Water extractable phytochemicals from Capsicum pubescens (tree pepper) inhibit lipid peroxidation induced by different pro-oxidant agents in brain: in vitro

This study seeks to determine the antioxidant and neuroprotective properties of aqueous extract of ripe and unripe Capsicum pubescens (tree pepper) on some pro-oxidant induced lipid peroxidation in rat’s brain (in vitro). The total phenol, vitamin C, ferric reducing antioxidant property (FRAP) and Fe (II) chelating ability of the extracts of C. pubescens were determined. Thereafter, the ability of the extracts to inhibit lipid peroxidation (induced by FeSO₄, sodium nitroprusside or quinolinic acid) in rat’s brain homogenates (in vitro) was determined. The results of the study revealed that ripe C. pubescens had a significantly higher (P < 0.05) total phenol content [ripe (113.7 mg/100 g), unripe (70.5 mg/100 g)] and reducing power than the unripe pepper. However, there was no significant difference (P > 0.05) in the vitamin C [ripe (231.5 μg/g), unripe (224.4 μg/g)] content and Fe (II) chelating ability of the extracts. However, both extracts significantly (P < 0.05) inhibited lipid peroxidation induced by the pro-oxidant agents [25 μM Fe(II), 7 μM sodium nitroprusside and 1 mM quinolinic acid] in the rat’s brain homogenates in a dose-dependent manner. Nevertheless, the ripe pepper extracts inhibited MDA (Malondialdehyhide) production in the rat’s brain homogenates than the unripe pepper. Conversely, both extracts did not significantly (P > 0.05) inhibit Fe (II)/H₂O₂ induced decomposition of deoxyribose. It was therefore concluded that ripe and unripe C. pubescens would inhibit lipid peroxidation in rat brain in vitro. However, the ripe pepper was a more potent inhibitor of lipid peroxidation in the rat’s brain; this is probably due to its higher phenol content and reducing power.     

Antioxidant activities and inhibitory effects of dietary plants against sodium nitroprusside induced lipid peroxidation in the mouse brain and liver

The antioxidant properties of aqueous extracts of 6 medicinal plants, Phyllanthus emblica, Terminalia chebula (black and yellow), Terminalia arjuna, Balsamodendron Mukul, and Alium sativum against lipid peroxidation in mouse tissues were investigated. Extracts showed inhibition against thiobarbituric acid reactive species (TBARS) induced by pro-oxidant (5 μM sodium nitroprusside) in the mouse brain and liver. Extracts displayed high free radical scavenging activities against DPPH (IC₅₀, 23.23±1.2 μg/mL, P. emblica), 20.24±0.9 μg/mL (T. chebula yellow), 17.33±1.1 μg/mL (T. chebula black), 19.44±0.45 μg/mL (T. arjuna), 56.59±2.1 μg/mL (Balsamo-dendron Mukul), and higher than 200 μg/mL (A. sativum). Higher antioxidant and inhibitory effects of T. chebula black are attributed to a higher phenolic content, Fe(II) chelating ability, reducing ability, nitric oxide radical scavenging, and free radical scavenging activity. Oxidative stress in the brain and liver could potentially be managed/prevented by dietary intake of these plants.     

Partial purification and characterization of peroxidase from olives (<Emphasis Type="Italic">Olea europaea</Emphasis> cv. Koroneiki)

The enzyme peroxidase (POD) activity was extracted from olives (Olea europaea cv. Koroneiki) and was partially purified by ammonium sulfate fractionation and gel permeation chromatography (Sephacryl S 300). Further characterization of the POD was performed using the ammonium sulfate purified fraction. POD showed a molecular mass of 44 ± 2 kDa and it expressed catalytic activity with 2,2′-azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS), N,N-dimethyl-p-phenylenediamine (DMPD) and some olive fruit phenols. However, the enzyme was found ineffective as regards the oxidation of oleuropein, the major polyphenol of olives, as well as with coumaric, ferulic, ascorbic and p-hydroxy benzoic acids. pH optimum of the peroxidase-catalyzed oxidation depended on the substrate used and it varied from 4.0 to 6.0. Olive peroxidase shows high thermal stability. Oleuropein, the major polyphenol of olives, drastically inhibited ABTS peroxidation by the POD preparation with an IC₅₀ value of 47 μM. The presence of POD enzyme activity in virgin olive oil samples was also confirmed.     

