Antimutagenic activity of 8-hydroxyisoflavones and 6-hydroxydaidzein from soybean miso

The antimutagenic activity of four isoflavones isolated from soybean miso toward three kinds of mutagens, AF-2, MNNG, and Trp-P-1, was evaluated by the Ames test. 8-Hydroxyisoflavones had greater suppressive potency than that of daidzein, and 6-hydroxydaidzein had almost the same activity as daidzein. These results indicated the number of hydroxy and methoxy groups and the position of these functional groups were important for antimutagenic activity.     

DPPH radical-scavenging compounds from dou-chi, a soybean fermented food

Dou-chi, a traditional soybean food fermented with Aspergillus sp., is usually used as a seasoning in Chinese food, and has also been used as a folk medicine in China and Taiwan. As 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavengers, four phenol compounds, one isoflavanone, eight isoflavones and one 4-pyrone have been isolated from dou-chi. Among these fourteen compounds, 3'-hydroxydaidzein, dihydrodaidzein and a 4-pyrone compound have not yet been isolated from soybean miso. The structure of the novel 4-pyrone compound, 3-((E)-2-carboxyethenyl)-5-(4-hydroxyphenyl)-4-pyrone-2-carboxylic acid was elucidated by using the same compound as that obtained from the biotransformation of daidzein. 3'-Hydroxydaidzein showed as high DPPH radical-scavenging activity as that of alpha-tocopherol, and 6-hydroxydaidzein had mushroom tyrosinase inhibitory activity with an IC(50) value of 10 muM. The order of estrogenic activity is as follows: genistein > daidzein > 3'-hydroxydaidzein > 8-hydroxygenistein, using a green fluorescent protein expression system. Furthermore, the contents of isoflavones in the fermentation process of dou-chi were measured.     

Antioxidative compounds from Crotalaria sessiliflora

Seven antioxidative compounds were isolated from the EtOAc extract of the aerial part of C. sessiliflora (Japanese name, tanukimame) by activity-guided fractionation with 2,2-diphenyl-1-picrylhydrazyl (DPPH). Among the isolated compounds, hydroxyeucomic acid showed the strongest free radical-scavenging activity, which was almost identical to that of epigallocatechin gallate, against DPPH. Orientin and isoorientin showed strong anti-peroxidative activities toward linoleic acid and protective effects against the bactericidal action of the tert-butyl peroxyl radical. Their activities were nearly equal to that of epigallocatechin gallate.     

Isolation of 8-hydroxyglycitein and 6-hydroxydaidzein from soybean miso

We isolated from soybean miso 8-hydroxyglycitein and 6-hydroxydaidzein as DPPH-radical scavengers, and elucidated their chemical structures by mass spectrometric, and (1)H- and (13)C-NMR spectrosopic analyses. These compounds showed DPPH-radical scavenging activity as high as that of alpha-tocopherol, 8-hydroxygenistein and 8-hydroxydaidzein. This is the first report of the isolation of 8-hydroxyglycitein from a natural source.     

Antioxidative polyphenols from berries of Pimenta dioica

The ethyl acetate-soluble part of allspice, berries of Pimenta dicica, showed strong antioxidant activity and radical-scavenging activity against 1,1diphenyl-2-picrylhydrazl (DPPH) radical. From the ethyl acetate-soluble part, two new compounds, 5-galloyloxy-3-4-dihydroxypentanoic acid and 5-(5-carboxmethyl-2-oxocyclopenty)3Z-penteny 6-O-galloy-beta-D-glucoside were isolated together with 11 known polyphenols by repeated column chromatography. Their structures were elucidated on the basis of MS and various NMR spectroscopic data. All isolated compounds were evaluated for antioxidative effects on oxidation of methyl linoleate under aeration and heating, anf on peroxidation of liposome induced by 2-2'-azobis-(2-amidinopropane)dihydrocloride (AAPH) as water-soluble initiator along with their radical-scavenging activity against DPPH. Quercetin and its glycoside showed remarkable activity for scavenging DPPH radical and inhibiting peroxidation of liposome. Two new compounds also exhibited strong DPPH radical-scavenging activity and inhibitory effect on the peroxidation od liposome as myricetin.     

