Chemical characterization and chemo-protective activity of cranberry phenolic powders in a model cell culture. Response of the antioxidant defenses and regulation of signaling pathways

Oxidative stress and reactive oxygen species (ROS)-mediated cell damage are implicated in various chronic pathologies. Emerging studies show that polyphenols may act by increasing endogenous antioxidant defense potential. Cranberry has one of the highest polyphenol content among commonly consumed fruits. In this study, the hepato-protective activity of a cranberry juice (CJ) and cranberry extract (CE) powders against oxidative stress was screened using HepG2 cells, looking at ROS production, intracellular non-enzymatic and enzymatic antioxidant defenses by reduced glutathione concentration (GSH), glutathione peroxidase (GPx) and glutathione reductase (GR) activity and lipid peroxidation biomarker malondialdehyde (MDA). Involvement of major protein kinase signaling pathways was also evaluated. Both powders in basal conditions did not affect cell viability but decreased ROS production and increased GPx activity, conditions that may place the cells in favorable conditions against oxidative stress. Powder pre-treatment of HepG2 cells for 20 h significantly reduced cell damage induced by 400 μM tert-butylhydroperoxide (t-BOOH) for 2 h. Both powders (5–50 μg/ml) reduced t-BOOH-induced increase of MDA by 20% (CJ) and 25% (CE), and significantly reduced over-activated GPx and GR. CE, with a significantly higher amount of polyphenols than CJ, prevented a reduction in GSH and significantly reduced ROS production. CJ reversed the t-BOOH-induced increase in phospho-c-Jun N-terminal kinase. This study demonstrates that cranberry polyphenols may help protect liver cells against oxidative insult by modulating GSH concentration, ROS and MDA generation, antioxidant enzyme activity and cell signaling pathways.     

High molecular weight persimmon tannin is a potent antioxidant both ex vivo and in vivo

The antioxidant activities of high molecular weight persimmon condensed tannin (HMWPT) were evaluated in an ex vivo tissue system and in vivo. Addition of HMWPT to mouse liver homogenate protected the samples against auto-peroxidation or H₂O₂- or Fe²⁺/ascorbic acid-induced lipid peroxidation. The IC₅₀ values for HMWPT were 4.32 ± 0.20 μg/mL (auto-oxidation), 1.36 ± 0.40 μg/mL (H₂O₂-induced peroxidation) or 0.20 ± 0.09 mg/mL (Fe²⁺/ascorbic acid-induced peroxidation). Mice were oxidatively stressed with bromobenzene to test the antioxidant activity of HMWPT in vivo. An oral dose of HMWPT at 200 or 400 mg/kg HMWPT significantly (P < 0.01) prevented the bromobenzene-induced decrease in serum and liver superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, and decreased liver malondialdehyde levels in bromobenzene-treated mice (P < 0.01). The results suggest that dietary HMWPT may provide protection from oxidative damage both ex vivo and in vivo.     

Anti-inflammatory and antioxidant activities of red pepper (Capsicum annuum L.) stalk extracts: Comparison of pericarp and placenta extracts

Red pepper stalks, an agricultural waste product, are casually discarded at landfills where they oxidize and harm the local ecology. To our knowledge, no feasible method has been designed to evaluate the bioavailability of red pepper stalks. Therefore, the present study focused on the stalk waste investigating its superoxide dismutase (SOD) activity and inhibitory effect on nitric oxide (NO) production in macrophages. Interestingly, by comparison with red pepper pericarp and placenta extracts, the stalks were found to have higher phenolic, flavonoid, and capsaicin contents. Chromatographic data showed differences in the amounts of phenolic compounds in various parts of red pepper. At a concentration of 100 μg/mL, the stalk, placenta, and pericarp had SOD activities of 52.3%, 7.4%, and 10.4%, respectively. A very high level of chlorogenic acid (3.82 mg/g d w) and p-coumaric acid (2.98 mg/g d w) gave the stalks of red peppers the most powerful antioxidant activity among the three tested parts. The high phenolic and SOD activity-containing stalks also had the most significant NO inhibitory effect (53.5%) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. These results demonstrated that there is an opportunity to develop a new anti-inflammatory agent from agricultural wastes.     