核桃多酚与蛋白质的作用方式及其抗氧化活性

以核桃为研究对象,将核桃碱提蛋白和酸提蛋白经溶剂作用后超滤,通过破坏核桃多酚-蛋白复合体间的作用力得到不同结合态多酚,测定多酚含量及其抗氧化活性,以期探究核桃酚类物质与核桃蛋白化学键结合机制。研究结果表明,在pH3.5和pH11条件下,游离态多酚含量分别为6.46、6.27 mg/g,占总酚含量的25.15%、29.77%,非共价结合态多酚含量分别为11.31、7.74 mg/g,占总酚含量的44.02%、36.75%,共价结合态含量7.92、7.05 mg/g,占总酚含量的30.83%、33.48%。由此可知,非共价结合为核桃多酚与核桃蛋白质的主要结合方式。在pH3.5和pH11条件下,游离态多酚对DPPH自由基的清除率分别为82.34%、43.68%,Fe2+螯合率分别为71.88%、49.96%,还原力吸光度值分别为1.157、0.857,脂质抗过氧化能力分别为47.71%、32.69%。在5种不同结合态多酚中,游离态多酚的抗氧化活性显著高于其他结合态多酚(p<0.05)。     

Antioxidant and antibacterial activities of polyphenolic compounds from bitter cumin (Cuminum nigrum L.)

Cumin is one of the commonly used spices in food preparations. It is also used in traditional ayurvedic medicine as a stimulant, carminative and astringent. Earlier we have reported that bitter cumin (Cuminum nigrum L.) possess the most potent antioxidant activity among cumin varieties—cumin, black cumin and bitter cumin. In this study, we have further characterized the polyphenolic compounds of bitter cumin and also their antioxidant and antibacterial activity using different model systems. The major polyphenolic compounds of cumin seeds were extracted with 70% methanol, 70% acetone, water, separated by HPLC and their structures were elucidated by LC-MS. The profile of phenolic acids/flavonols in bitter cumin were found to be gallic acid, protocatechuic acid, caffeic acid, ellagic acid, ferulic acid, quercetin and kaempferol. The antioxidant activity of the cumin extract was tested on 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging, soybean lipoxygenase-dependent lipid peroxidation, rat liver microsomal lipid peroxidation and superoxide anion (O²⁻) scavenging. The bitter cumin extract exhibited high antioxidant activity with IC₅₀ values of 14.0±0.5 μg, 28.0±3.0 μg, 110±14.0 μg and 125.4±8.7 μg of the extract, respectively for DPPH free radical scavenging, soybean lipoxygenase-dependent lipid peroxidation, rat liver microsomal lipid peroxidation and superoxide anion scavenging. Further, the extract offered a significant protection against DNA damage induced by hydroxyl radicals. Among a spectrum of food-borne pathogenic and spoilage bacteria tested, the cumin extract significantly inhibited the growth of Bacillus subtilis, Bacillus cereus and Staphylococcus aureus. Thus, bitter cumin with an array of polyphenolic compounds possesses potent antioxidant and antibacterial activities.An erratum to this article can be found at     

Chelating,antioxidant and antiproliferative activity of <Emphasis Type="Italic">Vicia sativa</Emphasis> polyphenol extracts

The metal chelating activity, antioxidant properties, and the effect on cell growth of a polyphenol extract from Vicia sativa have been investigated, and compared to those of soybean. The extracts from V. sativa seeds contained three and five times more polyphenols and flavonoids than soybean, respectively. The soybean polyphenol extracts showed higher copper and iron chelating activity than those from V. sativa, although polyphenols from V. sativa were more effective in preventing β-carotene oxidation and showed higher reducing power and scavenging activity than soybean polyphenols. In addition, V. sativa polyphenols were toxic to THP-1 leukemic cells, as opposed to polyphenols extracted from soybean that did not show any antiproliferative activity at similar concentrations. In conclusion, V. sativa polyphenol extracts show promising antioxidant and antiproliferative activities that may be of interest from a functional point of view and for the revalorization of this ancient crop.     

