Contributions of major components to the antimutagenic effect of Hsian-tsao (Mesona procumbens Hemsl.)

Our aim was to determine the antimutagenic activity of various solvent extracts from an herb Mesona procumbens Hemsl, normally called Hsian-tsao in China. We also investigated the relationships between the special components in the water extract of Hsian-tsao (WEHT) and the antimutagenic activity. It was found that the extracts at 0-0.6 mg/plate from three solvents (water, methanol, and ethyl acetate) exhibited a dose-dependent antimutagenic effect against benzo[a]pyrene [B(a)P] and 2-amino-3-methylimidazo(4,5-f)quinoline (IQ), both are indirect mutagens in Salmonella tester strains TA98 and TA100. The WEHT from three different plantations revealed a similar inhibitory effect on the mutagenicity of IQ in TA 98 at 2.5-5.0 mg/plate. The inhibitory effect of WEHT on the mutagenicity of IQ correlates with their polyphenol and ascorbic acid contents but not with their chlorophyll contents. These findings suggest that the antimutagenicity activity of WEHT may be attributed mainly to their polyphenolic compounds and ascorbic acid.     

Moscatilin from Dendrobium nobile, a naturally occurring bibenzyl compound with potential antimutagenic activity.

A bibenzyl compound that possesses antimutagenic activity was isolated from the storage stem of Dendrobium nobile. The isolated compound suppressed the expression of the umu gene following the induction of SOS response in Salmonella typhimurium TA1535/pSK1002 that have been treated with various mutagens. The suppressive compound was mainly localized in the n-hexane extract fraction of the processed D. nobile. This n-hexane fraction was further fractionated by silica gel column chromatography, which resulted in the purification and subsequent identification of the suppressive compound. EI-MS and (1)H and (13)C NMR spectroscopy were then used to delineate the structure of the compound that confers the observed antimutagenic activity. Comparison of the obtained spectrum with that found in the literature indicated that moscatilin is the secondary suppressive compound. When using 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) as the mutagen, moscatilin suppressed 85% of the umu gene expression compared to the controls at <0.73 micromol/mL, with an ID(50) value of 0.41 micromol/mL. Additionally, moscatilin was tested for its ability to suppress the mutagenic activity of other well-known mutagens such as 4-nitroquinoline-1-oxide (4NQO), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), UV irradiation, 3-amino-1,4-dimethyl-5H-pyrido[4,3b]indole (Trp-P-1), benzo[a]pyrene (B[a]P), and aflatoxin B(1) (AFB(1)). With all of the aforementioned chemicals or treatments, moscatilin showed a dramatic reduction in their mutagenic potential. Interestingly, moscatilin almost completely suppressed (97%) the AFB(1)-induced SOS response at concentrations <0.73 micromol/mL, with an ID(50) of 0.08 micromol/mL. Finally, the antimutagenic activities of moscatilin against furylfuramide and Trp-P-1 were assayed by the Ames test using the S. typhimurium TA100 strain. The results those experiments indicated that moscatilin demonstrated a dramatic suppression of the mutagenicity of only Trp-P-1 but not furylfuramide.     

Brassica oleracea L. Var. costata DC and Pieris brassicae L. aqueous extracts reduce methyl methanesulfonate-induced DNA damage in V79 hamster lung fibroblasts

Brassica oleracea L. var. costata DC leaves and Pieris brassicae L. larvae aqueous extracts were assayed for their potential to prevent/induce DNA damage. None of them was mutagenic at the tested concentrations in the Ames test reversion assay using Salmonella His(+) TA98 strains, with and without metabolic activation. In the hypoxanthine-guanine phosphoribosyltransferase mutation assay using mammalian V79 fibroblast cell line, extracts at 500 μg/mL neither induced mutations nor protected against the mutagenicity caused by methyl methanesulfonate (MMS). In the comet assay, none of the extracts revealed to be genotoxic by itself, and both afforded protection, more pronounced for larvae extracts, against MMS-induced genotoxicity. As genotoxic/antigenotoxic effects of Brassica vegetables are commonly attributed to isothiocyanates, the extracts were screened for these compounds by headspace-solid-phase microextraction/gas chromatography-mass spectrometry. No sulfur compound was detected. These findings demonstrate that both extracts could be useful against damage caused by genotoxic compounds, the larvae extract being the most promising.     

