X-ray crystal structure and antioxidant activity of salidroside, a phenylethanoid glycoside

The X-ray single-crystal structure of natural salidroside (=2-(4-hydroxyphenyl)ethyl beta-D-glucopyranoside; 1), isolated from Cistanche deserticola, is reported for the first time, as well as its absolute configuration. The radical-scavenging activity of 1 towards the superoxide radical anion (O*2-) was determined experimentally by chemiluminescence measurements of the pyrogallol-luminol system, and compared to that of the corresponding aglycone, i.e., tyrosol (=4-(2-hydroxyethyl)phenol; 2).     

A new cytotoxic, apoptosis-inducing triterpenoid from the rhizomes of Astilbe chinensis

A new ursane-based compound, astilbotriterpenic acid (1), was isolated from the rhizomes of Astilbe chinensis. Its structure was determined on the basis of chemical evidence and extensive spectroscopic methods, including 1D- and 2D-NMR. The pentacyclic triterpenoid 1 was assayed for its in vitro cytotoxicity against Bcap37, HeLa, HepG2, HO-8910, K562, PAA, SGC7901, and P388 cancer cells, as well as for its apoptosis-inducing activity in HeLa cells. Compound 1 was found to strongly inhibit tumor-cell growth through induction of apoptosis and may, thus, be further evaluated as a novel chemotherapeutic agent.     

Synthesis and antioxidant activities of novel 4-Schiff base-7-benzyloxy-coumarin derivatives

4-Schiff base-7-benzyloxy-coumarins 5a(1)-5h(2) and its derivative 6 were designed and synthesized based on the 7-benzyloxy-coumarin structure as novel antioxidants. The in vitro antioxidant activities screening revealed that 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of compounds 5b(1), 5d(1), 5f(1), 5f(2), 5g(1) and 5g(2), and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonate) cation (ABTS(+)) radical scavenging activities of compounds 5a(1), 5b(1), 5c(1), 5c(2), 5d(1), 5e(1), 5e(2), 5f(2), 5g(1), 5g(2) and 5h(1) were better than that of the commercial antioxidant butylated hydroxytoluene (BHT), while the superoxide anion radical scavenging activities of 5a(2) and 5g(2) were stronger than that of the commercial antioxidant butylated hydroxyanisole (BHA), and the hydroxyl radical scavenging activity of 5e(1) was much better than that of the common antioxidant ascorbic acid.     

Synthesis,antielastase, antioxidant and radical scavenging activities of 4-(aza substituted) methylene substituted dihydroxy coumarines

A series of some 4-(aza substituted) methylene substituted dihydroxy coumarines were evaluated for their antioxidant and antielastase activities. Different in vitro methodologies such as total reducing power, 1,1-diphenyl-2-picryl-hydrazil (DPPH·) free radical scavenging, ABTS radical scavenging activity were used as antioxidant activity. All the tested compounds exhibited potent free radical scavenging ability and antielastase activites.     

Chemical Composition and Biological Activities of the Essential Oil of Athanasia brownii Hochr. (Asteraceae) Endemic to Madagascar

The essential oil obtained from hydrodistillation of flowering aerial parts of Athanasia brownii (Asteraceae) was studied for its chemical composition by GC/FID and GC/MS, and for biological activity, namely, antioxidant, antimicrobial, and chemopreventive potential, by DPPH (=2,2‐diphenyl‐1‐picrylhydrazyl), ABTS (=2,2′‐azinobis[3‐ethylbenzothioline‐6‐sulfonic acid), and FRAP (=ferric reducing antioxidant power), disk diffusion test, and MTT (=3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay, respectively. The oil was characterized by a high content of oxygenated sesquiterpenes (71.2%), with selin‐11‐en‐4α‐ol (24.6%), caryophyllene oxide (8.7%), humulene epoxide II (5.1%), and (E)‐nerolidol (4.9%) as the predominant compounds. The oil showed a moderate activity against streptococci as well as radical‐scavenging potential, while the inhibitory effects against human cancer cells examined such as A375 (malignant melanoma) and HCT 116 (colon carcinoma) were significant, with IC₅₀ values of 19.85 and 29.53 μg/ml, respectively.     