Isolation and characterization of three antioxidant pentapeptides from protein hydrolysate of monkfish (Lophius litulon) muscle

In the current study, an efficient method had been developed to acquire the antioxidant hydrolysate of monkfish muscle protein (MPH) using trypsin by an orthogonal (L₉(3)⁴) test. Under the optimum conditions of enzymolysis time 4 h, enzyme-to-substrate ratio (E/S) 2%, enzymolysis temperature 40 °C and pH 8.0, the DH (Degree of hydrolysis) and hydroxyl radical scavenging activity of MPH reached 19.83 ± 0.82% and 58.05 ± 3.01%, respectively. By using ultrafiltration, gel filtration chromatography and reversed phase high performance liquid chromatography (RP-HPLC), three antioxidant pentapeptides were isolated from MPH, and their amino acid sequences were identified as Glu-Trp-Pro-Ala-Gln (MPH-P1), Phe-Leu-His-Arg-Pro (MPH-P2), and Leu-Met-Gly-Gln-Trp (MPH-P3) with molecular weights of 629.68 Da, 668.80 Da, and 633.77 Da, respectively. MPH-P1, MPH-P2, and MPH-P3 exhibited good scavenging activities on hydroxyl radical (EC₅₀ 0.269, 0.114 and 0.040 mg/ml), DPPH radical (EC₅₀ 2.408, 3.751, and 1.399 mg/ml), and superoxide anion radical (EC₅₀ 0.624, 0.101, and 0.042 mg/ml) in a dose-dependent manner. MPH-P3 was also effective against lipid peroxidation in the model system. The antioxidant activities of MPH-P1, MPH-P2, and MPH-P3 were due to their small sizes and the presence of antioxidant and hydrophobic amino acid residues within their sequences. The results of this study suggested that the protein hydrolysate and/or its isolated peptides might be effectively used as food additives for retarding lipid peroxidation occurring in foodstuffs.     

Evaluation and improvement of antioxidant and antibacterial activities of supercritical extracts from clove buds

For the first time, extracts from clove buds obtained by supercritical carbon dioxide extraction were screened for antioxidant and antibacterial activities. Additionally, antioxidant and antibacterial activities of extracts obtained by the supercritical extraction of the clove bud–oregano leaf mixtures were studied. Supercritical extract of pure clove had the highest eugenol (64%) and total phenolic content (530.56 mg GAE/g_extract). All extracts had antioxidant activity comparable to synthetic antioxidants against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and formation of peroxides. Presence of 0.6% and 5% of oregano extract in the clove extracts obtained from the clove–oregano plant mixtures improved their antioxidant activity with respect to the extract from pure clove. Clove extract showed moderate antibacterial activities against selected Staphylococcus and Enterococcus bacterial strains. Presence of 50% of the oregano extract improved antibacterial activity of clove extract against all tested strains and resulted in a synergistic antibacterial activity against Methicillin-resistant Staphylococcus haemolyticus strain (MIC ? 1.25 μg/mL). Study demonstrated great potential of supercritical clove extract as natural functional ingredient and the possibility of increasing its antioxidant and antibacterial efficiencies in order to apply lower concentrations and to reduce undesirable flavour notes and toxicological effects in final products.     

Myricetin modulates streptozotocin–cadmium induced oxidative stress in long term experimental diabetic nephrotoxic rats

Oxidative stress plays a pivotal role in the development of diabetic nephropathy. The present study was aimed to evaluate the modulatory potential of myricetin on streptozotocin (STZ)–cadmium (Cd) induced oxidative stress in diabetic nephrotoxic rats. Diabetic nephrotoxicity was induced by single intraperitoneal injection of STZ at a dose of (40 mg/kg body weight (b/w)) and Cd as cadmium chloride (CdCl₂) (100 p.p.m.). Myricetin was administered to diabetic nephrotoxic rats by intraperitoneally at 1.0 mg/kg b/w for a period of 12 weeks to assess its effects on fasting plasma glucose, plasma insulin, total haemoglobin, glycosylated haemoglobin, lipid peroxidation products viz., thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (LOOH), protein carbonyl content (PCO) and non-enzymatic antioxidants namely vitamins C and E and reduced glutathione (GSH) and also enzymatic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glutathione reductase (GR). Improvement of antioxidant status in myricetin supplemented diabetic nephrotoxic rats revealed its cellular protective effect. Histopathology of liver and kidney confirmed the protective effects of myricetin in diabetic nephrotoxic rats. The outcome of this study concludes that myricetin could be therapeutic flavonol for regulating oxidative mechanism in STZ–Cd induced diabetic nephrotoxic rats.     

