HPLC-MS/MS chemical characterization and biological properties of Origanum onites extracts: a recent insight

ABSTRACT

This study investigated into the phytochemical profile and biological properties of extracts (methanol and aqueous) of Origanum onites based on the antioxidant, enzyme inhibitory, and antibacterial activities. The aqueous extract exhibited higher antioxidant activities in the 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), ferric reducing antioxidant power, cupric reducing antioxidant capacity, phosphomolybdenum, and metal chelating assays, compared to the methanol extract. In contrast, the methanol extract was the most effective inhibitor of acetylcholinesterase, butyrylcholinesterase, tyrosinase, α-amylase, and α-glucosidase. The methanol extract also showed higher antibacterial activity with highest inhibition against Escherichia coli (MIC = 6.25 mg/mL). The total phenolic content was higher in the aqueous extract while the methanol extract possessed higher total flavonoid content. A total of 28 and 18 compounds (belonging to polyphenols, flavonoids, terpenoids, and ester classes) were identified from the methanol and water extracts, respectively. These findings suggest that O. onites could be helpful in the management of oxidative stress-associated diseases including diabetes and neurodegenerative complications.

Abbreviations: ABTS: 2,2‘-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid; ACAE: acarbose equivalent; AChE: acetylcholinesterase; AD: Alzheimer‘s disease; BChE: butyrylcholinesterase; CUPRAC: cupric reducing antioxidant capacity; DPPH: 1,1-diphenyl-2-picrylhydrazyl; EDTAE: EDTA equivalent; FRAP: ferric reducing antioxidant power; GAE: gallic acid equivalent; GALAE: galatamine equivalent; HPLC: high performance liquid chromatography; KAE: kojic acid equivalent; RE: rutin equivalents; TE: trolox equivalent; TPC: total phenolic content; TFC: total flavonoid content     

Solid-state bioconversion of chickpea (Cicer arietinum L.) by Rhizopus oligosporus to improve total phenolic content,antioxidant activity and hypoglycemic functionality

The objective of this investigation was to study the effect of time during solid state bioconversion (SSB) on total phenolic content (TPC), antioxidant activity (AoxA), and inhibitory properties against α-amylase and α-glucosidase of chickpea. Chickpea cotyledons were inoculated with a suspension of Rhizopus oligosporus and incubated at 35?°C for 24, 36, 48, 60, 72, 84, 96 and 108?h. The best time to produce bioprocessed chickpea (added with seed coats) flour with the highest AoxA was 108?h. SSB substantially increased TPC and AoxA of chickpea extracts in 2.78 and 1.80–1.94 times, respectively. At 36 and 96?h of fermentation, the SSB process improved in vitro α-amylase and α-glucosidase inhibition (AI and GI indexes) activities of chickpea extracts in 83 and 370%, respectively. SSB is a good strategy to enhance health-linked functionality of chickpea, due to improved TPC, AoxA and content of strong natural inhibitors of enzymes associated with diabetes.     

Bioactive compounds extracted from Indian wild legume seeds: antioxidant and type II diabetes–related enzyme inhibition properties

Seven different wild legume seeds (Acacia leucophloea, Bauhinia variegata, Canavalia gladiata, Entada scandens, Mucuna pruriens, Sesbania bispinosa and Tamarindus indica) from various parts of India were analyzed for total free phenolics, l-Dopa (l-3,4 dihydroxyphenylalanine), phytic acid and their antioxidant capacity (ferric-reducing antioxidant power [FRAP] and 2,2-diphenyl-1-picrylhydrazyl [DPPH] assay) and type II diabetes–related enzyme inhibition activitiy (α-amylase). S. bispinosa had the highest content in both total free phenolics and l-Dopa, and relatively low phytic acid when compared with other seeds. Phytic acid content, being highest in E. scandens, M. pruriens and T. indica, was highly predictive for FRAP (r = 0.47, p < 0.05) and DPPH (r = 0.66, p < 0.001) assays. The phenolic extract from T. indica and l-Dopa extract from E. scandens showed significantly higher FRAP values among others. All seed extracts demonstrated a remarkable reducing power (7–145 mM FeSO4 per mg extract), DPPH radical scavenging activity (16–95%) and α-amylase enzyme inhibition activity (28–40%).     

