alpha-Glucosidase inhibitory action of natural acylated anthocyanins. 2. alpha-Glucosidase inhibition by isolated acylated anthocyanins

Four diacylated pelargonidin (Pg: SOA-4 and SOA-6), cyanidin (Cy: YGM-3), and peonidin (Pn: YGM-6) 3-sophoroside-5-glucosides isolated from the red flowers of the morning glory, Pharbitis nil cv. Scarlett O'Hara (SOA), and the storage roots of purple sweet potato, Ipomoea batatas cv. Ayamurasaki (YGM), were subjected to an alpha-glucosidase (AGH) inhibitory assay, in which the assay was performed with the immobilized AGH (iAGH) system to mimic the membrane-bound AGH at the small intestine. As a result, the acylated anthocyanins showed strong maltase inhibitory activities with IC(50) values of <200 microM, whereas no sucrase inhibition was observed. Of these, SOA-4 [Pg 3-O-(2-O-(6-O-(E-3-O-(beta-D-glucopyranosyl)caffeyl)-beta-D-glucopyranosyl)-6-O-E-caffeyl-beta-D-glucopyranoside)-5-O-beta-D-glucopyranoside] possessed the most potent maltase inhibitory activity (IC(50) = 60 microM). As a result of a marked reduction of iAGH inhibitory activity by deacylating the anthocyanins, that is, Pg (or Cy or Pn) sophoroside-5-glucoside, acylation of anthocyanin with caffeic (Caf) or ferulic (Fer) acid was found to be important in the expression of iAGH (maltase) inhibition. In addition, the result that Pg-based anthocyanins showed the most potent maltase inhibition, with an IC(50) value of 4.6 mM, and the effect being in the descending order of potency of Pg > Pn/Cy strongly suggested that no replacement at the 3'(5')-position of the aglycon B-ring may be essential for inhibiting iAGH action.     

Molar absorptivity and color characteristics of acylated and non-acylated pelargonidin-based anthocyanins.

The effects of glycosylation and acylation on the spectral characteristics, molar absorptivity, and color attributes of purified acylated and non-acylated pelargonidin derivatives were compared. Pigments were obtained from strawberries, radishes, red-fleshed potatoes, and partially hydrolyzed radish pigments. Individual pigments were isolated by using semipreparative HPLC. Spectral and color (CIELch) attributes of purified pigments were measured. Molar absorptivity ranged from 15 600 to 39 590 for pelargonidin-3-glucoside (pg-3-glu) and pg-3-rutinoside-5-glucoside acylated with p-coumaric acid, respectively. The presence of cinnamic acid acylation had a considerable impact on spectral and color characteristics, causing a bathochromic shift of lambda(max). Sugar substitution also played an important role, with a hypsochromic shift caused by the presence of glycosylation. Pg-3, 5-diglu and pg-3,5-triglu possessed a higher hue angle (>40 degrees ) than the other pg derivatives at pH 1.0, corresponding to the yellow-orange region of the color solid. Acylation with malonic acid did not affect lambda(max) and showed little effect on color characteristics. The solvent system had an effect not only on the molar absorptivity, but also on the visual color characteristic of the pigments.     

Identification of reaction products of acylated anthocyanins from red radish with peroxyl radicals

Red radish anthocyanin extract, which consists of 12 known acylated anthocyanins, was reacted with 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) to generate peroxyl radicals under acidic pH conditions at 37 degrees C. The reaction products were isolated using preparative HPLC, and their chemical structures were determined to be p-hydroxybenzoic acid (1), 6-O-(E)-p-coumaroyl-2-O-beta-d- glucopyranosyl-alpha-d-glucopyranoside (3), p-coumaric acid (4), 6-O-(E)-feruloyl-2-O-beta-d-glucopyranosyl-alpha-d-glucopyranoside (5), and ferulic acid (6). Some products were not identified. HPLC analyses of the mixture of acylated pelargonidin isolated from red radish and AAPH revealed that the acylated pelargonidins possess the radical scavenging ability on some common sites even if the characteristics of the intramolecular acyl units are different. Degradation rates of acylated pelargonidins and the formation rates of the resulting reaction products were found to be quite different.     

