, indicating excellent antistress potential. Similarly, C2 and C3 significantly reduced the immobility times in FST and TST, demonstrating their antidepressant properties. The biomarkers study revealed that these compounds significantly enhanced hippocampus CAT, SOD and GSH, and reduced MDA levels in the scopolamine-induced stress mice model. These findings suggest the potential of curcumin analogues (C2 and C3) as antistress and antidepressant agents.

Chemical profile, antioxidant and antimicrobial effects of essential oil from the Moroccan endemic plant cladanthus scariosus (L.)

ABSTRACT In this study, chemical profile, antioxidant potential and antimicrobial interactions with conventional antimicrobials of essential oil (EO) isolated from Cladanthus scariosus aerial parts were investigated. The EO was analyzed by GC-MS (Gas Chromatography-Mass spectrometry). Forty-three components representing 98.7% of the oil were identified. The main components were o-cymene, caryophyllene oxide, γ-terpinene and α-sabinene. Furthermore, the antioxidant and antimicrobial activities against ten bacteria and two Candida strains were assessed. The results showed an interesting antioxidant effect with IC50 of 1.04 ± 0.04 mg/mL, 0.55 ± 0.01 mg/mL and 0.36 ± 0.14 mg/mL, respectively, for DPPH (2,2-Diphenyl-1-Picrylhydrazyl), FRAP (Ferric-Reducing-Ability-Power), and ABTS (2-2’azinobis-3-ethylbenzothiazoline-6-sulphonate) methods. The EO exhibited a strong antimicrobial activity, especially against Methicillin-resistant Staphylococcus aureus and Candida glabrata. In combination with antimicrobials, the studied EO revealed a high synergism effect in reducing gentamicin MICs of bacterial strains by 128- to 256-fold and by 2- to 8-fold Fluconazole MICs against Candida strains.

Antioxidant and bio-activities of leaf extracts from Eucalyptus globulus

Eucalyptus globulus member of Myrtacaea family, is one of the important medicinal widely used plant.In this study methanolic leaf extract of Eucalyptus globulus was studied for the estimation of phytochemical constituents , in-vitro antioxidant and anti-inflammatory activity . Fresh leaves were ground with methanol used for estimations. Phytochemical constituents were estimated by total phenolic content and total Flavonoid content determination. Spectroscopic analysis by UV-VIS, FT-IR and fluorescents analysis was also conducted. In vitro anti- inflammatory and antimicrobial activities were also monitored.Phytochemical screening revealed the presence of flavonoids , phenols , carbohydates and saponins. Considerable amount of phenolics (50 mg equivalent par g of dry weight) and flavonoids (23 mg equivalent par g of dry weight) were detected in extract. Extract exhibited considerable DPPH (1,1-diphenyl-2-picrylhydrazyl), ABTS (2,2’-azinobis-3-ethylbenzothiazoline-6-sulphonate) scavenging activities, Hydroxyl radical scavenging activity, Nitric oxide radical scavenging activity , Iron reducing power and Superoxide radical scavenging activity. Fluorescent spectroscopy revealed the presence of fluorophores in extracts. A strong anti-inflammatory activity of extract was observed using fluorescent spectroscopy. An appreciable in vitro antibacterial activity against gram-negative bacteria like gram-negative bacteria Escherichia coli, MTCC 40 was detected. This study confirmed that methanolic extract Eucalyptusglobulus possesses potent antioxidant anti-inflammatory and antibacterial activities possibly important quantity of flavonoid and phenolic content present in it .

Naturally occurring ureidobromophenols with potent antioxidant activities from the marine red alga Rhodomela confervoides

An extensive investigation on the chemical components with potential antioxidant activity resulted in the characterization of four new ureidobromophenols (1–4) and two related metabolites (5 and 6) from ethyl acetate extract of the marine red alga Rhodomela confervoides. Their structures were determined using spectroscopic analysis and comparisons with known compounds. Compound 1 possesses unique structure of an ureido group bearing γ-butyric acid and 2,3-dibromo-4,5-dihydroxybenzyl moieties on the same nitrogen atom. Compounds 1–4 displayed significant antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals with IC50 values ranging from 3.34 to 4.84 μM, which are more active than that of the positive controls ascorbic acid (IC50 = 20.1 μM) and butylated hydroxytoluene (IC50 = 82.1 μM). These compounds also exhibited potent activity against 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonate (ABTS) radicals with trolox equivalent antioxidant capacity (TEAC) values ranging from 3.25 to 5.01 mM, which are 3- to 5-fold potent than that of ascorbic acid (TEAC = 1.02 mM). The antioxidant activity of ureidobromophenols isolated from marine alga might boost the seaweed functional food ingredients or dietary food supplements in food industry.

