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 microg/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 alpha-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 microg gallic acid equivalent of phenols was detected in 1 mg WEBP and EEBP.     

Evaluation of in vitro antioxidant activity of Sida rhombifolia (L.) ssp. retusa (L.)

Sida rhombifolia (L.) ssp. retusa (L.) is widely used in Ayurvedic medicine for the treatment of fever as well as a diuretic. The comparative antioxidant potentials of ethanol extract of roots, stems, leaves, and whole plant were studied. Estimation of total polyphenolic content and high-performance thin-layer chromatography profile were determined. Further inhibition of oxygen-derived free radicals, viz., assays for free radical scavenging, reducing power, superoxide anion scavenging, nitric oxide scavenging, and anti-lipid peroxidation, were performed. All the antioxidant activities were compared with standard antioxidants such as butylated hydroxyanisole and alpha-tocopherol acetate. Extracts were found to be good scavengers of the 1,1-diphenyl-2-picrylhydrazyl radical in the order root > leaves > whole plant > stem with 50% inhibitory concentrations of 546.1, 852.8, 983.8, and 1,222.5 microg/mL, respectively. All extracts of this plant showed effective free radical scavenging activity, reducing power, and superoxide scavenging activity. Only root extract inhibited lipid peroxidation in rat liver and brain homogenate. All these antioxidant properties were concentration dependent. In addition, total polyphenolic contents of all the extracts were determined as gallic acid equivalents. The highest antioxidant activity was observed in root extract. The results obtained from the current study indicate that S. rhombifolia ssp. retusa is a potential source of natural antioxidants.     

Radical scavenging-linked antioxidant activities of commonly used herbs and spices in Korea

Herbs and spices not only variety and racy flavour to Korean foods, they also are the richest source for antioxidant power. The present study evaluates the radical scavenging-linked antioxidant activities of hot water extracts from commonly used herbs and spices in Korea. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities of bay extract were 39.5% and 22.1%, respectively. The hydroxyl radical scavenging activity was in order of dill (50.0%) > bay (31.3%) > garlic (27.9%) > white pepper and black pepper (15.1–15.3%) > onion (10.1%) extracts. Bay extract had the highest total phenolic content (17.86 μg CE/g). High correlation coefficients were found between the total phenol content and DPPH radical scavenging activity (R = 0.9162). These results indicate that herbs and spices had high antioxidant activity that is partly due to the phenolic compounds and provide basic data for further development of processed food products.     

Caffeic acid phenethyl ester (CAPE): correlation of structure and antioxidant properties

Caffeic acid phenethyl ester (CAPE), a plant polyphenolic concentrated in honeybee propolis, has been found to be biologically active in a variety of pathways. The aim of this study was to determine the antioxidant activity of CAPE using different methods such as total antioxidant activity by the thiocyanate method, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid radicals, 1,1-diphenyl-2-picryl-hydrazyl free radicals, N,N-dimethyl-p-phenylenediamine dihydrochloride radicals and superoxide anion radicals scavenging activities, reducing power and ferrous ions (Fe²⁺) chelating activities. CAPE showed 97.9% inhibition on lipid peroxidation of linoleic acid emulsion. On the other hand, butylated hydroxyanisole, butylated hydroxytoluene, α-tocopherol and trolox indicated an inhibition of 87.3, 97.6, 75.3 and 90.3% on peroxidation in the same system, respectively.     

Corni fructus scavenges hydroxy radicals and decreases oxidative stress in endothelial cells

