Inhibitory effect of polyphenol-rich extracts of jute leaf (Corchorus olitorius) on key enzyme linked to type 2 diabetes (α-amylase and α-glucosidase) and hypertension (angiotensin I converting) in vitro

Corchorus olitorius leaf is consumed in various parts of the world as leafy vegetable and folk remedy for the management of some degenerative diseases with dearth of information on its biochemical rationale. Therefore, this study sought to characterize the inhibitory action of polyphenol-rich extracts (free and bound) of C. olitorius on α-amylase, α-glucosidase and angiotensin I converting enzyme (ACE), as well as to identify the phenolic compound responsible for these activities. Our findings revealed that the extracts inhibited α-amylase and α-glucosidase (12.5–50.0 μg/mL), and ACE (10.0–50.0 μg/mL) in dose-dependently with free extracts having significantly (P < 0.05) higher α-amylase (17.5 μg/mL), α-glucosidase (11.4 μg/mL) and ACE (15.7 μg/mL) inhibitory activities as revealed by the IC₅₀. Reversed-phase HPLC analysis of the extracts revealed chlorogenic acid (7.5 mg/100 g) and isorhamnetin (51.1 mg/100 g) as the main phenolics in the free extract and caffeic acid (58.1 mg/100 g) in the bound extract. Therefore, the enzyme inhibitory activity of C. olitorius extracts may be attributed to the presence of caffeic acid, chlorogenic acid and isorhamnetin, thus justifying its use in folklore for the management of diabetes and hypertension.     

Licochalcone A: A lipase inhibitor from the roots of Glycyrrhiza uralensis

In order to develop a functional food and anti-obesity drug through the inhibition of absorption of dietary lipids, we investigated the inhibitory effects on pancreatic lipase of extracts from more than 800 species of herbs in Korea. In this study, licochalcone A was isolated from the ethyl acetate/n-hexane fraction of ethyl acetate extract of the roots of Glycyrrhiza uralensis. Its structure was elucidated by ¹H NMR, ¹³C NMR and HR-EI mass spectroscopy. Licochalcone A substantially inhibited activity with IC₅₀ value of 35 μg/mL (103.4 μM). In an investigation of reversibility, licochalcone A was shown to be reversible to pancreatic lipase. The inhibition mode of licochalcone A was a non-competitive inhibitor, determined by Lineweaver–Burk plot analysis, and K_i value was 11.2 μg/mL (32.8 μM). Furthermore, licochalcone A significantly reduced the production of oleic acid with not only artificial substrate DNPB but natural substrate triolein by pancreatic lipase.     

Purification and characterization of an antioxidant protein from Ginkgo biloba seeds

A new antioxidation protein named G4b was purified from Ginkgo biloba seed albumin. The results of chemical colorimetry and chemiluminescence methods showed that the hemi-inhibitory concentration (IC₅₀) of G4b on the hydroxyl radical were 78.1 μg/mL and 115.1 μg/mL, and the IC₅₀ on DPPH was 100.7 μg/mL, while the IC₅₀ on the superoxide anion and DNA injury were 23 μg/mL and 27 μg/mL, respectively, and the abundance of sulfur amino acids and aromatic amino acids contained in G4b might contribute to its strong antioxidation properties. G4b is a kind of homogeneous and novel protein with a molecular mass of 29,247 Da, consisting of two peptides with similar molecular weights linked by a disulfide bond. Result of β-elimination reaction showed that G4b is connected with a small quantity of polysaccharide by an oxygen-glucosidic bond.     

