LC-DAD-ESI/MS analysis of flavonoids and abscisic acid with chemometric approach for the classification of Slovenian honey

The flavonoid profiles of seven types of Slovenian honey were analysed. The flavonoids are phenolic compounds that have health-related properties, and their presence in honey is attributed to the plants visited by the bees. The flavonoids were extracted from honey samples by solid-phase extraction and analysed by liquid chromatography, with diode array detection and electrospray ionisation mass spectrometry (LC-DAD-ESI/MS). The honey samples had similar, but quantitatively different, flavonoid profiles. The flavonoids myricetin, luteolin, quercetin, naringenin, apigenin, kaempferol, pinocembrin, chrysin and galangin were identified using reference standards, while pinobanksin was tentatively identified through its retention time, m/z, UV spectrum and MS/MS data. Two non-phenolic compounds were also identified; cis–trans-abscisic acid and, tentatively, trans–trans-abscisic acid. The analysis did not show any specific compounds to use as markers for determination of the botanical origins of these different types of Slovenian honey. Further analyses of more honey samples with additional standards are needed to identify such potential markers, although linear discriminant analysis correctly classified 85% of these honey samples according to their botanical origins.     

Using flavonoids, phenolic compounds and headspace volatile profile for botanical authentication of lemon and orange honeys

This study evaluates the usefulness of flavonoids (naringenin, hesperetin, chrysin, galangin, kaempferol, luteolin, pinocembrin, and quercetin) and phenolic acids (caffeic acid and p-coumaric acid) together with 37 volatile compounds in the differentiation between lemon blossom honey (Citrus limon) and orange blossom honey (Citrus spp.). The total content of flavonoids and phenolic acids is twice as high in lemon honey (6.20 mg/100 g) as in orange honey (3.64 mg/100 g); naringenin and caffeic acid were the main compounds in all cases. Hesperetin, a floral marker of citrus honey, was not significantly different for the two types of honey. A multivariate PLS2 analysis showed that some volatile compounds such as, 4 lilac aldehydes and bencenacetaldehyde (all abundant in orange honey) were negatively correlated with 4 flavonoids: pinocembrin, chrysin, naringenin and quercetin, and caffeic phenolic acid (all abundant in lemon honey). Moreover, the last 5 compounds were positively correlated with: 6 alcohols, 2 ketones, acetaldehyde and furanmethanol. This is a first approach to employ all of these compounds together with appropriate statistical techniques to differentiate between two varieties of citrus honey, and therefore it could be an interesting tool for their authentication.     

Determination of red wine flavonoids by HPLC and effect of aging

A new method for simultaneous determination of 10 flavonols and 2 flavones by high performance liquid chromatography was developed in this paper. The identified compounds contained quercetin, kaempferol, myricetin, rhamnetin, isorhamnetin, quercetrin, rutin, morin, galangin, fisetin, apigenin and luteolin. The chromatographic separation of these flavonoids was performed in a single run by using the mobile phase gradient elution of acetonitrile–methanol–water mixture (1% tetrahydrofuran, THF) at 20 °C, with the flow rate at 1.0 ml/min and the detection wavelength at 360 nm. With direct injection of wine samples, seven red wine samples, differing in their origin of producing places and time, were analyzed for flavonoids content by this method. The results showed the presence of myricetin, luteolin, quercetin, kaempferol, isorhamnetin and galanin. Additionally, the changes of flavonoids in red wines stored in the three types of oak barrels with aging time were investigated, which indicated that the component of flavonoids in red wine is related to wine aging greatly. These provide a substantial basis for the further research on control of flavonoids during winemaking.     