Bioactive compounds extracted from Indian wild legume seeds: antioxidant and type II diabetes-related enzyme inhibition properties

Seven different wild legume seeds (Acacia leucophloea, Bauhinia variegata, Canavalia gladiata, Entada scandens, Mucuna pruriens, Sesbania bispinosa and Tamarindus indica) from various parts of India were analyzed for total free phenolics, l-Dopa (l-3,4 dihydroxyphenylalanine), phytic acid and their antioxidant capacity (ferric-reducing antioxidant power [FRAP] and 2,2-diphenyl-1-picrylhydrazyl [DPPH] assay) and type II diabetes-related enzyme inhibition activitiy (α-amylase). S. bispinosa had the highest content in both total free phenolics and l-Dopa, and relatively low phytic acid when compared with other seeds. Phytic acid content, being highest in E. scandens, M. pruriens and T. indica, was highly predictive for FRAP (r = 0.47, p < 0.05) and DPPH (r = 0.66, p < 0.001) assays. The phenolic extract from T. indica and l-Dopa extract from E. scandens showed significantly higher FRAP values among others. All seed extracts demonstrated a remarkable reducing power (7-145 mM FeSO4 per mg extract), DPPH radical scavenging activity (16-95%) and α-amylase enzyme inhibition activity (28-40%).     

An in vitro perspective to cholinesterase inhibitory and antioxidant activity of five Gentiana species and Gentianella caucasea

The dichloromethane (DCM), ethyl acetate (EtOAc), and methanol extracts from the leaves, roots, and flowers of the five species of Gentiana (Gentiana asclepiadea, Gentiana cruciata, Gentiana olivieri, Gentiana septemfida, and Gentiana verna) and Gentianella caucasea were investigated for their inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) and antioxidant effect using 2,2-diphenyl-1-picrylhydrazyl radical scavenging, metal-chelation capacity, and ferric-reducing antioxidant power assays. Total phenol and flavonoid contents of the extracts were determined spectrophotometrically. The presence of some characteristic compounds found in Gentiana species (gentiopicroside, swertiamarin, isoorientin, isovitexin and vitexin) was analyzed in the extracts by thin layer chromatography. The flower DCM extract of G. verna exerted the highest inhibition against AChE (53.65 ± 1.03%), whereas the root EtOAc extract of G. cruciata was the most effective in BChE inhibition assay (50.72 ± 0.75%) at 100 μg ml^{? 1}. The extracts of G. verna were also found to be more active in the antioxidant tests.     

Nutraceutical composition of Zizyphus mauritiana Lamk (Indian ber): effect of enzyme-assisted processing

Zizyphus (Indian ber) is an excellent source of several phenolic compounds. The effect of two cell wall degrading enzymes, namely pectinase and viscozyme, on the nutraceutical composition of Zizyphus juice was investigated in the present study. Enzyme assisted processing significantly (P < 0.05) improved the juice yield, total soluble solids, total phenolics and total antioxidant activity (AOX). There was significant increase in recovery of antioxidants, to the tune of 70.51%, 66%, and 45% respectively in ascorbic acid, total phenolics and total flavonoids through viscozyme. The in-vitro total AOX of juice extracted via enzyme-assisted processing was 20.9 and 15.59 μmol Trolox/ml in ferric-reducing antioxidant power and cupric-reducing antioxidant capacity assays, respectively. There was 41% increase in AOX of juice extracted with enzyme over straight pressed juice. Results indicate that enzyme-assisted processing can significantly improve the functional properties of the Zizyphus juice.     

Pomegranate ellagitannins inhibit α-glucosidase activity in vitro and reduce starch digestibility under simulated gastro-intestinal conditions

Abstract

Pomegranate extract was tested for its ability to inhibit α-amylase and α-glucosidase activity. Pomegranate extract strongly inhibited rat intestinal α-glucosidase in vitro whereas it was a weak inhibitor of porcine α-amylase. The inhibitory activity was recovered in an ellagitannins-enriched fraction and punicalagin, punicalin, and ellagic acid were identified as α-glucosidase inhibitors (IC₅₀ of 140.2, 191.4, and 380.9?μmol/L, respectively). Kinetic analysis suggested that the pomegranate extract and ellagitannins inhibited α-glucosidase activity in a mixed mode. The inhibitory activity was demonstrated using an in vitro digestion system, mimicking the physiological gastro-intestinal condition, and potatoes as food rich in starch. Pre-incubation between ellagitannins and α-glucosidase increased the inhibitory activity, suggesting that they acted by binding to α-glucosidase. During digestion punicalin and punicalagin concentration decreased. Despite this loss, the pomegranate extract retained high inhibitory activity. This study suggests that pomegranate ellagitannins may inhibit α-glucosidase activity in vitro possibly affecting in vivo starch digestion.     

