Structure elucidation and complete NMR spectral assignment of two triterpenoid saponins from Radix Hedysari

A new oleanane-type triterpenoid saponin with a carbonyl group at C-15, named polybosaponin A (1), together with a known triterpenoid saponin, dehydrosoyasaponin I (2), were isolated from Radix Hedysari. On the basis of one- and two-dimensional NMR and high resolution electrospray ionization mass spectrometry, the structure of 1 were elucidated and the ¹H and ¹³C NMR spectral signals were assigned totally. In addition, the complete assignment of ¹H NMR signals and revision of incorrect assignment of ¹³C NMR signals for 2 were also achieved based on one- and two-dimensional NMR spectrometry.     

Structure and antioxidant activity of polysaccharide POJ-U1a extracted by ultrasound from Ophiopogon japonicus

An ultrasonic technique was employed to extract polysaccharides from Ophiopogon japonicus. The ultrasonic extracted polysaccharides (POJ-U) were purified, and POJ-U1a (a homogeneous fraction) was obtained. The structural characteristics of POJ-U1a were investigated by infrared spectra, gas chromatography, high performance liquid chromatography, periodate oxidation, Smith degradation, methylation analysis, gas chromatography–mass spectrometry and nuclear magnetic resonance spectroscopy. The results indicated that the relative molecular weight of POJ-U1a was 4.02 × 10³ Da. POJ-U1a was an α-configuration polysaccharide with a highly branched structure, and consisted of pyranoside and funanside. The backbone of POJ-U1a consisted of 1,6-α-d-glucopyranose and 1,3,6-α-d-glucofuranose in the molar ratio of 7:3, while the branched chains were mainly composed of 1,3-α-d-glucopyranose and 1-α-d-glucopyranose in the molar ratio of 1:3. The branched structure of POJ-U1a was proved intuitively by AFM. Significant antioxidant activity of POJ-U1a has been proved as shown by its DPPH radical scavenging, hydrogen radical scavenging and superoxide anion scavenging activities, which indicated that POJ-U1a showed strong antioxidant activity.     

蓝靛果花色苷的分离纯化及抗氧化能力

[目的]比较分析不同纯化方法对蓝靛果花色苷的提取得率及抗氧化能力的影响情况,以筛选出最佳的纯化工艺,为蓝靛果花色苷的深加工与高值化利用提供理论参考依据.[方法]以蓝靛果栽培品种'蓝精灵'的成熟果实为研究对象,采用超声波辅助乙醇提取法制备其提取液后,采用色谱柱层析技术与静态吸附解析法,筛选能适用于其花色苷分离与纯化的固定...     

Chemical constituents from Gmelina arborea bark and their antioxidant activity

Gmelina arborea Roxb. is a fast-growing species and is known to have been used in traditional Indian medicine. Chemical constituents from the bark have not been reported, although some chemical constituents from part of this plant (heartwood, leaf, and root) are known. In this study, the bark meal was successively extracted with acetone and methanol. Fractionation of the acetone extract with n-hexane, diethyl ether, and ethyl acetate and subsequent chromatographic separation of the fractions led to the isolation of four compounds. The diethyl ether-soluble fraction yielded tyrosol [2-(4-hydroxyphenyl)ethanol] (1); (+)-balanophonin (2), an 8-5′ neolignan, with opposite optical rotation to known (−)-balanophonin; and gmelinol (3), a known lignan. The ethyl acetate-soluble fraction afforded a new phenylethanoid glycoside to the best of our knowledge, which was identified as (−)-p-hydroxyphenylethyl[5′″-O-(3,4-dimethoxycinnamoyl)-β-d-apiofuranosyl(1′" → 6′)]-β-d-glucopyranoside (4). From the methanol extract, two known compounds, 2,6-dimethoxy-p-benzoquinone (5) and 3,4,5-trimethoxyphenol (6), were isolated and identified. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay of the identifi ed compounds indicated that 3,4,5-trimethoxyphenol (6) exhibited moderate activity. Part of this report was presented at the 57th and 58th Annual Meetings of the Japan Wood Research Society, Hiroshima and Tsukuba, August 2007 and March 2008, respectively     