Influence of Intestinal Microbiota on the Catabolism of Flavonoids in Mice

Although in vitro studies have shown that flavonoids are metabolized into phenolic acids by the gut microbiota, the biotransformation of flavonoids by intestinal microbiota is seldom studied in vivo. In this study, we investigated the impact of the gut microbiota on the biotransformation of 3 subclasses of flavonoids (flavonols, flavones, and flavanones). The ability of intestinal microbiota to convert flavonoids was confirmed with an in vitro fermentation model using mouse gut microflora. Simultaneously, purified flavonoids were administered to control and antibiotic‐treated mice by gavage, and the metabolism of these flavonoids was evaluated. p‐Hydroxyphenylacetic acid, protocatechuic acid, p‐hydroxybenzoic acid, vanillic acid, hydrocaffeic acid, coumaric acid, and 3‐(4‐hydroxyphenyl)propionic acid were detected in the serum samples from the control mice after flavonoid consumption. The serum flavonoid concentrations were similar in both groups, whereas the phenolic metabolite concentrations were lower in the antibiotic‐treated mice than in the control mice. We detected markedly higher flavonoids excretion in the feces and urine of the antibiotic‐treated mice compared to the controls. Moreover, phenolic metabolites were upregulated in the control mice. These results suggest that the intestinal microbiota are not necessary for the absorption of flavonoids, but are required for their transformation.     

Flavonoids quercetin,myricetin, kaemferol and (+)‐catechin as antioxidants in methyl linoleate

The antioxidant effect of the flavonoids quercetin, myricetin, kaemferol, (+)‐catechin and rutin on methyl linoleate oxidation was investigated. In addition, the synergistic effects of flavonoids and α‐tocopherol were studied. Oxidation was monitored by conjugated diene measurement and by determining the formation of hydroperoxide isomers by HPLC. The antioxidant activity of flavonoids in non‐polar methyl linoleate differ from that previously reported in water‐containing systems, such as LDL and liposome systems. The activity of antioxidants (10–1000 μM ) measured by hydroperoxide formation decreased in the order: myricetin>quercetin>α‐tocopherol>(+)‐catechin >kaemferol=rutin. The antioxidant activity of flavonoids increased as the number of phenolic hydroxyl groups increased. In addition to the number of hydroxyl groups, other structural features such as the 2,3 double bond in the C‐ring and a glycoside moiety in the molecule had an effect on the antioxidant activity. Myricetin and rutin, especially had a synergistic effect with α‐tocopherol. Myricetin, quercetin and rutin protected α‐tocopherol from decomposition, myricetin being the most protective. The relative hydrogen‐donating activity measured by the ratio of cis,trans‐ to trans,transhydroperoxide isomers formed during oxidation decreased in the order: α‐tocopherol >myricetin>quercetin. Hydroperoxide isomeric distribution of the samples containing kaemferol or rutin did not differ from the control. Thus, although α‐tocopherol was the most effective hydrogendonor, myricetin and quercetin were more effective antioxidants in inhibiting the hydroperoxide formation in methyl linoleate. © 1999 Society of Chemical Industry     

Phenolic compound profile of selected vegetables frequently consumed by African Americans in the southeast United States

The phenolic composition of vegetables commonly consumed by African Americans in the southeast United States was analyzed with HPLC–MS. The vegetable samples included collard greens, mustard greens, kale, okra, sweet potato greens, green onion, butter beans, butter peas, purple hull peas, rutabagas, eggplant, and purslane. Five compounds out of total 29 peaks detected from the 12 samples – caffeic acid, ferulic acid, quercetin, kaempferol, and isorhamnetin – were identified. No gallic acid, p-coumaric acid, myricetin, luteolin, apigenin, hesperetin, naringenin, or flavanols was detected. The major flavonoids were isorhamnetin, quercetin and kaempferol. Isorhamnetin was found in kale, mustard greens, and purslane. The content ranged from 2.8 to 23.6 mg/100 g fresh edible part. Quercetin was found in collard greens, mustard greens, kale, okra, sweet potato greens, purple hull peas, and purslane. The content ranged from 1.3 to 31.8 mg/100 g with the highest content in kale and lowest content in purslane. Kaempferol was found in collard greens, mustard greens, kale, sweet potato greens, green onion, and purslane. The content ranged from 1.1 to 90.5 mg/100 g. Caffeic acid was only found in sweet potato greens. Ferulic acid was found in collard greens, mustard greens, kale, okra, purple hull peas, and purslane. Although some peaks were found in eggplant, butter beans, butter peas and rutabagas, these peaks were not identified due to lack of reference compound and no flavonoid or phenolic acid was quantified in these samples. The results suggest that these indigenous vegetables among African Americans are good sources of the phenolic compounds, which can be useful for the prevention of cardiovascular and other chronic diseases.     