Effects of β-carotene on soybean lipoxygenase activity: kinetic studies

β-carotene directly influences the amount of soybean lipoxygenase (LOX) in the reaction medium available for the catalytic conversion of linoleic acid into corresponding hydroperoxides. Inhibition of LOX by β-carotene was predominantly of the noncompetitive type. The mean K _m(app) value was estimated to be 13.25 μM ±0.15 μM for linoleic acid while the mean K _i value was estimated to be 2.56 μM ±0.14 μM for β-carotene. V _m(app) values decreased from 1.90ΔA _{234 nm}/min to 0.38ΔA _{234 nm}/min as the concentration of β-carotene increased. The IC₅₀ value for β-carotene was 2.49 μM±0.21 μM. It is shown here that β-carotene is an efficient LOX inhibitor, effective at low-level concentration enzyme-dependent peroxidation of linoleic acid. Presence of β-carotene keeps LOX in its reduced form of Fe(II) and the oxidation of linoleic acid is prevented.     

不同加工方式对青稞中酚类物质的影响

为探明不同加工方式对青稞全谷物中酚类物质的影响,最大程度地保留抗氧化和降血糖活性物质。以海南昆仑17号青稞籽粒为实验材料,分别采用蒸制、煮制、炒制、微波、烤制、空气炸锅等六种加工方式对青稞籽粒进行热加工处理,分析加工前后青稞中游离多酚、结合多酚、游离黄酮和结合黄酮的含量,以及抗氧化和降血糖活性的变化。结果表明,不同加工方式制备的青稞多酚和黄酮含量存在一定程度上的差异。与未加工相比,其他加工方式所得青稞游离多酚和游离黄酮的含量均显著降低（P<0.05）（除炒制外）,结合多酚和结合黄酮的含量均升高。与未加工相比,蒸制和煮制的方式对青稞游离多酚含量的损失高达43.77%和67.85%,炒制使青稞结合黄酮含量增加38.10%。此外,不同加工方式的青稞多酚提取物具有较好的DPPH自由基清除能力和α-葡萄糖苷酶抑制活性,且清除和抑制能力在一定浓度范围内具有浓度依赖性。在六种加工方式中,炒制处理青稞游离和结合多酚提取物（5 mg/mL）的DPPH自由基清除率最高,分别为70.01%、54.52%,且其α-葡萄糖苷酶抑制率也最高,分别为84.84%、75.70%。因此,炒制处理可较好地保留热加工前全谷物青稞中酚类物质的含量,从而发挥抗氧化和降血糖作用。     

凤眼果壳多酚的抗氧化和抗人肺癌细胞A549增殖活性

本研究以凤眼果壳为原料,提取凤眼果壳游离态和结合态多酚,通过不同极性有机溶剂萃取游离态多酚获得四相提取物,分别是正己烷相(HF),乙酸乙酯相(EAF),正丁醇相(BF)和水相(AqF).测量游离态、结合态和萃取后的四相提取物的总多酚和总黄酮含量,结果表明游离态的多酚和黄酮含量均比结合态高.萃取后的四相提取物中,EAF的...     

Water-extractable phytochemicals from Phyllanthus niruri exhibit distinct in vitro antioxidant and in vivo hepatoprotective activity against paracetamol-induced liver damage in mice

The antioxidative and hepatoprotective potential of Phyllanthus niruri, a widely used medicinal plant in Brazil, were investigated. The aqueous extracts of leaves showed inhibition against thiobarbituric acid-reactive species (TBARS), induced by different pro-oxidants (10 μM FeSO₄ and 5 μM sodium nitroprusside) in rat liver, brain and kidney homogenates. The extracts also lowered the formation of TBARS in phospholipids extracted from egg yolk. The plant exhibited strong antioxidant activity in the 2,2-diphenyl-1-picrylhydrazyl free radical (IC₅₀, 43.4 ± 1.45 μg/ml) and iron chelation assay. The hepatoprotective activity of the extracts were also demonstrated in vivo against paracetamol-induced liver damage, as evidenced by the decrease in serum glutamate oxaloacetate transaminase (GOT), and glutamate pyruvate transaminase (GPT), and increased catalase activity in the liver in treatment groups, compared to the control. The results of the present study suggest the potential use of P. niruri in the treatment of various diseases, among which liver disease is the most important, due to its ability to act as an antioxidant. Furthermore, since the treatment of human intoxications with paracetamol is always limited to the administration of N-acetyl-cysteine, additional studies would be important to determine whether aqueous extracts of P. niruri could increase the efficacy of N-acetyl-cysteine against paracetamol acute hepatotoxicity.     

