Antioxidant levels and activities of selected seeds of malaysian tropical fruits

The aims of this study are to determine and compare the antioxidant levels and activities (i.e. primary and secondary) between selected seeds of Malaysian tropical fruits - guava (Psidium guajava), mango (Mangifera indica L.) and papaya (Carica papaya L.). Seeds are among byproducts from the processing of fruitsbased products. Instead of discarding seeds as waste, seeds with high potential as antioxidants could be utilised for commercial purposes. Accordingly, the selected seeds of Malaysian tropical fruits were tested in this study for total phenolic content (TPC), free radical scavenging activity by 1, 1- diphenyl-2-picrylhydrazyl (DPPH) assay and metal ion chelating effect by ferrous ion chelating (FIC) assay. Extraction of antioxidant compounds from sample was done with 70% ethanol. TPCs of the seeds were expressed as gallic acid equivalents (GAE) in mg per 100 g fresh seed weight. TPC assay showed that mango seeds had the highest TPC (i.e. 32 ± 0.001 mg GAE) followed by guava seeds (i.e. 20 ± 0.001 mg GAE) and papaya seeds (8 ± 0.003 mg GAE). For DPPH assay, IC50 data showed that mango seed extract scavenged 50% DPPH radicals at the lowest concentration (0.11 ± 0.01 mg/mL) followed by the positive control BHA (0.13 ± 0.01 mg/mL), guava seed extract (0.26 ± 0.01 mg/mL) and papaya seed extract (0.34 ± 0.01 mg/mL). Interestingly, all seed extracts showed higher free radical scavenging activities than BHA after sample concentration of 0.60 mg/mL. However, FIC assay indicated that metal ion chelating effects of all seed extracts were weaker than BHA suggesting that the fruit seeds are not sources of good metal ion chelators. Overall, present results suggest that TPC of the seeds show strong negative correlation with their primary antioxidant activity (r= -0.985, R2= 0.970), and not all compounds in extracts which could scavenge DPPH radicals are good metal ion chelators. Mango seeds relatively showed the highest antioxidant level and primary antioxidant activity followed by guava seeds and papaya seeds.     

Comparison of antioxidant capacities of Ganoderma lucidum (Curtis) P. Karst and Funalia trogii (Berk.) Bondartsev & Singer by using different in vitro methods

The aim of the study was to investigate antioxidant activities of Ganoderma lucidum and Funalia trogii. Ethanol and water crude extracts from G. lucidum and F. trogii were investigated for their antioxidant capacity in some different assays, namely, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, metal chelating activity against ferrous ions, and plasma lipid peroxidation inhibitory. In addition, the amounts of total phenol, ascorbic acid, β-carotene, and lycopene components in the extracts were determined. Among the four mushroom extracts, G. lucidum water extract and G. lucidum ethanol extract showed the highest scavenging activity against DPPH radicals (50% inhibitory concentration?=?0.055?±?0.001?mg/mL). Total phenol was the major antioxidant component found in the mushroom extracts. These results showed that G. lucidum may be used in pharmaceutical applications because of its effective antioxidant properties.     

Phenolic compounds and biological activity of Kitaibelia vitifolia

This study was aimed at evaluating the antioxidant activity and efficacy of the ethanolic extract of the endemic plant species Kitaibelia vitifolia in inhibiting the growth of selected fungi and bacteria. Antimicrobial activity was tested using the broth dilution procedure for determination of minimum inhibitory concentration (MIC). MICs were determined for eight selected indicator strains. The highest susceptibility to K. vitifolia ethanolic extract among the bacteria tested was exhibited by Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 25923, and Klebsiella pneumoniae ATCC 13883 (MIC=15.62 μg/mL), followed by Escherichia coli ATCC 25922 and Proteus mirabilis ATCC 14153 (MIC=31.25 μg/mL), and Proteus vulgaris ATCC 13315 (MIC=62.50 μg/mL). Of the fungi, Candida albicans ATCC 10231 (MIC=15.62 μg/mL) showed the highest susceptibility, and Aspergillus niger ATCC 16404 (MIC=31.25 μg/mL) had the lowest. Results showed that K. vitifolia extract possesses antioxidant activity, with total antioxidant capacity of 75.45±0.68 μg of ascorbic acid/g and 50% inhibition concentration values of 47.45±0.55 μg/mL for 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, 35.35±0.68?μg/mL for inhibitory activity against lipid peroxidation, 95.25±0.52 μg/mL for hydroxyl radical scavenging activity, and 31.50±0.35 μg/mL for metal chelating activity. Total phenolics, flavonoids, condensed tannins, and gallotannins were 85.25±0.69 mg of gallic acid (GA)/g, 45.32±0.55 mg of rutin/g, 54.25±0.75 mg of GA/g, and 41.74±0.55 mg of GA/g, respectively. The phenolic composition of K. vitifolia extract was determined by high-performance liquid chromatography. Rosmarinic acid was found to be the dominant phenolic compound of the extract.     

