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1.
In the present study the quantification of the polyphenolic fraction, anthocyanins and other polar compounds, the antioxidant capacity and the anti-hyperlipemic action of the aqueous extract of Hibiscus sabdariffa has been achieved. Seventeen compounds were successfully quantified either by HPLC-DAD or HPLC-ESI-TOF-MS. Six of them were directly quantified by their corresponding standards, whereas the rest were indirectly quantified as equivalents using standards of similar compounds. The antioxidant capacity have also been estimated by comparing different assays, i,e, Trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and measurement of thiobarbituric acid reacting substances (TBARS). H. sabdariffa showed high reducing capacity in FRAP assay and significant capability to scavenge peroxyl radicals in the ORAC assay. Nevertheless, the extract exhibited poor efficacy to inhibit peroxyl radicals in lipid systems. The plant extract also exhibited the capacity to decrease serum triglyceride concentration on hyperlipemic mouse model.  相似文献   

2.
BACKGROUND: To evaluate health benefits attributed to Hibiscus sabdariffa L. a randomized, open‐label, two‐way crossover study was undertaken to compare the impact of an aqueous H. sabdariffa L. extract (HSE) on the systemic antioxidant potential (AOP; assayed by ferric reducing antioxidant power (FRAP)) with a reference treatment (water) in eight healthy volunteers. The biokinetic variables were the areas under the curve (AUC) of plasma FRAP, ascorbic acid and urate that are above the pre‐dose concentration, and the amounts excreted into urine within 24 h (Ae0–24) of antioxidants as assayed by FRAP, ascorbic acid, uric acid, malondialdehyde (biomarker for oxidative stress), and hippuric acid (metabolite and potential biomarker for total polyphenol intake). RESULTS: HSE caused significantly higher plasma AUC of FRAP, an increase in Ae0–24 of FRAP, ascorbic acid and hippuric acid, whereas malondialdehyde excretion was reduced. Furthermore, the main hibiscus anthocyanins as well as one glucuronide conjugate could be quantified in the volunteers' urine (0.02% of the administered dose). CONCLUSION: The aqueous HSE investigated in this study enhanced the systemic AOP and reduced the oxidative stress in humans. Furthermore, the increased urinary hippuric acid excretion after HSE consumption indicates a high biotransformation of the ingested HSE polyphenols, most likely caused by the colonic microbiota. Copyright © 2012 Society of Chemical Industry  相似文献   

3.
The relation between antioxidant activity and anthocyanin was determined in Roselle (Hibiscus sabdariffa L.) petals. Petals from Roselle, cultivar F141, were collected and dried in Taitung, Taiwan. Roselle extract was prepared by extracting dried Roselle petals in boiling water. The relation between the anthocyanin color and antioxidant capacity was elucidated by comparing absorbance at 520 nm, with ferric reducing ability of plasma (FRAP), oxygen radical absorbance capacity (ORAC) and total antioxidant status (TAS) antioxidant assays. The results showed that the antioxidant capacity of Roselle extract increased when extraction time or weight of petals increased. The FRAP assay showed a linear relationship with anthocyanin as determined at 520 nm. Comparisons between FRAP and ORAC or FRAP and TAS assays gave a linear relation. These results suggest that anthocyanin is the major source of antioxidant capacity in Roselle extract. Further purification using Amberlite XAD-2 and HPLC indicated that anthocyanin and a brown pigment in the extract account for about 51 and 24% of the antioxidant capacity, respectively. Under different processing temperatures and storage periods, anthocyanin content declines. However, other phenolic compounds increase and overall there is only a relatively small decrease in total phenolic compounds and antioxidant activity.  相似文献   

4.
Sugars, organic acids, carotenoids, tocopherols, chlorophylls, and phenolic compounds were quantified in fruit of 4 wild growing Prunus species (wild cherry, bird cherry, blackthorn, and mahaleb cherry) using HPLC‐DAD‐MSn. In wild Prunus, the major sugars were glucose and fructose, whereas malic and citric acids dominated among organic acids. The most abundant classes of phenolic compounds in the analyzed fruit species were anthocyanins, flavonols, derivatives of cinnamic acids, and flavanols. Two major groups of anthocyanins measured in Prunus fruits were cyanidin‐3‐rutinoside and cyanidin‐3‐glucoside. Flavonols were represented by 19 derivatives of quercetin, 10 derivatives of kaempferol, and 2 derivatives of isorhamnetin. The highest total flavonol content was measured in mahaleb cherry and bird cherry, followed by blackthorn and wild cherry fruit. Total phenolic content varied from 2373 (wild cherry) to 11053 mg GAE per kg (bird cherry) and ferric reducing antioxidant power antioxidant activity from 7.26 to 31.54 mM trolox equivalents per kg fruits.  相似文献   