Isolation and characterization of mutatoxanthin-epimers from red paprika (Capsicum annuum)

 (3S,5R,8R,3′R)- and (3S,5R,8S,3′R)-mutatoxanthin were isolated from red spice paprika (Capsicum annuum) and characterized by their UV-VIS, CD, ¹H-NMR, ¹³C-NMR and mass spectra. Received: 22 November 1999 / Revised version: 11 February 2000     

Novel Coulometric Approach to Evaluation of Total Free Polyphenols in Tea and Coffee Beverages in Presence of Milk Proteins

Electrogenerated hexacyanoferrate(III) ions have been used as coulometric titrant for the determination of total free polyphenols in beverages. Stoichiometric coefficients of natural flavonoids (rutin, quercetin, and taxifolin) in their reaction with [Fe(CN)₆]³⁻ ions were established. The number of electrons involved in the oxidation corresponds to number of phenolic OH groups in the molecule of polyphenols. Proteins (casein and bovine serum albumin) bind polyphenols in the complexes that leads to significant decrease of free polyphenols portion (in the range of 5–76%). Ferric reducing power (FRP) of eight tea and 17 coffee samples was determined. The absolute FRP values ranged from 224 to 405 and from 241 to 488 C cup⁻¹ for tea and coffee, respectively. Effect of milk proteins on total free polyphenols of tea and coffee and appropriate alteration of beverages FRP were evaluated. Milk addition decreases FRP of drinks in the range of 10–70% reflecting high content of inactive polyphenols.     

沙棘多糖清除自由基及抗脂质过氧化作用研究

目的:探讨沙棘多糖体外清除自由基及抗脂质过氧化作用。方法:采用体外抗氧化活性法测定沙棘多糖对DPPH自由基、羟自由基和超氧阴离子自由基清除能力及沙棘多糖总还原能力;制备5%小鼠肝脏匀浆,通过模拟建立体外小鼠肝匀浆自发性脂质过氧化模型、CCl₄体外诱导小鼠肝匀浆脂质过氧化模型、H₂O₂体外诱导小鼠肝匀浆脂质过氧化模型、Fe2+-V_C 体外诱导小鼠肝脏脂质过氧化模型,利用TBA显色法,观察沙棘多糖对脂质过氧化的抑制作用。结果:沙棘多糖对DPPH自由基、OH自由基和超氧阴离子自由基都具有一定的清除能力,其IC₅₀值分别为1.55、1.23、8.31 mg/mL,其浓度为2 mg/mL时,还原能力稍高于同浓度V_C。沙棘多糖对小鼠肝匀浆自发性脂质过氧化及CCl₄、H₂O₂、Fe2+-V_C所诱导的肝脏脂质过氧化均具有抑制作用,其IC₅₀值分别为1.10、1.59、9.13、1.39 mg/mL。结论:沙棘多糖具有一定的抗氧化活性及抗脂质过氧化作用。     

Benzyloxybenzaldehydethiosemicarbazone: Extractive Spectrophotometric Reagent for the Determination of Cu(II) in Food and Water Samples

Benzyloxybenzaldehydethiosemicarbazone (BBTSC) was prepared and developed a new method for the simple, highly selective, and extractive spectrophotometric determination of copper(II) with BBTSC at wavelength 370 nm. The metal ion formed a bluish green colored complex with BBTSC in acetate buffer of pH 5.0, which was easily extractable into n-butanol with 1:1(metal/ligand) composition. The method obeys Beer’s law in the range of 0.5–5.2 ppm. The molar absorptivity and Sandell’s sensitivity were found to be 1.5 × 10⁴ l mol⁻¹ cm⁻¹ and 0.00412 g cm⁻², respectively. The correlation coefficient of the Cu(II)–BBTSC complex was 0.998, which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD; n = 10), which was 0.377% and its detection limit 0.0204 μg ml⁻¹. The interfering effect of various cations and anions were also studied. The proposed method was successfully applied to the determination of copper(II) in food and water samples. Comparing the results with those obtained using an atomic absorption spectrophotometer tested the validity of the method.     

