Antioxidant properties of the methanol extracts from the leaves of Paullinia pinnata

Paullinia pinnata is an African woody vine widely used in traditional medicine for the treatment of malaria. In order to throw more light into its mechanisms of pharmacological actions, the in vitro antioxidant activities of the methanol extract of its leaves were evaluated using different testing systems. Its scavenging activities on 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid radicals as well as its ferric ion reducing power were assessed. The results showed that P. pinnata possessed strong scavenging activity and moderate reducing power. The total phenol, flavonoid, and proanthocyanidin contents of the extracts were very close to those reported for most medicinal plants and showed good correlation with its antioxidant activities. These properties are probably part of the reasons why P. pinnata is effective in folk medicine.     

Antioxidant activity of extracts from the leaves of Smallanthus sonchifolius

Summary. Background & Aims: Yacon (Smallanthus sonchifolius, Asteraceae) is a native Andean plant, cultivated for its tubers throughout South America. The leaves are used in folk medicine as a medicinal tea for hypoglycemia. This paper describes the antioxidant activity of various extracts from S. sonchifolius leaves for their content of phenolic components. Methods: The dried leaves were extracted in several ways. Two fractions were selected for their high content of phenolic compounds and analyzed by RP-HPLC. The antioxidant activity of these fractions was tested in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and xanthine/XOD superoxide radical scavenging assays, as inhibition of lipoperoxidation of subcellular membranes and as protective activity against oxidative injury of rat hepatocytes in primary cultures. Results and conclusions: The presence of protocatechuic (2.5 and 0.12 mg/g), chlorogenic (9.9 and 1.7 mg/g), caffeic (14.7 and 0.09 mg/g) and ferulic (traces) acids were determined in the two fractions. Both fractions showed potent antioxidant activity in DPPH (IC₅₀ = 16.1 ± 3.4 and 24.3 ± 2.7 mg/ml) and xanthine/XOD superoxide radical scavenging (42.0 ± 20.3 and 34.3 ± 11.4 SOD equivalents (U/mg)) tests, they inhibited the lipoperoxidation of rat liver subcellular membranes and they protected rat hepatocytes against oxidative injury. Our results may predetermine the use of S. sonchifolius leaves in human diet as a potential remedy in the prevention of chronic diseases caused by radicals, e. g., arteriosclerosis. Received: 10 July 2002, Accepted: 25 November 2002 Correspondence to: K. Valentova     

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.     

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 and radical scavenging properties in vitro of polyphenolic extracts from red wine

Summary Background & Aims Red wine polyphenols inhibit chemically-induced oxidative DNA damage in vivo in experimental animals through a mechanism which is still unclear. On this basis, we tried to clarify the mechanisms of inhibition of DNA oxidation in vitro by wine extracts containing monomeric and polymeric phenols (WE) and monomer-free complex polyphenols and tannins (WCPT) from red wine. Methods Oxidative DNA damage was induced by incubating DNA with GSH/Fe³⁺ or cumene hydroperoxide (CumOOH) in vitro and using 8-OH–2-deoxyguanosine (8-OHdG) levels as a measure of DNA oxidation. Levels of 8-OHdG were determined by HPLC coupled with electrochemical detector (ESA). Results and conclusions WCPT and WE, at μM concentrations, reduced concentration-dependently oxidative DNA damage induced by GSH/Fe³⁺. WCPT and WE also reduced DNA oxidation by CumOOH. In conclusion, complex polyphenols and tannin extracts from red wine, with or without small molecular phenols, prevent oxidative DNA damage through a dual mechanism, iron binding and direct free radical scavenging. Received: 27 November 2000 / Accepted: 11 April 2001     

Effects of methanolic extracts from broad beans on cellular growth and antioxidant enzyme activity