5.
In this study, fifty‐one monofloral Sardinian honeys from ten various floral origins were screened for their phenolic content, antioxidant activity, colour and electrical conductivity. The total phenolic amounts have been evaluated by Folin–Ciocalteu method, whereas quantification of several phenolic compounds (phenolic acids and flavonoids) has been carried out by HPLC‐DAD technique. The richest sample in phenolic compounds resulted strawberry tree honey with about 40 mg GAE/100 g, as well FRAP test and DPPH˙ test confirm that antioxidant activity of strawberry tree honey extract exceed both honey extracts and synthetic antioxidants like BHA and BHT. Among the studied phenolic compounds a total of five phenolic acids (ferulic, syringic, trans‐cinnamic, chlorogenic and p‐hydroxycinnamic) and nine flavonoids (catechin, kaempferol, rutin, quercetin, luteolin, apigenin, galangin, pinocembrin and pinobanksin) were identified. Our results show good correlations between total polyphenol amount and antioxidant activity and between colour and electrical conductivity.  相似文献   

6.
Eight phenolic compounds including: p‐coumaric acid, vanillic acid, caffeic acid, chlorogenic acid, trolox, quercetin, curcumin, and resveratrol were treated with riboflavin (RF) photosensitization and in vitro antioxidant capacities of the mixtures were determined by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH), 2,2’ azino bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays. Mixtures containing p‐coumaric acid and vanillic acid under RF photosensitization showed increases in ferric ion reducing ability and radical scavenging activity of DPPH, whereas mixtures of other compounds had decreases in both radical scavenging ability and ferric reducing antioxidant power. Hydroxycoumaric acid and conjugated hydroxycoumaric and coumaric acids were tentatively identified from RF photosensitized p‐coumaric acid, whereas dimmers of vanillic acid were tentatively identified from RF photosensitized vanillic acid. RF photosensitization may be a useful method to enhance antioxidant properties like ferric ion reducing abilities of some selected phenolic compounds.  相似文献   

7.
The residue from a hydroalcoholic extract of the mushroom Agaricus blazei (MAR) was evaluated for phenolic compounds, flavonoids and antioxidant activity. The ability of MAR to slow the oxidation of Omega‐3 resulting from light exposure in milk matrix, and its bioavailability after in vitro digestion was investigated. MAR presented phenolic compounds and flavonoids and showed antioxidant activity. At each concentration, addition of MAR to Omega‐3‐supplemented milk inhibited the production of conjugated dienes and malonaldehyde compared with samples without MAR. The bioavailability assay showed that polyphenols were still present after in vitro digestion and had antioxidant activity.  相似文献   

8.
The influences of ultrasound‐assisted, pharmacopeia, and supercritical fluid extraction methods on bioactive compounds and biological activities of propolis were evaluated. Results showed that propolis extracted by ultrasound‐assisted method contained more phenolic compounds, and showed the highest total phenolic content (245.84 ± 6.41 mg GAE/g DW), total flavonoids content (198.82 ± 5.74 mg RE/g DW), and stronger in vitro antioxidant activity (DPPH·: 1.03 ± 0.04 mmol Trolox/g DW, ABTS+·: 2.19 ± 0.05 mmol Trolox/g DW, and FRAP: 1.48 ± 0.12 mmol FeSO4/g DW) than those of pharmacopoeia and supercritical fluid methods. A total of 36 phenolic compounds were identified in propolis. Among them, quercetin, quercetin‐3‐methyl‐ether, kaempferol, isorhamnetin, luteolin‐methyl‐ether, and quercetin‐7‐methyl‐ether could only be found in ultrasound‐assisted and pharmacopoeia methods. Moreover, the phenolic compounds had the similar metabolic pathways in rats and were mainly metabolized by sulfation and glucuronidation pathways. Additionally, ultrasonic‐treated propolis have good in vivo antioxidant activity and could repair D‐galactose‐induced oxidative damage in rats. Therefore, ultrasound‐assisted method could replace pharmacopeia method to be considered as bioactive compounds extraction from propolis, taking into consideration of yield, short extraction time, and high antioxidant activity.  相似文献   