Air-dried capsicum annuum var. acuminatum medium and big: Determination of bioactive constituents,antioxidant activity and carbohydrate-hydrolyzing enzymes inhibition

In the present study the total phenols, flavonoids, carotenoids and capsaicinoids content, the in vitro antioxidant and hypoglycemic activities of extracts of air-dried fruits from two Capsicum annuum cultivars were investigated. A different composition between the two cultivars was evidenced. C. annuum var. acuminatum medium extract presented a major content of phenols, carotenoids, capsaicin and dihydrocapsaicin while C. annuum var. acuminatum big extract is characterized by the highest quercetin, luteolin and kaempferol content with 68.0, 87.6 and 29.7 μg/g dried weight, respectively, analyzed by HPLC. Medium pepper showed the highest radical scavenging activity in DPPH assay (IC₅₀ of 85.3 μg/ml) while big pepper have an interesting activity in ABTS assay (IC₅₀ of 16.4 μg/ml) and the highest inhibition of linoleic acid oxidation with an IC₅₀ value of 1.2 μg/ml after 30 min of incubation. A selective inhibitory activity against α-amylase was demonstrated for C. annuum var. acuminatum big lipophilic fraction (IC₅₀ values of 8.7 μg/ml). The obtained results suggest that C. annuum cultivars could be used as valuable flavor with functional properties for foods.     

Cocoa brew inhibits in vitro α-glucosidase activity: The role of polyphenols and high molecular weight compounds

Cocoa brew showed a dose-dependent inhibitory activity against α-glucosidase (IC₅₀ 7.87 mg/mL). The cocoa brew was fractionated by ultrafiltration in a low molecular weight fraction (LMW < 10 kDa) and two melanoidin-rich fractions called high molecular weight (HMW > 30 kDa) and intermediate molecular weight (IMW 10–30 kDa) fractions. All fractions tested caused some inhibition with IMW that was the most active (IC₅₀ 2.37 mg/mL). LMW fraction was separated with Sephadex LH-20 in an unbound (containing monomeric and dimeric catechins) and a bound fraction. All the inhibitory activity was recovered in the unbound fraction. All the phenolic compounds identified with HPLC showed α-glucosidase inhibitory activity. IMW and HMW fractions were fractionated by ethanol precipitation. The fractions from IMW precipitated with 75 and 25% ethanol were found to contain power inhibitors of α-glucosidase activity (IC₅₀ 0.87 and 1.01 mg/mL, respectively). In the HMW sample, the fractions precipitated with 50 and 75% ethanol were found to be active against α-glucosidase activity. Most of the inhibitory activity against α-glucosidase of cocoa brew was due to the LMW fraction (56%) whereas IMW and HMW contributed for about 47% of the inhibitory activity. This study suggests that different components of cocoa may influence α-glucosidase activity.     

NMR-based quantification of rosmarinic and carnosic acids,GC–MS profile and bioactivity relevant to neurodegenerative disorders of Rosmarinus officinalis L. extracts

A comparative study of phytochemicals content and biological properties of eight Rosmarinus officinalis (rosemary) populations (RO1–RO8) collected in different areas of Tunisia was carried out. Two of the main rosemary constituents, rosmarinic and carnosic acids, were quantified by an NMR technique. Carnosic acid content was higher than that of rosmarinic acid. The non-polar constituents were examined by GC and GC–MS. Total phenols and flavonoids content were also determined in order to discuss the possible correlation between these phytochemicals and bioactivity. Antioxidant activity was investigated through different in vitro assays. Sample RO3 from a sub-humid area showed the highest potency in 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC₅₀ of 6.74 μg/mL) while RO5 from arid area exhibited the highest radical 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) scavenging activity (IC₅₀ of 5.92 μg/mL). The most active sample in Ferric Reducing Antioxidant Power (FRAP) assay was RO4 (62.21 μM Fe(II)/g), followed by RO1–RO3 and RO8 harvested in sub-humid areas with values in the range 49.61–58.72 μM Fe(II)/g. Extracts were able to inhibit acethylcholinesterase (AChE) and butyrylcholinesterase (BChE). Sample RO5 exhibited a promising AChE inhibitory activity (IC₅₀ of 4.47 μg/mL). Thus, we suggest rosemary extracts as a functional food ingredient for preventing AD.     