美藤果籽粕多酚的提取及其抗氧化活性测定

采用超声波辅助乙醇法提取美藤果籽粕多酚,通过单因素和正交试验法确定了美藤果籽粕多酚的较佳提取条件。结果显示,较佳提取条件为乙醇体积分数80%、料液比1∶10、提取时间40 min和提取次数3次,在此条件下,美藤果籽粕多酚含量为0.623 mg/g。采用DPPH自由基清除活性测定方法评价了美藤果籽粕多酚的抗氧化活性,其清除DPPH自由基的SC50值为159.303μg/m L。     

Extraction, purification and antioxidant activity of polysaccharides from bamboo leaves

Ultrasonic extraction (UE) was employed for the extraction of bamboo leaf polysaccharides (BLP). The influential parameters of UE procedure including extraction time, ultrasonic power and solid/liquid ratio were optimized by orthogonal experiments. DEAE-cellulose col- umn chromatography was applied to purify BLP and then the radical scavenging activity of BLP was also evaluated. Optimal extraction conditions were: extraction time of 15 min, ultrasonic power of 300 W, and solid/liquid ratio of 1:15. Four kinds of polysaccharides were obtained by DEAE-cellulose column chromatography; the maximum superoxide radical scavenging rate (20.4%) of BLP was inferior to that of vitamin C (VC, the control) and the hydroxyl radical scavenging rate (50%) was equivalent to that of VC.     

鸭儿芹精油成分、抗氧化与抑菌活性研究

为给鸭儿芹的综合利用提供科学依据,以鸭儿芹茎、叶为原料,采用水蒸气蒸馏法提取鸭儿芹精油,利用气相色谱-质谱联用技术(GC-MS)对鸭儿芹精油成分进行了分析,利用DPPH、ABTS自由基清除能力试验与FRAP试验及打孔法抑菌试验对其精油的抗氧化抗菌活性进行了分析。结果表明:(1)精油成分方面,从鸭儿芹精油中共分离出32个峰,占总离子峰的93.75%,共鉴定出30种化合物,其主要成分分别为α-芹子烯(42.01%)、β-芹子烯(19.86%)、(Z)-β-金合欢烯(12.76%)、镰叶芹醇(4.16%)、α-没药醇(3.93%)等;(2)抗氧化能力方面,当鸭儿芹精油浓度由19μg/m L上升到38μg/m L时,DPPH反应液中Trolox的当量由0.003μmol上升到0.007μmol,ABTS反应液中Trolox的当量由0.069μmol上升到0.074μmol,FRAP反应液中Trolox的当量由0.225μmol上升到0.280μmol,当精油浓度在一定范围内,其DPPH清除能力、ABTS自由基清除能力及铁离子还原抗氧化能力与其浓度间均呈量效关系,且均呈正相关效应,表明鸭儿芹精油具有良好的抗氧化能力;(3)抗菌活性方面,当鸭儿芹精油浓度为1 280 mg/m L时,金黄色葡萄球菌的抑菌圈直径可达7.05 mm,表现出一定的抑菌活性,且其对金黄色葡萄球菌的抑菌效果显著优于其对大肠杆菌的抑菌效果。     

Screening of antioxidant activity of three Euphorbia species from Turkey

Euphorbia acanthothamnos, E. macroclada and E. rigida were investigated for their antioxidant activity. The antioxidant potential of extracts of E. acanthothamnos, E. macroclada and E. rigida was evaluated using different complementary antioxidant tests.     

黄连木叶的多酚提取和抗氧化研究

以黄连木叶为原料,比较了不同溶剂以及超声和微波辅助对多酚提取率的影响,在单因素实验的基础上采用正交实验对多酚提取工艺参数进行了优化。结果显示最佳提取条件为乙醇50%、超声时间20 min、提取温度70℃、料液比1∶20,多酚得率15.39%。滤液经乙酸乙酯萃取,减压蒸馏,低温干燥成粉末,多酚纯度达到78.96%。用DPPH清除法对提取物的自由基清除作用进行测定,其体外抗氧化活性高于维生素C(Vc),与纯度为98%的茶多酚相当。     