A sensitive, high-throughput fluorescent method for the determination of lactoperoxidase activities in milk and comparison in human, bovine, goat and camel milk

Lactoperoxidase (LPO) is one of the major antibacterial ingredients in milk and an extensively employed indicator for milk heat treatment. The traditional method for LPO activity measurement using ABTS (2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonate) cannot achieve high sensitivity and is affected by indigenous milk thiocyanate. A more sensitive microplate fluorescent assay was developed by monitoring generation of red-fluorescent resorufin from LPO catalysed oxidation of Amplex® Red (1-(3,7-dihydroxyphenoxazin-10-yl)ethanone) in this study. The assay is particularly suitable for milk LPO activity measurement as it eliminates the influences of indigenous milk hydrogen peroxide and thiocyanate. The method limit of detection was 7.1x10−6 U/mL of LPO in milk and good intra-run and inter-run precision was obtained. The LPO activities ranked as bovine > goat > camel > human in the four types of milk analysed. The high sensitivity and low cost of this assay makes it suitable for LPO activity analyses in both laboratory and commercial scales.

Enhancement of the Antioxidant, Anti-Tyrosinase, and Anti-Hyaluronidase Activity of Morus alba L. Leaf Extract by Pulsed Electric Field Extraction.

In this study we aimed to compare the chemical composition and biological activity between Morus alba L. leaf extract obtained with 95% v/v ethanol using a pulsed electric field (PEF) and the conventional maceration method. Extracts of M. alba leaves collected from Chiang Mai (CM), Sakon Nakon (SK), and Buriram (BR), Thailand, were investigated for 1-deoxynojirimycin content by high-performance liquid chromatography and for total phenolic content by the Folin–Ciocalteu method. Antioxidant activity was investigated by 2,2′-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azinobis-3-ethylbenzothiazoline-6-sulphonate (ABTS), and ferric reducing antioxidant power (FRAP) assay. Anti-tyrosinase and anti-hyaluronidase activity was investigated by in vitro spectrophotometry. The results show that this is the first study to indicate PEF as a novel method for enhancing the phenolic content and antioxidant, anti-tyrosinase, and anti-hyaluronidase activity of M. alba leaf extract (P < 0.05). PEF extract of M. alba leaves collected from BR had comparable ABTS•+ scavenging activity to l-ascorbic acid and comparable anti-tyrosinase activity to kojic acid (P > 0.05). On the other hand, PEF extract of M. alba leaves collected from SK exhibited significantly high anti-hyaluronidase activity, comparable to that of oleanolic acid (P > 0.05). Therefore, PEF is suggested for further M. alba leaf extraction in the production of natural whitening and anti-aging cosmetic ingredients.

Evaluation of in vitro biological activities: antioxidant; anti-inflammatory; anti-cholinesterase; anti- xanthine oxidase, anti-superoxyde dismutase, anti-α-glucosidase and cytotoxic of 19 bioflavonoids

