Pomological features, nutritional quality, polyphenol content analysis, and antioxidant properties of domesticated and 3 wild ecotype forms of raspberries (Rubus idaeus L.)

Abstract: The raspberry (Rubus idaeus L.) is an economically important berry crop that contains many phenolic compounds with potential health benefits. In this study, important pomological features, including nutrient content and antioxidant properties, of a domesticated and 3 wild (Yayla, Yavuzlar, and Yedigöl) raspberry fruits were evaluated. Also, the amount of total phenolics and flavonoids in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were calculated as gallic acid equivalents (GAEs) and quercetin equivalents (QE). The highest phenolic compounds were found in wild Yayla ecotype (26.66 ± 3.26 GAE/mg extract). Whilst, the highest flavonoids were determined in wild Yedigöl ecotype (6.09 ± 1.21 QA/mg extract). The antioxidant activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were investigated as trolox equivalents using different in vitro assays including DPPH^?, ABTS^?+, DMPD^?+, and O^??₂ radical scavenging activities, H₂O₂ scavenging activity, ferric (Fe³⁺) and cupric ions (Cu²⁺) reducing abilities, ferrous ions (Fe²⁺) chelating activity. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α‐tocopherol, pyrogallol, p‐hydroxybenzoic acid, vanillin, p‐coumaric acid, gallic acid, and ascorbic acid in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were detected by high‐performance liquid chromatography and tandem mass spectrometry (LC‐MS‐MS). The results clearly show that p‐coumaric acid is the main phenolic acid responsible for the antioxidant and radical scavenging activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits.     

Isolation of a free radical‐scavenging antioxidant from water spinach (Ipomoea aquatica Forsk)

Ipomoea aquatica Forsk, a green leafy vegetable that is a rich source of vitamins and amino acids with many health benefits, has been explored for the isolation and identification of its bioactive compounds. Activity‐guided repeated fractionation of a methanol extract on a silica gel column followed by an XAD column yielded a compound that exhibited antioxidant activity with an EC₅₀ value of 83 ± 1.02 µg ml^?1 reaction mixture. It also showed very strong lipid peroxidation‐inhibitory activity in a liposome model system with an EC₅₀ value of 72.2 ± 0.9 µg ml^?1. However, it showed negligible metal‐chelating activity. Based on UV, 2D nuclear magnetic resonance and gas chromatography/mass spectrometry studies, the compound was tentatively identified to be 7‐O‐β‐D ‐glucopyranosyl‐dihydroquercetin‐3‐O‐α‐D ‐glucopyranoside. This is the first report on the antioxidant properties of I aquatica leaf extracts. Copyright © 2005 Society of Chemical Industry     

Lactobacillus plantarum AR501 Alleviates the Oxidative Stress of D‐Galactose‐Induced Aging Mice Liver by Upregulation of Nrf2‐Mediated Antioxidant Enzyme Expression

Lactic acid bacteria (LAB) have been used as ingredients of functional foods to promote health and prevent diseases because of their beneficial effects. This study aimed to investigate the antioxidative effects of LAB on the hepatotoxicity in D‐galactose‐induced aging mice. LAB were isolated from the traditional Chinese fermented foods and screened by the tolerance of hydrogen peroxide (H₂O₂). Male ICR (Institute of Cancer Research) mice were subcutaneously injected with D‐galactose for 5 weeks and then gastric gavage with LAB for 6 weeks. The results showed that Lactobacillus plantarum AR113 and AR501, and Pediococcu pentosaceus AR243 could tolerate up to 1.5 mM H₂O₂ in vitro, and they could live through simulated gastrointestinal tract (GIT) to colonizing the GIT of host. In vivo, oral administration of L. plantarum AR113 and AR501 improved the antioxidant status of D‐galactose‐induced oxidative stress mice such as alleviated liver damages and reduced abnormal activities of superoxide dismutase, glutathione peroxidase, and catalase to normal levels. In addition, L. plantarum AR501 markedly elevated the gene expression of nuclear factor erythroid‐2‐related factor 2 and upregulated the expressions of several antioxidant genes such as glutathione reductase, glutathione S‐transferase, glutamate‐cysteine ligase catalytic subunit, glutamate‐cysteine ligase modifier subunit, and NAD(P)H quinone oxidoreductase 1 in the liver of an aging mice. Therefore, L. plantarum AR501 could be a good candidate for producing antiaging functional foods.     

