Quercetin and its ester derivatives inhibit oxidation of food, LDL and DNA.

Quercetin was esterified with fatty acids (FA) in order to expand its application in a wide range of food and biological systems. The antioxidant potential of the esters were examined using hydroxyl radical scavenging activity, antioxidation in oil-in-water emulsion and bulk oil, inhibition of low-density lipoprotein (LDL) oxidation and deoxyribonucleic acid (DNA) scission. Except for oil-in-water emulsion system, quercetin derivatives demonstrated similar and/or better antioxidant activity than quercetin itself in bulk oil (quercetin with C18:1 and C22:6), hydroxyl radical scavenging assay (quercetin with C3:0-C8:0), DNA scission (quercetin with C3:0-C8:0), and LDL oxidation (quercetin with C14:0-C22:6, except C18:0). These results suggest that esterification did not compromise the antioxidant activity of the parent compound and quercetin derivatives might be useful as possible antioxidants in food and biological systems.

Lipophilized epigallocatechin (EGC) and its derivatives: Inhibition of oxidation of ß-carotene-linoleate oil-in-water emulsion and DNA strand scission.

Tea epigallocatechin (EGC) was acylated with selected fatty acids, namely propionic acid [C3:0], caprylic acid [C8:0], lauric acid [C12:0], stearic acid [C18:0] and docosahexaenoic acid (DHA; C22:6 n-3). Antioxidant activity of EGC and its lipophilized derivatives were examined in various food (ß-carotene-linoleate oil-in-water emulsion and bulk oil) and biological (supercoiled DNA and LDL) systems in vitro in order to evaluate the effect of increased lipophilicity on their antioxidant capacity. Lipophilized EGC derivatives were more effective in ß-carotene-linoleate oil-in-water emulsion and bulk oil than their parent EGC molecule. Meanwhile, EGC and its derivatives showed more than 60% inhibition against DNA strand scission induced by hydroxyl or peroxyl radical. Moreover, lipophilization of EGC had a negative effect on the inhibition of human LDL cholesterol peroxidation. Overall, this study revealed that EGC and its lipophilized derivatives could potentially be used as health promoting and disease preventing compounds.

Epigallocatechin (EGC) esters as potential sources of antioxidants.

Epigallocatechin (EGC) was acylated with selected fatty acids, namely propionic acid [C3:0], caprylic acid [C8:0], lauric acid [C12:0], stearic acid [C18:0]) and docosahexaenoic acid (DHA)[C22:6n-3] in order to increase its lipophilicity. Monoesters were identified as the predominant products (~40%) followed by diesters (~33%), triesters (~9%) and trace amounts of tetra- and pentaesters. 1H NMR, 13C NMR and HPLC-DAD-MS were used to elucidate the acylation sites and structures of new EGC esters. According to the HPLC-MS analysis of the caprylate esters, EGC-4'-O-caprylate (27%), EGC-3'-O-caprylate or EGC-5'-O-caprylate (12%) and EGC-3',5'-O-dicaprylate (16%) were the major compounds generated upon the acylation reaction of EGC. The acylation significantly increased the lipophilicity of EGC. In addition, EGC and its esters showed radical scavenging activities against DPPH radical and ABTS radical cation. Therefore, EGC esters could serve as potential sources of antioxidants for application in both hydrophilic and lipophilic media.

Preparation of Quercetin Esters and Their Antioxidant Activity.

Quercetin, a polyphenolic compound, is widely distributed in plants and has numerous health benefits. However, its hydrophilicity can compromise its use in lipophilic systems. For this reason, quercetin was esterified with 12 different fatty acids as their acyl chlorides with varying chain lengths and degrees of unsaturation. Two monoesters (Q-3'-O-monoester and Q-3-O-monoester) and four diesters (Q-7,3'-O-diester, Q-3',4'-O-diester, Q-3,3'-O-diester, and Q-3,4'-O-diester) were the major products as was shown by HPLC-MS and 1H-NMR data. The lipophilicity of quercetin derivatives was calculated; this was found to increase with fatty acid chain length. The antioxidant potential of quercetin and its derivatives was evaluated by using DPPH radical and ABTS radical cation scavenging activity; quercetin showed the highest radical scavenging activity among all tested samples. Despite the decrease of antioxidant activity in this study, the derivatives may show better antioxidant activity in lipophilic media and display improved absorption and bioavailability in the body once consumed.