Tomato waste: a potential source of hydrophilic antioxidants

Waste obtained from six genotypes of tomato was subjected to evaluation as potential sources of hydrophilic antioxidants on the basis of content of total phenolics (TPh; from 11.7 to 18.6 mg/g), total flavonoids (TFl; from 7.62 to 12.1 mg/g) and ascorbic acid (AA; from 0.51 to 1.89 mg/g), and antioxidant activities. The antioxidant activities of tomato waste extracts were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferrous ion chelating activity (CA) and reducing power (RP) assay. The O(2) tomato waste extract was found to have the strongest antioxidant activity in scavenging DPPH radicals (effective concentration, EC(50) = 0.18 mg/ml). The Saint Pierre tomato waste extract showed the best performance in RP assay (EC(50) = 1.57 mg/ml). The Rutgers tomato waste extract exhibited a strongest CA (EC(50) = 1.49 mg/ml). The linear correlation analysis produced moderate-to-high correlation coefficients between the antioxidant activities and TPh, TFl and AA.     

Antioxidant properties of extracts from a white mutant of the mushroom Hypsizigus marmoreus

A white mutant of Hypsizigus marmoreus (Peck) Bigelow (Tricholomataceae) is a new edible mushroom currently available in Taiwan. The ethanolic and hot water extracts were prepared from fruit bodies and mycelia and their antioxidant properties studied. In addition to EC₅₀ values in scavenging abilities on hydroxyl radicals, almost EC₅₀ values were less than 10 mg/mL indicating that these extracts were effective in antioxidant properties assayed. The major antioxidant components found in hot water extracts were total phenols (10.01–13.14 mg/g) and those in ethanolic extracts were total tocopherols (33.33–10.92 mg/g). Correlations of contents of total antioxidant components and total tocopherols (plus β-carotene) with EC₅₀ values of antioxidant activity, reducing power, scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals and chelating ability on ferrous ions were established (r=0.445–0.940), whereas the correlation of total phenol content was established only with that of scavenging ability on hydroxyl radicals (r=0.882).     

Antioxidant properties of selected tropical wild edible mushrooms

Selected species of wild edible mushrooms were obtained from the interior areas of East Malaysia to determine the total phenolics and antioxidant properties, including free radical scavenging, reducing power and metal chelating activities. The in vitro antioxidant activities of petroleum ether (PE) and methanolic extracts of the edible wild mushrooms were comparable to the cultivated oyster mushroom. The radical scavenging activity was the highest in PE extract of Pleurotus porrigens (angel's wings) (85%), while methanolic extract of Hygrocybe conica (witch's hat mushroom) exhibited the highest (94%) chelating effect at 20 mg/ml. PE extracts were more effective than methanolic extract in scavenging ability on DPPH radicals, whereas methanolic extracts were more effective in reducing power and chelating ability on ferrous ions as evidenced by their lower EC₅₀ values. Principal component analysis (PCA) indicated phenolic group was the primary factor contributing to the metal chelating ability for PE extract although phenolic was better correlated with reducing power in methanolic extracts.     