Assessing and comparing antioxidant activities of lactobacilli strains by using different chemical and cellular antioxidant methods

Some lactobacilli strains had beneficial effects on human beings due to their antioxidant activities. In this study lactobacilli strains stored in our laboratory were screened for potential antioxidant activities by investigating their 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity, oxygen radical absorbance capacity, resistance to H₂O₂, and hydroxyl free radical scavenging activity; then the antioxidant activities of the screened strains were evaluated by cellular antioxidant assay and protection for HT-29 cells against H₂O₂ injury assay. The results showed that Lactobacillus plantarum Y44 could scavenge oxygen free radicals, inhibit the production of intracellular reactive oxygen species without creating obvious cytotoxic effects, and protect HT-29 cells against H₂O₂ injury evidenced by the significant decrease of the Bcl-2-associated X protein (Bax)/B-cell lymphoma 2 (Bcl-2) ratio and heat shock protein 70 expression, increase of superoxide dismutase and glutathione peroxidase activities, and decrease of malondialdehyde level of HT-29 cells damaged by H₂O₂. It was speculated that L. plantarum Y44 protect HT-29 cells against oxygen radical injury through scavenging reactive oxygen species and activating intracellular antioxidant enzymes. A significant correlation was observed among the results of the hydroxyl radical scavenging assay, protection assay for HT-29 cells against H₂O₂ injury, and the cellular antioxidant assay. The findings indicated that L. plantarum Y44 could be a probiotic candidate with antioxidant properties and combining several chemical antioxidant methods and antioxidant cellular models could be an effective procedure to screen lactobacilli strains with antioxidant activity.     

The antioxidant activity and transcellular pathway of Asp‐Leu‐Glu‐Glu in a Caco‑2 cell monolayer

Asp‐Leu‐Glu‐Glu (DLEE) is one of the antioxidant peptides purified from Chinese dry‐cured Xuanwei ham in our previous study. In the current work, the stability in a simulated digestion system, the transportation pathway and the antioxidant ability of DLEE were further investigated in a Caco‐2 cell monolayer. In the simulated gastrointestinal digestion system, no oligopeptides were generated. In the transport trial, the inhibitors cytochalasin D increased the transport of DLEE across the Caco‐2 cell monolayer, with P_app values of 3.22 × 10^?6 cm s^?1. A decreased expression occludin was observed with the DLEE incubation in the cell monolayer, and the antioxidant activity showed to be increased gradually in basolateral side. This study indicates that the absorption of DLEE could mainly occur via paracellular transport and provides information about its antioxidant activity after being absorbed across a cell monolayer.     

S‐Allyl cysteine,S‐ethyl cysteine and S‐propyl cysteine alleviate oxidative stress‐induced damage within PC12 cells

BACKGROUND: The PC12 cell line is a suitable model for the investigation of neurodegenerative diseases. In this study, PC12 cells were used to examine in vitro antioxidative and antiapoptotic protection by S‐allyl cysteine (SAC), S‐ethyl cysteine (SEC) and S‐propyl cysteine (SPC). PC12 cells were treated with these agents at 5 and 10 µmol L^?1 before exposure to hydrogen peroxide (H₂O₂). RESULTS: H₂O₂ treatment significantly decreased mitochondrial membrane potential (MMP) and cell viability and increased lactate dehydrogenase (LDH) release and DNA fragmentation (P < 0.05). The pre‐treatments with SAC, SEC and SPC significantly and concentration‐dependently elevated cell viability and MMP and lowered LDH release and DNA fragmentation (P < 0.05). H₂O₂ treatment also significantly increased levels of malondialdehyde (MDA), reactive oxygen species (ROS) and oxidised glutathione (GSSG) and decreased glutathione (GSH) content (P < 0.05). The pre‐treatments with SAC, SEC and SPC significantly decreased subsequent H₂O₂‐induced formation of MDA, ROS and GSSG (P < 0.05) and also alleviated H₂O₂‐induced GSH depletion (P < 0.05). Finally, H₂O₂ treatment significantly decreased Na⁺‐K⁺‐ATPase activity and elevated caspase‐3 activity (P < 0.05). The pre‐treatments with SAC, SEC and SPC significantly attenuated H₂O₂‐induced Na⁺‐K⁺‐ATPase activity reduction and caspase‐3 activity elevation (P < 0.05). CONCLUSION: The results obtained support that the three cysteine‐containing compounds studied are potent neuroprotective agents. Copyright © 2008 Society of Chemical Industry     