Corni fructus has been used as a tonic, analgesic, and diuretic in Korean herbal medicine. The present investigation was undertaken to evaluate the antioxidative effect of corni fructus and its capacity to protect cells against oxidative damage. The radical scavenging activity of corni fructus extracts was measured using 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the antioxidant activity was determined by measuring the peroxide value in a linoleic acid emulsion system. In addition, human umbilical vein endothelial cells (HUVECs) were treated with corni fructus extracts and incubated with H(2)O(2) to investigate protection against apoptosis induction. Both ethanol and water extracts of corni fructus produced higher DPPH radical scavenging activity than hexane, chloroform, and ethyl acetate extracts. Strong antioxidative activities of both water and ethanol extracts were observed in an emulsion system containing linoleic acid and phosphate buffer. The incubation of HUVECs with the addition of ethanol extract significantly decreased H(2)O(2)-initiated damage of endothelial cells, but the water extract did not. The pretreatment with ethanol extract, but not with water extract, significantly decreased apoptotic damage of the H(2)O(2)-treated HUVECs and kept the morphological normality. This study demonstrates that corni fructus is a potent antioxidant substance, and suggests that further investigation is needed to characterize the difference between extract types and to identify its antioxidant compounds.     

In vitro antioxidant and free radical scavenging activity of Cyperus rotundus

Cyperus rotundus (Family Cyperaceae) is used both as a functional food and as a drug. In this study, the antioxidative potential of a hydroalcoholic extract of C. rotundus (CRE) was evaluated by various antioxidant assays, including antioxidant capacity by the phosphomolybdenum method, total antioxidant activity in linoleic acid emulsion systems, 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, hydroxyl radicals, and nitric oxide (NO) scavenging. We further evaluated the reducing potential of the extract as well as Fe(2+)/ascorbate-induced lipid peroxidation in rat liver homogenate. These various antioxidant activities were compared to standard antioxidants such as butylated hydroxytoluene, tocopherol, L-ascorbic acid, and catechin. Total phenolic and flavonoid content of CRE was also determined by a colorimetric method. The extract exhibited high reduction capability and powerful free radical scavenging, especially against DPPH and superoxide anions as well as a moderate effect on NO. CRE also showed inhibited lipid peroxidation in rat liver homogenate induced by Fe(2+)/ascorbate and prevented deoxyribose degradation in both non-site-specific and site-specific assays showing the hydroxyl radical scavenging and metal chelating activity of the hydroalcoholic extract. Moreover, the peroxidation inhibiting activity of CRE was demonstrated in the linoleic acid emulsion system. These results clearly established the antioxidative potency of C. rotundus, which may account for some of the medical claims attributed to this plant.     

Radical scavenging-linked antioxidant activities of commonly used herbs and spices in Korea

Herbs and spices not only variety and racy flavour to Korean foods, they also are the richest source for antioxidant power. The present study evaluates the radical scavenging-linked antioxidant activities of hot water extracts from commonly used herbs and spices in Korea. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities of bay extract were 39.5% and 22.1%, respectively. The hydroxyl radical scavenging activity was in order of dill (50.0%) > bay (31.3%) > garlic (27.9%) > white pepper and black pepper (15.1-15.3%) > onion (10.1%) extracts. Bay extract had the highest total phenolic content (17.86?μg CE/g). High correlation coefficients were found between the total phenol content and DPPH radical scavenging activity (R?=?0.9162). These results indicate that herbs and spices had high antioxidant activity that is partly due to the phenolic compounds and provide basic data for further development of processed food products.     

Antioxidant properties of methanolic extracts from leaves of Rhazya stricta

Because of increased safety concerns about synthetic antioxidants, exploitation of cheaper and safer sources of antioxidants based on natural origin is the focus of research nowadays. Rhazya stricta is a medicinally important plant native to South Asia. Extraction of antioxidants was carried out in different solvent systems, i.e., water, 80% methanol, 70% ethanol, and diethyl ether. The methanolic extract exhibited the highest total phenolic content among the extracts; therefore for further studies the methanolic extract was employed. Antioxidant activity measurement in the linoleic acid system, metal chelating activity, reducing power, scavenging effect on 1,1-diphenyl-2-picrylhydrazyl free radical, and superoxide anion radical scavenging activity were taken as the parameters for assessment of antioxidant potential of methanolic extracts. Results were compared with alpha-tocopherol and the synthetic antioxidant butylated hydroxyanisole. The antioxidant potential of methanolic extracts of R. stricta leaves was comparable with previously exploited potent antioxidants and is strongly concentration dependent.     