Effect of sprouting on antioxidant and inhibitory potential of two varieties of Bengal gram (Cicer arietinum L.) against key enzymes linked to type-2 diabetes

Type 2 diabetes is a chronic metabolic disease, and the current treatment for type 2 diabetes targets oxidative stress and postprandial hyperglycemia via the inhibition of α-glucosidase and α-amylase, key enzymes linked to type 2 diabetes. In the present study, two varieties of sprouted and non-sprouted Bengal gram (white coated and brown coated) extracts were assayed for total phenolic content, DPPH radical scavenging activity, total antioxidative capability and the inhibition of α-glucosidase and α-amylase activity. Sprouting increased the total phenolic content in both the varieties of Bengal gram and exhibited significant DPPH radical scavenging activity and antioxidant capability compared with that of non-sprouted Bengal gram. Sprouting also increased the inhibitory potential of Bengal gram against α-glucosidase and α-amylase compared with the non-sprouted variety. The overall results suggest that increased antioxidant and inhibitory potential of sprouted Bengal gram against α-glucosidase and α-amylase makes them desirable for dietary management/prevention of diabetes. This finding also provides essential information for the development of sprouted Bengal gram-derived antidiabetic products.     

Effect of sprouting on antioxidant and inhibitory potential of two varieties of Bengal gram (Cicer arietinum L.) against key enzymes linked to type-2 diabetes

Type 2 diabetes is a chronic metabolic disease, and the current treatment for type 2 diabetes targets oxidative stress and postprandial hyperglycemia via the inhibition of α-glucosidase and α-amylase, key enzymes linked to type 2 diabetes. In the present study, two varieties of sprouted and non-sprouted Bengal gram (white coated and brown coated) extracts were assayed for total phenolic content, DPPH radical scavenging activity, total antioxidative capability and the inhibition of α-glucosidase and α-amylase activity. Sprouting increased the total phenolic content in both the varieties of Bengal gram and exhibited significant DPPH radical scavenging activity and antioxidant capability compared with that of non-sprouted Bengal gram. Sprouting also increased the inhibitory potential of Bengal gram against α-glucosidase and α-amylase compared with the non-sprouted variety. The overall results suggest that increased antioxidant and inhibitory potential of sprouted Bengal gram against α-glucosidase and α-amylase makes them desirable for dietary management/prevention of diabetes. This finding also provides essential information for the development of sprouted Bengal gram-derived antidiabetic products.     

Potential of cranberry-based herbal synergies for diabetes and hypertension management

Water soluble cranberry-based phytochemical combinations with oregano, rosemary, and Rhodiola rosea were evaluated for total phenolic content, related antioxidant activity and inhibition of diabetes management-related alpha -glucosidase, pancreatic alpha-amylase inhibition, and hypertension-related ACE-I inhibitory activities. Water extracts of oregano had 114.9 mg/g DW of phenolics which was highest among all the extracts tested, whereas the 75% cranberry with 25% oregano combinations had the highest phenolics (38.9 mg/g DW) among all the combinations tested. The water extracts of oregano had the highest DPPH radical inhibition activity (73.6 %), whereas among combinations the 75% cranberry and 25% oregano had the highest DPPH radical inhibition activity (50.8 %). These results indicated a correlation between total phenolic content and antioxidant activity. The water extracts of pure Rhodiola rosea had the highest alpha -glucosidase inhibition, whereas the 75% cranberry and 25% Rhodiola rosea combination had the highest inhibition among the combinations. In the case of alpha -amylase inhibition the water extracts of Rhodiola rosea had the highest inhibition, whereas the 75% cranberry with 25% Rhodiola rosea combination had the highest inhibition among the combinations. All the water extracts tested indicated that they had anti-ACE-I inhibitory activity. More specifically, among the water extracts 100% cranberry had the highest ACE-I inhibitory activity and among the combination the 75% cranberry with 25% rosemary had the highest ACE-I inhibitory activity. The analysis of alpha -glucosidase,alpha -amylase, and ACE-I inhibitory activities suggested that inhibition depend on the phenolic profile of each unique extract and by bringing together synergistic combinations to cranberry, health beneficial functionality was enhanced. This enhanced functionality in terms of high alpha -glucosidase and alpha -amylase inhibitory activities indicate the potential for diabetes management, and high ACE-I inhibitory activity indicates the potential for hypertension management.     