Comparison of the antioxidant and pro‐oxidant activities of broccoli amino acids with those of common food additives

The antioxidant and pro‐oxidant activities of broccoli amino acids were compared with those of common food additives. In decreasing order, the data showed that Asp, SMC, GABA, Glu, Gln, Pro, Phe, Leu, Lys, Arg, Asn, Val, Ile, His, Ser, Gly, Orn and Ala, when dissolved in water at concentrations of 0.5 and 0.05 mM , partially inhibited damage to deoxyribose in the presence of ferric‐EDTA and H₂O₂. In contrast, Tyr and Thr acted as pro‐oxidants in this system. The amino acids present in broccoli had no hydrogen peroxide‐scavenging effect. When dissolved in water, methanol or ethanol, SMC, Glu, Thr, Gln, Ser, GABA, Pro, Ala, Ile, Phe, Asp, Orn and Tyr inhibited lipid peroxidation. However, Asn, Val, Arg, Leu, Lys, His and Gly were not effective in decreasing peroxidation at concentrations of 0.5 and 0.05 mM . Asp > SMC > Ala > Phe > Hys > Orn > Gln = Ser > Lys > Leu = GABA = Gly > Tyr > Arg = Thr > Val > Asn > Pro > Ile > Glu (p < 0.025) showed scavenging activity towards hypochlorous acid, protecting α₁‐antiproteinase against inactivation. In this paper it has been established that some amino acids premixed with propyl gallate increase its hypochlorous acid‐scavenging capacity, while other amino acids have an additive effect with propyl gallate, permitting smaller quantities of propyl gallate to be used as food additives in some products which contain these amino acids. © 2001 Society of Chemical Industry     

The Evaluation of Antioxidant Interactions among 4 Common Vegetables using Isobolographic Analysis

Isobolographic analysis was used to assess the antioxidant interactions (synergism, addition, and antagonism) of 4 common vegetables (tomato [T], carrot [C], eggplant [E], and purple potato [P]). The lipophilic (L) extracts of T and C (main carotenoids), the hydrophilic (H) extracts of E and P (main phenolics) were mixed by the certain ratios (1:9, 3:7, 1:1, 7:3, 9:1, w/w) and their antioxidant activities were investigated by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2’‐Azinobis‐(3‐ethylbenzthiazoline‐6‐sulphonate) (ABTS) radical scavenging assays, respectively. Most of the binary mixtures (LC‐HE, LC‐HP, HE‐HP, LT‐HE, and LT‐HP combinations) showed the synergistic antioxidant effects. In DPPH assay, the greatest antioxidant activity of vegetable combinations was 1:9 LT‐HP (EC₅₀: 2.45 ± 0.13 mg/mL), followed by 9:1 HE‐HP (EC₅₀: 3.62 ± 0.12 mg/mL) and 1:9 LC‐HE (EC₅₀: 3.74 ± 0.47 mg/mL). In ABTS assay, the greatest antioxidant activity of vegetable combinations was 9:1 HE‐HP (EC₅₀: 4.20 ± 0.10 mg/mL), followed by 7:3 HE‐HP (EC₅₀: 4.41 ± 0.63 mg/mL) and 1:1 HE‐HP (EC₅₀: 5.35 ± 0.85 mg/mL). Among these combinations, 1:1 LC‐HE combination showed the highest synergistic antioxidant effects in DPPH assay (synergistic rate: 87.4%), and 7:3 LC‐HE combination showed the highest synergistic antioxidant effects in ABTS assay (synergistic rate: 87.0%). The mixtures of phenolics and carotenoids with suitable ratios in vegetables effectively enhanced the synergistic antioxidant effects.     

Identification of Bioactive Candidate Compounds Responsible for Oxidative Challenge from Hydro‐Ethanolic Extract of Moringa oleifera Leaves

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.     