Anthocyanins in berries of ribes including gooseberry cultivars with a high content of acylated pigments

Consumption of berries from various sources including the genus Ribes has been associated with diverse potential health benefits. The 14 examined cultivars of European gooseberry (R. grossularia L.) contained in various proportions the 3-glucoside (3), 3-rutinoside (4), 3-xyloside (7), 3-O-beta-(6' '-E-caffeoylglucopyranoside) (8), and 3-O-beta-(6' '-E-p-coumaroylglucopyranoside) (10) of cyanidin and the 3-rutinoside (6) and 3-glucoside of peonidin (5). Pigments 3, 4, delphinidin 3-rutinoside (2), delphinidin 3-glucoside (1), and minor amounts of 6, 7, and 10 were found in red flowering currant (R. sanguineum Pursh). Golden currant (R. aureum Pursh) contained 3, 4, and trace amounts of 1, 6, and 7, while alpine currant (R. alpinum L.) contained 3, 4, and trace amounts of 10. The major anthocyanins in two cultivars of jostaberries (R. x nidigrolaria Bauer), 1-4, 8, and 10, reflected that this hybrid contained the major anthocyanins of both parents, black currant and gooseberry. This is the first complete identification of 8 and the ring size of the sugar of 10. Pigment 9 was tentatively identified as cyanidin 3-(6' '-Z-p-coumaroylglucoside). This new pigment occurred in minor amounts (<2%) in all R. grosssularia and R. x nidigrolaria cultivars. No commercially available berries have been reported to contain such high proportions of aromatic acylated anthocyanins as found in the gooseberry cultivars "Sams?", "Hinnom?ki Red", "Taastrup", "Lofthus", and "Glendal", which are in this context the most obvious candidates for consumption, colorant, and breeding programs.     

effect of dose size on bioavailability of acylated and nonacylated anthocyanins from red cabbage (Brassica oleracea L. Var. capitata)

Recent studies indicate that anthocyanin intake conveys a variety of health benefits, which depend on absorption and metabolic mechanisms that deliver anthocyanins and their bioactive metabolites to responsive tissues. The anthocyanin bioavailability of red cabbage (Brassica oleracea L. var. capitata) was evaluated as reflected by urinary excretion of anthocyanins and anthocyanin metabolites. Twelve volunteers consumed 100, 200, and 300 g of steamed red cabbage (containing 1.38 micromol of anthocyanins/g of cabbage) in a crossover design. Anthocyanin concentration in cabbage extract and urine was measured by HPLC-MS/MS. Six nonacylated and 30 acylated anthocyanins were detected in red cabbage, and 3 nonacylated anthocyanins, 8 acylated anthocyanins, and 4 metabolites were present in urine. Mean 24 h excretion of intact anthocyanins increased linearly from 45 (100 g dose) to 65 nmol (300 g dose) for acylated anthocyanins and from 52 (100 g dose) to 79 nmol (300 g dose) for nonacylated anthocyanins. Urinary recovery of intact anthocyanins (percent of anthocyanin intake) decreased linearly from 0.041% (100 g dose) to 0.020% (300 g dose) for acylated anthocyanins and from 0.18% (100 g dose) to 0.09% (300 g dose) for nonacylated anthocyanins. Anthocyanin metabolites consisted of glucuronidated and methylated anthocyanins. The results show that red cabbage anthocyanins were excreted in both intact and metabolized forms and that recovery of nonacylated anthocyanins in urine was >4-fold that of acylated anthocyanins.     

Stability to light, heat, and hydrogen peroxide at different pH values and DPPH radical scavenging activity of acylated anthocyanins from red radish extract