α-Glucosidase and α-amylase inhibitory constituent of Carex baccans: Bio-assay guided isolation and quantification by validated RP-HPLC–DAD

Carex baccans is used extensively as food additive for its medicinal and nutritional properties. Its extract demonstrated significant inhibition of α-glucosidase and α-amylase with IC₅₀ 43.32 ± 1.22 and 562.18 ± 5.98 μg/mL, respectively. A bio-assay guided approach was employed to identify the active constituent(s). Fractionation and purification of the extract led to the isolation of a potent inhibitor, (+)-α-viniferin, and of weak inhibitors smiglasides A and B. (+)-α-Viniferin was quantified in the extract and fractions using HPLC and the method was validated for linearity, limit of detection, limit of quantification, precision, and accuracy. The calibration curve showed good linearity (r² > 0.999) in the range of 7.813–250 μg/mL. The identification of α-glucosidase and α-amylase inhibitory activity in C. baccans supports the possible use of the plant as functional food for the management of diabetes. The validated HPLC method for the study of plant extracts will be useful in future research.     

Antioxidant Activity of Ethanol and Lipophilic Extracts of Common Fruity Vegetables in Bangladesh

The amount of phenolics, flavonoids, and anthocyanins in ethanol extracts and antioxidant activity of both ethanol and lipophilic extracts of common fruity vegetables in Bangladesh were studied. Among the ethanol extracts of 15 fruity vegetables, M. oleifera had the highest total polyphenol content (85.05 mg gallic acid equivalent/g extract) followed by L. acutangula (61.74 mg gallic acid equivalent/g extract) and A. esculentus (48.92 mg gallic acid equivalent/g extract). L. acutangula had high a content of flavonoids (14.46 mg (+)-catechin equivalent/g extract), which was almost similar to L. siceraria (13.67 mg catechin equivalent/g extract) followed by A. esculentus (11.95 mg catechin equivalent/g extract) and S. melongena (11.42 mg catechin equivalent/g extract). Highest anthocyanins content was in F. hispida (2.22 μmol/g extract) followed by S. melongena (1.04 μmol/g extract). Ethanol extracts of A. esculentus, F. hispida, L. acutangula, L. siceraria, and S. melongena exhibited high DPPH free radical scavenging activity with IC₅₀ of 70.4, 64.9, 70.4, 64.9, and 94.3 μg/mL respectively, whereas for the same lipophilic extracts of F. hispida and S. melongena showed lowest (37 μg/mL) IC₅₀ followed by M. oleifera (47.6 μg/mL), L. siceraria (57.5 μg/mL), and A. esculentus (63.3 μg/mL). These vegetables also showed high reducing powers, NO scavenging and total antioxidant capacity. Therefore, the top five potential fruity vegetables consist of both hydrophilic and lipophilic antioxidant(s), the order being F. hispida > M. oleifera > A. esculentus, L. acutangula > L. siceraria > and S. melongena.     

Glycine max (L.) Merr., Vigna radiata L. and Medicago sativa L. sprouts: A natural source of bioactive compounds

The consumption of sprouts, common in Asia, has been growing in western countries, once they are a natural healthy food and considered as a valuable dietary supplement. Comparing with their mature counterparts, sprouts are usually richer in health-promoting phytochemicals. So, the nutritional composition and the biological potential of widely consumed sprouts of three species – Glycine max (L.) Merr., Vigna radiata L. and Medicago sativa L. – were compared for the first time. Phenolic compounds and phytosterols were analyzed by HPLC–DAD and organic acids by HPLC–UV. The volatile profile was determined by HS-SPME/GC–IT/MS. Fourteen phenolic compounds (including four isoflavones), three sterols one triterpene, sixteen fatty acids, seven organic acids and thirty volatile compounds were determined. The antioxidant activity was assessed against DPPH^?, superoxide and nitric oxide radicals. G. max sprouts were the most active against DPPH^? (IC₅₀ = 1.337 mg/mL), while those of M. sativa were the most effective against superoxide and nitric oxide radicals (IC₅₀ = 67 μg/mL and IC₅₀ = 426 μg/mL, respectively). Data provide evidence of great similarities between G. max and M. sativa sprouts, both being rich in phenolic compounds, fatty acids and volatiles, and exhibiting better antioxidant activity. On the other hand, V. radiata showed higher amounts of sterols, triterpenes and organic acids. In this study it was found that the sprouts are a good source of bioactive compounds in our diet with health-promoting antioxidants.     