Ameliorating effects of ethyl acetate fraction from onion (Allium cepa L.) flesh and peel in mice following trimethyltin-induced learning and memory impairment

The anti-amnesic effects of onion (Allium cepa L.) flesh (OF)¹ and peel (OP)² on trimethyltin (TMT)³-induced learning and memory dysfunction were investigated to confirm learning and memory function. The inhibitory effect against cellular acetylcholinesterase (AChE)⁴ showed that the EtOAc fraction of OP (EOP⁵, IC₅₀ value = 37.11 μg/mL) was higher than the EtOAc fraction of OF (EOF⁶, IC₅₀ value = 433.34 μg/mL). The cognitive effects in ICR mice were also evaluated using Y-maze, passive avoidance, and Morris water maze tests. After the behavioral tests, AChE activity (control = 100%, TMT = 128%, EOF 20 = 108%, EOP 10 = 104%, and EOP 20 = 98%), superoxide dismutase (SOD)⁷ activity, oxidized glutathione (GSSG)⁸/total glutathione (GSH)⁹ and malondialdehyde (MDA)¹⁰ production were examined. These results indicate that both EOF and EOP improved learning and memory function. The main compounds of the EOF and EOP were analyzed by Q-TOF UPLC/MS, and the results were as follows: The EOF (quercetin and quercetin-4′-glucoside) and the EOP (quercetin-4′-glucoside and isorhamnetin-4′-glucoside). Consequently, our results suggest that both EOF and EOP could be efficacious in improving cognitive function through AChE inhibition and antioxidant activity in mice brains.     

Identification and characterization of papain-generated antioxidant peptides from palm kernel cake proteins

Novel peptides with antioxidant activity were isolated and identified from papain generated palm kernel cake (PKC) proteolysate. The proteolysate was fractionated into individual peptides based on hydrophobicity and isoelectric point using reversed-phase high-performance liquid chromatography and isoelectric focusing techniques. The individual peptides were identified by tandem mass spectrometry and their respective antioxidant activities were evaluated using 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and metal chelating activity assays. Peptide sequences, AWFS, WAF, and LPWRPATNVF showed the highest radical scavenging activities of 71%, 56%, and 50%, respectively, while peptide sequences GGIF, YGIKVGYAIP and YLLLK showed the highest metal chelating activities of 56%, 53%, and 50%, respectively. However, the best IC₅₀ values of peptides measured by DPPH assay were displayed by GIFE, GVQEGAGHYALL and GGIF at 0.02 μM, 0.09 μM and 0.35 μM, respectively, while the best half maximal inhibitory concentration values measured using metal chelating activity were shown by LPWRPATNVF, AWFS and YGIKVGYAIP at 0.001 μM, 0.002 μM and 0.087 μM, respectively. It can be concluded that the peptides derived from PKC proteolysate were more potent and distinctive compared to those previously reported from other plant protein sources.     

Antioxidant potential and radioprotective effect of soy isoflavone against gamma irradiation induced oxidative stress

The in vitro antioxidant potential and in vivo radioprotective ability of soy isoflavones was studied. Male Wistar rats were orally administered with soybean isoflavones (60 mg/kg) for 21 days followed by gamma irradiation exposure. Survival studies in rats exposed at 10 Gy and endogenous spleen colony forming unit assay (CFU) at 6.0 Gy were performed in order to find radioprotective and immunomodulatory nature of the compound. The rat liver post mitochondrial supernatant and erythrocytes were used to measure lipid peroxidation (LPO) and glutathione (GSH) content along with various antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) after gamma irradiation exposure at 2.0 Gy. Pretreatment with soy isoflavone, prior to gamma irradiation resulted in the increased survival rate of the animals as compared to irradiated group. CFU counts in the isoflavone treated group followed by gamma irradiation at 6 Gy were significantly high as compared to control and the irradiated group, showing immunomodulatory nature of the isoflavones. Pretreatment with isoflavones also significantly reduced the LPO, enhanced the activity of antioxidant enzymes and improved haematological and histological parameters. The present study suggests that supplementation with isoflavone has potent antioxidant activity and act as probable radioprotector against gamma radiation induced oxidative damage.     