The stability of red radish extract to light, heat, and hydrogen peroxide at different pH values (3, 5, and 7) was examined, in which major anthocyanins were pelargonidin glycosides acylated with a combination of p-coumaric, ferulic, or caffeic acids. The light irradiation (fluorescence light, 5000 lx; at 25 degrees C) indicated that the red radish extract was more stable at lower pH than at higher pH. The HPLC analyses revealed that diacylated anthocyanins in the extract were more stable to light at pH 3 than monoacylated anthocyanins. No significant difference in degradation rates of acylated anthocyanins at pH 5 was observed, whereas anthocyanins acylated with p-coumaric or ferulic acids were more stable at pH 7 than ones with caffeic acids. The stability to heat (at 90-95 degrees C) showed a tendency similar to that for light. The number of intramolecular acyl units contributes to stability to light and heat at lower pH, whereas the characteristics of intramolecular acyl units influence the stability at higher pH. The degradation behavior of red radish extract to H2O2 were almost the same to those of light and heat, depending on the pH. However, HPLC analyses revealed that the stability of individual acylated anthocyanins were independent of the pH. These data suggest that the characteristics, the number, and the binding site of intramolecular acyl units affect the stability of anthocyanin to H2O2. DPPH radical scavenging activity of all acylated anthocyanins was higher than those of pelargonidin and perlargonidin-3-glucoside. The activity of acylated anthocyanins mostly depended on the activity of intramolecular acyl units (caffeic acid > ferulic acid > p-coumaric acid). However, the activity was highly affected by the binding site of intramolecular acyl units even if anthocyanins have common acyl units.     

Sources of antioxidant activity in Australian native fruits. Identification and quantification of anthocyanins

Selected native Australian fruits, muntries (Kunzea pomifera F. Muell., Myrtaceae), Tasmanian pepper berry (Tasmanian lanceolata R. Br., Winteraceae), Illawarra plum (Podocarpus elatus R. Br. ex Endl., Podocarpaceae), Burdekin plum (Pleiogynium timorense DC. Leenh, Anacardiaceae), Cedar Bay cherry (Eugenia carissoides F. Muell., Myrtaceae), Davidson's plum (Davidsonia pruriens F. Muell. var. pruriens, Davidsoniaceae), and Molucca raspberry (Rubus moluccanus var. austropacificus van Royen, Rosaceae), were evaluated as sources of antioxidants by 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power assays and compared with blueberry (Vaccinum spp. cv. Biloxi). The total reducing capacity of five fruits was 3.5-5.4-fold higher than that of blueberry, and the radical scavenging activities of muntries and Burdekin plum were 1.5- and 2.6-fold higher, respectively. The total phenolic level by Folin-Ciocalteu assay highly correlated with the antioxidant activity. Therefore, systematic research was undertaken to identify and characterize phenolic complexes. In the present study we report on the levels and composition of anthocyanins. The HPLC-DAD and HPLC/ESI-MS-MS (ESI = electrospray ionization) analyses revealed simple anthocyanin profiles of one to four individual pigments, with cyanidin as the dominating type. This is the first evaluation of selected native Australian fruits aiming at their utilization for the development of novel functional food products.     

天然花青素提取物与壳聚糖明胶复合膜的制备和表征

为了开发天然的抗氧化活性包装材料,以紫甘蓝、黑米、玫瑰、蓝莓为原料制备天然花青素提取物与壳聚糖明胶的复合膜,比较分析了不同天然花青素提取物对复合膜的物理、机械、抗氧化活性及形貌结构的影响。结果表明：天然花青素提取物的加入,增加了膜的厚度,显著（P<0.05）影响膜的含水率、水溶性及外观形貌。壳聚糖明胶复合膜的水蒸汽透过率（water vapor permeability,WVP）为10.69×10-11 g/(m·s·Pa)。玫瑰花青素提取物的加入使得WVP值降低,而其他花青素提取物的加入使得WVP值增大。玫瑰复合膜的拉伸强度最大,达到27.03 MPa,断裂伸长率最小,黑米花青素提取物可增加复合膜的延展性,断裂伸长率最大为57.67%。傅里叶红外光谱表明天然花青素提取物的羟基基团与壳聚糖的氨基基团产生相互作用。扫描电镜结果表明花青素提取物影响微观结构,而且生物相容性较好。加入天然花青素提取物后,复合膜抗氧化活性均显著（P<0.05）提高,且玫瑰复合膜有着较高的抗氧化活性,1,1-二苯基-2-苦基肼（DPPH）自由基清除能力达到95.47%。结果表明：玫瑰花青素提取物更有利于开发阻湿性能好,水溶性低,抗拉伸和抗氧化活性高的包装材料,具有良好的应用前景。     

Antiulcer activity of anthocyanins from Rubus coreanus via association with regulation of the activity of matrix metalloproteinase-2