Objective There are several reports of cellular-aging-dependent alterations in the antioxidant capacity of human fibroblasts. Fibroblasts show slower the growth rate at late passages (referred to hereafter as old cells) than at early passages (referred to hereafter as young cells). Antioxidants may control cellular growth by modulating reactive oxygen species (ROS). Methanolic extracts from broad beans (MEBB) contain phenolic compounds and have ROS-scavenging activities. In this study, we investigated the effects of MEBB on cellular growth and antioxidant levels in normal human lung fibroblasts. Methods To determine cytosolic superoxide dismutase (SOD) activities, cytosolic glutathione peroxidase (GSH-Px) activities, catalase activities, reduced glutathione (GSH) concentrations, and growth rate, MEBB treatments were performed on young and old cells. Results In young and old cells treated with 120 μg/ml MEBB, the growth rates increased by 28.1 and 15.2%, respectively, compared with controls. The MEBB treatment of young cells caused a 62.5% increase in SOD activity, but the treatment of old cells caused a 39.5% decrease. The catalase activities of the young and old cells treated with MEBB were equal to those of control cells. Young and old cells treated with MEBB were equal to the control cells in terms of GSH-Px activity. The GSH concentrations in the young and old cells treated with 120 μg/ml MEBB increased by 22.1 and 45.9%, respectively. Conclusion These studies elucidated a new cellular growth mechanism whereby human lung fibroblasts modulate intracellular GSH levels via the action of MEBB.     

Antioxidant capacity of water soluble extracts from Parmigiano-Reggiano cheese

Abstract

In this work the antioxidant capacity of water soluble extracts of Parmigiano-Reggiano cheese (Water Soluble Extracts – WSEs) at different aging time was studied, by measuring their radical scavenging capacity with a standard ABTS assay. The WSEs were also fractionated by semi-preparative HPLC-UV and for each fraction the antioxidant capacity and the molecular composition was determined by LC/ESI-MS, in order to identify the most active antioxidant compounds. The antioxidant capacity was also determined after simulated in vitro gastrointestinal digestion of WSEs. The data indicated that antioxidant capacity in WSE from Parmigiano-Reggiano cheese, quite unaffected by ripening time and gastrointestinal digestion, is mostly due to free amino acids, mainly tyrosine, methionine and tryptophan, and only in minimal part to antioxidant peptides.     

Antioxidant and flavor properties of Angelica sinensis extracts as affected by processing

Angelica sinensis (AS) was extracted with water or 20% ethanol for different time periods, and the antioxidant activity as well as flavor quality of the extracts were investigated. The AS extracts contained significant amount of phenolic acids, including nicotinic acid, phthalic acid, p-coumaric acid, and ferulic acid. Regardless the water or alcohol extraction, most of the phenolic acids reached their maximum values in 15 min. Assays including inhibition of 1,1-diphenylpicrylhydrazyl (DPPH), lipid peroxidation, and DNA relaxation activities also indicated that 15 min extraction resulted in a product with the highest antioxidant activity. The 15 min AS extracts in the concentration range of 20–200 μg/ml also showed inhibitory effects on NO production in LPS-activated RAW 264.7 macrophage in a dose-dependent manner. Statistical analysis revealed that the antioxidant activity and phenolic acid concentration for all AS extracts exhibited a positive and significant linear correlation, suggesting that the phenolic acids are the important contributors for the antioxidant activity of the AS extracts. The contents of volatile compounds of AS were much higher in the 20% ethanol extracts than those in water extracts. In the 20% ethanol extracts, the amount of ligustilide, butylidene phthalide and butyl phthalide were higher in the 30-min extracts than that prepared for longer time. Considering both of antioxidant activity and flavor quality, the AS extract should be prepared with 20% ethanol with extraction time less than 30 min.     

Antioxidant, hepatoprotective, and ameliorative effects of methanolic extract of leaves of Grewia mollis Juss. on carbon tetrachloride-treated albino rats

The methanolic extract of Grewia mollis leaves was evaluated in vivo for its antioxidant and hepatoprotective properties. Oxidative stress was induced in rats by administering carbon tetrachloride (CCl(4)) intraperitoneally at a dose of 0.6 mL/kg, whereas the crude plant extract and standard antioxidant (vitamin E) were administered at a dose of 5 mg/kg and 50 mg/kg, respectively. The effect of G. mollis crude extracts and vitamin E on malondialdehyde (MDA) and liver function parameters such as protein, bilirubin, aspartate aminotransferase, and alanine aminotransferase were measured spectrophotometrically. The methanolic extract of G. mollis leaves and vitamin E showed a significant (P<.05) hepatoprotective potential by lowering the serum levels of bilirubin, aspartate aminotransferase, and alanine aminotransferase and decreasing MDA levels in rats pretreated or post-treated with CCl(4). Based on these results, it is concluded that G. mollis leaves contain potent antioxidant compounds that could offer protection against hepatotoxicity as well as ameliorate preexisting liver damage and oxidative stress conditions.     