The antioxidant properties of brown seaweed (Sargassum siliquastrum) extracts

Antioxidant properties of brown seaweed (Sargassum siliquastrum) extracts were evaluated using various antioxidant measurements, i.e., inhibitory effect on thiobarbituric acid-reactive substances (TBARS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, metal chelating effect, reducing power effect, and total phenolic compounds. When the extraction solvents n-hexane, chloroform, ethanol, and water were compared, the water extract showed the highest yield in extracted mass. Total phenolic compounds were the highest in the ethanol extract, with 127.4 mg/g. The TBARS inhibition of chloroform and ethanol extracts at 10 mg/mL was 90.9% and 80.9%, respectively. DPPH radical scavenging capacity was more than 90% in all extracts at 1 mg/mL. The chloroform extract exhibited the highest metal ion chelating ability of 69.6% at 10 mg/mL. The reducing power was found to be the highest in the ethanol extract at 10 mg/mL, showing an effect similar to ascorbic acid. Thus, the ethanol extract of S. siliquastrum has potential as a natural antioxidant.     

Radical scavenging, antibacterial, and antiproliferative activities of Melissa officinalis L. extracts

The aromatic herb Melissa officinalis L. can be used as an easily accessible source of natural antioxidants and as a possible food supplement and as a phytochemical. Radical scavenging, antibacterial, and antiproliferative activities of petroleum ether, chloroform, ethyl acetate, n-butanol, and water extracts of M. officinalis L. extracts were investigated. The results of antioxidative activity, obtained by electron spin resonance spectroscopy, confirmed that investigated extracts suppressed the formation of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and lipid peroxyl radicals in all investigated systems in a dose-dependent manner. The maximum DPPH and hydroxyl radical scavenging activities (SA(DPPH) = SA(OH) = 100%) were achieved in the presence of n-butanol extract at concentrations of 0.4 mg/mL and 0.5 mg/mL, respectively. The highest lipid peroxyl scavenging activity (93.20%) was observed at a higher concentration (5 mg/mL) of n-butanol extract in the lipid peroxidation system. The most effective antibacterial activities were expressed by petroleum ether and ethyl acetate extracts on Sarcina lutea. Chloroform extract showed the strongest antiproliferative effect with 50% inhibitory concentration values of 0.09 mg/mL and 0.10 mg/mL for HeLa and MCF-7 cell lines, respectively. The present study demonstrated the high phenolic content and radical scavenging, antibacterial, and antiproliferative activities of extracts of M. officinalis L. originating from Serbia.     

Antioxidant activity of methanolic extract of emblica fruit (Phyllanthus emblica L.) from six regions in China

The phenolic contents of methanolic extracts of emblica (Phyllanthus emblica L.) fruit from six regions in China were measured in this work. The antioxidant activities of these extracts were also evaluated. Total phenolic content was ranged from 81.5 to 120.9 mg gallic acid equivalents (GAE)/g and the flavonoid content was varied from 20.3 to 38.7 mg quecetin equivalents (QE)/g, while proanthocyanidin content was ranged from 3.7 to 18.7 mg catechin equivalents (CE)/g. Among all the methanolic extracts analyzed, the Huizhou sample exhibited a significantly higher phenolic content than other samples (P<0.05). The antioxidant activities were evaluated by in vitro experiments using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, hydroxyl radicals, and superoxide anion radicals, chelating ability of ferrous ion, reducing power, and inhibition capability of Fe (II)-induced lipid peroxidation, respectively. The Huizhou sample was found to have the strongest antioxidant activities in scavenging DPPH radicals, superoxide anion radicals, and had the highest reducing power, while the Chuxiong sample showed the best performance in chelating iron and inhibiting lipid peroxidation. Furthermore, the Chuxiong sample exhibited a stronger inhibition activity of the hydroxyl radicals compared with other samples. The high correlation coefficient was existed between the phenolic content and superoxide anion radical scavenging activity, but no significant correlation was found between the former and hydroxyl radical scavenging activity. Methanolic extracts of emblica fruit from some selected regions exhibited stronger antioxidant activities compared to those of the commercial compounds (quercetin and BHA). It might be considered as a potential plant source of antioxidants.     