Anthocyanins were extracted from the fruits of Rubus coreanus. Whether their antioxidant properties and antiulcer activity in gastric ulceration have been accompanied by the activation of matrix metalloproteainse-2 (MMP-2) was investigated. To assess the effect of anthocyanins on gastric ulcer, the rats were administered with anthocyanins (20, 50, and 80 mg/kg of body weight) before treatment with naproxen (80 mg/kg of body weight) to induce gastric ulceration. Lipid peroxidation and the activities of radical scavenging enzymes such as catalase, superoxide dismutase, and glutathione peroxidase were determined. The MMP-2 level was tested by zymography and Western blot. Anthocyanins of R. coreanus exhibit possible antiulcer activity in acute ulcer in a rat model by preventing lipid peroxidation and a significant increase in the activities of antioxidant enzymes such as catalase, superoxide dismutase, and glutathione peroxidase. Also, anthocyanins induce activation of MMP-2 and attenuate the activity of the proinflammatory molecules, such as tumor necrosis factor-α and interleukin-1β.     

alpha-Glucosidase inhibitory activity of some Sri Lanka plant extracts, one of which, Cassia auriculata, exerts a strong antihyperglycemic effect in rats comparable to the therapeutic drug acarbose

Some Sri Lanka plant stuffs were examined regarding in vitro and in vivo alpha-glucosidase (AGH) inhibitory actions. According to the results, water extracts and methanol extracts of dried fruits of Nelli (Phylanthus embelica), methanol extracts of dried flowers of Ranawara (Cassia auriculata), and water extracts of latex of Gammalu (Pterocarpus marsupium) were found to have a potential AGH inhibitory activity. In particular, Ranawara methanol extract showed the strongest AGH inhibitory activity in vitro preferably on maltase giving an IC(50) value of 0.023 mg/mL and inhibited the maltase activity competitively. As a result of single oral administration of Ranawara (C. auriculata) methanol extract in Sprague-Dawley rats, a significant and potent lowering of blood glycemic response toward maltose ingestion was observed at 30 min after dosing of 5 mg/kg, thus, concurrently suppressed insulin activity. The ED(50) of the extract (4.9 mg/kg) clearly indicated that the antihyperglycemic effect was as potent as that of therapeutic drug, acarbose (ED(50) 3.1 mg/kg).     

Tyrosinase inhibitory activity of the olive oil flavor compounds.

A series of alpha,beta-unsaturated aldehydes, otherwise known as (2E)-alkenals, characterized from the olive Olea europaea L. (Oleaceae) oil flavor was found to inhibit the oxidation of L-3, 4-dihydroxyphenylalanine (L-DOPA) catalyzed by mushroom tyrosinase, and the inhibition kinetics analyzed by a Lineweaver-Burk plot found that they are noncompetitive inhibitors. The inhibition mechanism presumably comes from their ability to form a Schiff base with a primary amino group in the enzyme. In addition, the hydrophobic alkyl chain length from the hydrophilic enal group seems to relate to their affinity to the enzyme, and this results in their inhibitory potency.     

Antimutagenic activity of cacao: inhibitory effect of cacao liquor polyphenols on the mutagenic action of heterocyclic amines

We investigated the effect of polyphenols derived from cacao liquor on the mutagenic action of heterocyclic amines (HCAs) in vitro and ex vivo. In the Ames test, the cacao liquor polyphenols showed antimutagenic effects in bacteria treated with HCA in the presence of an S-9 mixture; however, they showed less efficacy than quercetin. On the other hand, the cacao liquor polyphenols showed potent antimutagenic activity in bacteria treated with activated forms of HCA, compared with quercetin. We also evaluated the effect of these compounds on enzymatic activation of HCA. They weakly suppressed the production of activated HCA. In the host-mediated assay in mice, a method used to estimate the potential carcinogenicity of chemicals ex vivo, oral administration of the cacao liquor polyphenols, reduced the number of colonies of revertant bacteria recovered from the liver. These data suggest that the cacao liquor polyphenols have an antimutagenic effect not only in vitro, but also ex vivo.     

Effect of pepper lipoxygenase activity and its linked reactions on pigments of the pepper fruit.