Effect of a Polyphenol–Vacuum Packaging on Lipid Deterioration During an 18-Month Frozen Storage of Coho Salmon (<Emphasis Type="Italic">Oncorhynchus kisutch</Emphasis>)

A packaging system combining a polyphenol-rich film and vacuum (PPRF–VP) was applied to farmed coho salmon (Oncorhynchus kisutch) muscle for an 18-month storage (−18 °C). For it, two different concentrations of polyphenol compounds (namely, p-coumaric and ferulic acids) obtained from a barley husk extract were applied (PPRF–VP conditions) and compared to vacuum packaging without polyphenol presence (vacuum control; VP condition) and to packaging in the absence of vacuum and polyphenols (control; CP condition). The study was addressed to lipid hydrolysis and oxidation development and to lipid changes related to nutritional value. Both PPRF–VP conditions provided an inhibitory effect (p < 0.05) on conjugated diene and fluorescent compound formation in frozen salmon. Compared to CP condition, vacuum packaging (PPRF–VP and VP conditions) led to lower (p < 0.05) peroxide and anisidine values and to an inhibitory effect (p < 0.05) on α- and γ-tocopherol losses. No effect (p > 0.05) of polyphenol presence and vacuum packaging could be inferred on free fatty acid formation (hydrolysis development) and on polyunsaturated fatty acid retention (polyene index assessment). A low rancid odour development was observed in all kinds of fish samples, this being lower (p < 0.05) in fish kept under vacuum (PPRF–VP and VP) conditions.     

挤压膨化对青稞中不同形态多酚组成及抗氧化活性的影响

以独立花青稞为材料,探究挤压膨化对青稞中不同形态多酚组分及抗氧化活性的影响。采用福林酚法测定膨化前后青稞样品的多酚含量;采用高效液相色谱法测定醇提物中的7种多酚单体含量;采用1,1-二苯基-2-三硝基苯肼自由基清除法测定抗氧化能力的变化。结果表明,经挤压膨化处理后,总多酚、游离型多酚和结合型多酚分别降低了52.7%,89.3%,23.7%,酯化型多酚含量较低,略微增加了2.49 mg/100 g;游离型多酚中检测出的多酚种类增加了3种,7种多酚单体在结合型多酚中均有测出;其中阿魏酸含量最高且主要以结合态存在,其含量处理后显著增加;此外,两种条件下青稞提取物抗氧化活性分别为1.76,0.93 mg/g,多酚含量与抗氧活性呈极显著正相关。表明挤压膨化技术运用于青稞加工之中,在改变青稞质构和口感的同时会降低多酚含量及抗氧化活性。     

Purification and characterization of antioxidative peptide derived from muscle of conger eel (Conger myriaster)

The tryptic hydrolysate of conger eel (Conger myriaster) muscle protein was fractionated according to the molecular weights using ultrafiltration (UF) membrane system. The lowest molecular weight fraction (<1 kDa) with higher antioxidative properties was purified using consecutive chromatographic techniques and designated conger eel antioxidative peptide (CEAP). Sequence determination revealed that it contained nine amino acids in its sequence (LGLNGDDVN) and the molecular mass was identified to be 928 Da. CEAP performed better than the natural antioxidant, α-tocopherol for the prevention of lipid peroxidation in vitro. Additionally, it scavenged hydroxyl radicals and carbon-centered radicals at IC₅₀ values of 74.1 μM and 78.5 μM, respectively. Therefore these results suggested that the peptides derived from conger eel protein hydrolysates are responsible for higher antioxidative properties and molecular weight as well as presence of hydrophobic amino acids highly contributed for their antioxidation.     