In vitro studies of polyphenol compounds,total antioxidant capacity and other dietary indices in a mixture of plants (Prolipid)

The best health and nutrition results can be achieved not only from the consumption of fruits and vegetables with high antioxidant capacities, but also from medicinal plants and herbs. Therefore, in the present investigation, the bioactive compounds (polyphenols and flavonoids) and the radical scavenging capacities of Prolipid, a mixture of herbs, were studied. Water extracts showed relatively high capacity of about 61.5% inhibition with the β-carotene–linoleic acid assay. In order to support the data obtained with β-carotene–linoleic acid assay, three different antioxidant assays were used: ferric-reducing/antioxidant power, trolox equivalent antioxidant capacity, and 1,1-diphenyl-2-picrylhydrazyl radical with prolonged time of their reactions. It was found that the amounts of polyphenols in water and methanol extracts were 22.849±2.267 and 3.241±0.325 mg gallic acid equivalent/g dry weight, and the antioxidant capacities in same extracts as determined by the 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) test after 120min were 275.81±27.58 and 62.25±6.11 micromole Trolox equivalents (µMTE) dry weight, respectively. The correlation coefficients between polyphenols and antioxidant capacities of Prolipid with 1,1-diphenyl-2-picrylhydrazyl radical and β-carotene–linoleic acid assay were about 0.97 and 0.98. In conclusion, the bioactivity of Prolipid was high and the total polyphenols were the main contributors to the overall antioxidant capacity. The results of our investigation in vitro are comparable with other medicinal plants and fruits widely used in the treatment of humans without known side effects. Prolipid, a mixture of herbs, can therefore be used as a supplement for nutritional and healthy purposes.     

Caffeic acid phenethyl ester (CAPE): correlation of structure and antioxidant properties

Caffeic acid phenethyl ester (CAPE), a plant polyphenolic concentrated in honeybee propolis, has been found to be biologically active in a variety of pathways. The aim of this study was to determine the antioxidant activity of CAPE using different methods such as total antioxidant activity by the thiocyanate method, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid radicals, 1,1-diphenyl-2-picryl-hydrazyl free radicals, N,N-dimethyl-p-phenylenediamine dihydrochloride radicals and superoxide anion radicals scavenging activities, reducing power and ferrous ions (Fe(2+)) chelating activities. CAPE showed 97.9% inhibition on lipid peroxidation of linoleic acid emulsion. On the other hand, butylated hydroxyanisole, butylated hydroxytoluene, α-tocopherol and trolox indicated an inhibition of 87.3, 97.6, 75.3 and 90.3% on peroxidation in the same system, respectively.     

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.     

In vitro antioxidant and radical-scavenging capacities of Citrullus colocynthes (L) and Artemisia absinthium extracts using promethazine hydrochloride radical cation and contemporary assays

A new, quick and economical decolorization assay based upon the generation of a radical cation made from promethazine hydrochloride (PMZH) is described for screening of antioxidant activity of plants/herbal extracts. PMZH radical cations, produced through a reaction between PMZH and potassium persulfate (K(2)S(2)O(8)) in phosphoric acid medium, have maximum absorption at 515?nm in their first-order derivative spectrum. Theconcentrations of chromagen and K(2)S(2)O(8) were optimized (final concentration of PMZH and K?S?O? were 0.166?mM and 0.11?mM, respectively) for better stability and sensitivity of the radical cation produced. Agood linear correlation was found between the percentage inhibition and the increasing amounts of standard antioxidants, with correlation coefficients ranging from 0.989 to 0.999. The newly developed assay was employed to evaluate the antioxidant capacity of Citrullus colocynthes L. and Artemisia absinthium extracts. The proposed assay involved a more stable radical cation and required only 1 h for preparation of a working solution in comparison to the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation decolorizaion assay, which was reported to be less sensitive at low pH and almost 12-16 h were required for preparation of a working ABTS solution. Other assays employed to evaluate the antioxidant potential andradical-scavenging capacities of the extracts were the ferric-reducing antioxidant power, 2,2'-diphenyl-1-picrylhydrazyl radical scavenging, total phenolic contents assay, total flavonoid contents and metal-chelating activity assays, and the lipid peroxidation value in linoleic acid emulsion systems. The results indicate that boththe plants have potent free radical-scavenging activity and the ability to prevent lipid peroxidation and radical chain reactions.     