Pure compounds belonging to phenolic family were studied for their biological potential such as 5,8-dihydroxy-1,4-naphthoquinone (M1), rutin hydrate (M2), 2,3-dichloro-5,8-dihydroxy-1,4-naphthoquinone (M3), taxifolin (M4), myricetin (M5), plumbagin (M6), silibinin (M7), dihydromyricetin (M8), shikonin (M9), quercetin 3-β-D-glucoside (M10), (±)-taxifolin hydrate (M11), cardamonin (M12),(-)-epicatechin (M13), 9-chloro-10-hydroxy-anthracene-1,4-dione (M14), 9-chloro-10-hydroxy-2,3-dimethyl-anthracene-1,4-dione (M15), 2-chloro-3-(2-hydroxy-5-methylanilino)-1,4-naphthoquinone (M16), 2-chloro-3-(4-hydroxy-phenylamino)-(1,4) naphthoquinone (M17), 2-chloro-3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-(1,4)-naphtoquinone (M18), and myricitrin dihydrate (M19). These molecules were chosen based on two reasons; the limited or total absence of their exploitation in several studied activities and the use of other tests for the same activity. The evaluation of the in vitro anti-acetyl-cholinesterase (AChE), anti-5-lipoxygenase (5-LOX), anti-xanthine oxidase (XOD), anti-alpha glucosidase, anti-superoxide dismutase (SOD), anti-oxidant (DPPH (1, 1-diphenyl-2-picrylhydrazyl) and ABTS (2, 2- azinobis-3-ethylbenzothiazoline-6-sulphonate)), and anticancer activities of mentioned 19 molecules was explored during this work. M3, M14, M15, M16, M17, M18, M19 were exploited for the first time for such purposes. Tested compounds were shown to have interesting radical scavenging abilities against DPPH radicals, and the highest molecules among them were M19 and M5 (IC50 = 12.0 and 15.5 µM, respectively), and M4, M19 and M2 against ABTS (IC50= 1.9, 4.3 and 4.3 µM, respectively). Moreover, the majority of products showed very important cytotoxic activity since IC50 values were ranging between (IC50= 0.2 µM (M1) and 79 µM (M8)) against HCT116 cell line, and values of IC50= 0.2 µM for M1 against MCF7 cell line. All new molecules (non studied before) were shown to have great cytotoxic effect against both cancer cell lines.Furthermore, molecule M5 was shown to have anti-inflammatory potential via the inhibition of 5-LOX enzyme (65% at 100 µM). In addition, M19 showed important anti XOD activity with 47% of inhibition at 100 µM. Also, it has been found that compound M3 had the best anti alpha glucosidase activity with 43.8 % of inhibition at 100 µM, the highest anti-AChE effect (IC50= 14.5 µM), and the best effect towards SOD (IC50= 10.0 µM). A structure-activity relationship study was also performed.

The Relationship of Free Radical Scavenging and Total Phenolic and Flavonoid Contents of Garcinia lasoar PAM

The radical scavenging assays of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic (ABTS) acid for various extracts and fractions of Garcinia lasoar Pam stem bark had been examined. The methanol extract showed high total phenolic (272.98 mg GAE (gallic acid equivalent)/100 g) and total flavonoid (223.16 mg QE (quercetin equivalent)/100 g) contents with potential antioxidant activity (DPPH: 0.72 μg/mL; ABTS: 0.24 μg/mL). The ethyl acetate fraction of methanol extract has higher activity than the dichloromethane fraction with IC50 values of 1.90 and 0.90 μg/mL in DPPH and ABTS assays, respectively. The Pearson correlation coefficients were calculated in order to identify the relationship between antioxidant activity and the total phenolic and total flavonoid contents. The antioxidant activity showed high positive relationship in both assays (r = 0.762, p < 0.05). The highest positive correlation between total flavonoid content and ABTS radical scavenging activity for methanol extract and then ethyl acetate had correlation between total flavonoid content. These results suggest that G. lasoar stem bark extracts can be used as a natural source of antioxidants.

Repeated heating of edible oils: effects on polyphenolic content and antioxidant capacity

Dietary free radicals carry significant health risks. Antioxidant capacity and total phenolic content of seven edible oil types [coconut oil-I (loosely packed-wholesale), coconut oil-II (pure, sold in bottles), olive oil, soya oil, sunflower oil, palm oil and mee (Madhuca longifolia) oil] were measured at unheated, heated and reheated stages, to determine the effects of repeated heating on the antioxidant activity. Free radical scavenging assay - 2,2–azinobis-3–ethylbenzothiazoline–6-sulphonate, expressed as Trolox equivalent antioxidant capacity (TEAC) per gram of oil and Folin-Ciocalteu method were used to determine the antioxidant capacity and the total polyphenolic content respectively. Statistical significance was tested using ANOVA Tukey’s post-hoc test. At an unheated stage, mee oil had the highest antioxidant capacity (220.71±5.45 μg/g TEAC) followed by olive oil (22.10±2.77μg/g TEAC) and coconut oil-I (13.02±2.77μg/g TEAC). Other unheated oils showed negligible antioxidant capacities. First heating significantly reduced (p

Broccoli (Brassica oleracea L. var. italica) Sprouts as the Potential Food Source for Bioactive Properties: A Comprehensive Study on In Vitro Disease Models.