Phenolic compounds from the rhizomes of Dioscorea bulbifera

One new bibenzyl, 7, and one new diarylheptanone, diobulbinone A (18), together with sixteen known compounds, 1-6 and 8-17, have been isolated form the rhizomes of Dioscorea bulbifera. Their structures were elucidated by NMR and MS analyses. Compound 7 showed high antioxidant capacity in FRAP assay and DPPH radical-scavenging activity.     

Study on the inhibitory effects of Korean medicinal plants and their main compounds on the 1,1-diphenyl-2-picrylhydrazyl radical

A 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-generating system was used to evaluate the antioxidant properties of Korean medicinal plants that have been used widely as folk medicines for several disorders, as well as compounds isolated from them. Among the Rosaceae, Rosa rugosa and Rosa davurica showed strong DPPH radical-scavenging activity. The most effective medicinal plant from families other than Rosaceae was Cedrela sinensis, followed in order by Nelumbo nucifera, Eucommia ulmoides, Zanthoxylum piperitum, Cudrania tricuspidata and Houttuynia cordata. These results serve as a good index of the free radical-scavenging activities of Korean medicinal plants. Furthermore, the polyphenols isolated from these plants, procyanidin B-3, (+)-catechin, gallic acid, methyl gallate, quercetin, quercetin-3-O-beta-D-glucoside, quercetin-3-O-beta-galactoside, quercetin-3-O-rutinose and kaempferol, exerted strong DPPH radical-scavenging activity. These results suggest that the Korean medicinal plants and the polyphenols isolated from them that exhibited effective radical-scavenging activity may be promising agents for scavenging free radicals and treating diseases associated with excess free radicals.     

New phenolic constituents from Balanophora polyandra with radical-scavenging activity

The 80% acetone extract of Balanophora polyandra Griff. (Balanophoraceae) was found to exhibit high radical-scavenging activity (SC(50)=14.48 mug/ml) towards 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Further chemical investigation led the isolation of two new hydrolysable tannins, balapolyphorins A (1) and B (2), together with 20 known phenolic compounds (3-22). Their structures were established by detailed spectroscopic analysis, and the radical-scavenging properties of all isolated compounds were determined by DPPH assay.     

Isolation and Structure of a Novel Indophenol-reducing and 1,1-Diphenyl-2-picrylhydrazyl Radical-scavenging Compound from a Fungus

A novel indophenol-reducing and DPPH radical-scavenging compound (1) was isolated from a fungal metabolite. The structure of 1 was determined by a spectroscopic analysis, and the absolute configuration of 1 was determined by the modified Mosher’s method. Compound 1 showed slow-reacting DPPH radical-scavenging activity (ED₅₀ value of 298 μM after 96 hr).     

Isolation, structure elucidation, and antioxidant evaluation of cydonioside A, an unusual terpenoid from the fruits of Cydonia vulgaris

A novel terpenoid, cydonioside A (1), was isolated from the fruits of Cydonia vulgaris Pers. Its structure and relative configuration were elucidated on the basis of in-depth spectroscopic analyses, including 2D-NMR experiments as well as MM+ calculations. Compound 1 was assayed for its radical-scavenging activity towards the DPPH radical and the superoxide radical anion (O2*-), as well as for its overall antioxidant activity, as assessed by the formation of a phosphomolybdenum complex.     

Antioxidant phenolic compounds from the stems of Entada phaseoloides

The EtOH extract of the stems of Entada phaseoloides displayed potent antioxidant activity when assessed by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging, reducing power, β-carotene-bleaching, and superoxide radical-scavenging analyses. Fractionation of the EtOH extracts showed that the AcOEt fraction is the most active, followed by the H(2) O fraction, while BuOH fraction was least active. Further activity-guided fractionation studies on the active fractions resulted in the isolation of 22 compounds. The identities of these compounds were established based on extensive spectroscopic studies. Furthermore, the antioxidant activities of the isolated compounds were evaluated by using the above-mentioned five assays. The results demonstrated that the EtOH extract of E. phaseoloides stems exhibits an excellent antioxidant activity and thus presents a great potential as a source of natural antioxidants.     