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.     

Purification and characterization of angiotensin I-converting enzyme inhibitory peptides of small red bean (Phaseolus vulgaris) hydrolysates

Angiotensin I-converting enzyme (ACE) inhibitory activity was investigated for small red bean (Phaseolus vulgaris) protein hydrolysate produced by sequential digestion of Alcalase, papain followed by in vitro gastrointestinal simulation. The hydrolysate had ACE inhibitory activity with IC₅₀ of 67.2 ± 1.8 μg protein/mL. Peptides responsible for potent ACE inhibitory activity were isolated by a three-step purification process, including ultrafiltration, gel filtration and preparative reverse phase high performance chromatography (RP-HPLC). The fraction obtained after RP-HPLC fractionation with the highest activity yielded an IC₅₀ of 19.3 ± 1.4 μg protein/mL. Enzymatic kinetic studies using this fraction demonstrated competitive inhibition with K_i of 11.6 ± 1.7 μg protein/mL. Mass spectrometric characterization identified for the first time the octapeptide PVNNPQIH which demonstrated an IC₅₀ value of 206.7 ± 3.9 μM. The results expand the knowledge base of ACE inhibitory properties of small red bean protein hydrolysate and should be useful in further identification of specific ACE inhibitory peptides in beans.     

Cyanidin-3-glucoside,nutritionally important constituents and in vitro antioxidant activities of Santalum album L. berries

Anthocyanins are ubiquitous plant pigments. They are hydrophilic, and have high tinctorial value hence, used as natural food colorant. The main aim of this study was characterization of Santalum album L. berries for its pigment content, nutritionally important phytoconstituents and functional attributes. Major pigment identified was cyanidin-3-glucoside (0.21% FW) as confirmed by spectral characteristics including LC–MS. Nutrients such as total carbohydrates (8.5), proteins (5.8), free amino acids (0.8 g), oil (1.5 g), ascorbic acid (1.5 μg), tocopherols (0.3 mg) and niacin (5.2 mg) per 100 g berries were determined along with total soluble solids (13.4°Brix) and phenols (3.1 mg GAE/g). Reducing power and DPPH· scavenging assays showed highest activity in methanol extract, which also efficiently protected bleaching of β-carotene (EC₅₀ 285 μg/mL) in β-carotene–linoleate model. Pigment rich crude extract was not toxic to HepG2 cells during 24 h exposure, whereas cyanidin-3-glucoside was cytotoxic (IC₅₀ 0.1 μg/mL).     

Antioxidant activity of dulse (Palmaria palmata) extract evaluated in vitro

Palmaria palmata (dulse) is traditionally consumed as a snack food and garnish; but, little is known about its potential as a source of antioxidants. A 1-butanol soluble fraction extracted from dulse exhibited OH scavenging activity ± EDTA (non-site and site specific activity) in a deoxyribose assay. EC₅₀ concentrations of dulse extract to quench DPPH and ABTS⁺ free radicals were 12.5 and 29.5 mg/ml. Dulse extract inhibited (p < 0.05) conjugated diene production in a linoleic acid emulsion at 24, 48 and 52 h, 38 °C; and inhibited (p = 0.044) thiobarbituric acid reactive substances (TBARS) production at 52 h. One milligram dulse extract exhibited reducing activity = 9.68 μg l-ascorbic acid and total polyphenol content = 10.3 μg gallic acid; the dulse extract did not chelate transition metal ions. The antioxidant activity of the dulse extract was associated with aqueous/alcohol-soluble compounds characterized by phenolic functional groups with reducing activity.     