Phenolic composition,antioxidant and antimicrobial activities of free and bound phenolic extracts of Moringa oleifera seed flour

Phenolic compounds, antioxidant and antibacterial activities of defatted Moringa oleifera seed flour (DMF) were investigated. The total phenolic and flavonoid contents were measured using colorimetric methods. Free phenolic acid and flavonoid profiles were analyzed by high performance liquid chromatography, while antioxidant capacities were evaluated using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), ferric reducing antioxidant power and total antioxidant capacity. The results showed that extractability of phenolic compounds was significantly higher (p < 0.05) in bound phenolic extract (4173.00 ± 32.22 mg gallic acid equivalents (GAE)/100 g) than in free phenolic extract (780.00 ± 14.2 mg GAE/100 g) and it showed higher antioxidant and antimicrobial activities. The IC₅₀ value for DPPH radical scavenging activity was 0.9 ± 0.05 and 14.9 ± 0.07 mg/mL for bound phenolic and free phenolic extracts, respectively. Bound phenolic extract was more effective (minimum inhibitory concentration (MIC), 0.06–0.157%) than free phenolic extract (MIC, 0.117–0.191%) against tested bacteria. Ten phenolic compounds (gallic acid, p-coumaric acid, ferulic acid, caffeic acid, protocatechuic acid, cinnamic acid, catechin, epicatechin, vanillin and quercetin) were identified and quantified in both extracts. These natural plant phenolics from Moringa seeds could be a good source of antioxidants and antibacterials for food and pharmaceutical industries.     

Amelioration of hyperglycemia,hyperlipidemia, oxidative stress and inflammation in steptozotocin-induced diabetic rats fed a high fat diet by riceberry supplement

Dark purple riceberry bran contains a higher dietary fiber and antioxidant compounds than unpigmented rice bran. Riceberry supplement (RB) was used to evaluate the effects on biochemical parameters, skeletal muscle glucose transporter 4 (GLUT4), oxidative stress and inflammation in a streptozotocin (STZ)-induced diabetes rat. To elucidate the effects were due to dietary fiber supplementation and/or bioactive components, equivalent amounts of dietary fiber present in RB were also fed to STZ-induced diabetic rats. Diabetes Sprague–Dawley rats (non-FBG ? 16.65 mM) were randomly divided into five groups: DM fed a high fat (HF) diet, DM-RB1 fed 5% RB, DM-RB2 fed 41% RB, DM-F1 fed 0.6% fiber and DM-F2 fed 5% fiber. After 12 weeks, significant improvement of BG, insulin, HbA1_C, IPGTT and GLUT4 levels were observed in DM-RB1 and DM-RB2 groups. Hyperlipidemia was significantly improved in DM-RB2 and DM-F2 groups. Oxidative stress (TBARS), antioxidant enzymes (SOD, CAT, and GPx), antioxidant capacity (ORAC), pro-inflammation cytokine (TNF-α and IL-6) were improved in DM-RB1 and DM-RB2 groups. Improvement of pancreas and spleen histology was found in DM-RB1 and DM-RB2 groups. These indicate the potential of RB to improve hyperglycemia and hyperlipidemia conditions as well as alleviate oxidative stress and inflammation.     

Dihydrocaffeic acid,a major microbial metabolite of chlorogenic acids,shows similar protective effect than a yerba mate phenolic extract against oxidative stress in HepG2 cells

The hepatoprotective effect of a yerba mate phenolic extract (YMPE), rich in chlorogenic acids, and its main circulating metabolites dihydrocaffeic (DHCA) and dihydroferulic (DHFA) acids were assessed in human hepatoma HepG2 cells subjected to oxidative damage induced by tert-butylhydroperoxide (t-BOOH). Direct treatment of HepG2 cells with realistic concentrations of YMPE (1, 10 and 50 μg/mL), DHCA or DHFA (0.2, 1, 10 μM) for 20 h was not cytotoxic and significantly decreased ROS generation. Pre-treatment with YMPE and DHCA prevented the cytotoxicity and macromolecular damage induced by t-BOOH. Moreover, decreased levels of reduced glutathione (GSH), and increased ROS levels and antioxidant enzyme activity induced by t-BOOH were dose-dependently recovered. DHFA only showed a slight protection against cell cytotoxicity, lipid oxidation and GSH depletion. In conclusion, YMPE and one of its major microbial metabolites, DHCA, confer significant protection against oxidative damage, adding evidences to the beneficial health effects associated with mate intake.     