A novel oxidative dimer from protocatechuic esters: contribution to the total radical scavenging ability of protocatechuic esters

A novel oxidative dimer was isolated as a major product from a reaction mixture of methyl protocatechuate and DPPH radical in methanol. Its unusual benzobicyclo[3.2.1]octane structure was elucidated by extensive spectral analysis. This result suggests that the regeneration of catechol structures by the nucleophilic addition of an alcohol molecule on o-quinones and subsequent dimerization is one of the key reactions in the high radical-scavenging activity of protocatechuic esters in an alcoholic solvent.     

Antioxidative activity of anthocyanins from purple sweet potato, Ipomoera batatas cultivar Ayamurasaki

We evaluated the antioxidative activity of anthocyanins from an extract of the tuber of purple sweet potato (PSP) (Ipomoea batatas cultivar Ayamurasaki). Anthocyanins from PSP showed stronger 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity than anthocyanins from red cabbage, grape skin, elderberry, or purple corn, and eight major components of the anthocyanins from PSP showed higher levels of activity than ascorbic acid. In PSP anthocyanin-injected rats and PSP beverage-administered volunteers, DPPH radical-scavenging activity in the urine increased. The elevation of plasma transaminase activities induced by carbon tetrachloride was depressed in rats administered PSP anthocyanin solution. Two components, cyanidin 3-O-(2-O-(6-O-(E)-caffeoyl-beta-D-glucopyranocyl)-beta-D-glucopyranoide)-5-O-beta-D-glucopyranoside and peonidin 3-O-(2-O-(6-O-(E)-caffeoyl-beta-D-glucopyranocyl)-beta-D-glucopyranoide)-5-O-beta-D-glucopyranoside, which were detected in the plasma, protected low density lipoprotein from oxidation at a physiological concentration. These results indicate that PSP anthocyanins have antioxidative activity in vivo as well as in vitro.     

New potent antioxidative hydroxyflavanones produced with Aspergillus saitoi from flavanone glycoside in citrus fruit

Potent antioxidative hydroxyflavanones were produced with Aspergillus saitoi from hesperidin or naringin, which are flavanone glycosides in citrus fruit with weak antioxidative activity. The hydroxyflavanone produced from hesperidin was identified as 8-hydroxyhesperetin (8-HHE), a novel substance, and those from naringin were identified as carthamidin (6-hydroxynaringenin) and isocarthamidin (8-hydroxynaringenin) by FAB-MS, 1H-NMR and 13C-NMR analyses. The antioxidative activity of these hydroxyflavanones was examined by using the free radical-scavenging system of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the methyl linoleate oxidation system. The hydroxyflavanones (8-HHE, carthamidin, and isocarthamidin) exhibited stronger activity than the flavanone glycosides (hesperidin or naringin) and their aglycones (hesperetin or naringenin). The activity of 8-HHE and isocarthamidin was comparable to that of alpha-tocopherol, and that of carthamidin was weaker than that of isocarthamidin. The hydroxyflavanones, which were hydroxylated on A ring of flavanone by Aspergillus saitoi, were obtained as potent antioxidants.     

Phenolic antioxidants from the whole plant of Phyllanthus urinaria

The 1,1-diphenyl-2-picrydydrazyl (DPPH) assay on the extract of Phyllanthus urinaria L. (Euphorbiaceae) displayed considerable radical-scavenging activity (SC50 = 14.3 microg/ml). Further bioassay-guided purification of the extract led to the isolation of a series of 15 phenolic compounds, including the ellagitannins 1-7, the flavonoids 8-10, and the simple hydroxylated (or glycosylated) aromatic acids 11-15. Their structures were identified by spectroscopic analyses and comparison with authentic samples or literature data. The structure of repandinin B (1) was for the first time fully assigned by 1D- and 2D-NMR experiments. The phenolic compounds 1, 3, 4, 6, 9, 11, and 15 have not been isolated before from the title plant. The antioxidant activities and mushroom-tyrosinase-inhibitory activities of all compounds were determined by DPPH-radical-scavenging and mushroom-tyrosinase-inhibitory assays (Table 2).     

Vialinin A, a novel 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenger from an edible mushroom in China

While screening for bioactive compounds from edible mushrooms, a new potent antioxidant, vialinin A (1), together with a known compound, ganbajunin B (2), and a mixture of ganbajunins D (3) and E (4), were isolated from the dry fruiting bodies of Thelephora vialis. The structure of 1, 5',6'-bis(phenylacetoxy)-1,1':4',1'-terphenyl-2',3',4,4'-tetraol, was elucidated by spectroscopic and chemical methods. This compound had strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging activity with an EC(50) value of 14.0 microM, nearly equal to that of butylated hydroxytoluene (BHT; EC(50) = 10.0 microM). A radical scavenging experiment using 1 and DPPH radicals indicated that 1 donated two hydrogen atoms to two molecules of the DPPH radical under hydrophobic conditions.     