Antimutagenicity of supercritical CO2 extracts of Terminalia catappa leaves and cytotoxicity of the extracts to human hepatoma cells

Natural antimutagens may prevent cancer and are therefore of great interest to oncologists and the public at large. Phytochemicals are potent antimutagen candidates. When the Ames test was applied to examine the antimutagenic potency of supercritical carbon dioxide (SC-CO(2)) extracts of Terminalia catappa leaves at a dose of 0.5 mg/plate, toxicity and mutagenicity were not detected. The antimutagenic activity of SC-CO(2) extracts increased with decreases of temperature (60, 50, and 40 degrees C) and pressure (4000, 3000, and 2000 psi) used for extraction. The most potent antimutagenicity was observed in extracts obtained at 40 degrees C and 2000 psi. At a dose of 0.5 mg of extract/plate, approximately 80% of the mutagenicity of benzo[a]pyrene (B[a]P, with S-9) and 46% of the mutagenicity of N-methyl-N '-nitroguanidine (MNNG, without S-9) were inhibited. Media supplemented with SC-CO(2) extracts at a range of 0-500 microg/mL were used to cultivate human hepatoma (Huh 7) and normal liver (Chang liver) cells. The viability of the cells was assayed by measuring cellular acid phosphatase activity. A dose-dependent growth inhibition of both types of cells was observed. The SC-CO(2) extracts were more cytotoxic to Huh 7 cells than to Chang liver cells. The observation that SC-CO(2) extracts of T. catappa leaves did not induce mutagenicity at the doses tested while exhibiting potent antimutagenicity and were more cytotoxic to human hepatoma cells than to normal liver cells is of merit and warrants further investigation.     

Toxicological and analytical investigations of noni (Morinda citrifolia) fruit juice

Morinda citrifolia (noni) is known to contain genotoxic anthraquinones in the roots. Because of the widespread use of noni juice, the possible genotoxic risk was examined through a battery of short-term tests. Noni juice was also chemically analyzed for the possible presence of anthraquinones. Noni juice extract in the Salmonella microsome assay showed a slight mutagenic effect in strain TA1537, due to the presence of flavonoids. No mutagenicity was observed in the mammalian mutagenicity test with V79 Chinese hamster fibroblasts. Rats treated with a noni juice concentrate did not show DNA repair synthesis (UDS) in primary rat hepatocytes, nor could DNA adducts or DNA strand breaks be observed. HPLC analysis of noni juice for anthraquinones was negative, with a sensitivity of <1 ppm. In summary, chemical analysis and genotoxicity tests reveal that noni juice does not have a genotoxic potential and that genotoxic anthraquinones do not exist in noni juice.     

Lutein from ozone-treated corn retains antimutagenic properties

The present study was conducted to determine the influence of an ozonation process on lutein and protein in clean and contaminated corns. This study aimed to determine the levels of lutein and protein in corn before and after ozonation and to verify the antimutagenic potential of the extracted lutein against aflatoxin using the Ames test. The lutein content was analyzed by high-performance liquid chromatography. Nitrogen analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis were used to analyze protein. Clean ozone-treated corn had a total lutein content of 28.36 microg/g, which was higher than that of 22.75 microg/g in the untreated clean corn. However, the lutein content was 11.69 microg/g in the ozone-treated contaminated corn, which was lower than that of 16.42 microg/g in the untreated contaminated corn. In both corn samples, the protein content of ozone-treated corn was lower than that of untreated corn, indicating that protein could be destroyed by the ozonation process, which may influence the nutritious value of the corn. Lutein extracts alone showed no mutagenic potential against Salmonella typhimurium tester strains TA100. Lutein extracts from corn inhibited the mutagenicity of AFB1 in a dose-response manner more efficiently than lutein standard. Lutein extracts from different corn samples had similar antimutagenic potentials against AFB1, so the ozone treatment did not affect the antimutagenic potentials of lutein extracts.     