In vitro antioxidant study of vegetable oils containing conjugated linolenic acid isomers

The study aimed to evaluate the antioxidant activity (in vitro) of vegetable oils containing conjugated linolenic acid (CLnA) isomers such as α-eleostearic and punicic acid and also to evaluate the comparative effectiveness of these vegetable oils due to presence of cis–trans isomers in variable amount. Different in vitro methods were used to evaluate the free radical scavenging activity, hydroxyl radical scavenging activity, metal chelating activity and reducing activity of oils at different concentrations of CLnA isomers such as 125, 250 and 375 μg/mL. Inhibition on lipid peroxidation was evaluated by measuring thiobarbituric acid responsive substance (TBARS) and conjugated diene formation at 125 and 250 μg/mL concentrations of CLnA. Both the oils showed potent free radical scavenging activity at 375 μg/mL concentration. In contrary, these oils showed higher hydroxyl radical scavenging, metal chelation and reducing activity at lower concentration i.e. 125 μg/mL. TBARS formation and conjugated diene formation was lower i.e. inhibition of lipid peroxidation was maximum at 125 μg/mL of both CLnA isomers. Overall, both the oils showed better antioxidant activity at lower concentration due to better oxidative stability and bitter gourd oil showed more prominent antioxidant activity than snake gourd oil due to presence of higher trans content.     

In vitro antioxidant activities of the methanol extracts of five Allium species from Turkey

This study was designed to examine the in vitro antioxidant activities of the methanol extracts of five Allium species, namely Allium nevsehirense, A. sivasicum, A. dictyoprosum, A. scrodoprosum subsp. rotundum and A. atroviolaceum; the former two are endemic for the Turkish flora. The extracts were screened for their possible antioxidant activities by two complementary tests; DPPH free radical-scavenging and β-carotene/linoleic acid assays. In the first case, non-polar subfractions of the extracts did not show any antioxidant potential, while the polar subfractions exhibited marked activity. Among the polar ones, the most active one was A. atroviolaceum with an IC₅₀ of 79.0 ± 2.75 μg/ml. In the β-carotene/linoleic acid assay, the inhibition ratios of the oxidation of linoleic acid by A. atroviolaceum and A. dictyoprosum were too close to each other (71.2 ± 2.20% and 72.3 ± 1.20%, respectively), while that of the synthetic antioxidant, BHT, was 96%.     

Purification and identification of antioxidant peptides from corn gluten meal

Corn gluten meal was hydrolyzed by alkaline protease and Flavourzyme to obtain the antioxidant peptides. The antioxidant activities of the hydrolysates or peptides were evaluated by free radical scavenging capacity (1,1-diphenyl-2-picrylhydrazyl/2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt/hydroxyl radical/superoxide radical anion), metal ion (Fe²⁺/Cu²⁺) chelating activity and lipid peroxidation inhibitory capacity. The hydrolysates were separated by ultrafiltration, and those with molecular weight <10 kDa exhibited highest antioxidant activity in all relevant assays. The hydrolysates were subsequently purified by gel filtration chromatography, and fraction F3 showed the highest antioxidant activity. Three peptides were identified from fraction F3 using LC–ESI–Q–TOF MS/MS as Leu-Pro-Phe (375.46 Da), Leu-Leu-Pro-Phe (488.64 Da) and Phe-Leu-Pro-Phe (522.64 Da). These peptides exhibited good free radical scavenging activity and lipid peroxidation inhibitory effect. Thus, corn gluten meal may be used as a potential source of antioxidant peptides for food and nutraceutical applications.     

The in vivo antioxidant and antifibrotic properties of green tea (Camellia sinensis,Theaceae)

The in vivo antioxidant and antifibrotic properties of green tea (Camellia sinensis, Theaceae) were investigated with a study of carbon tetrachloride (CCl₄)-induced oxidative stress and hepatic fibrosis in male ICR mice. Oral administration of green tea extract at doses of 125, 625 and 1250 mg/kg for 8 weeks significantly reduced (p < 0.05) the levels of thiobarbituric acid-reactive substances (TBARS) and protein carbonyls in the liver by at least 28% compared with that was induced by CCl₄ (1 mL/kg) in mice. Moreover, green tea extract administration significantly increased (p < 0.05) the activities of catalase, glutathione peroxidase (GSH-Px) and glutathione reductase (GSH-Rd) in the liver. Our study found that oral administration of green tea extract prevented CCl₄-induced hepatic fibrosis, as evidenced by a decreased hydroxyproline level in the liver and a reduced incidence of hepatic fibrosis by histological observations. These results indicate that green tea exhibits potent protective effects against CCl₄-induced oxidative stress and hepatic fibrosis in mice by inhibiting oxidative damage and increasing antioxidant enzyme activities.     