Omega-3 Polyunsaturated Fatty Acids and Their Health Benefits.

Omega-3 polyunsaturated fatty acids (PUFAs) include α-linolenic acid (ALA; 18:3 ω-3), stearidonic acid (SDA; 18:4 ω-3), eicosapentaenoic acid (EPA; 20:5 ω-3), docosapentaenoic acid (DPA; 22:5 ω-3), and docosahexaenoic acid (DHA; 22:6 ω-3). In the past few decades, many epidemiological studies have been conducted on the myriad health benefits of omega-3 PUFAs. In this review, we summarized the structural features, properties, dietary sources, metabolism, and bioavailability of omega-3 PUFAs and their effects on cardiovascular disease, diabetes, cancer, Alzheimer's disease, dementia, depression, visual and neurological development, and maternal and child health. Even though many health benefits of omega-3 PUFAs have been reported in the literature, there are also some controversies about their efficacy and certain benefits to human health.

Biological Activities of Camelina and Sophia Seeds Phenolics: Inhibition of LDL Oxidation, DNA Damage, and Pancreatic Lipase and α-Glucosidase Activities.

The free, esterified and insoluble-bound phenolics of defatted meals of camelina and sophia seeds were extracted using an ultrasonic-assisted procedure and alkaline hydrolysis. The antioxidant activities of the extracts were evaluated using DPPH and hydroxyl radical scavenging assays as well as inhibition of bleaching of ß-carotene in an oil-in-water system. Moreover, inhibition activity against pancreatic lipase, α-glucosidase, low density lipoprotein (LDL) oxidation and DNA damage induced by peroxyl and hydroxyl radicals were examined for all seed extracts using in vitro systems. The seed extracts of camelina and sophia not only showed significant antioxidant activity but also inhibited pancreatic lipase and α-glucosidase activities effectively. These enzymes in the digestive tract are associated with lipid and carbohydrate digestion, respectively, and control obesity and blood glucose level in the human body. The findings of this work may provide supporting information that camelina and sophia meals may inhibit human LDL oxidation and DNA nicking caused by free radicals and upon consumption may also exert anti-obesity and antidiabetic effects. However, further research is required to confirm these biological activities in vivo. PRACTICAL APPLICATION: The seed phenolic extracts of camelina and sophia not only showed significant antioxidant activity but also effectively inhibited the activities of pancreatic lipase and α-glucosidase. Thus, camelina and sophia seed meals may serve as nutritional ingredients with bioactive phenolics that show in vitro antioxidant and biological effects. However, further research is required to confirm these health effects in vivo.

Identification of phenolic antioxidants and bioactives of pomegranate seeds following juice extraction using HPLC-DAD-ESI-MSn.

Phenolics from free and hydrolyzed fractions of pomegranate juice (PJ) and seeds (PS) were evaluated. In general, total phenolic contents and scavenging of ABTS+, DPPH and hydroxyl radicals, as well as metal chelation of the soluble fraction from PS, were higher than those for PJ. Insoluble-bound phenolics from PS accounted for up to 27% of total scavenging capacity (free+esterified+insoluble-bound). Phenolic acids (13), monomeric flavonoids (8), hydrolysable tannins (12), proanthocyanidin (1) and anthocyanins (12) were tentatively characterized using HPLC-DAD-ESI-MSn. Several compounds were identified for the first time in PJ or PS. The inhibition of DNA damage (induced by hydroxyl and peroxyl radicals), copper-induced LDL-cholesterol peroxidation, as well as alpha-glucosidase and lipase activities were demonstrated, therefore supporting the potential exploitation of PJ and PS as sources of bioactive compounds.