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.     

Antioxidant activity of far-infrared radiated rice hull extracts on reactive oxygen species scavenging and oxidative DNA damage in human lymphocytes

The antioxidant activities of methanolic extracts of far-infrared irradiated rice hull (FRH) and non-irradiated intact rice hull (IRH) were determined. The antioxidant effects against reactive oxygen species (ROS) were evaluated by measuring scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide, hydrogen peroxide (H2O2), and nitric oxide radical and capacity for chelating metals. Except for H2O2 scavenging activity, FRH showed higher scavenging activity than IRH; for example, the 50% inhibitory concentration (mg/mL) values for DPPH radical scavenging of FRH and IRH were 0.067 and 0.085, respectively, as compared with 0.362 and 0.012 for butylated hydroxytoluene and alpha-tocopherol, respectively. The effect of rice hull extract on DNA damage induced by H2O2 in human lymphocytes was also evaluated by comet assay. The protective effect of rice hull extract increased as its concentration increased from 12.5 to 50 microg/mL, as indicated by DNA strand breakage decreasing from 38% to 22% with FRH and from 49% to 28% with IRH as compared with H2O2-treated positive controls. When human lymphocytes were post-incubated with rice hull extract for 30 minutes after exposure to H2O2, the protective ability of the rice hulls remained unchanged. These results suggest that methanol extracts of rice hulls possess significant ROS scavenging and metal chelating activities and protective effect against oxidative DNA damage.     

Anthocyanins in Red Jasmine Rice (Oryza sativa L.) Extracts and Efficacy on Inhibition of Herpes Simplex Virus,Free Radicals and Cancer Cell

Rice is one of the most important food crops in many countries, with nutritional value and health benefits. In this study, the ethanolic and aqueous extracts of red jasmine rice from Chiang Mai, Thailand were examined for their anthocyanins and phenolic contents. The antioxidant and antiviral activity against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2), as well as anticancer activity, were investigated. The total anthocyanins content of 708.03 ± 11.56 mg Cy-3-glc equivalent/g extract, determined from the ethanolic extract, was higher than the aqueous extract. However, the aqueous extract showed the highest total phenolic compound of 81.91 ± 0.51 mg GAE/g extract. In addition, the ethanolic extract demonstrated higher antioxidant activity than aqueous extract using DPPH, ABTS, and FRAP assays by 28.91 ± 3.26 mg GAE/g extract, 189.45 ± 11.58 mg 24 TEAC/g extract, and 3292.46 ± 259.64 g FeSO₄/g extract, respectively. In the antiviral assay, it was found that the ethanolic extract of red jasmine rice could inhibit HSV-1 more effectively than HSV-2 when treated before, during, and after the viral attachment on Vero cells, with 50% effective doses of 227.53 ± 2.41, 189.59 ± 7.76, and 192.62 ± 2.40 µg/mL, respectively. The extract also demonstrated the highest reduction of HSV-1 particles at 4 h after treatment and the inhibition of HSV-1 replication. The ethanolic extract exhibited a higher toxicity level than the aqueous extract, as well as the potential to induce DNA fragmentation by intrinsic and extrinsic apoptosis pathways on the Caco-2 cells. These findings suggest that red jasmine rice extract demonstrates nutritional value and biological activity on HSV, free radicals, and cancer cell inhibition.     

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 (IC(50)) value of 34.8 μg/ml. Moreover, this extract exhibited good hypoglycemic activity against α-amylase (IC(50) = 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.     