Partridgeberry polyphenols protect primary cortical and hippocampal neurons against β-amyloid toxicity

β-Amyloid (Aβ) deposition elicits a toxic effect on neurons and plays a crucial role in the etiology and/or progression of Alzheimer's disease (AD). Polyphenols found in fruits are endorsed for nutritional intervention in AD, since they are known to have extensive therapeutic properties apropos of brain health owing to their anti-oxidative effects against Aβ and neural reactive oxygen species (ROS). The present study was aimed to investigate the neuroprotective potential of polyphenols of partridgeberry (Vaccinium vitis-idaea L.) and elucidate the mechanism by which they confer protection against Aβ toxicity in rat primary neurons in vitro. The pre-treatment of rat primary cortical and hippocampal neurons with partridgeberry polyphenols (10–200 μg mL^− 1) significantly attenuated Aβ-induced cell death and membrane damage. The flavan-3-ol- and flavonol-rich fractions of the partridgeberry exhibited the strongest ability to maintain cell viability (EC₅₀ 5.9 μg mL^− 1) and prevent lactose dehydrogenase release (IC₅₀ 0.01 μg mL^− 1) (P ≤ 0.05). Similar to the maintenance of cellular viability, the flavan-3-ol- and flavonol-rich fractions also amplified the greatest activity of SOD and catalase among all polyphenol preparations exposed to neurons (P ≤ 0.05). All four partridgeberry polyphenol preparations reduced the intracellular Aβ levels by 7–15 folds, and initiated Aβ clearance from neurons as compared to untreated cells (P ≤ 0.05). Partridgeberry derived polyphenol preparations; especially the flavonol-rich fraction (IC₅₀ 97.1 μg mL^− 1) significantly modulated the apoptotic targets and in vitro acetylcholinesterase activity (P ≤ 0.05), indicating potential pharmacotherapy application in AD. Furthermore, the restoration of hyperactive caspases and Bcl2 family of apoptotic architects added to the neuroprotective candidacy of PPFs. These findings suggest that partridgeberry polyphenols, especially flavan-3-ol- and flavonol-rich fractions, could be of importance in prevention and/or treatment of AD.     

Antioxidant and cell growth activities of beet root pomace extracts

Beetroot (Beta vulgaris) pomace, processing by-product from food industry, was investigated in this work as a starting raw material. The contents of phenolics (1.87–11.98 mg GAE/g of dry weight) and betalains (0.75–3.75 mg betalains/g of dry weight) in the extracts were determinated spectrophotometrically. Some individual phenolic compounds, including ferulic, vanillic, p-hydroxybenzoic, caffeic and protocatehuic acids, were identified and quantified by HPLC. The antioxidative activity of beetroot extracts was tested using DPPH, hydroxyl and superoxide anion radicals by ESR spectroscopy. ${\text{IC}}_{50}^{{}^{\text{<mglyph src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/rad"></mglyph>}}\text{OH}}$ (0.05–0.108 mg/ml), $\text{IC}{50}^{{\text{DPPH}}^{\text{<mglyph src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/rad"></mglyph>}}}$ (0.183–0.333 mg/ml), and ${\text{IC}}_{50}^{{\text{O}}_2^{\text{<mglyph src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/16/entities/rad"></mglyph>}-}}$ (0.198–1.000 mg/ml) were calculated. The regression analysis produced moderate to high correlation coefficients between the scavenging activities and phenolics, and some individual phenolic compounds which indicated that beetroot pomace may be used as functional food ingredient. Cell growth effects were determined in MCF7 and MRC-5 cell lines, using SRB assay. IC₅₀ values were in the range of 362.478–503.525 and 383–587.880 μg/ml in MRC-5 and MCF7, respectively.     

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.     