Broccoli sprouts are an excellent source of health-promoting phytochemicals such as vitamins, glucosinolates, and phenolics. The study aimed to investigate in vitro antioxidant, antiproliferative, apoptotic, and antibacterial activities of broccoli sprouts. Five-day-old sprouts extracted by 70% ethanol showed significant antioxidant activities, analyzed to be 68.8 μmol Trolox equivalent (TE)/g dry weight by 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic (ABTS) assay, 91% scavenging by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, 1.81 absorbance by reducing power assay, and high phenolic contents by high-performance liquid chromatography (HPLC). Thereafter, sprout extract indicated considerable antiproliferative activities towards A549 (lung carcinoma cells), HepG2 (hepatocellular carcinoma cells), and Caco-2 (colorectal adenocarcinoma cells) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, with IC50 values of 0.117, 0.168 and 0.189 mg/mL for 48 h, respectively. Furthermore, flow cytometry confirmed that Caco-2 cells underwent apoptosis by an increase of cell percentage in subG1 phase to 31.3%, and a loss of mitochondrial membrane potential to 19.3% after 48 h of treatment. Afterward, the extract exhibited notable antibacterial capacities against Bacillus subtilis and Salmonella Typhimurium with minimum inhibition concentration (MIC) values of 0.39 and 0.78 mg/mL, appropriately, along with abilities against Staphylococcus aureus and Escherichia coli with an MIC value of 1.56 mg/mL. Thus, broccoli sprouts were confirmed as a potential food source for consumers’ selection and functional food industry.

Laccase Production and Humic Acids Decomposition by Microscopic Soil Fungi

Laccase (para-diphenol:oxygen oxidoreductase, EC 1.10.3.2) is a phenol oxidase widespread in fungi and bacteria. In basidiomycetes, this enzyme is involved in the transformation of lignin and humic substances (HS) in soil. The role of laccases of soil ascomycetes and deuteromycetes in HS degradation is not established, and conditions of the enzyme production have been poorly studied. In the present work soil micromycetes, potential laccase producers, were isolated from typical soils of the forest, steppe, and foreststeppe zones of European Russia by plating on agar media with ABTS (2,2'-azino-bis(3-ethylbenzothiazoline- 6-sulphonic acid, sodium salt)) as the substrate. Their abundance, species composition, conditions of laccase production, and its relation to humic acids (HA) degradation in liquid and solid media were studied. Out of 68 strains isolated, 20 exhibited ABTS oxidation at initial plating on agar media. In pure cultures on agar media, oxidation was less pronounced, but in the presence of HA laccase production by some strains was higher than without HA. Significant and weak extracellular laccase production in liquid medium was observed for Acremonium murorum (Corda) W. Gams Z1710 and Botritis cinerea Pers. ex Fries Z1711, respectively. The level of laccase production by A. murorum was the same without inducers and in the presence of HA, while B. cinerea produced laccase only without inducers. No direct correlation was found between the presence of laccase and/or its activity and ability of the fungi to decolorize (degrade) HA. In liquid media active laccase producer A. murorum caused lower HA decolorization (43%) than B. cinerea (62%) and the fungi lacking extracellular laccase (54–81%). The role of micromycete oxidative systems in HA degradation requires further investigation.

Effects of in vitro digestion on the composition of flavonoids and antioxidant activities of the lotus leaf at different growth stages

SummaryThe lotus leaf is rich in phenolic compounds and has good antioxidant activity. The effects of simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) digestions on the active substances and antioxidant activity of the lotus leaf in different growth stages (D25, D45 and D65) were investigated. The total phenolic content of D25 and D45 significantly increased by SGF digestion but not D65 compared to the DW treatment. However, SIF treatment saw markedly increased total phenolic content across all growth stages (D25, D45 and D65). Moreover, the total flavonoid content at all growth stages was increased by SIF digestion compared to SGF treatment. The pepsin and trypsin had different effects on the FRAP and ABTS (2, 2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid)) antioxidant activities of the lotus leaf. The SGF digestion increased the FRAP antioxidant capacity of the lotus leaf, and SIF digestion increased the ABTS antioxidant capacity of the lotus leaf. The HPLC results showed that the main flavonoid compound in the lotus leaf was isoquercetin. This study provides a theoretical basis for the development and utilisation of the lotus leaf as an inexpensive natural and functional food ingredient.