Radical quenching activity, ferric-reducing antioxidant power, and ferrous ion-chelating capacity of 16 Ballota species and their total phenol and flavonoid contents

The ethyl acetate, methanol, and water extracts of 16 Ballota species (Family Lamiaceae)-Ballota acetabulosa, Ballota antalyanse, Ballota cristata, Ballota glandulosissima, Ballota inaequidens, Ballota larendana, Ballota latibracteolata, Ballota macrodonta, Ballota nigra ssp. anatolica, B. nigra ssp. foetida, B. nigra ssp. nigra, B. nigra ssp. uncinata, Ballota pseudodictamnus ssp. lycia, Ballota rotundifolia, Ballota saxatilis ssp. brachyodonta, and B. saxatilis subsp. saxatilis-were screened for their 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical quenching, ferric-reducing antioxidant power, and ferrous ion-chelating capacity at 1mg/mL. Hispanolone, a major diterpene found in the Ballota genus, was also tested in the same manner. Total phenol and flavonoid contents of the extracts were determined by Folin-Ciocalteau and AlCl(3) reagents, respectively. The extracts showed insignificant quenching activity against DPPH radical, but they had moderate antioxidant activity (0.597 ± 0.03 to 1.342 ± 0.01) in the ferric-reducing test compared to chlorogenic acid (the reference compound) (3.618 ± 0.01). All of the extracts (ranging from 65.1 ± 0.64% to 96.3 ± 0.09%) and hispanolone (97.31 ± 0.30%) exerted a remarkable ferrous ion-chelating effect. The highest total phenol (gallic acid equivalent) and flavonoid (quercetin equivalent) contents were found in the ethyl acetate extract of B. glandulosissima (393.7 ± 3.03 and 140.6 ± 1.97 mg/g of extract, respectively). Therefore, Ballota species could be a good source of natural preservatives in foodstuffs.     

Radical scavenging,antioxidant and metal chelating activities of Annona cherimola Mill. (cherimoya) peel and pulp in relation to their total phenolic and total flavonoid contents

This study aimed to evaluate the total phenolic and flavonoid content, radical scavenging activity (by DPPH and ABTS tests) and antioxidant capacity (by β-carotene bleaching test) of Annona cherimola (cherimoya) fruits cultivated in Italy for human consumption. The metal chelating activity and ferric reducing power were also determined. A. cherimola peel and pulp were characterized by a total phenolic content of 14.6 and 12.6 mg chlorogenic acid equivalents/100 g fresh weight, respectively. A similar trend was observed with flavonoid content. Both extracts exhibited high antioxidant activity through different mechanisms of action. In particular, peel extract demonstrated the strongest free radical scavenging activity with an IC₅₀ value of 57.7 μg/mL. The same extract was more effective in preventing β-carotene oxidation (IC₅₀ value of 63.5 μg/mL after 60 min) and showed higher chelating ability (IC₅₀ value of 79.6 μg/mL) than pulp extract. This work demonstrated the high quality of cherimoya fruits cultivated in Italy, and recommends the peel of this fruit product that may be of interest from a functional point of view as a major source of natural antioxidants.     

Inhibitory potential of the leaves and berries of Myrtus communis L. (myrtle) against enzymes linked to neurodegenerative diseases and their antioxidant actions

The dichloromethane (DCM), acetone, ethyl acetate and methanol extracts of the leaves and berries of Myrtus communis L. were screened against acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and tyrosinase (TYRO), the enzymes linked to neurodegenerative diseases, at 200 μg ml?1. Antioxidant activity was tested using radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and N,N- dimethyl-p-phenylenediamine (DMPD) radicals, metal chelation capacity, ferric-reducing antioxidant power (FRAP) and phosphomolybdenum-reducing antioxidant power (PRAP) assays. Total phenol and flavonoid quantification of the extracts was calculated spectrophotometrically. The extracts showed a moderate AChE (17.49 ± 3.99% to 43.15 ± 1.55%) and TYRO inhibition (4.48 ± 1.50% to 40.53 ± 0.47%). The leaf extracts were ineffective against BChE, while the berry extracts displayed inhibition between 21.83 ± 3.82% and 36.80 ± 2.00%. The polar extracts exerted remarkable scavenging effect against DPPH and DMPD and also in the FRAP assay, where the DCM extract of the berries had the best metal chelation capacity (79.29 ± 1.14%). This is the first study that demonstrates in vitro neuroprotective effects of myrtle.     