Studies on the anthocyanin profile and biological properties from the fruits of Acanthopanax senticosus (Siberian Ginseng)

The anthocyanin profile and biological activities, including antioxidant, xanthine oxidase inhibitory, angiotensin converting enzyme (ACE) inhibitory, and anticancer of Acanthopanax senticosus fruits were evaluated for the first time. The acidified 80% methanol extract of this species exhibited high biological properties at a concentration of 60 μg/ml. Moreover, cyanidin-3-O-(2″-O-xylosyl)-glucoside was identified using C₁₈ column chromatography, NMR spectroscopy, and HPLC-DAD-ESI/MS analysis. This compound was present at 5.2 mg/g, representing approximately 91% of the total peak area and possessed strong antioxidant effects against DPPH, ABTS, and hydroxyl radicals (IC₅₀ of 85.2, 43.7, and 126.6 μg/ml, respectively). Cyanidin-3-O-(2″-O-xylosyl)-glucoside also exhibited significant inhibitory activities against xanthine oxidase and ACE (IC₅₀: 55.5 and 47.1 μg/ml, respectively). Especially, LNCap (prostate), MOLT-4F (leukaemia), and ACHN (renal) cell lines exhibited potent anticancer effects, with IC₅₀ of 5.2, 11.2, and 22.5 μg/ml, respectively, in comparison with other cancer cell lines. Therefore, A. senticosus fruit may be utilised as an effective source for food and nutraceutical uses due to its high anthocyanin content as well as various biological properties.     

Citharexylum solanaceum fruit extracts: Profiles of phenolic compounds and carotenoids and their relation with ROS and RNS scavenging capacities

Citharexylum solanaceum is a native fruit from Brazil, which both bioactive compounds and antioxidant potential were not yet investigated. Thus, the freeze-dried extracts of seed and pulp + skin of C. solanaceum fruits were obtained after solid-liquid extraction with ethanol and their bioactive compounds composition, namely phenolic compounds and carotenoids, were determined. The antioxidant capacity of both extracts against physiologically relevant reactive oxygen species (ROS) and reactive nitrogen species (RNS) was further investigated. Both C. solanaceum extracts showed high contents of phenolic compounds; however, pulp + skin extract presented 2.4-times more phenolic compounds (33.54 mg/g) than the seed extract (14.09 mg/g). Verbascoside (phenylpropanoid) was the major compound identified in both extracts (11–25 mg/g). Regarding the carotenoid composition, all-trans-lutein (14–42 μg/g) and all-trans-β-carotene (13–44 μg/g) were the major compounds in both extracts. The high content of phenolic compounds and carotenoids in pulp + skin extract might explain its higher scavenging capacity against all the ROS/RNS as compared to seed extract. In general, both extracts showed better scavenging capacity for the RNS than for the ROS. Our results indicate that C. solanaceum fruits can be explored as an important natural source of antioxidant compounds.     

Angiotensin I-converting enzyme inhibitory activity of chickpea and pea protein hydrolysates

ACE inhibitory activity was studied for different hydrolysates obtained from protein concentrates of chickpea (kabuli and desi) and yellow pea (Golden) using in vitro gastrointestinal simulation, alcalase/flavourzyme, and papain. Protein/peptide profiles studied by SDS–PAGE and SE-HPLC, showed a rich composition of the hydrolysates in small peptides having MWs under 4 kDa. Papain hydrolysed yellow pea proteins showed the highest ACE inhibitory activity. In addition, chickpea desi proteins hydrolysed by in vitro gastrointestinal simulation showed higher ACE inhibition (IC₅₀ of 140 ± 1 μg/ml) compared to its digests obtained by alcalase/flavourzyme (IC₅₀ of 228 ± 3 μg/ml) or papain (IC₅₀ of 180 ± 1 μg/ml) and to chickpea kabuli hydrolysed by gastrointestinal simulation (IC₅₀ of 229 ± 1 μg/ml). The results demonstrate that enzymatic hydrolysates of chickpea and pea proteins contain bioactive ACE inhibitory peptides; furthermore, the type of enzyme used for hydrolysis affects the ACE inhibitory activity.     

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.