Polyphenol–cellulose interactions: effects of pH,temperature and salt

Response surface methodology was employed to investigate the effects of common food and digestive tract conditions (pH, temperature, sodium chloride) on the adsorption of polyphenols to cellulose. Major dietary polyphenols selectively bound to cellulose to different extents and exhibited different binding behaviour changes with the environment. Three factors were studied, of which pH (3–7) was found to be the most influential factor, followed by temperature (4–37 °C), while NaCl (0–100 mm ) had no significant effect on polyphenol adsorption. Polyphenol adsorption was sensitive to variation in physicochemical parameters: cyanidin‐3‐glucoside > ferulic acid > (+/?)‐catechin. Second‐order polynomial equation was a significant and adequate model to express the interaction relationships between polyphenol adsorption and changes in the binding conditions, as the experimental test values agreed with predicted adsorption values under optimised binding conditions. These findings contribute to knowledge on the mechanism of polyphenol–cellulose interactions, important for both food quality and nutritional value.     

Iron(II)-induced isomerization of (<Emphasis Type="Italic">all</Emphasis>-<Emphasis Type="Italic">E</Emphasis>)-xanthophyll pigments lutein,zeaxanthin, and β cryptoxanthin in acetone

Lutein, zeaxanthin, and β-cryptoxanthin are xanthophyll pigments that own conjugated double bonds; some factors can convert (all-E)-xanthophylls to their (Z)-isomers such as high temperature, illumination, and oxidants. In the present work, the Fe(II)-induced isomerization of (all-E)-lutein, (all-E)-zeaxanthin, and (all-E)-β-cryptoxanthin in acetone were analyzed by HPLC coupled with DAD and APcI-MS. The three (all-E)-xanthophylls were baseline separated and their (Z)-isomers were identified by the chromatographic retention, UV/vis spectra and positive mass spectrometry with reference values reported in the literature. The results showed that Fe(II) exhibited a rapidly isomerization induction of (all-E)-xanthophylls to their (Z)-isomers exceeding a 8/1 mass ratio of Fe(II)/pigments. The (13-Z)-lutein and (13′-Z)-lutein were identified as the major (Z)-isomers of (all-E)-lutein treated with FeSO₄·7H₂O, and (13-Z)-zeaxanthin was identified as the major isomerization product of (all-E)-zeaxanthin. Furthermore, a type of (Z)-β-cryptoxanthin was also detected. Increasing either mass ratio of Fe(II)/pigments or the incubation time of FeSO₄·7H₂O and (all-E)-xanthophylls may affect on the stabilities of (Z)-isomers derived from (all-E)-xanthophylls.     

Fermentation Changes the Nutritive Value,Polyphenol Distribution,and Antioxidant Properties of Parkia biglobosa Seeds (African Locust Beans)

This present study was carried out to investigate the effect of natural fermentation on the nutritive value (proximate composition), polyphenolic distribution, and antioxidant properties of African locust beans (Parkia biglobosai). African locust bean (ALB) seeds were boiled for 12 h, dehulled and subjected to natural solid substrate fermentation without any inoculation for 4 days. The proximate composition of the fermented and unfermented locust bean seeds was subsequently determined. Thereafter, the polyphenol distribution, reducing power, DPPH free-radical scavenging antioxidant activity, and inhibition of lipid peroxidation were determined for soluble free and bound polyphenol extracts. The results of the study revealed that fermentation caused a significant increase (P < 0.05) in the ALB protein content with 18.3% in unfermented and 36% in fermented. The fat content in unfermented was 13.2% versus 26.8% in fermented, while there was no significant changes (P > 0.05) in ash, crude fiber, or moisture content. However, there was a significant decrease (P < 0.05) in the carbohydrate content. The total phenolic content, reducing ability and free-radical scavenging ability were high in both the fermented and unfermented ALB. Fermentation caused a significant increase (P < 0.05) in the free phenolic content of the ALB and a significant decrease (P < 0.05) in the bound phenolic content of ALB. The free-phenolic fraction from both fermented and unfermented ALB had high reducing power, free radical scavenging ability, and inhibition of lipid peroxidation using cow brain tissues. Free phenolic extract from the fermented ALB had a significantly higher (P < 0.05) antioxidant activity than that of unfermented ALB. Results suggest that fermentation will increase the nutritive values, free phenolic and antioxidant activity of the African locust bean, making it a potential functional food in addition to its traditional role of dietary protein source.