Structural characterization and antioxidant activity of a low-molecular polysaccharide from Dendrobium huoshanense

The present study aimed at investigating the structural features and antioxidant activities of a polysaccharide fraction (DHP1A) obtained from Dendrobium huoshanense, a precious herb medicine in China. DHP1A mainly consisted of mannose (Man), glucose (Glc) and a trace of galactose (Gal), with a molecular weight of 6700 Da. Its backbone contained (1 → 4)-linked α-D-Glcp, (1 → 6)-linked α-D-Glcp and (1 → 4)-linked β-D-Manp, with a branch of terminal β-D-Galp. The in vitro antioxidant evaluation revealed that DHP1A had a remarkable inhibition effect on the FeCl₂-induced lipid peroxidation. Furthermore, DHP1A pretreatment decreased the production of malondialdehyde (MDA), and restored the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), as well as the level of glutathione (GSH) in the livers of CCl₄-treated mice. These results suggested that DHP1A was a potential antioxidant component in D. huoshanense.     

Characterization and antioxidant activity of Amazonian woods

The heartwood and sapwood characteristics of 11 Amazonian trees were investigated. Whereas 7 of the specimens had densities greater than 0.7 g/cm³, the heartwood density of ipê amarelo (Tabebuia serratifolia), maçaranduba (Manilkara huberi), cumaru-ferro (Dipteryx odorata), and guarita (Astronium lecointei) exceeded 1.0 g/cm³. Jatobá contained small amounts of Klason lignin and α-cellulose, and large amounts of holocellulose and alkali extract, suggesting that it has a high polysaccharide content that can be dissolved in an alkaline medium. The difference in the syringyl/guaiacyl (S/G) ratios of the samples before and after alkali extraction suggests that alkali extracts contain syringyl-type polyphenols. In all of the samples, the heart-wood methanol extracts were larger in volume than the sapwood methanol extracts, and the sapwood alkali extracts were larger in volume than the heartwood alkali extracts. The antioxidant activities of the methanol and alkali extracts were assayed by measuring the levels of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and super oxide dismutase (SOD)-like activity, respectively. The heart-wood methanol extract of jatobá (Hymenaea courbaril) exhibited the highest level of activity (EC₅₀ = 44 mg/l), which exceeded that of α-tocopherol (EC₅₀ = 48 mg/l), and the heartwood alkali extracts of jatobá and ipê amarelo had high SOD-like activity comparable with red wine.     

Essential oil composition and antioxidant activity of aerial parts of Grindelia robusta from Central Italy

The chemical composition of the essential oil obtained from Grindelia robusta aerial parts from central Italy was analyzed by GC and GC/MS and 45 components were identified. Borneol (15.2%), alpha pinene (10.3%), trans-pinocarveol (7.0%), bornyl acetate (4.5%), limonene (4.3%) were the main components. The antioxidant activity of the essential oil was evaluated using the DPPH and 5-lipoxygenase tests.     

Monitoring the antioxidant activity of extracts originated from various Serratula species and isolation of flavonoids from Serratula coronata

The antioxidant effect of aqueous methanolic herb extracts of Serratula coronata, S. wolffii and S. tinctoria was investigated using both enzyme-dependent and enzyme-independent systems. The extracts displayed concentration-dependent inhibition of lipid peroxidation. Flavonoids and ecdysteroids present in the extracts were evaluated as antioxidant components. The flavonoid-containing fraction of the herb extract of S. coronata was more effective in lipid peroxidation than the ecdysteroid-containing fraction. This paper also reports the isolation of quercetin 3-O-methyl ether, apigenin, luteolin, quercetin, luteolin 4'beta-D-glucoside and quercetin 4'beta-D-glucoside from S. coronata.     

竹醋液与茶多酚协同抗氧化性能研究

通过研究竹醋液与茶多酚复配后的协同抗氧化效果,考察了两种复配液(竹醋液与茶多酚的体积比分别为10∶1和5∶1)对DPPH、超氧阳离子O2·-和羟基自由基·OH的清除能力.结果显示:竹醋液与茶多酚复配液的抗氧化能力优于单独竹醋液或单独茶多酚,即复合抗氧化剂具有协同清除自由基的作用.可见,竹醋液与茶多酚复配后,产生了协同效应,复配液抗氧化能力不仅与复配物本身性质有关,并且与复配物的比例有关.     