Antimutagenicity of some edible Thai plants,and a bioactive carbazole alkaloid,mahanine, isolated from Micromelum minutum

The antimutagenic activity against Trp-P-1 of methanolic extracts of 118 samples (108 species) of edible Thai plants was examined by the Ames Test. The activity was evaluated by the amount of plant extracts which suppressed 90% of the mutagenesis (ED90). Five plants, Micromelum minutum, Oroxylum indicum, Cuscuta chinensis, Azadirachta indica, and Litsea petiolata, exhibited significant activity with antimutagenic ED90 values lower than 5 microL/plate (0.1 mg of dry plant material equivalent). The activity-guided fractionation of the extract of M. minutum, which exhibited the highest antimutagenic activity in the screening, resulted in the isolation of an active principle, (+)-mahanine (1) as confirmed by its physicochemical properties. Compound 1 showed a wide variety of biological activity, including antimutagenicity against heterocyclic amines such as Trp-P-1 with an IC50 of 5.2 microM, cytotoxicity against a tumor cell line HL60 with a MIC100 of 4.0 microg/mL, and antimicrobial activity against Bacillus cereus and Staphylococcus aureus with MIC100 values of 6.25 and 12.5 microg/mL, respectively.     

Evaluation of the dietetic and therapeutic potential of a high molecular weight hydroxycinnamate-derived polymer from Symphytum asperum Lepech. Regarding its antioxidant, antilipoperoxidant, antiinflammatory, and cytotoxic properties

A water-soluble hydroxycinnamate-derived polymer (>1000 kDa) from Symphytum asperum Lepech. (Boraginaceae) strongly reduced the diphenylpicrylhydrazyl radical (IC(50) approximately 0.7 microg/mL) and inhibited the nonenzymatic lipid peroxidation of bovine brain extracts (IC(50) approximately 10 ng). This polymer exhibited only a low hydroxyl radical scavenging effect in the Fe(3+)-EDTA-H(2)O(2) deoxyribose system (IC(50) > 100 microg/mL) but strongly decreased superoxide anion generation in either the reaction of phenazine methosulfate with NADH and molecular oxygen (IC(50) approximately 13.4 microg/mL) or in rat PMA-activated leukocytes (IC(50) approximately 5 microg/mL). The ability to inhibit both degranulation of azurophil granules and superoxide generation in primed leukocytes indicates that the NADPH oxidase responsible for this later effect is inhibited, pointing to the Symphytum asperum polymer as a potent antiinflammatory and vasoprotective agent. At all concentrations tested (0-200 microg/mL), we observed no cytotoxicity on normal human fibroblasts and neither antiproliferative effects nor proliferation activation on neoplastic cells.     

Novel biological properties of Oenothera paradoxa defatted seed extracts: effects on metallopeptidase activity

In this study, for the first time, we used the in vitro metallopeptidase model for the identification of a potential novel activity of defatted evening primrose seed extracts. Prepared extracts of different polarity (aqueous, 60% ethanolic, isopropanolic, and 30% isopropanolic) at concentrations of 1.5-100 microg/mL exhibited a significant and dose dependent inhibition of three tested enzymes. The 50% inhibition of enzymes activity showed that aminopeptidase N (APN) was the enzyme affected to the greatest extent with IC50 at the level of 2.8 microg/mL and 2.9 microg/mL for aqueous and 30% isopropanolic extracts, respectively. The activity of neutral endopeptidase (NEP) was quite strongly inhibited by the extracts as well. The HPLC-DAD analysis and bioguided fractionation led to the identification of four active compounds: (-)-epicatechin gallate, proanthocyanidin B3, oenothein B, and penta-O-galloyl-beta-D-glucose (PGG). Oenothein B has been shown previously to inhibit metallopeptidases. The three other compounds are known to inhibit angiotensin-converting enzyme (ACE), but they have not been previously reported to inhibit the NEP and APN activity. PGG and procyanidins with different degrees of polymerization, as the dominating compounds in O. paradoxa seeds, seemed to play a role in the crude extract activity.     

Mutagenicity determination of the wastewater emitted from petrochemical industry in Taiwan

Thirty-eight wastewater samples were collected from 19 petrochemical plants located in Taiwan during 1991. These plants represented most of petrochemical industry in Taiwan. Water samples were passed through an XAD-2 resin column and then eluted by acetone. The mutagenicity of wastewater was determined by the Ames Salmonella/microsome test. 52.6 and 26.3% of wastewater collected respectively in summer and winter were found to exhibit mutagenic activity in Salmonella typhimuriumTA 98 and TA 100. Four samples collected from 2 plants had higher levels of mutagenicity. The measurement and identification of mutagenic pollutants in this kind of wastewater need further investigation.     