The products formed during the enzymatic reaction catalyzed by the lipoxygenase of pepper (variety Agridulce) have in vitro a strong destructive action on the carotenoid pigments of the fruit. When conditions and proportions of enzyme and pigments are similar to those found in the fruit, and at a reaction temperature of 20 degrees C, almost 30% of the pigments are destroyed after 24 h of reaction. Of this amount, 2.5% is due to autoxidation of pigments, 4. 5% to oxidation induced by the presence of linoleic under saturating conditions, and the remaining 22% to the presence in the medium of reaction products of the lipoxygenase-catalyzed reaction. When the enzyme acts under substrate-saturating conditions, the rate of pigment destruction by lipoxygenase can be considered maximal at the experimental temperature. The fact that in vitro pepper lipoxygenase induces a heavy destruction of pigments and that, in vivo, its activity remains almost constant during over-ripening could explain why up to 40% of the pigment content in some varieties is lost during the postharvest period.     

Antioxidant activity of Centaurium erythraea infusion evidenced by its superoxide radical scavenging and xanthine oxidase inhibitory activity.

Centaurium erythraea Rafin. (Gentianaceae) has long been used in traditional medicine. This plant contains considerable amounts of polyphenolic compounds, namely, xanthones and phenolic acids as the main constituents. Because phenolic groups exhibit activity as radical scavengers and/or metal chelators, this study evaluated the superoxide radical scavenging properties of a lyophilized infusion obtained from C. erythraea flowering tops. Superoxide radical scavenging activity was assayed using enzymatic (xanthine/xanthine oxidase) and nonenzymatic (NADH/phenazine methosulfate) superoxide generating systems. This study provided evidence that C. erythraea exhibits interesting antioxidant properties, expressed either by the capacity to scavenge superoxide radical or to noncompetitively inhibit xanthine oxidase. The main phenolic compounds present in this extract were several esters of hydroxycinnamic acids, namely, p-coumaric, ferulic, and sinapic acids.     

Persistence of Bacillus Thuringiensis serovar. Israelensis toxic activity in the environment and interaction with natural substrates

The persistence of Bacillus thuringiensis serovar. israelensis (B.t.i.) toxic crystals was studied using environmental chambers filled with a commercial formulation of B.t.i. and natural substrates found in field treatment conditions. The chambers were kept near the bottom of a small oligotrophic lake. In cold waters, toxicity remained stable at least 21 days in the presence of lake water. The presence of solids substrates produced a rapid loss of toxicity. This was caused in part, by interactions between the substrates and the larvicidal crystals of B.t.i.. Toxicity reached a low point between day 43 and 69 and increased thereafter, except for the samples containing organic sediments. This increase in toxicity could be correlated with the behavior of the spore and viable cell counts of B.t.i., in the chambers. These counts indicated that in cold temperate climates, B.t.i. could sporulate and release new crystals.     

Characterization of Aloeride, a new high-molecular-weight polysaccharide from Aloe vera with potent immunostimulatory activity

We have characterized a new immunostimulatory polysaccharide called Aloeride from commercial aloe vera (Aloe barbadensis) juice. Aloeride is between 4 and 7 million Da, and its glycosyl components include glucose (37.2%), galactose (23.9%), mannose (19.5%), and arabinose (10.3%). At 0.5 microg/mL Aloeride increased NF-kappa B directed luciferase expression in THP-1 human monocytic cells to levels 50% of those achieved by maximal concentrations (10 microg/mL) of LPS. Aloeride induced the expression of the mRNAs encoding IL-1beta and TNF-alpha to levels equal to those observed in cells maximally activated by LPS. Acemannan, the major carbohydrate component from aloe, used at 200 microg/mL in the macrophage assay resulted in negligible NF-kappa B activation. Analysis of acemannan and Aloeride using size-exclusion chromatography suggests that the low activity of acemannan is due to trace amounts of Aloeride. Although Aloeride comprises only 0.015% of the aloe juice dry weight, its potency for macrophage activation accounts fully for the activity of the crude juice.     