Flavonoids of Helichrysum compactum and their antioxidant and antibacterial activity

From the capitula of Helichrysum compactum, the flavonoids apigenin, kaempferol, luteolin, naringenin, 3,5-dihydroxy-6,7,8-trimethoxyflavone, kaempferol-3-O-glucoside, luteolin-7-O-glucoside and luteolin-4',7-di-O-glucoside and from the leafy stems apigenin, kaempferol, luteolin, quercetin, apigenin-7-O-glucoside, luteolin-7-O-glucoside, and quercetin-3-O-glucoside were isolated. Extracts of the capitula of H. compactum show antioxidant activity by inhibition of lipid peroxidation and also show antibacterial activity.     

响应面法优化罗汉松总二萜提取及抗氧化研究

采用响应面法优化罗汉松总二萜的提取工艺。在单因素试验基础上,采用Box-Behnken中心组合法设计多因素试验,研究提取温度、甲醇浓度、液料比对罗汉松总二萜得率的影响,建立试验工艺参数与提取量之间的数学模型,确立最佳提取工艺。结果表明:罗汉松总二萜的最佳提取工艺参数为:甲醇浓度80.00%、提取温度63.00℃、液料比26∶1(mL/g),此时罗汉松总二萜得率为1.13%。抗氧化活性试验表明,罗汉松总二萜对DPPH自由基、羟自由基、超氧阴离子具有不同的清除能力,最大清除率分别达到了81.71%、66.27%、38.60%。本研究为罗汉松中二萜类物质的研究和开发利用提供参考。     

In vitro antioxidant and antibacterial activity of Rhaphidophora pertusa stem

Methanol extract of Rhaphidophora pertusa stem was analyzed for its antioxidant (DPPH, reducing power and Fe(3+) metal chelation methods) and antibacterial activities. The extract was found effective against the three antioxidant test models and exhibited strong and moderate antibacterial activity against the tested pathogenic bacteria.     

Screening of Costus speciosus extracts for antioxidant activity

Different parts of Costus speciosus were investigated for their polyphenol content and antioxidant activity.     

Radical scavenging, antioxidant and cytotoxic activity of Brazilian Caatinga plants

Extracts of 32 plants from the Brazilian northeastern semi-arid region called Caatinga were evaluated through DPPH radical scavenging assay, beta-carotene bleaching, and brine shrimp lethality tests (BST). Among the extracts studied Byrsonima cf. gardneriana, Mascagnia coriacea, Cordia globosa, Diodia apiculata and Hypenia salzmannii showed the highest activities in DPPH radical scavenging test. In the beta-carotene bleaching test the highest activities were observed for Passiflora cincinnata, Chamaecrista repens, B. cf. gardneriana, Rollinia leptopetala, Serjania glabrata, Diospyros gaultheriifolia, C. globosa, Mimosa ophtalmocentra, M. coriacea and Lippia cf. microphylla. In contrast, R. leptopetala, Zornia cf. brasiliensis and Leonotis nepetifolia were the most active species in the BST.     

Exploitation of polyphenol-rich pine barks for potent antioxidant activity

The phenolic composition of pine bark from a variety of Pinus species was estimated by measuring Klason lignin, acid-soluble lignin, and a 1% NaOH extract. Polyphenol contents of hot water extracts from pine bark were determined by the Folin-Ciocalteu assay and the vanillin-H₂SO₄ assay. Among the pine bark varieties investigated, Pinus radiata bark showed the highest polyphenol content and potent antioxidant activity. Pinus rigida bark was also a usable polyphenol-rich source, whereas Pinus densiflora bark had a low yield (5.1%) of hot water extract, although it showed potent antioxidant activity. Correlations between proanthocyanidin content in pine bark and antioxidant activity were observed. The results suggested that proanthocyanidin was the crucial contributor to potent antioxidant activity in pine bark. The publication of this article was made possible by an Emachu Research Fund. The authors are grateful for the fund.