Chelating,antioxidant and hypoglycaemic potential of Muscari comosum (L.) Mill. bulb extracts

Abstract

The metal chelating activity, antioxidant properties and the effect on carbohydrate-hydrolysing enzyme inhibition of Muscari comosum extracts have been investigated. M. comosum bulbs contain a total amount of the phenols with a value of 56.6 mg chlorogenic acid equivalent per gram of extract and a flavonoid content of 23.4 mg quercetin equivalent per gram of extract. In order to evaluate the non-polar constituents, n-hexane extract was obtained. Gas chromatography–mass spectrometry analysis revealed the presence of fatty acids and ethyl esters as major constituents, with different aldehydes and alkanes as minor components. Ethanolic extract had the highest ferric-reducing ability power (66.7 μM Fe(II)/g) and DPPH scavenging activity with a concentration giving 50% inhibition (IC₅₀) value of 40.9 μg/ml. Moreover, this extract exhibited a good hypoglycaemic activity with IC₅₀ values of 81.3 and 112.8 μg/ml for α-amylase and α-glucosidase, respectively. In conclusion, M. comosum bulbs show promising antioxidant and hypoglycaemic activity via the inhibition of carbohydrate digestive enzymes. These activities may be of interest from a functional point of view and for the revalorization of this ancient non-cultivated vegetable of Mediterranean traditional gastronomy.     

Determination of antioxidant effects of some plant species wild growing in Turkey

In this study, the antioxidant activity of 50% aqueous methanol extracts of Crataegus tanacetifolia (Lam.) Pers, Crataegus bornmuelleri Zaberi, Crataegus orientalis Pall. ex M.Bieb. var. orientalis, Crataegus szovitsii Pojark, Crataegus curvisepala Lindm., Crataegus monogyna Jacq. subsp. monogyna, Crataegus monogyna Jacq.subsp. azarella (Gris.) Franco, Crataegus micophylla C.Koch, Rosa foetida Herrm., Rosa hemisphaerica J.Herrm., Rosa pulverulenta M.Bieb., Rosa canina L., Rubus discolor Weihe & Nees, Rubus canescens DC. var. canescens, Rubus sanctus Screber, Rubus caesius L., Sorbus umbellata (Desf.) Fritsch var. umbellata, Prunus avium L. (Moench.) and Prunus cerasus L. Mespilus germenica was evaluated by various antioxidant assays, including free radical scavenging, hydrogen peroxide scavenging and metal-chelating activities. The extracts of R. hemisphaerica J.Herrm., P. cerasus L. and R. canina L. showed more stronger free radical scavenging and hydrogen peroxide scavenging activities, and the extracts of R. foetida Herrm. (62.54%) and P. cerasus L. showed stronger metal-chelating activity. The results obtained in the present study indicated that the R. hemisphaerica J.Herrm., P. cerasus L. and R. canina are potential sources of natural antioxidant. These antioxidant properties depend on the concentration of the sample.     

The antioxidant and radical scavenging activities of black pepper (Piper nigrum) seeds

Water and ethanol crude extracts from black pepper (Piper nigrum) were investigated for their antioxidant and radical scavenging activities in six different assay, namely, total antioxidant activity, reducing power, 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both water extract (WEBP) and ethanol extract (EEBP) of black pepper exhibited strong total antioxidant activity. The 75?µg/ml concentration of WEBP and EEBP showed 95.5% and 93.3% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, at the same concentration, standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and α-tocopherol exhibited 92.1%, 95.0%, and 70.4% inhibition on peroxidation of linoleic acid emulsion, respectively. Also, total phenolic content in both WEBP and EEBP were determined as gallic acid equivalents. The total phenolics content of water and ethanol extracts were determined by the Folin-Ciocalteu procedure and 54.3 and 42.8?µg gallic acid equivalent of phenols was detected in 1?mg WEBP and EEBP.     