9.
The molecular structures of the radical scavenging compounds present in extracts of Potentilla fruticosa blossoms were elucidated and the antioxidant activities of various extracts were determined. The activities of the different fractions were monitored by off‐line and on‐line RP‐HPLC DPPH? and ABTS?+ scavenging methods. Twelve compounds were isolated and identified, namely ellagic acid, catechin, quercetin‐3‐β‐glucopyranoside, quercetin‐3‐β‐galactopyranoside, quercetin‐3‐β‐rutinoside, quercetin‐3‐β‐glucuronopyranoside, quercetin‐3‐α‐arabinofuranoside, kaempferol‐3‐β‐rutinoside, kaempferol‐3‐O‐β‐(6″‐O‐(E)‐p‐coumaroyl)glucopyranoside, rhamnetin‐3‐β‐glucopyranoside and rhamnetin‐3‐β‐galactopyranoside. The radical scavenging activity of each isolated compound was measured using DPPH? and ABTS?+ assays and compared with the activity of rosmarinic acid. Catechin and ellagic acid were found to be the most active radical scavengers. The antioxidant properties of plant fractions were assessed in model systems by measuring superoxide anion and hydrogen peroxide scavenging, β‐carotene bleaching, hexanal production in edible oil, peroxide formation, and the increase in UV absorbance in the course of oxidation. Copyright © 2004 Society of Chemical Industry  相似文献   

10.
Although Trifolium pratense (Red Clover) is considered to be one of the leading crops for livestock grazing, it could also be used as a potential source of bioactive compounds in phytopharmacy. The aim of this study was to investigate the phenolic content and its biological activity at the growth phases (30 cm, 50 cm, and bud) of this plant. The phenolic compounds in methanolic extracts of T. pratense leaves at three growth stages, obtained by Microwave Assisted Extraction, were quantified using the HPLC-ESI-MS/MS technique, and their antioxidant and antimicrobial activity were assessed. Isoflavonoids, genistein, and daidzein, as well as other phenols, p-hydroxybenzoic and caffeic acids, kaempferol 3-O-glucoside, quercetin 3-O-glucoside, and hyperoside were found in all the extracts, but the content of these compounds was the highest in the extract of the plant at the lowest growth stage (30 cm, vegetative). Therefore, this extract showed the best antioxidant potential and it was most effective against bacterial strains such as Escherichia coli and Enterobacter aerogenes. These results indicated that red clover has potential health benefits, and that growth phase contributes to its biological activity. The extract of red clover at the growth stage of 30 cm is a great source of bioactive compounds and could be used in phytotherapy and nutrition.  相似文献   

11.
The health-promoting effects attributable to dietary phenolic compounds strongly depend on their bioaccesibility from the food matrix and their consequent bioavailability. We carried out a pilot randomized controlled cross-over study to evaluate the effect of addition of an oil matrix during tomato sauce processing, on the bioavailability of tomato phenolics. Healthy subjects consumed a single dose of tomato sauce elaborated without oil (OO-F) and with the addition of 5% virgin olive oil (VOO-E) or refined olive oil (ROO-E). Plasma and urine samples were subjected to solid-phase extraction, followed by HPLC–MS/MS analysis. Six phenolic compounds, three aglycones (naringenin, ferulic and caffeic acids) and their corresponding glucuronide metabolites, were identified and quantified in urine after the ingestion of the tomato sauces. Two of the six phenolic urinary metabolites were also quantified in plasma samples. Only after ingestion of the oil-enriched tomato sauces, did the glucuronide metabolites of naringenin show a bi-phasic profile of absorption in plasma, suggesting that the lipid matrix added to the sauce may stimulate the occurrence of re-absorption events by enterohepatic circulation, potentially enhancing the apparent plasma half-life of the flavanone prior to excretion. The interindividual response variability observed underlies the need for further large-scale investigations.  相似文献   