Induction of caspase-mediated apoptosis using Alnus japonica extracts in AGS human gastric carcinoma cells

Alnus japonica has been used as a traditional oriental medicine for many diseases such as fever, haemorrhage and alcoholism. In this study, A. japonica extracts were evaluated for their in vitro antioxidant potentials and anticancer effects in AGS human gastric carcinoma cell line. The antioxidant properties of A. japonica extracts were evaluated using several biochemical assays, including FRAP (ferric reducing antioxidant power) assay, ABTS (2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid)), DPPH (2,2-diphenyl-1-picrylhydrazyl), alkyl and hydroxyl radical scavenging activity assay. Our study showed that ethanol extract of A. japonica (AJE) has a more potent antioxidant activity than its water extract. In addition, AJE extract inhibited the cell growth and induced the cell death by increasing reactive oxygen species (ROS) production in AGS cells. Moreover, AJE extract specifically triggered the apoptosis mediated through the activation of caspase-8, 7, 3, and poly-ADP ribose polymerase (PARP). Thus, these results suggest that AJE extract could be potentially useful as a new promising strategy in the therapy for gastric carcinoma cancer.

Scenedesmus obliquus: Antioxidant and antiviral activity of proteins hydrolyzed by three enzymes.

PurposeTo obtain protein hydrolysates from fresh water green algae Scenedesmus obliquus by three different enzymes and evaluate its antioxidant and antiviral activity.MethodsEnzymatic hydrolysates of green algae Scenedesmus obliquus protein were prepared by treatment with: 1.2% solution of pepsin, trypsin or papain. Protein was extracted from S. obliquus by three different extraction methods. Protein extracts and hydrolysates were assessed from stained gels following SDS–PAGE of samples. Antioxidant activity of protein hydrolysates was investigated.ResultsS. obliquus cells and protein extracts were rich in Arg, Lys, Asp, Ala, and His. Protein hydrolyzed by papain (Sd1pa) and protein hydrolyzed by trypsin (Sd2Try) induced highest antioxidant activity based on 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging (41.41% and 40.62%) respectively, and on 2,2′-azinobis 3-ethyl-benzothiazoline-6-sulphonate (ABTS) radical (87.03% and 45.12%) respectively, at 150 µg/ml. The inhibitory effect and mode of action of protein hydrolysates were evaluated against Coxsackie B3 virus (CVB3). Protein hydrolyzed by papain (Sd2pa) and protein hydrolyzed by pepsin (Sd1pep) at 100 µg/ml exhibited antiviral activity (66.2% and 57.6%, respectively), against (CVB3) from all protein hydrolysates.ConclusionS. obliquus protein hydrolysates have a potential as antioxidative neutraceutical ingredients and a potential therapeutic agent against CVB3.

Two New Diphenylketones and a New Xanthone from Talaromyces islandicus EN-501, an Endophytic Fungus Derived from the Marine Red Alga Laurencia okamurai.

Two new diphenylketones (1 and 2), a new xanthone (3), and a known xanthone analogue (4) were isolated and identified from Talaromyces islandicus EN-501, an endophytic fungus obtained from the fresh collected marine red alga Laurencia okamurai. Their structures were elucidated on the basis of NMR spectroscopic and X-ray crystallographic analysis. The joint isolation of benzophenones and xanthones from the same fungal strain supports the biogenesis of xanthones via a benzophenone intermediate. It is worth mentioning that xanthones 3 and 4 have a methyl group at C-6 and C-2, respectively, which is uncommon compared with typical xanthones usually having a methyl group at C-8. Compounds 1–4 exhibited potent antioxidative activities against DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonate) radicals with IC50 values ranging from 0.58 to 6.92 μg/mL, which are stronger than that of the positive controls BHT (butylated hydroxytoluene) and ascorbic acid. Compounds 1, 3, and 4 also showed inhibitory activities against several pathogenic bacteria.

Heterologous expression and characterisation of a laccase from Colletotrichum lagenarium and decolourisation of different synthetic dyes.

Laccases have received considerable attention in recent decades because of their ability to oxidise a large spectrum of phenolic and non-phenolic organic substrates and highly recalcitrant environmental pollutants. In this research, a laccase gene from Colletotrichum lagenarium was chemically synthesised using yeast bias codons and expressed in Pichia pastoris. The molecular mass of the recombinant laccase was estimated to be 64.6kDa by SDS-PAGE, and the enzyme exhibited maximum activity at pH 3.6-4.0 but more stability in buffer with higher pH (>pH 3.6). The optimal reaction temperature of the enzyme was 40°C, beyond which stability significantly decreased. By using 2,2'-azino-bis-(3-ethylbenzothiazoline)-6-sulphonate (ABTS) as a substrate, K m and V max values of 0.34mM and 7.11mMmin(-1)mg(-1), respectively, were obtained. Using ABTS as a mediator, the laccase could oxidise hydroquinone to p-benzoquinone and decolourise the synthetic dyes malachite green, crystal violet and orange G. These results indicated that the laccase could be used to treat industrial effluents containing artificial dyes.