Free radical scavengers and antioxidants from Lemongrass (Cymbopogon citratus (DC.) Stapf.)

Methanol, MeOH/water extracts, infusion, and decoction of Cymbopogon citratus were assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the superoxide anion, and inhibition of the enzyme xanthine oxidase (XO) and lipid peroxidation in human erythrocytes. The extracts presented effect in the DPPH and superoxide anion assay, with values ranging between 40 and 68% and 15-32% at 33 and 50 microg/mL, respectively, inhibited lipid peroxidation in erythrocytes by 19-71% at 500 microg/mL and were inactive toward the XO at 50 microg/mL. Isoorientin, isoscoparin, swertiajaponin, isoorientin 2' '-O-rhamnoside, orientin, chlorogenic acid, and caffeic acid were isolated and identified by spectroscopic methods. Isoorientin and orientin presented similar activities toward the DPPH (IC(50): 9-10 microM) and inhibited lipid peroxidation by 70% at 100 microg/mL. Caffeic and chlorogenic acid were active superoxide anion scavengers with IC(50) values of 68.8 and 54.2 microM, respectively, and a strong effect toward DPPH. Caffeic acid inhibited lipid peroxidation by 85% at 100 microg/mL.     

Antimutagenic activity of phenylpropanoids from clove (Syzygium aromaticum)

Phenylpropanoids that possess antimutagenic activity were isolated from the buds of clove (Syzygium aromaticum). The isolated compounds suppressed the expression of the umu gene following the induction of SOS response in the Salmonella typhimurium TA1535/pSK1002 that have been treated with various mutagens. The suppressive compounds were mainly localized in the ethyl acetate extract fraction of the processed clove. This ethyl acetate fraction was further fractionated by silica gel column chromatography, which resulted in the purification and subsequent identification of the suppressive compounds. Electron impact mass spectrometry, IR, and (1)H and (13)C NMR spectroscopy were then used to delineate the structures of the compounds that confer the observed antimutagenic activity. The secondary suppressive compounds were identified as dehydrodieugenol (1) and trans-coniferyl aldehyde (2). When using 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) as the mutagen, compound 1 suppressed 58% of the umu gene expression as compared to the controls at a concentration of 0.60 micromol/mL, with an ID(50) (50% inhibitory dose) value of 0.48 micromol/mL, and compound 2 suppressed 63% of the umu gene expression as compared to the controls at a concentration of 1.20 micromol/mL, with an ID(50) value of 0.76 micromol/mL. Additionally, compounds 1 and 2 were tested for their ability to suppress the mutagenic activity of other well-known mutagens such as 4-nitroquinolin 1-oxide (4NQO) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which do not require liver metabolizing enzymes, and aflatoxin B(1) (AfB(1)) and 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), which require liver metabolizing enzymes and activated Trp-P-1 and UV irradiation. Compounds 1 and 2 showed dramatic reductions in their mutagenic potential of all of the aforementioned chemicals or treatment. For the search of the structure-activity relationship, the derivatives of 1 and 2 (1a and 2a-c) were also assayed with all mutagens. Finally, the antimutagenic activities of compounds 1, 1a, 2, and 2a-c against furylfuramide, Trp-P-1, and activated Trp-P-1 were assayed by the Ames test using the S. typhimurium TA100 strain.     

Antioxidant capacity and cytotoxicity of essential oil and methanol extract of Aniba canelilla (H.B.K.) Mez

The leaves and fine stems, bark, and trunk wood oils of Aniba canelilla showed yields ranging from 0.2 to 1.3%. The main volatile constituent identified in the oils was 1-nitro -2-phenylethane (70.2-92.1%), as expected. The mean of DPPH radical scavenging activity (EC 50) of the oils (198.17 +/- 1.95 microg mL(-1)) was low in comparison with that of wood methanol extracts (4.41 +/- 0.12 microg mL(-1)), the value of which was equivalent to that of Trolox (4.67 +/- 0.35 microg mL(-1)), used as antioxidant standard. The mean amount of total phenolics (TP) (710.53 +/- 23.16 mg of GAE/g) and this value calculated as Trolox equivalent antioxidant capacity (TEAC) (899.50 +/- 6.50 mg of TE/g) of the wood methanol extracts confirmed the high antioxidant activity of the species. On the other hand, in the brine shrimp bioassay the values of lethal concentration (LC50) for the oils (21.61 +/- 1.21 microg mL(-1)) and 1-nitro-2-phenylethane (20.37 +/- 0.99 microg mL(-1)) were lower than that of the wood methanol extracts (91.38 +/- 7.20 microg mL(-1)), showing significant biological activities.     