12.
Red wines are typically high in phenolic and antioxidant capacity and both of which can be increased by vinification techniques. This study employed 3 vinification techniques to assess the increase in phenolic compounds and antioxidant capacity. Wines were obtained from Bo?azkere grape cultivar by techniques of classical maceration, cold maceration combined with ultraviolet light (UV) irradiation, and thermovinification combined with UV irradiation and changes in phenolic contents were examined. Total phenolic and anthocyanin contents and trolox equivalent antioxidant capacity of wines were measured spectrophotometrically and phenolic contents (+)‐catechin, (–)‐epicatechin, rutin, quercetin, trans‐resveratrol, and cis‐resveratrol were measured by High Pressure Liquid Chromatography with Diode Array Detection (HPLC‐DAD). As a result of the study, the highest phenolic content except for quercetin was measured in the wines obtained by thermovinification combined with UV irradiation. We demonstrated that the highest phenolic compounds with health effect, total phenolic compounds, total anthocyanin, and antioxidant activity were obtained from thermovinification with UV‐C treatment than classical wine making.  相似文献   

13.
14.
After consumption of plant‐derived foods or beverages, dietary polyphenols such as quercetin are absorbed in the small intestine and metabolized by the body, or they are subject to catabolism by the gut microbiota followed by absorption of the resulting products by the colon. The resulting compounds are bioavailable, circulate in the blood as conjugates with glucuronide, methyl, or sulfate groups attached, and they are eventually excreted in the urine. In this review, the various conjugates from different intervention studies are summarized and discussed. In addition, the substantial variation between different individuals in the measured quercetin bioavailability parameters is assessed in detail by examining published human intervention studies where sources of quercetin have been consumed in the form of food, beverages, or supplements. It is apparent that most reported studies have examined quercetin and/or metabolites in urine and plasma from a relatively small number of volunteers. Despite this limitation, it is evident that there is less interindividual variation in metabolites which are derived from absorption in the small intestine compared to catabolites derived from the action of microbiota in the colon. There is also some evidence that a high absorber of intact quercetin conjugates could be a low absorber of microbiota‐catalyzed phenolics, and vice versa. From the studies reported so far, the reasons or causes of the interindividual differences are not clear, but, based on the known metabolic pathways, it is predicted that dietary history, genetic polymorphisms, and variations in gut microbiota metabolism would play significant roles. In conclusion, quercetin bioavailability is subject to substantial variation between individuals, and further work is required to establish if this contributes to interindividual differences in biological responses.  相似文献   

15.
以无水乙醇、70%乙醇、40%乙醇和水分别对丝瓜花进行提取,并测定各提取物中总酚、总黄酮含量,采用DPPH·清除能力、超氧化物自由基清除能力、FRAP抗氧化能力和亚铁离子螯合能力等方法评价其抗氧化活性,通过HPLC分析其中酚类成分。结果表明,70%和40%乙醇提取物总酚及总黄酮含量较高,而且DPPH·清除活性、FRAP还原力最强,40%乙醇提取物、水提物分别具有最强的超氧阴离子自由基清除活性和亚铁离子螯合能力。总酚含量与DPPH·清除活性之间存在较强的相关性(R2=0.8688)。HPLC分析检出提取物中9种酚类化合物,其中含量最高的为杨梅素。试验结果说明,70%乙醇、40%乙醇可能是丝瓜花抗氧化性物质提取的较好溶剂。结果表明丝瓜花是一种较好的抗氧剂资源。  相似文献   

16.
Gynura formosana Kiamnra (Compositae) is a herbal folk medicine that is a popular vegetable in Taiwan. The free‐radical scavenging activities of a 70% aqueous acetone extract from the herb G formosana were evaluated. Bioassay‐guided fractionation, column separation on Diaion, Toyopearl HW 40(C), Sephadex LH‐20 and MCI CHP20P, and high‐performance liquid chromatography (HPLC) were used to isolate for the first time in G formosana four potent phenolics [caffeic acid ( I ), quercetin 3‐O‐rutinoside ( II ), kaempferol 3‐O‐rutinoside ( III ) and kaempferol 3‐O‐robinobioside ( IV )]. The IC50 values of 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activity for compounds I – IV were 6.7, 7.7, 300.3 and 286.7 µM , respectively, and, for superoxide radical scavenging activity, they were 187.3, 25.8, 55.3 and 87.4 µM , respectively. Using a spin trapping electron spin resonance (ESR) method, caffeic acid ( I ) and quercetin 3‐O‐rutinoside ( II ) exhibited good hydroxyl radical activity. The free radical scavenging activity of G formosana phenolics may improve the economic value of this herb and assist in its development as a health food. Copyright © 2004 Society of Chemical Industry  相似文献   