Antioxidant and antidiabetic activities of extracts from Cirsium japonicum roots

This study investigated the antioxidant activity of methanol (MeOH) and water extracts from roots of Cirsium japonicum in vitro. MeOH extract showed a stronger free radical scavenging activity than water extract. However, both of extracts showed a concentration dependent hydroxyl radical scavenging activity, reducing power and metal chelating ability. MeOH extract had greater phenolic and flavonoid contents than water extract. The antidiabetic activity of these two extracts was evaluated by the α-glucosidase inhibition assay. The water extract showed a considerable α-glucosidase inhibitory activity. To our knowledge, this may be the first time to report the antioxidant and antidiabetic activities in Cirsium japonicum roots.     

Scavenging effects of methanolic extracts of broad beans on free-radical species

This report describes the antioxidant characteristics of methanolic extracts from broad beans (Vicia fava). The methanolic extracts of broad beans (MEBB) exhibited a marked scavenging effect on superoxide. MEBB also exerted scavenging activities on hydrogen peroxide and 1, 1-diphenyl-2-picrylhydrazyl radical. The radical scavenging activity of MEBB was highest when the scavenging effect of MEBB on Superoxide (IC₅₀ = 0.15 mg/ml) was examined. These results suggest that MEBB have effective activities both as a radical scavenger and as a hydrogen donor. The chelating activity of MEBB (0.70 mg/ml) on Fe²⁺ and Cu²⁺ was 31.2% and 28.5%, respectively. The antioxidant effect of MEBB on lipid peroxidation might be attributed to their properties of scavenging free-radical species and their chelating activity on metal ions. The antioxidant activity of MEBB against tert-butyl hydroperoxide (BHP)-induced oxidative stress in WI-38 cells was assessed. The activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSH-Px) were measured as indices of oxidative stress. WI-38 cells incubated with 0.1 mM BHP for 2 hr exhibited the increase of SOD, catalase and GSH-Px activities over the control. When the cells incubated in MEBB (45–450 μg/ml) for 18 hr were subjected to a BHP challenge test, SOD activity returned to its control value or lower at all levels tested. When catalase activity was determined, a similar trend occurred except in the cells incubated in 112.5 μ g/ml MEBB. These results imply that MEBB inhibit oxidative stress in WI-38 cells.     

Antioxidant and cytotoxic properties of lyophilized beer extracts on HL-60 cell line

An impressive number of studies have suggested that red wine can be considered the protective beverage of choice against chronic and degenerative pathologies. Only few and controversial data are available on a potential, similar role for beer, which represents a more cost-effective, safe, and widely available beverage. Starting from the evidence that many antioxidant compounds present in red wine are also present at similar or even higher concentrations in beers, we first screened 48 commercially available beers and selected one (Mrt-HP) with very high polyphenol concentration and antioxidant activity estimated by ferric reducing antioxidant power. We demonstrated that a lyophilized preparation of Mrt-HP beer was cytotoxic with respect to a beer with low polyphenolic content (Trt-LP) when assayed on HL-60 human leukemia cell line. We measured a 60% decrease in cell viability at a polyphenol concentration of 250 microM quercetin equivalents. We also demonstrated that Mrt-HP cytotoxicity was not an artifact due to cell growth conditions because addition of Mrt-HP extracts to cell medium generated peroxide levels indistinguishable from controls. By means of cytofluorimetric analysis of pre-G1 population and caspase 3 activation, we demonstrated that Mrt-HP extracts activated apoptosis in HL-60 cell line. Finally, we found that the concentration of quercetin, resveratrol, and gallic acid in Mrt-HP was 10, 4.6, and 4.6-fold higher, respectively, than in Trt-LP, suggesting that the presence of these molecules might be responsible for the observed cytotoxicity. These data, together with the low in vivo beer toxicity reported in the literature, suggest a possible chemopreventive role for this beverage that requires further studies in animal models.     