Antimutagenic effect of fruit and vegetable ethanolic extracts against N-nitrosamines evaluated by the Ames test.

The inhibitory effect of nine fruit and vegetable ethanolic extracts against the mutagenicity of N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosodibutylamine (NDBA), and N-nitrosopiperidine (NPIP) was evaluated by means of the Ames test. Licorice ethanolic extract was the only one that showed an inhibitory effect (ranging from moderate to strong) against mutagenicity of all N-nitrosamines tested. This ethanolic extract showed the greatest inhibition effect against NPIP (72%), NDMA (45%), and NPYR (39%). The greatest inhibition effect (51%) of the mutagenicity of NDBA was shown by kiwi ethanolic extract. Vegetable and fruit ethanolic extracts that exhibited an antimutagenic effect (at the range 50-2000 microg/plate), in decreasing order, against NDMA and NPYR were as follows: licorice > kiwi > carrot and licorice > broccoli > pineapple > kiwi, respectively. Decreasing orders against NDBA and NPIP were, respectively, kiwi > onion > licorice = garlic > green pepper > carrot and licorice > garlic > pineapple > carrot.     

Antimutagenic activity of isoflavones from soybean seeds (Glycine max merrill)

Two isoflavones, daidzein (1) and genistein (2), were isolated from soybean hypocotyls. Daidzein and genistein showed a suppressive effect on umu gene expression of the SOS response in Salmonellatyphimurium TA1535/pSK1002 against the mutagen 3-amino-1, 4-dimethyl-5H-pyrido[4,3b]indole (Trp-P-1), which requires liver metabolizing enzymes. Compound 1 suppressed 73% of the SOS-inducing activity at concentrations <0.74 micromol/mL, and the ID(50) value was 0.37 micromol/mL. Compound 2 suppressed 95% of the SOS-inducing activity at concentrations <0.74 micromol/mL, and the ID(50) value was 0.17 micromol/mL. Compounds 1 and 2 were also assayed with the mutagen 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide (furylfuramide) and activated Trp-P-1. In addition to the antimutagenic activities of daidzein and genistein against Trp-P-1, frylfuramide and activated Trp-P-1 were assayed by an Ames test using S. typhimurium TA100.     

Radical scavenging capacity and antimutagenic properties of purified proteins from Solanum betaceum fruits and Solanum tuberosum tubers

In this study, antioxidant activities in free-radical-mediated oxidative systems and the genotoxic/antigenotoxic effects of two proteins with molecular mass around 17 kDa, purified from Solanum betaceum fruits (cyphomine) and Solanum tuberosum tubers (solamarine), were investigated. Both proteins inhibited uric acid formation with IC(50) values between 55 and 60 μg/mL, and both proteins were able to reduce oxidative damage by scavenging hydroxyl radicals and superoxide anion in a dose-dependent manner. Furthermore, the DPPH? reduction assay showed SC(50) values of 55-73 μg/mL. Cyphomine and solamarine were able to retain their antioxidant activity after heat treatment at 80 °C for 15 min. Allium cepa and Salmonella /microsome assays showed no genotoxic and mutagenic effects. Solamarine showed an antimutagenic effect against a direct mutagen (4-nitro-o-phenylenediamine). Consequently, the present study showed that the investigated proteins are promising ingredients for the development of functional foods with a beneficial impact on human health and an important source for the production of bioactive peptides.     