Effect of air-drying temperature on extractable and non-extractable phenolics and antioxidant capacity of lime wastes

The lime industry is generating more waste due to the increasing demand of juice. In this study, extractable and non-extractable phenolics in the Gallega lime waste, dried at different temperatures were determined and their antioxidant capacities were evaluated using DPPH (2,2-diphenyl-picrylhydrazyl), ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6/sulphonic acid) and, ORAC (oxygen radical absorbance capacity) methods. The amount of non-extractable phenolics measured in lime waste dried at 60, 90, and 120°C were 38.4%, 39.2%, and 33.5%, respectively higher, compared to the amount of extractable phenolics. Dried lime waste is rich in extractable and non-extractable hesperidin (213.87 and 181.32mg/g, respectively), and eriocitrin (55.22 and 97.24mg/g, respectively) and non-extractable gallic acid (42.45μg/g,). The antioxidant capacities of extractable and non-extractable phenolics were from highest to lowest: ABTS>ORAC>DPPH and ABTS>DPPH>ORAC, respectively. The information reported here may encourage lime industry operators to re-evaluate their by-products, extending the application of lime fruits and reducing waste.

Phenolic Compounds and Metals in Tommy Atkins Mango (Mangifera indica L) Peels

Polyphenolic compounds and metals in lyophilized mango peels were identified and antioxidant capacities of these extracts were evaluated using in vitro assays. The concentrations of calcium, potassium, sodium, phosphorus, copper, iron, magnesium, manganese, zinc, cadmium and nickel were 2177, 7149, 7.416, 542.6, 3.227, 12.78, 1270, 23.47, 3.833, 0.040 and 1.125, respectively. To obtain the phenolics, two extracts were obtained (Ext-5 and Ext-7) using 80% methanol and 80% acetone, at 25 and 37.5 °C with stirring for 30 and 60 min, respectively. The extracts were applied to solid-phase extraction (SPE) cartridges and analyzed by liquid chromatography (HPLC-diode array detector) to identify and quantify polyphenols. The DPPH and ABTS radicals scavenging capacity was evaluated in these extracts. Phenolic acids, flavonoids, and one xanthone were identified in both extracts, independently of the conditions used in the extraction process. Compounds identified include syringic and sinapic acids, as well as taxofolin, isoquercetin, and mangiferin. The results suggest that the extracts’ capacity to sequester DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2’-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid)radicals was significant and may result from either the high concentrations of some of the identified polyphenols or synergy with polyphenols at lower concentrations. Keywords: ABTS, Antioxidant capacity, antioxidants, DPPH, flavonoids, free radicals scavenging capacity, mango, metals, mango peel, phenolic acids, phenols.

Identification, quantification and antioxidant activity of acylated flavonol glycosides from sea buckthorn (Hippophae rhamnoides ssp. sinensis)

A novel acylated flavonol glycoside: isorhamnetin (3-O-[(6-O-E-sinapoyl)-β-d-glucopyranosyl-(1→2)]-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside) (1), together with two known acylated flavonol glycosides: quercetin (3-O-[(6-O-E-sinapoyl)-β-d-glucopyranosyl-(1→2)]-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside) (2) and kaempferol (3-O-[(6-O-E-sinapoyl)-β-d-glucopyranosyl-(1→2)]-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside) (3) were isolated from the n-butanol fraction of sea buckthorn (Hippophae rhamnoides ssp. sinensis) berries for the first time by chromatographic methods, and their structures were elucidated using UV, MS, 1H and 13C NMR, and 2D NMR. Compounds 1–3 showed good scavenging activities, with respective IC50 values of 8.91, 4.26 and 30.90μM toward the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical; respective Trolox equivalent antioxidant capacities of 2.89, 4.04 and 2.44μMμM−1 toward 2,2′-azino-bis-3-ethyl-benzothiazoline-6-sulphonate (ABTS) radical. The quantitative analysis of the isolated acylated flavonol glycosides was performed by HPLC–DAD method. The contents of compounds 1–3 were in the range of 12.2–31.4, 4.0–25.3, 7.5–59.7mg/100g dried berries and 9.1–34.5, 75.1–182.1, 29.2–113.4mg/100g dried leaves, respectively.