17.
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  相似文献   

18.
The free and bound phenolic compounds in 10 common Chinese edible flowers were investigated using reversed phase high‐performance liquid chromatography. Their antioxidant capacities were evaluated using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging activity, 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) radical‐scavenging activity, oxygen radical absorption capacity (ORAC), ferric reducing antioxidant power (FRAP), and cellular antioxidant activity (CAA). Free factions were more prominent in phenolic content and antioxidant capacity than bound fractions. Paeonia suffruticosa and Flos lonicerae showed the highest total phenolic content (TPC) 235.5 mg chlorogenic acid equivalents/g of dry weight and total flavonoid content 89.38 mg rutin equivalents/g of dry weight. The major phenolic compounds identified were gallic acid, chlorogenic acid, and rutin. P. suffruticosa had the highest antioxidant capacity in the DPPH, ABTS, and ORAC assays, which were 1028, 2065, 990 μmol Trolox equivalents/g of dry weight, respectively, whereas Rosa chinensis had the highest FRAP value (2645 μmol Fe2+ equivalents /g of dry weight). The P. suffruticosa soluble phenolics had the highest CAA, with the median effective dose (EC50) 26.7 and 153 μmol quercetin equivalents/100 g of dry weight in the phosphate buffered saline (PBS) and no PBS wash protocol, respectively. TPC was strongly correlated with antioxidant capacity (R = 0.8443 to 0.9978, P < 0.01), which indicated that phenolics were the major contributors to the antioxidant activity of the selected edible flowers.  相似文献   

19.
Hibiscus sabdariffa L extract (HSE) is an aqueous extract of Hibiscus sabdariffa L flowers that is used as a local soft drink and medical herb in Taiwan. Oxidation of low‐density lipoprotein (LDL) has been shown to increase the incidence of atherosclerosis. In this study, we determined the antioxidative activity of HSE on LDL oxidation by examining relative electrophoretic mobilities (REM) and thiobarbituric acid‐reactive substances (TBARS). The data revealed an inhibitory effect of HSE on Cu2+‐mediated REM and TBARS. HSE exhibited a remarkable ability to reduce cholesterol degradation and ApoB fragmentation. Overall, HSE showed a high potency to inhibit the production of oxidized LDL induced by copper and, specifically, to reduce serum triglycerides in high‐fructose diet (HFD) fed rats and serum cholesterol in high‐cholesterol diet (HCD) fed animals. The levels of LDL and the ratio of LDL‐cholesterol (LDL‐C) to HDL‐cholesterol (HDL‐C) were reduced by HSE in both hyperlipidaemia models. Based on these findings, we suggest that HSE may be used to inhibit LDL oxidation and to prevent various types of hyperlipidaemia in HFD‐ or HCD‐fed rats. Copyright © 2004 Society of Chemical Industry  相似文献   

20.
Free radicals trigger chain reaction and inflict damage to the cells and its components, which in turn ultimately interrupts their biological activities. To prevent free radical damage, together with an endogenous antioxidant system, an exogenous supply of antioxidant components to the body in the form of functional food or nutritional diet helps undeniably. Research conducted by the Natl. Inst. of Health claimed that Moringa oleifera Lam possess the highest antioxidant content among various natural food sources based on an oxygen radical absorbent capacity assay. In this study, a 90% (ethanol:distilled water—90:10) gradient solvent was identified as one of the best gradient solvents for the effectual extraction of bioactive components from M. oleifera leaves. This finding was confirmed by various antioxidant assays, including radical scavenging activity (that is, 1, 1‐diphenyl‐2‐picrylhydrazyl, H2O2, and NO radical scavenging assay) and total antioxidant capacity (that is, ferric reducing antioxidant power and molybdenum assay). High‐performance liquid chromatography (HPLC) fingerprints of the 90% gradient extract visually showed few specific peaks, which on further analysis, using HPLC–DAD–ESI–MS, were identified as flavonoids and their derivatives. Despite commonly reported flavonoids, that is, kaempferol and quercetin, we report here for the 1st time the presence of multiflorin‐B and apigenin in M. oleifera leaves. These findings might help researchers to further scrutinize this high activity exhibiting gradient extract and its bio‐active candidates for fruitful clinical/translational investigations.  相似文献   

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