In vitro study on antioxidant activities of peanut protein hydrolysate

Peanut protein was hydrolysed with a commercial protease, Alcalase 2.4L, and the resulting hydrolysate was investigated for its antioxidant activities, including the ability to inhibit the autoxidation of linoleic acid, the scavenging effect on the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) free radical, the reducing power and the inhibition of liver lipid oxidation. As compared with the peanut protein, peanut protein hydrolysate showed strong inhibition of the autoxidation of linoleic acid, to scavenge DPPH free radical and showed strong reducing power. Moreover, peanut protein hydrolysate also displayed noticeable inhibition of liver lipid autoxidation and lipid oxidation induced by H₂O₂ or Fe²⁺ in vitro. All these effects of the sample were concentration‐dependent. These results suggest that peanut protein hydrolysate could be a suitable natural antioxidant and may be a health food for humans. Copyright © 2006 Society of Chemical Industry     

Rapid Identification and Comparison of Compounds with Antioxidant Activity in Coreopsis tinctoria Herbal Tea by High‐Performance Thin‐Layer Chromatography Coupled with DPPH Bioautography and Densitometry

A simple and efficient method based on high‐performance thin‐layer chromatography coupled with 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) bioautography (HPTLC‐DPPH) was established for the screening and comparison of antioxidants in different parts of Coreopsis tinctoria herbal tea from different origins and other related herbal tea materials, which used Chrysanthemum morifolium cv. “Gongju” and “Hangju” in this study. Scanning densitometry after DPPH derivatization was applied for the determination of antioxidant capacities of isolated compounds in each sample. It is considered that ethanol extracts of C. tinctoria had stronger antioxidant activity and more characteristic bands than those of 2 compared samples, C. morifolium cv. “Gongju” and “Hangju.” Chemometric analysis results showed that the combination of hierarchical clustering analysis and principal component analysis based on determined antioxidant capacities could be used for the discrimination of different parts of C. tinctoria and C. morifolium. Results showed that 7 compounds made up the major contributions of antioxidant activity in C. tinctoria, including okanin, isookanin, marein, flavanomarein, 5,7,3′,5′‐tetrahydroxyflavanone‐7‐O‐glucoside, 3,5‐dicaffeoylquinic acid, and chlorogenic acid. Therefore, 7 compounds were identified as major antioxidant biomarkers for quality control of C. tinctoria. Results demonstrated that the established method could be applied for the identification of C. tinctoria, and were beneficial for the bioactivity‐based quality control of C. tinctoria.     

The in vitro antioxidant and antimicrobial activities of the essential oil and various extracts of Origanum syriacum L var bevanii

The present work examines the in vitro antioxidant and antimicrobial properties of the essential oil and various extracts from the herbal parts of Origanum syriacum L var bevanii. Polar subfractions of methanol extracts from both deodorised and non‐deodorised materials showed the highest DPPH (2,2‐diphenyl‐l‐picrylhydrazyl) radical‐scavenging activity, with IC₅₀ values of 21.40 and 26.98 µg ml^?1 respectively, whereas the IC₅₀ of the essential oil was 134.00 µg ml^?1. The antioxidant potential of the extracts appeared to be closely related to the presence of polar phenolics. However, the inhibitive effect on linoleic acid oxidation might be promoted by the presence of non‐polar phenolics, as both hexane and dichloromethane extracts showed high antioxidant activities. The antimicrobial activity of the essential oil was superior to those of the other extracts. Nineteen compounds representing 962 g kg^?1 of the essential oil were identified; carvacrol (669 g kg^?1) was the main component. Overall, the results suggest that the essential oil and extracts from the herbal parts of O syriacum could be used as natural preservative ingredients in the food industry. Copyright © 2004 Society of Chemical Industry     

Oregano: chemical analysis and evaluation of its antimalarial, antioxidant, and cytotoxic activities

Abstract: GC‐FID and GC‐MS analysis of essential oil from oregano leaves (Origanum compactum) resulted in the identification of 46 compounds, representing more than 98% of the total composition. Carvacrol was the predominant compound (36.46%), followed by thymol (29.74%) and p‐cymene (24.31%). Serial extractions with petroleum ether, ethyl acetate, ethanol, and water were performed on aerials parts of Origanum compactum. In these extracts, different chemical families were characterized: polyphenols (gallic acid equivalent 21.2 to 858.3 g/kg), tannins (catechin equivalent 12.4 to 510.3 g/kg), anthocyanins (cyanidin equivalent 0.38 to 5.63 mg/kg), and flavonoids (quercetin equivalent 14.5 to 54.7 g/kg). The samples (essential oil and extracts) were subjected to a screening for antioxidant (DPPH and ABTS assays) and antimalarial activities and against human breast cancer cells. The essential oil showed a higher antioxidant activity with an IC₅₀= 2 ± 0.1 mg/L. Among the extracts, the aqueous extract had the highest antioxidant activity with an IC₅₀= 4.8 ± 0.2 mg/L (DPPH assay). Concerning antimalarial activity, Origanum compactum essential oil and ethyl acetate extract showed the best results with an IC₅₀ of 34 and 33 mg/mL, respectively. In addition, ethyl acetate extract (30 mg/L) and ethanol extract (56 mg/L) showed activity against human breast cancer cells (MCF7). The oregano essential oil was considered to be nontoxic.     