Metabolic pathways of the colonic metabolism of procyanidins (monomers and dimers) and alkaloids

Procyanidins are metabolised by endogenous gastrointestinal microflora into several small molecules that may exert systemic effects. However, the metabolic pathways of procyanidins are still largely uncharacterised. The aim of this study was to evaluate the colonic metabolism of procyanidins (catechin, epicatechin, epicatechin gallate, epigallocatechin gallate and dimer B2) and alkaloids (theobromine and caffeine) by an in vitro colonic fermentation model using rat colonic microflora. Simultaneously, a nuts-cocoa cream was incubated and the colonic metabolism of procyanidins and alkaloids was evaluated. Results showed that most of the procyanidins tested were catabolised after 24–48 h of fermentation. Fermentation of the dimer B2 did not produce the same catabolic compounds as epicatechin fermentation and differences were observed between the fermentation of catechin and epicatechin. The alkaloids were not metabolised by the colonic microflora and this fact was verified in vivo. The results showed an intense metabolism of procyanidins and poor metabolism of alkaloids.     

Phenolic composition,antioxidant and pancreatic lipase inhibitory activities of Chinese sumac (Rhus chinensis Mill.) fruits extracted by different solvents and interaction between myricetin‐3‐O‐rhamnoside and quercetin‐3‐O‐rhamnoside

This work was designed to investigate the phenolic composition, antioxidant and pancreatic lipase inhibitory activities of Rhus chinensis Mill. fruits extracted by different solvents, and to illustrate which major phenolic compounds were responsible for lipase inhibition and to evaluate their interactions. Results showed that R. chinensis Mill. fruits were rich in phenolics, which included 13 types identified and quantified by UHPLC‐ESI‐HRMS/MS. Among the identified phenolics, myricetin‐3‐O‐rhamnoside and quercetin‐3‐O‐rhamnoside were the most dominant detected in all extracts. Extracts with 80% methanol, 80% ethanol and 80% acetone exhibited strong antioxidant and pancreatic lipase inhibitory activities in vitro, and these activities were positively correlated with phenolic contents. Myricetin‐3‐O‐rhamnoside and quercetin‐3‐O‐ rhamnoside demonstrated good lipase inhibitory activities in a dose‐dependent manner and synergistically inhibited lipase. This work may provide insights into the potential uses of R. chinensis Mill. fruits in food and nutraceutical industries.     

Antioxidant properties of major metabolites of quercetin

Dietary flavonoids have been related to health promotion, which has been attributed in part to their antioxidant properties as demonstrated in many in vitro studies. However, in the human organism most flavonoids are little bioavailable and largely transformed to different metabolites that are crucial to explain the health effects associated with their dietary intake, although little is known about their biological activities. Quercetin is a majority flavonoid in the human diet that has been commonly used in studies on the flavonoid and health relationships. In this study, the antioxidant activity of different conjugated metabolites of quercetin (quercetin 3′-O-sulphate, quercetin 4′-O-sulphate, quercetin 3-O-glucuronide and isorhamnetin 3-O-sulphate) prepared in the laboratory, and of some phenolic acids that may result from its colonic degradation, was investigated by two in vitro assays (ABTS and FRAP assays). As expected, substitution of the hydroxyl groups of quercetin by the conjugating substituents resulted in a decrease in the antioxidant activity with regard to the parent compound. Despite this, the conjugated metabolites still retained significant antioxidant activity and behave as significantly better radical scavengers and reducing compounds than usually recognized antioxidants like α-tocopherol. Greater antioxidant activity of the metabolites was found in the ABTS assay, conducted at pH 7.4, suggesting that quercetin derivatives could act as potential radical scavengers in physiological conditions. Similarly, antioxidant activity significantly higher than α-tocopherol was also found in the ABTS assay for 3,4-dihydroxyphenylacetic, 3-methoxy-4-hydroxyphenylacetic and 3-(3,4-dihydroxyphenyl)propionic acids, described as products of the colonic degradation of quercetin. Phenylacetic acids were more active than benzoic and phenylpropionic acids, and the activity increased with the number of phenolic hydroxyls in the molecule; methoxylated derivatives showed, in general, lower activity than the equivalent O-dihydroxylated forms but greater than that of the monohydroxylated precursor. The results obtained are expected to contribute to the understanding of the mechanisms involved in the biological effects associated with the intake of flavonoid-rich diets.     