Structure–mechanism relationship of antioxidant and ACE I inhibitory peptides from wheat gluten hydrolysate fractionated by pH

The aims of this study were to assess bioactive properties (ACE inhibition and antioxidant capacity) from wheat gluten hydrolysate peptides fractionated by pH (4.0, 6.0 and 9.0), to determine peptide action mechanism, and to relate it to the secondary structure and functional groups of peptides. Gluten hydrolysate extracts (GHE) were enriched in peptides with medium hydrophobicity and molecular weight (≈ 60% MH and 5.5 kDa, respectively). Gluten peptides inhibited ACE I by uncompetitive mechanism and a direct relationship between α-helix structure and IC50% value was obtained (r = 0.9127). TEAC and cooper chelating activity from GHE 6.5 were the highest and directly correlated with MH peptides. GHE 9.0 had high carotene bleaching inhibition (47.5 ± 0.3%) and reducing power activity (163.1 ± 2.9 mg S₂O₃^2 − equivalent g^− 1 protein), which were directly related to disulfide bonds content of peptides (r = 0.9982 and 0.9216, respectively). pH was a good alternative to select bioactive peptides from wheat gluten hydrolysate.     

Identification of bioactive peptides after digestion of human milk and infant formula with pepsin and pancreatin

Seven human milks were subjected to an in vitro digestion with pepsin and pancreatin to identify the peptides released from human proteins. On the basis of their sequences, 11 of the 23 peptides were synthesised and their angiotensin converting enzyme (ACE)-inhibitory and antioxidant activities were measured. The β-casein peptides HLPLP and WSVPQPK showed potent ACE-inhibitory and antioxidant activity, with a protein concentration needed to inhibit 50% ACE activity (IC₅₀) of 21 μm and a Trolox Equivalent Antioxidant Capacity (TEAC) of 1.297 μmol 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) equivs μmol⁻¹ of peptide, respectively. These activities were determined after digestion of eight infant formulas and compared with those found in digested human milk. One of the infant formulas exhibited a low IC₅₀ value (60.11 μg protein mL⁻¹ of reconstituted formula) and a high TEAC value (1.7056 μmol Trolox equivs mg⁻¹ of protein) and was therefore selected to identify the peptides responsible of these activities.     

Bioactive substance contents and antioxidant capacity of raw and blanched vegetables

Five commonly consumed vegetables in Malaysia namely, four-angled bean (Psophocarpus tetragonolobus D.C.), French bean (Phaseolus vulgaris L.), long bean (Vigna sesquipedalis L.), snow pea (Pisum sativum var. macrocarpon L.) and snap pea (Pisum sativum) were blanched in boiling water for 10 min. The contents of total phenolics, ascorbic acid and β-carotene, and the antioxidant capacity as typified by β-carotene and free radical scavenging activity (DPPH) assays were determined for the raw and blanched vegetables. The study revealed that blanching caused a significant (p < 0.05) increase in β-carotene content [fresh (389–539 µg/100 g), blanched (510–818 µg/100 g)], except in snow pea. Conversely, there was a significant (p < 0.05) decrease in ascorbic acid content [fresh (1.2–7.8 mg/100 g), blanched (0.67–3.8 mg/100 g)]. After blanching, the total phenolic content and antioxidant activity either decreased or increased depending on the type of vegetables. The total phenolic content was positively correlated with the antioxidant activity of the studied vegetables to some extent, but not with ascorbic acid or β-carotene.Industrial relevanceBeans (four-angled bean, French bean and long bean), and peas (snow and snap pea) are commonly consumed vegetables in Malaysia. However, the scientific information regarding blanching and its effect on the total phenolic content and antioxidant activities is very limited. This work showed that blanching caused an increase in the carotene, total phenolic content and antioxidant activities in some of the selected vegetables. This work is important since, consumption of raw vegetables does not have high nutritional qualities and antioxidant activities as shown in this work.