Phenolics of Selected Cranberry Genotypes (Vaccinium macrocarpon Ait.) and Their Antioxidant Efficacy.

Free, esterified, and bound phenolic fractions of berries from five different cranberry genotypes and two market samples were evaluated for their total phenolic, flavonoid, and monomeric anthocyanin contents as well as their antioxidant efficacy using TEAC, ORAC, DPPH radical, reducing power, and ferrous ion chelation capacity assays. HPLC-MS/MS analysis was performed for two of the rich sources (Pilgrim and wild clone NL2) of phenolics and high antioxidant activity. Among the genotypes, Pilgrim showed the highest phenolic and flavonoid contents and wild clones NL3 and NL2 showed the highest monomeric anthocyanin and proanthocyanidin content, respectively. Protocatechuic and syringic acids were detected only in Pilgrim, whereas luteolin 7-O-glucoside, quercetin 3-O-rhamnoside, quercetin 3-O-galactoside, proanthocyanidin B-type, and myricetin 3-O-galactoside were found in wild clone NL3 genotype. Moreover, proanthocyanin trimer A-type and dimer B-type predominated in the wild clone NL2, whereas proanthocyanidin dimer B and trimer A were predominant in Pilgrim.

Phenolic Compounds of Pomegranate Byproducts (Outer Skin, Mesocarp, Divider Membrane) and Their Antioxidant Activities.

Pomegranate peel was separated into outer leathery skin (PS), mesocarp (PM), and divider membrane (PD), and its phenolic compounds were extracted as free (F), esterified (E), and insoluble-bound (B) forms for the first time. The total phenolic content followed the order PD > PM > PS. ABTS(•+), DPPH, and hydroxyl radical scavenging activities and metal chelation were evaluated. In addition, pomegranate peel extracts showed inhibitory effects against α-glucosidase activity, lipase activity, and cupric ion-induced LDL-cholesterol oxidation as well as peroxyl and hydroxyl radical-induced DNA scission. Seventy-nine phenolic compounds were identified using HPLC-DAD-ESI-MS(n) mainly in the form of insoluble-bound. Thirty compounds were identified for the first time. Gallic acid was the major phenolic compound in pomegranate peel, whereas kaempferol 3-O-glucoside was the major flavonoid. Moreover, ellagic acid and monogalloyl-hexoside were the major hydrolyzable tannins, whereas the dominant proanthocyanidin was procyanidin dimers. Proanthocyanidins were detected for the first time.

Antioxidant potential of date (Phoenix dactylifera L.) seed protein hydrolysates and carnosine in food and biological systems.

Date seed protein hydrolysates were evaluated for antioxidant activity as well as solubility and water-holding capacity in food and biological model systems. Date seed protein hydrolysates as well as carnosine exhibited >80% of solubility over a pH range of 2-12. The hydrolysates and carnosine at 0.5% (w/w) were also found to be effective in enhancing water-holding capacity and cooking yield in a fish model system, which was nearly similar to sodium tripolyphosphate (STPP; 0.3%, w/w). Incorporation of hydrolysates (200 ppm) in fish model systems resulted in the highest inhibition (30%) of oxidation in comparison to butylated hydroxytoluene (BHT; 9%). In addition, hydrolysates and carnosine inhibited ß-carotene oxidation by 75%. The hydrolysates (0.1 mg/mL) inhibited LDL cholesterol oxidation by 60%, whereas carnosine inhibited oxidation by 80% after 12 h of incubation. Additionally, hydrolysates and carnosine effectively inhibited hydroxyl (6 mg/mL) and peroxyl (0.1 mg/mL) radical-induced DNA scission. Therefore, date seed protein hydrolysates could be used as a potential functional food ingredient for health promotion.