Antimutagenic effect of various honeys and sugars against Trp-p-1

Honey has been used since ancient times as a flavorful sweetener and for its therapeutic and medicinal effects. Consumers' demand for natural, healthy products has driven renewed interest in honey's health benefits. The commonly encountered food mutagen, Trp-p-1, has been demonstrated to be mutagenic in bacteria and carcinogenic in animals. Chemically, honey is quite complex. Honey is comprised primarily of sugars; however, it contains many other potentially biologically active components, such as antioxidants. Sugars have been reported to display both mutagenic and antimutagenic effects in different systems; antioxidants often display antimutagenic activity. Little information exists about potential antimutagenic effects of honey. Antimutagenicity of honeys from seven different floral sources against Trp-p-1 was tested via the Ames assay and compared to that of a sugar analogue and to individually tested simple sugars. All honeys exhibited significant inhibition of Trp-p-1 mutagenicity; most demonstrated a linear correlation between percentage inhibition and log transformed honey concentration from 10 microg/mL to 20 mg/mL. Each displayed significant degrees of inhibition of mutagenicity above concentrations of 1 mg/mL, with individual variations in degree of effectiveness. Buckwheat honey displayed the greatest inhibition at 1 mg/mL, with slightly less effectiveness at higher concentrations. A sugar analogue demonstrated a pattern of inhibition similar to that of the honeys, with enhanced antimutagenicity at concentrations greater than 1 mg/mL. Glucose and fructose were also similar to honeys and were more antimutagenic than maltose and sucrose.     

In vitro activity of the essential oil of Cinnamomum zeylanicum and eugenol in peroxynitrite-induced oxidative processes

The essential oil obtained from the bark of Cinnamomum zeylanicum Blume (Lauraceae) and three of its main components, eugenol, (E)-cinnamaldehyde, and linalool (representing 82.5% of the total composition), were tested in two in vitro models of peroxynitrite-induced nitration and lipid peroxidation. The essential oil and eugenol showed very powerful activities, decreasing 3-nitrotyrosine formation with IC50 values of 18.4 microg/mL and 46.7 microM, respectively (reference compound, ascorbic acid, 71.3 microg/mL and 405.0 microM) and also inhibiting the peroxynitrite-induced lipid peroxidation showing an IC50 of 2.0 microg/mL and 13.1 microM, respectively, against 59.0 microg/mL (235.5 microM) of the reference compound Trolox. On the contrary, (E)-cinnamaldehyde and linalool were completely inactive.     

Suppression of the SOS-inducing activity of mutagenic heterocyclic amine, Trp-P-1, by triterpenoid from Uncaria sinensis in the Salmonella typhimurium TA1535/pSK1002 Umu test

The methanol extract from Uncaria sinensis showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 3-amino-1,4-dimethyl-5H-pyrido[4,3b]indole (Trp-P-1), which requires liver metabolizing enzymes. The methanol extract from U. sinensis was re-extracted with hexane, CH2Cl2, BuOH, and water, respectively. CH2Cl2 extract showed a suppressive effect. A suppressive compound 1 in CH2Cl2 extract was isolated by SiO2 column chromatography. Compound 1 was identified as ursolic acid by IR, electron ionization EI-MS, and NMR spectroscopy. Suppressive effects of ursolic acid (1) and its derivatives, methyl ursolate (1M), acetylursolic acid (1A), and methyl acetylursolate (1MA), were determined in the umu test. These compounds suppressed 61.3, 37.7, 71.5, and 37.8% of the Trp-P-1-induced SOS response at a concentration of 0.4 micromol/mL, respectively. The ID50 values of compounds 1 and 1A were 0.17 and 0.20 micromol/mL. In addition, these compounds were assayed with the activated Trp-P-1. Suppressive effects on activated Trp-P-1 were decreased as compared with those of Trp-P-1.     

Radical scavenging and anti-lipoperoxidative activities of Smallanthus sonchifolius leaf extracts

Radical scavenging and anti-lipoperoxidative effects of two organic fractions and two aqueous extracts from the leaves of a neglected Andean crop-yacon (Smallanthus sonchifolius Poepp. & Endl., Asteraceae) were determined using various in vitro models. The extracts' total phenolic content was 10.7-24.6%. They exhibited DPPH (IC50 16.14-33.39 microg/mL) and HO* scavenging activities (4.49-6.51 mg/mL). The extracts did not scavenge phenylglyoxylic ketyl radicals, but they retarded their formation. In the xanthine/xanthine oxidase superoxide radical generating system, the extracts' activities were 26.10-37.67 superoxide dismutase equivalents/mg. As one of the extracts displayed xanthine oxidase inhibitory activity, the effect of the extracts on a nonenzymatically generated superoxide was determined (IC50 7.36-21.01 microg/mL). The extracts inhibited t-butyl hydroperoxide-induced lipoperoxidation of microsomal and mitochondrial membranes (IC50 22.15-465.3 microg/mL). These results make yacon leaves a good candidate for use as a food supplement in the prevention of chronic diseases involving oxidative stress.