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.     

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.     

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.     

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.     

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.     

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.     

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.     

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 (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 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.     

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.     

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.     

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.     

Antioxidant activity of selected commercial seaweeds

This study aims to evaluate the antioxidant activity (total antioxidant and free radical scavenging activities) of seaweeds commercially available in the Malaysian supermarket. Four types of seaweeds namely Nori (Porphyra sp.), Kumbu (Laminaria sp.), Wakame (Undaria sp.) and Hijiki (Hijikia sp.) were used in the study. The extracts were prepared with water and ethanol, respectively. The b-carotene bleaching and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used to determine antioxidant properties of seaweeds by measuring the decrease in absorbance at 470 and 517 nm. In water extract, Kumbu showed the highest total antioxidant activity of 63% compared with other samples. Kumbu, Nori and Hijiki exhibited higher radical scavenging activity than Wakame when extracted with water. Wakame exhibited the highest antioxidant and free radical scavenging activities in ethanolic extract with 58% and EC50 = 0.42 mg/ml respectively. The results of ANOVA analysis show significant differences (p<0.05) in the means of total antioxidant and free radical scavenging activities of the seaweeds. The results showed that processed commercial seaweeds exhibited varying degrees of antioxidant properties.     

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.     

In vitro and vivo antioxidant activities of daylily flowers and the involvement of phenolic compounds

Daylily (Hemerocallis fulva Linn.) flowers were hot air-dried and freeze-dried after harvest. Antioxidant properties of water and ethanol extracts prepared from these dried flowers were evaluated in terms of total antioxidant activity, reducing capacity, and metal chelating activity. Extracts from daylily flowers exhibited strong antioxidant activity. Ethanol was more efficiency to extract antioxidants than water, and freeze-drying preserved higher activities than air-drying. Rutin, (+)-catechin, and gallic acid were identified in the extracts by HPLC, and were highly related to the antioxidant activities. The antioxidant activity was further evaluated by feeding mice with ethanol extract from freeze-dried daylily flowers for 60 days. The results demonstrated that the extract at dosage of 40-225 mg/100 g significantly increased the activity of SOD (superoxide dismutase) and reduced the lipid peroxidation in both blood and liver of rat.     

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.     

蛋清蛋白酶解物抗氧化与血管紧张素转换酶抑制活性的研究

目的研究三种蛋白酶的蛋清蛋白酶解物(EWPH)的抗氧化及血管紧张素转换酶(ACE)抑制活性。方法分别采用Fenton体系、邻苯三酚自氧化体系和亚油酸自氧化体系测定胰蛋白酶、木瓜蛋白酶及alcalase碱性蛋白酶的EWPH清除羟自由基、超氧阴离子及抑制脂质过氧化的能力。利用高效液相色谱法测定ACE抑制活性。超滤分离上述三种蛋白酶的EWPH,检测各组分的抗氧化和ACE抑制活性。结果抗氧化活性最强的是木瓜蛋白酶的EWPH,在浓度10mg/ml时,对羟自由基和超氧阴离子清除率分别为53.14%和27.87%,在浓度0.8mg/ml时,对亚油酸自氧化的抑制率73.72%(D7)。ACE抑制效果最明显的是胰蛋白酶的EWPH,其IC50值为0.985mg/ml。低分子量(Mw3ku)组分酶解物的活性优于高分子量(Mw3ku)组分。结论三种蛋白酶的EWPHs均具有抗氧化和ACE抑制活性,但两种活性之间无明显的相关,且小分子组分的活性最强。     

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.     

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.