川芎粗多糖抗氧化和细胞毒活性研究

通过川芎粗多糖(LCP)对DPPH离子、超氧阴离子、.OH、总抗氧化能力、螯合能力、还原性和脂质过氧化能力的抗氧化效果和对肝癌细胞HepG2的抑制作用研究。结果显示:LCP具有较强的还原力,对超氧阴离子自由基、脂质过氧化产物有良好的抑制作用,其对肝癌细胞HepG2也具有一定的抑制作用。LCP有望作为天然抗氧化剂及功能性食品得到开发与应用。     

Anti-oxidative and anti-inflammatory activities of two different species of a Chinese herb I-Tiao-Gung

The anti-oxidative and anti-inflammatory activities of two different species of traditional Chinese medicines that shared the same name have been studied. The extracts of Glycine radix have higher activities in free radical-scavenging activity determined with DPPH, reduction in hemoglobin-catalyzed lipid auto-oxidation and inhibition of the lipoxygenase (LOX) and cyclooxygenase (COX)-catalyzed arachidonate oxidation compared to the activities of extract of Flemingia. One of the significant bioactive constituents of Glycine radix has been isolated and identified as daidzein.     

4种地衣提取物抗氧化和抗肿瘤活性研究

本研究初步评估了4种药用地衣(太白茶、金刷把、黑石耳、红石耳)不同溶剂提取物的抗氧化活性及其粗多糖的抗肿瘤活性。通过测定清除DPPH自由基、羟基自由基和还原能力,对4种地衣不同溶剂提取物进行体外抗氧化活性评价,结果表明,金刷把和黑石耳的甲醇提取相清除DPPH自由基能力高于其它溶剂提取相,其IC50值(半抑制浓度)分别为0.7847 mg/mL和0.5595 mg/mL;黑石耳甲醇提取相(IC50=0.5747 mg/mL)清除羟基自由基能力优于阳性对照物Vc(IC50=0.6126 mg/mL);黑石耳氯仿提取相、金刷把乙酸乙酯提取相和太白茶甲醇提取相清除羟基自由基能力与Vc相当;4种地衣甲醇提取相还原能力均较强,且与其浓度呈较好的量效关系。利用MTT法分析4种地衣多糖对HeLa、A375和Hep G2细胞体外生长增殖的抑制作用,结果显示黑石耳粗多糖对Hep G2细胞的抑制作用较为突出(IC50=0.2567 mg/mL),而金刷把抑制HeLa细胞的生长增殖作用最强,其IC50值为0.4332 mg/mL。     

对黄豆苷原具转化作用的耐氧突变株Aeroto-AUH-JLC140未知代谢产物分离、鉴定及抗氧化活性测定

【目的】与原出发菌株AUH-JLC140相比,耐氧突变株Aeroto-AUH-JLC140在其生长过程中产生一种未知物质,且该未知物质的产生与添加底物黄豆苷原无关。对该未知物质进行分离纯化和结构鉴定,并测定其产生动态及抗氧化活性。【方法】利用高效液相色谱对未知物质进行分离,经紫外吸收图谱、质谱、核磁共振氢谱和碳谱等分析,对未知物质进行结构鉴定;通过1,1-二苯基-2-苦味酰基自由基(DPPH)清除试验测定其抗氧化活性。【结果】Aeroto-AUH-JLC140产生的未知物质被鉴定为吲哚,接种后15 h菌株产吲哚最高,所产吲哚量为19.89 mg/L。浓度为0.2 mmol/L(即23.40 mg/L)的吲哚除对DPPH自由基具有明显清除作用外,还能有效降低脑心浸液(BHI)液体培养基的氧化-还原电位。【结论】耐氧突变株Aeroto-AUH-JLC140产生的未知代谢产物为吲哚,菌株通过产生吲哚降低培养基氧化-还原电位,进而为该菌株的生长提供适宜的低氧微环境。