Antioxidant capacity of crude extracts from clones of banana and plane species

Banana and plane are the most important fruits in world trade, behind citric plants. In this work we studied the antioxidant capacity of banana and plane varieties of fruits obtained from interspecies crossed varieties of Musa acuminata and Musa balbisiana, named Harton plane, Cavendish banana, and Manzano banana. With this purpose we evaluated banana and plane crude extracts using the ferrous ion oxidation with xylenol orange method, the thiobarbituric acid method, determination of antioxidant activity, and effect on superoxide anion and hydroxyl radical and the radicals generated by ultraviolet light. The experiments showed that all extracts have the capacity to decrease the concentrations of lipid hydroperoxides and malondialdehyde, produced in the lipid peroxidation process, in a manner comparable to that of other widely studied antioxidants like melatonin and vitamin E. Moreover, all extracts had the capacity to inhibit the generation of superoxide anion, hydroxyl radical, and the radicals generated by ultraviolet light. When antioxidant activity was calculated, a value was found that was equivalent to a concentration of uric acid between 0.20 and 0.30 mM at the highest concentration of extract used, with uric acid being a potent antioxidant at 1 mM.     

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.     

Antioxidant properties of enzymatic hydrolysates from royal jelly

Enzymatic hydrolysates were prepared from royal jelly using three enzymes (pepsin, trypsin, and papain), and their antioxidative properties were evaluated. The yield of these hydrolysates was very high, about 20-26% on a raw weight basis. In comparison with the antioxidative activities of water extract and alkaline extract of royal jelly, the antioxidative activities and scavenging activities against active oxygen species such as superoxide anion radical and hydroxyl radical of each hydrolysate were high in the sample with a low protein concentration. These results suggest that once royal jelly is hydrolyzed using enzyme, the hydrolysate possesses much higher antioxidative activity and scavenging activity against active oxygen species. Royal jelly will act as a medicinal food in the human body.     

Antidiabetic and antidiarrheal effects of the methanolic extract of Phyllanthus reticulatus leaves in mice

ObjectiveTo assess the anti-diabetic and antidiarrheal activity of methanolic extract of Phyllanthus reticulates (P. reticulates) leaves in an animal model.MethodsPhytochemical screening of methanolic extract of P. reticulatus leaves has been performed. Antidiabetic activity have been done by OGTT, normoglycemic hyperglycemia and alloxan induced diabetic mice. Plant extracts (150 mg/kg and 300 mg/kg, b.w.) were administered orally in fasting glucose loaded mice with regard to normal control and in alloxan induced (110 mg/kg body weight i.p.) diabetic mice in comparison with reference drug Metformin hydrochloride (100 mg/kg) during 7 day test period. Antidiarrheal test was conducted by castor oil and magnesium sulfate.ResultsFindings confirmed that the continuous post-treatment for 7 days with both extracts showed significant (P < 0.05) hypoglycemic activity in OGTT, normoglycemic and alloxan induced mouse models. Castor oil and Magnesium sulfate induced diarrheal test of the extract (200 and 400 mg/kg) has given significant effect in compairing to control diarrheal group.ConclusionMethanolic extract of P. reticulatus leaves have shown significant antidiabetic and antidiarrheal properties.     