Preparation and biological evaluation of enzyme-assisted extracts from edible seaweed (Enteromorpha prolifera) as antioxidant, anti-acetylcholinesterase and inhibition of lipopolysaccharide-induced nitric oxide production in murine macrophages

The multifunctional bioactive materials were prepared from Enteromorpha prolifera by enzyme-assisted extraction using four proteases and seven carbohydrases, and the biological activities of the enzyme-assisted extracts were evaluated as antioxidant, anti-acetylcholinesterase (AChE) and anti-inflammatory effect as the measures of inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 cells. The enzyme-assisted extracts were rich in polyphenols in the range 124 ± 4.2 to 844 ± 9.1 mg/100 g and flavonoids in the range 453 ± 6.0 to 675 ± 5.2 mg/100 g, and Protamex and Viscozyme extracts, which were rich in polyphenols and flavonoids, showed the highest 2,2-diphenyl-1-picrylhydrazyl scavenging, hydrogen peroxide scavenging, ferrous ion chelating and reducing power. Flavourzyme extract (89.92%) and Promozyme extract (93.64%) showed the highest AChE inhibitory activities at the concentration of 1.0 mg/ml. All enzyme-assisted extracts showed no cytotoxic effect on RAW264.7 cells at the tested concentration and significantly inhibited the LPS-induced NO production in RAW264.7 cells.     

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.     

Anti-acetylcholinesterase and antioxidant assets of the major components (salicin, amentoflavone, and chlorogenic acid) and the extracts of Viburnum opulus and Viburnum lantana and their total phenol and flavonoid contents

Some Viburnum species are used for preparation of the traditional drink called gilaburu in Anatolia. In the current study, our goal was to evaluate acetylcholinesterase (AChE) inhibitory and antioxidant activities of the ethyl acetate, methanol, and water extracts prepared from the branches, leaves, and fruits of Viburnum opulus and Viburnum lantana along with salicin, amentoflavone, and chlorogenic acid, three major compounds abundantly found in these species. AChE enzyme inhibition was tested in vitro using an enzyme-linked immunosorbent assay microplate reader at 50, 100, and 200?μL/mL concentrations. Antioxidant activity was examined by ferrous ion chelating capacity, ferric reducing antioxidant power, and β-carotene bleaching assay at 500, 1,000, and 2,000?μg/mL. Total phenol and flavonoid contents of the extracts were also established by Folin-Ciocalteau and AlCl(3) reagents, respectively. Our data revealed that the leaf methanol extract of V. opulus displayed a significantly high inhibitory effect against AChE (57.63?±?1.23%, 87.41?±?0.99%, and 93.19?±?0.87% at 50, 100, and 200?μg/mL, respectively). The extracts of V. lantana exerted higher antioxidant activity.     

Antioxidant properties of palm fruit extracts

Phenolic compounds have been shown to exhibit bioactive properties, and in particular antioxidant effects. A phenolic-rich fraction has been isolated from the aqueous by-product obtained during the milling of oil palm fruits. The objectives of the study were to determine the phenolic content of the crude and ethanolic extracts of oil palm fruits and to evaluate the antioxidant properties of these extracts. The total phenolics content of the crude and ethanol extracts as determined by the Folin-Ciocalteu method were found to be 40.3 +/- 0.5 and 49.6 +/- 0.6 mg GAE/g extract (dry basis), respectively. The radical scavenging activity of the extracts determined using 2,2 diphenyl-1-picrylhydrazyl radical (DPPH.) indicated that both crude and ethanol extracts exhibit hydrogen-donating capacity, and have antiradical power (ARP) comparable to ascorbic acid. The DPPH radical scavenging activity of the extracts were less than that of gallic acid, but the time-course variations of the scavenging curves suggest that the extracts acted by a mechanism similar to that of gallic acid. The electron-donating potentials of the extracts were inferred from the hydrogen peroxide scavenging and reducing power assays. The reducing power of crude and ethanol extracts at 1 mM GAE were found to be comparable to that of 0.3 mM gallic acid. The extracts indicated complete scavenging of hydrogen peroxide at concentrations above 0.4 mM GAE. These findings suggest that the crude and ethanol extracts are able to scavenge free radicals, by either hydrogen or electron donating mechanisms, and can therefore act as primary antioxidants.