In vitro antioxidant and hypoglycemic activities of Ethiopian spice blend Berbere

The metal chelating activity, antioxidant properties, and the effect on carbohydrate-hydrolyzing enzymes of Ethiopian spice blend Berbere have been investigated. Berbere contains a total amount of phenols corresponding to 71.3 mg chlorogenic acid equivalent per gram of extract and a total flavonoid content of 32.5 mg quercetin equivalent per gram of extract. An increase of the resistance towards forced oxidation was obtained when Berbere was added to sunflower oil. In order to evaluate the bioactivity of the non-polar constituents, an n-hexane extract was obtained from Berbere. The gas chromatography–mass spectrometry analysis revealed the presence of 19 fatty acids constituents (98.1% of the total oil content). Among them, linoleic acid was the major component (72.0% of the total lipids). The ethanolic extract had the highest ferric-reducing ability power (35.4 μM Fe(II)/g) and DPPH scavenging activity with a concentration giving 50% inhibition (IC₅₀) value of 34.8 μg/ml. Moreover, this extract exhibited good hypoglycemic activity against α-amylase (IC₅₀ = 78.3 μg/ml). In conclusion, Ethiopian spice blend Berbere showed promising antioxidant and hypoglycemic activity via the inhibition of carbohydrate digestive enzymes. These activities may be of interest from functional point of view and for the revalorization of the spice blend in gastronomy also outside the African country.     

The effect of traditional stir-frying process on hydrophilic and lipophilic antioxidant capacities of pine nut kernels

Abstract

The effect of traditional stir-frying process at different heating temperatures (50–150?°C) and time periods (5–20?min) on hydrophilic part (total and individual phenolics), lipophilic part (tocopherol and phytosterol compounds) and their corresponding antioxidant capacities in pine nut kernels were investigated. The concentrations of total phenolics, phenolic acids, tocopherols and phytosterols in raw pine nut kernels were 15.76?mg gallic acid equivalents/100?g dry weight (mg GAE/100?g DW), 12.15?mg/100?g DW, 28.67?mg/100?g DW and 198.81?mg/100?g DW, respectively. Stir-frying at low temperatures over short time periods led to an increase of phenolics, phytosterols and hydrophiliic antioxidant capacities. However, these values decreased under the longer heating time and the higher temperature. Tocopherols and lipophilic antioxidant capacities did not show clear changes at lower heating temperatures or shorter heating times, while they had an apparent decreasing trend at higher heating temperatures or longer heating times. Gallic acid might be the main component, which is responsible for the hydrophilic antioxidant capacity (R^2?=?0.84, 0.81 and 0.81 using DPPH, FRAP and H-ORAC assays), and tocopherols might be the main antioxidant components in the lipophilic part (R^2?=?0.87 and 0.89 using DPPH and L-ORAC assays).     

Evaluation of α-glucosidase, α-amylase and protein glycation inhibitory activities of edible plants

Abstract

The present study was to investigate in vitro α-glucosidase, pancreatic α?amylase and protein glycation inhibitory activities of nine edible plants. The results indicated that total phenolics, flavonoids, and condensed tannins of nine edible plants showed marked variations, ranging from 12.2 to 80.1 mg gallic acid equivalent/g extract, 2.34 to 13.65 mg quercetin equivalent/g extract, and 97.2 to 460.1 mg catechin equivalent/g extract, respectively. Our findings showed that grape seed, Cat's whiskers and Sweetleaf extract were the most effective pancreatic α-amylase, intestinal maltase, and sucrase inhibitor with IC₅₀ values of 0.29 ± 0.01 mg/ml, 0.97 ± 0.10 mg/ml and 0.86 ± 0.01 mg/ml, respectively. All extracts (1 mg/ml) markedly inhibited the glycation of bovine serum albumin in fructose-mediated non-enzyme glycation by 50–30% at week 1. It was found that Pennywort maintained the high percentage inhibition among those of the extracts during the 4 weeks of experiment. These edible plants may be used for controlling blood glucose level and prevention of the development of type 2 diabetes.     