Flavonoids,phenolic acids and abscisic acid in Australian and New Zealand Leptospermum honeys

Flavonoids, phenolic acids and abscisic acid of Australian and New Zealand Leptospermum honeys were analyzed by HPLC. Fifteen flavonoids were isolated in Australian jelly bush honey (Leptospermum polygalifolium), with an average content of 2.22 mg/100 g honey. Myricetin (3,5,7,3′,4′,5′-hexahydroxyflavone), luteolin (5,7,3′,4′-tetrahydroxyflavone) and tricetin (5,7,3′,4′,5′-pentahydroxyflavone) were the main flavonoids identified. The mean content of total phenolic acids in jelly bush honey was 5.14 mg/100 g honey, with gallic and coumaric acids as the potential phenolic acids. Abscisic acid was quantified as twice the amount (11.6 mg/100 g honey) of the phenolic acids in this honey. The flavonoid profile mainly consisted of quercetin (3,5,7,3′,4′-pentahydroxyflavone), isorhamnetin (3,5,7,4′-tetrahydroxyflavone 3′-methyl ethyl), chrysin (5,7-dihydroxyflavone), luteolin and an unknown flavanone in New Zealand manuka (Leptospermum scoparium) honey with an average content of total flavonoids of 3.06 mg/100 g honey. The content of total phenolic acids was up to 14.0 mg/100 g honey, with gallic acid as the main component. A substantial quantity (32.8 mg/100 g honey) of abscisic acid was present in manuka honey. These results showed that flavonoids and phenolic acids could be used for authenticating honey floral origins, and abscisic acid may aid in this authentication.     

Screening of selected flavonoids and phenolic acids in 19 berries

Selected flavonoids (kaempferol, quercetin, myricetin) and phenolic acids (p-coumaric, caffeic, ferulic, p-hydroxybenzoic, gallic and ellagic acids) were simultaneously detected from 19 berries using a simple High Performance Liquid Chromatographic (HPLC) method. These phenolics have been proposed to have beneficial effects on health as antioxidants and anticarcinogens. Marked differences were observed in the phenolic profiles among the berries, with certain similarities within families and genera. The major phenolic compound analyzed in the genus Vaccinium was quercetin in lingonberry and cranberry, and its level was high also in blueberries and bilberry. In the genus Ribes, quercetin was the main compound in gooseberry, red currant and black currant. Ellagic acid was the main phenolic compound in the berries of the genus Rubus (red raspberry, Arctic bramble and cloudberry) and genus Fragaria (strawberry). Our data suggest that berries have potential as good dietary sources of quercetin or ellagic acid.     

Use of the pig caecum model to mimic the human intestinal metabolism of hispidulin and related compounds

Up to now, the metabolism of hispidulin (5,7,4'-trihydroxy-6-methoxyflavone), a potent ligand of the central human benzodiazepine receptor, has not been investigated. To elucidate the metabolism of hispidulin in the large intestine, its biotransformation by the pig caecal microflora was studied. In addition, the efficiency of the pig caecal microflora to degrade galangin (3,5,7-trihydroxyflavone), kaempferol (3,5,7,4'-tetrahydroxyflavone), apigenin (5,7,4'-trihydroxyflavone), and luteolin (5,7,3',4'-tetrahydroxyflavone) was investigated. Identification of the formed metabolites was performed by high-performance liquid chromatography (HPLC)-diode array detection, HPLC-electrospray ionization-tandem mass spectrometry, and high-resolution gas chromatography-mass spectrometry. The caecal microflora transformed hispidulin to scutellarein (5,6,7,4'-tetrahydroxyflavone), an effective alpha-glucosidase inhibitor, and 3-(4-hydroxyphenyl)-propionic acid; galangin to phenylacetic acid and phloroglucinol; kaempferol to 4-hydroxyphenylacetic acid, phloroglucinol, and 4-methylphenol; apigenin to 3-(4-hydroxyphenyl)-propionic acid and 3-phenylpropionic acid, and luteolin to 3-(3-hydroxyphenyl)-propionic acid, respectively. To elucidate to what extent different hydroxylation patterns on the B-ring influence the degradation degree of flavonoids, the conversions of galangin and kaempferol as well as that of apigenin and luteolin were compared with those of quercetin (3,5,7,3',4'-pentahydroxyflavone) and chrysin (5,7-dihydroxyflavone), respectively. Regardless of the flavonoid subclass, the presence of a hydroxy group at the 4'-position seems to be a prerequisite for fast breakdown. An additional hydroxy group at the B-ring did not affect the degradation degree.     