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.     

Consumer acceptability of liquorice root (Glycyrrhiza glabra L.) as an alternative sweetener and correlation with its bioactive content and biological activity

Consumer acceptability and sensory properties of liquorice root (Glycyrrhiza glabra L.) were evaluated. Quantitation of total polyphenolics and glycyrrhizic acid (GA), as well as the antioxidant capacity of liquorice extracts, was conducted and their biological effects (cytotoxic, antioxidative/pro-oxidative activity, lipid peroxidation on human laryngeal carcinoma cell line) compared to the ones of their predominant bioactive compound – GA. Conducted consumer survey revealed poor familiarity with liquorice (12.37% of correspondents), but willingness towards its use as an alternative sweetener (77.32% of consumers). Polyphenolic content of evaluated extracts ranged from 1018.18 to 1277.27?mg gallic acid equivalents (GAE)/l while GA content varied between 2179.53 and 2944.13?mg/l. The most pronounced cytotoxic effect (60%) and lipid peroxidation were exerted by treatment with the highest applied extract concentrations (10?mg/ml). Pure GA exhibited cytotoxic and pro-oxidative effects at concentrations of 0.12–0.6?mg/ml. Due to high GA content, coupled with its pronounced cytotoxic activity, the intake of liquorice root should be limited.     

Free radical scavenger and antioxidant capacity correlation of alpha-tocopherol and Trolox measured by three in vitro methodologies

The objective of this study was to correlate the free radical scavenging and antioxidant activity of two known substances (Trolox and alpha-tocopherol), using three in vitro methods (linoleic acid emulsion, brain homogenate and 2,2-diphenyl-1-picryl-hydrazyl [DPPH]). At steady state, alpha-tocopherol showed a greater inhibition of spontaneous oxidation of brain homogenate (59.42%+/-1.91) than Trolox (38.50%+/-2.38), while the latter showed a better antioxidant activity performance regarding inhibition of linoleic acid peroxidation (100% versus 84.02%+/-1.98) and free radical scavenging activity (93.56%+/-5.71 versus 66.72%+/-6.28). When the IC50 value was used as a parameter, alpha-tocopherol presented greater antioxidant activity than Trolox evaluated in brain homogenate and DPPH, without a significant difference when using linoleic acid emulsion. Both compounds showed the same antioxidant efficiency measured by DPPH kinetics (0.37 mM). Antioxidant activity significantly changed according to the substrate, the parameter adopted to compare the substances in the same method and the form used to express antioxidant concentration.     

Antioxidant and free radical scavenging capacity of the underutilized legume, Vigna vexillata (L.) A. Rich

The raw and processed seeds of the underutilized legume, Vigna vexillata (L.) A. Rich were extracted with 70% acetone and used for the evaluation of its antioxidant potential. The different heat treatments included dry heating, soaking followed by autoclaving with 0.1% sodium bicarbonate, soaking followed by autoclaving and autoclaving without soaking. The raw seed extract contained higher levels of total phenolics (11.7 g/100 g) and tannins (5.9 g/100 g) than the processed seed extracts. The extracts were further evaluated for their antioxidant activities using FRAP, Fe²⁺ chelation, phosphomolybdenum reduction, DPPH and ABTS⁺ radical scavenging, antihemolytic and β-carotene/linoleic acid emulsion systems. In general, the raw seed extracts were the most potent antioxidant suppliers and free radical scavengers. Interestingly, among the various processing methods, acetone extract of dry heated seed sample registered higher antihemolytic activity (86.2%) at the concentration of 500 μg/ml, whereas, in β-carotene/linoleic acid emulsion system, the extracts of raw seeds and the presoaked seeds followed by autoclaving with 0.1% sodium bicarbonate exhibited higher and comparable activity than other processed seed extracts.     