Recovery of pigments from Origanum majorana L. by extraction with supercritical carbon dioxide

Extraction of pigments (chlorophylls and carotenoids) from marjoram (Origanum majorana L.) with supercritical carbon dioxide was investigated. The aim of this study was to map the effects of extraction pressure and temperature on the yield of coloring materials by applying a 3(2) full factorial design with three repeated tests in the center of the design. For comparison, laboratory and pilot plant Soxhlet extractions were carried out using ethanol and n-hexane solvents. The compositions of pigments in marjoram extracts were determined by HPLC. Similar amounts of carotenoids, in addition to 40% of chlorophylls and their derivatives, were recovered from the supercritical fluid extraction, in comparison to the ethanol Soxhlet extraction.     

Synthesis of water-soluble 9,10-anthraquinone analogues with potent cyanobactericidal activity toward the musty-odor cyanobacterium Oscillatoria perornata

A series of water-soluble 9,10-anthraquinone analogues were prepared and evaluated for their selective toxicity toward Oscillatoria perornata, which grows in catfish production ponds and causes "musty" off-flavor in channel catfish ( Ictalurus punctatus). Water-soluble mono- and dicationic salts were prepared by conjugating various small amines directly or through a methylene or ethylene bridge to the 9,10-anthraquinone nucleus. One of the dicationic salts, 2-[ N-(1'-methyl-4'- N, N-diethylaminobutyl)aminometyl]anthraquinone diphosphate, exhibited very high water solubility and potent selective toxicity toward O. perornata. However, the tendency of this compound to potentially bind to suspended sediments may be the reason for its limitations in controlling O. perornata in catfish production ponds. The monocationic salt, 2-[ N-(1'-methylethyl)]aminomethyl]anthraquinone monophosphate, showed good solubility and high selective toxicity toward O. perornata. Neutral water-soluble analogues prepared by conjugating terta- or pentaethylene glycol directly or by a methylene bridge to the 9,10-anthraquinone nucleus had less activity than the parent compound.     

Influence of vine vigor on grape (Vitis vinifera L. Cv. Pinot Noir) anthocyanins. 1. Anthocyanin concentration and composition in fruit

The relationships between grapevine (Vitis vinifera) vigor variation and resulting fruit anthocyanin accumulation and composition were investigated. The study was conducted in a commercial vineyard consisting of the same clone, rootstock, age, and vineyard management practices. The experimental design involved assigning vigor zones in two vineyard sites based upon differences in vine growth. Fruits and wines were analyzed by HPLC from designated vigor zones in 2003 and 2004. Average berry weight (grams), average dry skin weight (milligrams), degrees Brix, and pH were higher and titratable acidity (grams per liter) was lower in 2003 compared to 2004. In 2003, only the highest and lowest vigor zones had differences in berry weight, whereas there were no differences in 2004. In both years, high vigor zones had lower degrees Brix and higher titratable acidity (milligrams per liter). Accumulation of anthocyanins (milligrams per berry) was greater in 2003 compared to 2004. There was a trend for lower anthocyanin concentration (milligrams per berry) in high vigor zones in both years. In 2004 compared to 2003, there was a higher proportion of malvidin-3-O-glucoside and lower proportions of the other four anthocyanins (delphinidin-, cyanidin-, petunidin-, and peonidin-3-O-glucosides) found in Pinot Noir. In both years, site A had proportionally higher peonidin-3-O-glucoside and lower malvidin-3-O-glucoside than site B. Some of these differences may be related to the higher exposure and temperatures found in site B compared to site A and also in the low vigor zones.     

Bioactivity-guided fractionation for the butyrylcholinesterase inhibitory activity of furanocoumarins from Angelica archangelica L. roots and fruits

Isolation and identification of the inhibitors of butyrylcholinesterase (BChE), obtained from the extracts of roots and fruits of Angelica archangelica L., are reported. Our results confirmed the weak inhibitory effect of Angelica roots on acetylcholinesterase activity. BChE inhibition was much more pronounced at a concentration of 100 μg/mL for hexane extracts and attained a higher rate than 50%. The TLC bioautography guided fractionation and spectroscopic analysis led to the isolation and identification of imperatorin from the fruit's hexane extract and of heraclenol-2'-O-angelate from the root's hexane extract. Both compounds showed significant BChE inhibition activity with IC(50) = 14.4 ± 3.2 μM and IC(50) = 7.5 ± 1.8 μM, respectively. Only C8-substituted and C5-unsubstituted furanocoumarins were active, which could supply information about the initial structures of specific BChE inhibitors.