基于非靶向代谢组学评价传统发酵对客家酸芥菜酚类化合物组成的影响

芥菜的酚类物质组成及乳酸发酵对其影响仍未完全探明。该文采用高效液相色谱串联质谱的非靶向代谢组学,结合主成分分析、相关性分析和偏最小二乘判别分析等,对广西传统客家酸芥菜(客家擦菜)的原料和成品进行了酚类物质组成分析与对比。结果表明,新鲜芥菜和客家擦菜共初步定性检出136种酚类物质,其中119种(包括25种多酚类物质、34种酚酸物质、60种黄酮类物质)为芥菜产品中首次报道,例如大豆苷元、雌马酚。发酵改变了芥菜的酚类物质组成,其中发酵后原儿茶酸等7种酚酸、槲皮素等9种黄酮类物质和血竭素的含量显著升高,水杨酸等7种酚酸和槲皮素-3-O-葡萄糖醛酸苷等5种黄酮类物质的含量显著下降。通过KEGG数据库的比对分析可知,发酵后的酚类差异代谢物涉及发酵过程的7条代谢通路。基于非靶向代谢组学分析,该文首次较系统报道了芥菜及其乳酸发酵产品的酚类物质组成和它们的差异,为探明多酚物质在蔬菜乳酸发酵过程中的变化机制提供理论参考。     

Evaluation of antioxidant and inhibitory activities for different subclasses flavonoids on enzymes for rheumatoid arthritis

Antioxidant activities of flavonoids were decreased in the order of flavonols > flavanones > flavones. Inhibitory intensities for hyaluronidase and collagenase reaction differed clearly according to flavonoid subclasses. Kaempferol, quercetin, myricetin, and rutin in flavonols inhibited hyaluronidase reaction specifically, while apigenin, luteolin, baicalin, and baicalein in flavones showed specific inhibition to collagenase reaction. In addition, the flavonoids, except baicalin and catechin, inhibited potently LPS-induced nitrite production in a dose-dependent manner, which might be mainly due to the suppression of inducible nitric oxide (NO) synthase. Quercetin and luteolin showed the strongest inhibitory activities on 15-lipoxygenase (LOX), and quercetin showed relatively potent inhibition on cyclooxygenase-1 (COX-1) reaction. Otherwise, all tested flavonoids possessed the inhibitory activity to COX-2 reaction, and especially luteolin, kaempferol, hesperetin, and naringin showed relatively the potent inhibition on COX-2 reaction. This report elucidated the anti-inflammatory activities, such as the antioxidant property, inhibition of NO production, and inhibition of inflammatory enzymes (hyaluronidase, collagenase, LOX, and COXs) of several subclass flavonoids.     

Phenolics and antioxidant properties of bayberry (Myrica rubra Sieb. et Zucc.) pomace

Five cultivars of Myrica rubra, Biqi, Wandao, Dongkui, Dingao, and Zaodamei, were collected to analyze the phenolic compounds and evaluate the antioxidant properties of bayberry pomaces. The main anthocyanin was cyanidin-3-o-glucoside (3073.3–6219.2 mg/kg dry weight (DW)) and the main flavonol was quercetin-3-o-glucoside (296.2–907.9 mg/kg dry weight). Quercetin and myricetin were also found in the bayberry pomaces, and quercetin deoxyhexoside and myricetin deoxyhexoside were tentatively identified. The dominant phenolic acids were gallic acid (102.9–241.7 mg/kg dry weight) and protocatechuic acid (29.5–57.2 mg/kg dry weight). Other phenolic acids such as p-hydroxybenzoic, vanillic, caffeic, p-coumaric, and ferulic acids were also present in the bayberry pomaces, whereas, chlorogenic acid was only detected in Dongkui (1.58 mg/kg dry weight). The antioxidant activity of Wandao was the strongest of the five cultivars, whereas the activity of Dongkui was the weakest, and a significant positive relationship was observed between antioxidant activity and total phenolic content or total anthocyanins.     