Carbohydrase inhibition and anti-cancerous and free radical scavenging properties along with DNA and protein protection ability of methanolic root extracts of Rumex crispus

The study elucidated carbohydrase inhibition, anti-cancerous, free radical scavenging properties and also investigated the DNA and protein protection abilities of methanolic root extract of Rumex crispus (RERC). For this purpose, pulverized roots of Rumex crispus was extracted in methanol (80% and absolute conc.) for 3 hrs for 60℃ and filtered and evaporated with vacuum rotary evaporator. RERC showed high phenolic content (211 µg/GAE equivalent) and strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging (IC₅₀ = 42.86 (absolute methanol) and 36.91 µg/mL (80% methanolic extract)) and reduced power ability. Furthermore, RERC exhibited significant protective ability in H₂O₂/Fe³⁺/ascorbic acid-induced protein or DNA damage and percentage inhibition of the HT-29 cell growth rate following 80% methanolic RERC exposure at 400 µg/mL was observed to be highest (10.2% ± 1.03). Moreover, methanolic RERC inhibited α-glucosidase and amylase effectively and significantly (P < 0.05). Conclusively, RERC could be considered as potent carbohydrase inhibitor, anti-cancerous and anti-oxidant.     

Antiobesity activity of extracts from Lagerstroemia speciosa L. leaves on female KK-Ay mice

Banaba in the Tagalog name, Lagerstroemia speciosa L., has been used as a folk medicine for a long time among diabetics in the Philippines. Extracts from banaba leaves have been reported to reduce diabetic symptoms in genetically diabetic mice (Type II, KK-Ay). In the present study, female mice of the same strain showing remarkable body weight gain were used to examine the antiobesity effect of dietary banaba extract. Five-week-old female KK-Ay mice were fed a control diet or test diet containing 5% of a hot-water extract from banaba leaves instead of cellulose for 12 wk. Neither group showed any changes in diet intake during the experimental period. Body weight gain and parametrial adipose tissue weight were lowered significantly in the banaba diet group. Blood glucose levels were not suppressed in the banaba diet group, but hemoglobin A1C was found to be suppressed at the end of the experiment. No effects on the serum lipids were observed, but the mice fed banaba extract showed a significant decrease, to 65% of the control level in total hepatic lipid contents. This decrease was due to a reduction in the accumulation of triglyceride. These results suggest that banaba had a beneficial effect on obese female KK-Ay mice.     

Biological properties of different protein extracts from selenium-enriched Ganoderma lucidum

Our previous studies showed that Ganoderma lucidum bio-transformed 20–30% of inorganic selenium from substrate to organic forms by preferentially incorporating selenium into proteins. In the present study, four kinds of protein extracts from selenium-enriched G. lucidum were prepared with different extracting solvents, which contain water-soluble, alkaline-soluble, salt-soluble and alcohol-soluble protein extracts, and the effects on antioxidant activity of characterizations of protein extracts were studied. Results showed that water-soluble extract showed strongest antioxidant properties among all extracts as suggested by spin trapping experiment due to its characterizations, followed by the alkaline-soluble > the salt-soluble >the alcohol-soluble protein extracts, a result demonstrating that selenium content and amino acids composition of the protein extracts play important and direct roles in enhancing their antioxidant activities, and the protein distribution and sugar content have an indirect effect by influencing the characters and structures. The activity of water-soluble crude protein was verified by CuSO₄–Phen–Vc–H₂O₂–DNA chemiluminescent analysis, and it should be selected as the subject to be studied and purified further.     

Biological properties of different protein extracts from selenium-enriched Ganoderma lucidum

Our previous studies showed that Ganoderma lucidum bio-transformed 20-30% of inorganic selenium from substrate to organic forms by preferentially incorporating selenium into proteins. In the present study, four kinds of protein extracts from selenium-enriched G. lucidum were prepared with different extracting solvents, which contain water-soluble, alkaline-soluble, salt-soluble and alcohol-soluble protein extracts, and the effects on antioxidant activity of characterizations of protein extracts were studied. Results showed that water-soluble extract showed strongest antioxidant properties among all extracts as suggested by spin trapping experiment due to its characterizations, followed by the alkaline-soluble > the salt-soluble > the alcohol-soluble protein extracts, a result demonstrating that selenium content and amino acids composition of the protein extracts play important and direct roles in enhancing their antioxidant activities, and the protein distribution and sugar content have an indirect effect by influencing the characters and structures. The activity of water-soluble crude protein was verified by CuSO4 Phen-Vc-H2O2-DNA chemiluminescent analysis, and it should be selected as the subject to be studied and purified further.