Wild-growing lignicolous mushroom species as sources of novel agents with antioxidative and antibacterial potentials

Crude extracts of two edible and two medicinal lignicolous mushroom species: Meripilus giganteus, Agrocybe aegerita, Fomes fomentarius and Xylaria polymorpha, growing wild in Serbia, were analyzed for their antioxidative and antibacterial potentials. Free radical scavenging capacity (RSC) on DPPH^? and ^?OH was evaluated both by spectrophotometer and by Electron Spin Resonance (ESR) spectroscopy against DPPH^?. The highest antioxidant and antibacterial bioactivity was obtained with F. fomentarius extracts (IC₅₀?≈?10.7?µg/ml in DPPH^? assay; 136.6?mg ascorbic acid equivalents (AAE)/g dry weight (d.w.) for ferric reducing antioxidant power FRAP). It also showed the highest total phenol (TP) (82.54?mg gallic acid equivalents (GAE)/g dry weight (d.w.)) and total flavonoid (TF) content (76.8?µg rutin equivalents (RE)/g dry weight (d.w.)). A. aegerita showed the best antioxidant activity (IC₅₀?=?0.87?mg/ml) against DPPH^? in ESR analysis. Total redox potential of extracts was in direct positive correlation with TP content (r^2?=?0.98) and TF content (r^2?=?0.58). GC/MS analysis detected major constituents of extracts, confirming the presence of the following organic and phenolic acids: fumaric, succinic, mallic, 4-hydroxy benzoic, gentisic, protocatechuic, vanillic, gallic and p-coumaric acid.     

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.     

The inhibiting activity of areca inflorescence extracts on human low density lipoprotein oxidation induced by cupric ion

The oxidative modification of human low density lipoprotein (LDL) plays a significant role in atherosclerosis. In this study, the inhibiting activity of areca inflorescence extracts (AIEs) on LDL oxidation was investigated by an in vitro study with Trolox as the standard antioxidant. The kinetics of LDL oxidation, thiobarbituric acid reactive substances assay, ferric-reducing antioxidant power assay and copper chelation assay were also evaluated to assess the antioxidant activities of AIEs, and the results revealed that AIEs could delay the lag time and inhibit the formation of malondialdehyde in the process of LDL peroxidation induced by Cu²⁺. The boiled water extract displayed the highest antioxidant activity compared with the ambient water extract and ethanol extract. The total phenolic contents and phenolic components of AIEs were also measured by high performance liquid chromatography method. Epicatechin, gallic acid and coumalic acid were the primary phenolic acids in AIEs.     

Comparative analysis of the in vitro antioxidant activity of white and black pepper

As a result of normal metabolic processes, the human body produces reactive oxygen species capable of oxidizing biomolecules that can damage DNA, cells, and contribute to chronic disease. This process can be attenuated or perhaps reversed by diets containing spices that have the ability to scavenge reactive oxygen species. The present study measured the concentration of polyphenols in peppercorn (black and white) using the Folin-Ciocalteu method and investigated the radical scavenging activities of hydrolyzed and nonhydrolyzed pepper extracts using 1,1-diphenyl-2-picrylhydrazyl, the superoxide radical, and the hydroxyl radical as substrates. The hydrolyzed and nonhydrolyzed extracts of black pepper contained significantly (P < .001) more polyphenols compared with those of white pepper. For either of these peppercorns, the hydrolyzed extract contained significantly (P < .001) more polyphenols compared with the nonhydrolyzed extract. A dose-dependent effect was observed in the free radical and reactive oxygen species scavenging activities of all the extracts, with the black pepper extracts being the most effective. Peppercorns especially black pepper, which constitutes an important component in the diet of many sub-Saharan and oriental countries, can therefore be promoted for their nutritional importance as antioxidants and radical scavengers.