Effect of atmosphere composition on the quality of ready‐to‐use broccoli raab (Brassica rapa L.)

BACKGROUND: Many leafy brassicas are widely used for ready‐to‐use salads. Broccoli raab (Brassica rapa L.), also called turnip top, or rapini, is extensively cultivated in southern Italy. The edible portion is made up of the green, immature inflorescences and the stem with its most tender leaves. Recently, interest in this crop has increased among European consumers; moreover, a substantial increase in consumption could come from the ready‐to‐use product. RESULTS: The effects of four different atmosphere compositions (air, 3% O₂ in nitrogen, 3% O₂ + 10% CO₂ in air, and 10% CO₂ in air) on quality attributes of ready‐to‐use broccoli raab were studied. Controlled atmosphere affected appearance, composition, respiration rate, weight loss, and presence of off‐odours. Storage of broccoli raab florets under low oxygen conditions delayed post‐cutting deterioration during storage at 5 °C and preserved appearance and typical odour, up to 17 days. Moreover, respiration rate as well as loss of green colour, chlorophyll and vitamin C were also slowed down in this condition. Finally, in this study no effect of controlled atmosphere storage was found on total phenols content and antioxidant activity. CONCLUSION: Results showed that cold storage in 3% O₂ can be beneficial in order to maintain quality of ready‐to‐use, broccoli raab for up to 17 days. Copyright © 2010 Society of Chemical Industry     

The triterpenoids of Ganoderma tsugae prevent stress‐induced myocardial injury in mice

Ganoderma mushrooms (Lingzhi in Chinese) have well‐documented health benefits. Ganoderma tsugae (G. tsugae), one of the ganoderma species, has been commercially cultivated as a dietary supplement. Because G. tsugae has high antioxidant activity and because oxidative stress is often associated with cardiac injury, we hypothesized that G. tsugae protects against cardiac injury by alleviating oxidative stress. We tested the hypothesis using a work‐overload‐induced myocardial injury model created by challenging mice with isoproterenol (ISO). Remarkably, oral G. tsugae protected the mice from ISO‐induced myocardial injury. Moreover, the triterpenoid fraction of G. tsugae, composed of a mixture of nine structurally related ganoderic acids (GAs), provided cardioprotection by inhibiting the ISO‐induced expression of Fas/Fas ligand, oxidative stress, and apoptosis. The antioxidant activity of GAs was tested in cultured cardio‐myoblast H9c2 cells against the insult of H₂O₂. GAs dissipated the cellular reactive oxygen species imposed by H₂O₂ and prevented cell death. Our findings uncovered the cardioprotective activity of G. tsugae and identified GAs as the bioactive components against cardiac insults.     

Comparison and Characterization of Compounds with Antioxidant Activity in Lycium barbarum Using High‐Performance Thin Layer Chromatography Coupled with DPPH Bioautography and Tandem Mass Spectrometry

Methanol extracts from 50 batches of Lycium barbarum (L. barbarum, wolfberry) in China were compared and characterized using high‐performance thin‐layer chromatography coupled with 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) bioautography (HPTLC‐DPPH) and electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry (ESI‐Q‐TOF‐MS/MS), respectively. Results showed that similar components occupying the major antioxidant activity existed in L. barbarum collected from different origins. However, the average antioxidant capacities of methanol extracts of L. barbarum collected in Ningxia were significantly higher than those of Qinghai, Xinjiang, Inner Mongolia, and Gansu, which may contribute to rational use of L. barbarum in China. Furthermore, the chemical structure of compound with the highest antioxidant capacity was tentatively identified as 2‐O‐β‐d ‐glucopyranosyl‐l ‐ascorbic acid using ESI‐Q‐TOF‐MS/MS analysis, which possessed high potentials to be used as an antioxidant biomarker for the quality control of L. barbarum. Results are helpful for the bioactivity‐based quality control of L. barbarum, and beneficial for the improvement of their performance in functional/health foods area, suggesting that HPTLC‐DPPH bioautography with ESI‐Q‐TOF‐MS/MS could be used as a routine approach for quality control of antioxidant components in L. barbarum.     