Determination of phenolic antioxidants in tuna fillets canned in hydrosols with HPLC-DAD

Canned tuna was fortified with a mixture of brine and hydrosols of aromatic plants (i.e. oregano, laurel, sage and lemon balm). An HPLC-DAD method was developed and validated for the simultaneous determination of thirteen antioxidants in tuna fillets, including phenolic acids (gallic acid, vanillic acid, syringic acid and rosmarinic acid), flavonoids (catechin, epicatechin, vanillin, myricetin, rutin, quercetin, luteolin and apigenin) and one hydroxybenzaldehyde (syringaldehyde). The analytes showed satisfying recovery efficiency (82.1–92.1%), and the method presented excellent linearity (r² > 0.99). The precision limit was ≤5.6% RSD_r for intra-day and ≤7.2% RSD_R for inter-day experiments. The determined analytes ranged between 8.86 mg (quercetin) and 512 mg (rosmarinic acid) per 100g tuna flesh (n = 10), verifying that the hydrosols fortified the tuna fillets.     

Polyphenolic composition of bark extracts fromEucalyptus camaldulensis,E. globulus andE. rudis

Polyphenolic composition (flavonoids and phenolic acids and aldehydes) is studied in the Et₂O soluble fractions of the methanolic extracts ofEucalyptus camaldulensis, E. globulus andE. rudis bark. Gallic, protocatechuic, vanillic and ellagic acids, and protocatechuic aldehyde were identified in the three species; eriodictyol, quercetin and naringenin, inE. camaldulensis andE. globulus; vanillin, inE. camaldulensis andE. rudis; naringin, quercitrin, luteolin and kaempferol, inE. camaldulensis; taxifolin and apigenin, inE. globulus; and methyl benzoates and cinnamates, inE. rudis. Some unidentified ellagitannins, flavonols and flavanones were also detected. Significant differences in composition among species were found:E. rudis showed the lowest concentration in flavonoids andE. globulus presented higher concentration and variety of ellagitannins than the others.

     

接种发酵对葡萄酵素多酚生物利用度及抗氧化活性的影响

为明确接种发酵对葡萄酵素多酚生物利用度及抗氧化活性的影响,研究葡萄酵素发酵过程中发酵特性、酚类物质及抗氧化活性的变化,并采用体外模拟胃肠道消化实验对其多酚的生物利用度进行评估.结果 表明:葡萄酵素发酵过程中还原糖质量浓度由31.91 g/L逐渐降低至0.46 g/L,pH值由3.77降至3.19,乙醇体积分数于发酵第6...     

Phenolic content,antioxidant and physico‐chemical properties of Sardinian monofloral honeys

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.     

Synergistic and Antagonistic Interactions of Phenolic Compounds Found in Navel Oranges

Abstract: Phenolic compounds are known to have antioxidant and antimicrobial properties. These properties may be useful in the preservation of foods or beverages. The interactive antioxidant capacity of phenolic compounds within foods has not been well explored. Interactions of individual phenolic compounds (chlorogenic acid, hesperidin, luteolin, myricetin, naringenin, p-coumaric acid, and quercetin) at the concentrations found in navel oranges (Citrus sinensis) were analyzed for their antioxidant capacity to observe potential antagonistic, additive, or synergistic interactions. Mixtures of 2, 3, and 4 phenolic compounds were prepared. The Oxygen Radical Absorbance Capacity (ORAC) assay was used to quantify the antioxidant capacities of these combinations. Three different combinations of 2 compounds and 5 combinations of 3 compounds were found to be synergistic. One antagonistic combination of 2 was also found. No additional synergism occurred with the addition of a 4th compound. A model was developed to explain our results. Reduction potentials, relative concentration, and the presence or absence of catechol (o-dihydroxy benzene) groups were factors in the model. Practical Application: Understanding how combinations of fruit antioxidants work together will support their future use in preservation of foods and/or beverages.