First isolation of tryptophan from edible lotus (Nelumbo nucifera Gaertn) rhizomes and demonstration of its antioxidant effects

Abstract

Various vegetables were investigated for antioxidant activities in two assays, namely, inhibition of lysis of erythrocytes induced by peroxyl radicals and inhibition of lipid peroxidation. The lotus (Nelumbo nucifera Gaertn) rhizome showed the strongest antioxidant activity in both assays. The crude extract (L) of lotus rhizome was chromatographed on a macroporous adsorption resin named NKA. The resulting three fractions were designated L1, L2 and L3, respectively. L2 showed the highest antioxidant activity and was further fractionated by Sephadex LH-20 chromatography. Eight fractions were obtained and named from L2a to L2h, respectively. L2c showed the strongest activity in inhibiting hemolysis of erythrocytes and was further purified by high-performance liquid chromatography. L2c-3 was identified as tryptophan. Its inhibitory concentration of 50% (IC₅₀) value in inhibiting hemolysis of erythrocytes was 156.3 μg/ml (i.e. 765.4 μM). This is the first report on isolation of tryptophan from the aqueous extract of lotus rhizome and demonstration of their antioxidant activities.     

Antioxidant effectiveness of organically and non-organically grown red oranges in cell culture systems

Summary Background Consumers consider plant food products from organic origin healthier than the corresponding conventional plant foods. Clear experimental evidence supporting this assumption is still lacking. Aim of the study To determine if the organic red oranges have a higher phyto–chemical content (i. e., phenolics, anthocyanins and ascorbic acid), total antioxidant activity and in vitro bioactivity, in terms of protective effect against oxidative damage at cellular level, than nonorganic red oranges. Methods Total phenolics were measured using the Folin Ciocalteau assay, while total anthocyanins and ascorbic acid levels were determined by spectrophotometric and HPLC analysis, respectively. In addition, the total antioxidant activity of red orange extracts was measured by the ABTS^•+ test. The ability of red orange extracts to counteract conjugated diene containing lipids and free radical production in cultured rat cardiomyocytes and differentiated Caco–2 cells, respectively, was assessed. Results Organic oranges had significantly higher total phenolics, total anthocyanins and ascorbic acid levels than the corresponding non–organic oranges (all p < 0.05). Moreover, the organic orange extracts had a higher total antioxidant activity than non–organic orange extracts (p < 0.05). In addition, our results indicate that red oranges have a strong capacity of inhibiting the production of conjugated diene containing lipids and free radicals in rat cardiomyocytes and differentiated Caco–2 cells, respectively. Statistically higher levels of antioxidant activity in both cell models were found in organically grown oranges as compared to those produced by integrated agriculture practice. Conclusions Our results clearly show that organic red oranges have a higher phytochemical content (i. e., phenolics, anthocyanins and ascorbic acid), total antioxidant activity and bioactivity than integrated red oranges. Further studies are needed to confirm whether the organic agriculture practice is likely to increase the antioxidant activity of other varieties of fruits and vegetables.     

The edible mushroom Laetiporus sulphureus as potential source of natural antioxidants

Hot water extract (LN), partially purified polysaccharides (LP) and hot alkali extracted polysaccharides (LNa) obtained from fruiting bodies of the wild basidiomycete Laetiporus sulphureus were examined for their antioxidant activities. LNa was the most active antioxidant, as shown by the median effective concentrations (EC₅₀ values) of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (0.5 ± 0.2 mg/ml), reducing power (4.0 ± 0.3 mg/ml) and ferrous ion-chelating ability (1.5 ± 0.1 mg/ml). LNa contained the highest level of α-glucan (17.3 ± 1.2 g/100 g dw), whereas LP contained mostly β-glucans (66.8 ± 1.3 g/100 g dw). The prevalent monosaccharide in all extracts was glucose. The EC₅₀ values of all three antioxidant activity assays were well-correlated with the α-glucan content. Strong and significant correlation was found between total phenolic compounds and DPPH scavenging ability and also reducing power. The three investigated extracts (at concentrations of 0.1–10 mg/ml) were not toxic to HTR-8/SVneo trophoblast cell line.     

Effect of freeze drying and oven drying on antioxidant properties of fresh wheatgrass

The effects of freeze drying and hot air drying on total phenolics, total flavonoids and antioxidant properties of flour from seven-day-old fresh wheatgrass (Triticum aestivum L.) were investigated. In the quantitative analysis of antioxidative components, fresh wheatgrass samples had the highest amount of ascorbic acid and chlorophyll, but the lowest amount of total flavonoids and phenolics. In the analysis of ferric-reducing antioxidant power assay (FRAP), ethanolic extract from freeze-dried wheatgrass gave the highest value, while the α-tocopherol gave the lowest value. In the analysis of 2,2-diphenyl-1-picrylhydrazyl scavenging ability, freeze-dried wheatgrass samples exhibited the highest activity among the three samples.