Antioxidant Activity of Oxygen Evolving Enhancer Protein 1 Purified from Capsosiphon fulvescens

This study was conducted to determine the antioxidant activity of a protein purified from Capsosiphon fulvescens. The purification steps included sodium acetate (pH 6) extraction and diethylaminoethyl‐cellulose, reversed phase Shodex C4P‐50 column chromatography. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis analysis indicated that the molecular weight of the purified protein was 33 kDa. The N‐terminus and partial peptide amino acid sequence of this protein was identical to the sequence of oxygen evolving enhancer (OEE) 1 protein. The antioxidant activity of the OEE 1 was determined in vitro using a scavenging test with 4 types of reactive oxygen species (ROS), including the 2,2‐diphenyl‐1‐picrylhydrazyl radical, hydroxyl radical, superoxide anion, and hydrogen peroxide (H₂O₂). OEE 1 had higher H₂O₂ scavenging activity, which proved to be the result of enzymatic antioxidants rather than nonenzymatic antioxidants. In addition, OEE 1 showed less H₂O₂‐mediated ROS formation in HepG2 cells. In conclusion, this study demonstrates that OEE 1 purified from C. fulvescens is an excellent antioxidant.     

Studies on antioxidant activities of mucuna seed (Mucuna pruriens var utilis) extract and various non‐protein amino/imino acids through in vitro models

The antioxidant activities of a methanolic extract of mucuna beans (Mucuna pruriens var utilis) and several non‐protein amino/imino acids, namely L ‐3,4‐dihydroxyphenylalanine (L ‐dopa), L ‐3‐carboxy‐6,7‐dihydroxy‐1,2,3,4‐tetrahydroisoquinoline (compound I), (?)‐1‐methyl‐3‐carboxy‐6,7‐dihydroxy‐1,2,3,4‐tetrahydroisoquinoline (compound II) and 5‐hydroxytryptophan (5‐HTP), were evaluated. By virtue of their hydrogen‐donating ability, all the tested compounds and the mucuna seed extract showed excellent reducing power, with the highest values being recorded for L ‐dopa in a dose‐dependent manner. Similarly, as compared with synthetic antioxidants (BHT and BHA) and quercetin, all the tested compounds and the seed extract were found to be more potent in free radical‐scavenging activity (P < 0.05) against α,α‐diphenyl‐β‐picrylhydrazyl (DPPH^?) radicals. Hydroxyl radicals (OH^?) and superoxide anion radicals (O₂^??) were effectively scavenged by the tested compounds, with the exception that no scavenging activity of 5‐HTP was observed on (O₂^??) up to a concentration of 2 mg ml^?1, as was also the case for BHA. Among the tested non‐protein amino/imino acids and seed extract the highest peroxidation‐inhibiting activity (95%) was recorded for 5‐HTP. On the other hand, in the linoleic acid/β‐carotene‐bleaching system, L ‐dopa, compound I and compound II acted as pro‐oxidants, whereas the seed extract showed only weak antioxidant activity as in the linoleic acid emulsion system. Copyright © 2003 Society of Chemical Industry     

Carotenoid compositions of coloured tomato cultivars and contribution to antioxidant activities and protection against H2O2-induced cell death in H9c2

The carotenoid compositions, antioxidant activities and the potential cardio-protective role of 13 tomato cultivars with distinct colour were studied. Colour coordinates were evaluated by colorimeter and the carotenoid compositions were analysed by UPLC. Red tomatoes had the highest total carotenoid contents (TCC) and antioxidant activities, followed by purple, orange, pink and yellow ones. The TCC were 120.5–278.0 μg/g DW, and the antioxidant activities were 21.32–40.07 μmol TE/g DW (PCL), 64.42–89.98% (DPPH) and 10.47–13.76 μmol TE/g DW (ORAC), respectively. The lipophilic extracts were also found to prevent cell death in a cell-based model system using cardiac H9c2 cells and H₂O₂, via attenuation of the caspase-3 and matrix metalloproteinase-2 activities. The extracts of different tomatoes showed strong but different antioxidant activities. Roles of total and individual carotenoids in the antioxidant activities were studied and lycopene showed the highest correlation. Results of this study can be used to guide the development of new tomato cultivars and functional foods, and benefit the consumers.