Antioxidant and cytotoxic activities of xanthones from Cudrania tricuspidata

The new catecholic xanthone, 1,3,7-trihydroxy-4-(1,1-dimethyl-2-propenyl)-5,6-(2,2-dimethylchromeno)-xanthone (1), was isolated from the root bark of Cudrania tricuspidata together with seven known xanthones. The structures were fully characterized by analysis of physical and spectral (UV, IR, mass, and NMR) data. Relationships between the structural characteristics of xanthones and their antioxidant activities (DPPH, superoxide, and hydroxyl radical) were studied. Among the range of catecholic xanthones, 6,7-dihydroxyl xanthones (3–8) exhibited a strong scavenging effect on the DPPH radical. When one of the catecholic hydroxyl groups was protected as in compounds 1 and 2, DPPH radical scavenging activity was markedly decreased (IC₅₀ > 200 μM). DPPH activities were consistent with electrochemical response by cyclic voltammetry. Interestingly, compounds (1, 2) which had the weak activities on DPPH, exhibited both potent superoxide and hydroxyl radical scavenging activities. The strong activity on the hydroxyl radical of compounds (1, 2) could be rationalized by their chelating effect with iron (Fe²⁺) due to a redshift of its complex. The catecholic xanthones (3–8), being able to convert quinone methide intermediate, showed potent cytotoxicities against human cancer cell lines (HT-29, HL-60, SK-OV3, AGS, and A549). In particular, compounds 3, 6, and 7 had strong cytotoxic activities against AGS (LD₅₀ < 5 μM). DNA fragmentation patterns induced by catecholic xanthones revealed that tumor cell death was due to apoptosis.     

Acylated quercetagetin glycosides with antioxidant activity from Tagetes maxima

The fractionation of a methanolic extract of Tagetes maxima guided for antioxidant activity resulted in the isolation of three acylated quercetagetin glycosides, quercetagetin-7-O-(6-O-caffeoyl-beta-D-glucopyranoside), quercetagetin-7-O-(6-O-p-coumaroyl-beta-D-glucopyranoside) and quercetagetin-7-O-(6-O-galloyl-beta-D-glucopyranoside), as well as four known flavonoid glycosides. The structural elucidation was accomplished by spectroscopic methods (ESI-MS/MS and NMR). The antioxidant activity of fractions and isolated compounds was determined by checking the scavenging activity against three different radicals: 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH*), hydroxyl (*OH), and superoxide (O2*-). The three isolated compounds exhibited a high radical scavenging activity in comparison with reference compounds.     

斑点嗜蓝孢孔菌化学成分、生物活性及水提物荧光猝灭研究

对斑点嗜蓝孢孔菌乙醇提取物进行分级萃取,利用柱层析技术得到6个单体化合物。经核磁数据比对为β-谷甾醇(1)、麦角甾醇(2)、麦角甾-7,22-二烯-3β-醇(3)、5,8-过氧麦角甾-6,22-二烯-3β-醇(4)、3-乙酰齐墩果酸(5)、白桦脂醇(6)。采用Alamar Blue法检测各有机相及单体化合物对NCI-H460人非小细胞肺癌细胞增殖的影响,用DPPH自由基清除法检测其抗氧化活性。利用荧光光谱及紫外-可见光光谱研究方法在模拟人体生理条件下,研究了斑点嗜蓝孢孔菌水提物与人纤维蛋白原的相互作用,实     

Diethanolamine Pd(II) complexes in bioorganic modeling as model systems of metallopeptidases and soybean lipoxygenase inhibitors

The reaction of PdCl₂ with diethanolammonium chloride (DEAxHCl), in the molar ratio 1:2, affords the [HDEA]₂[PdCl₄] complex (1). The hydrolytic activity of the novel Pd(II) complex 1 was tested in reaction with N-acetylated L-histidylglycine dipeptide (AcHis-Gly). Complex 1, as well as earlier prepared trans-[PdCl₂(DEA)₂] complex (2), and DEA, as their precursor, were tested for their in vitro free radical scavenging activity. UV absorbance-based enzyme assays were done in order to evaluate their inhibitory activity of soybean lipoxygenase (LOX). Also, assays with superoxide anion radical were done. The scavenging activities of the complexes were measured and compared with those of their precursors and caffeic acid. Complex 2 exhibits the highest antioxidant activity and the highest inhibitory effect against the soybean LOX.     

乌鳖黑色素理化性质及其抗氧化活性研究

本试验以乌鳖肌肉为原料,采用"脱脂-酶解-酸解"三步法制备乌鳖黑色素,研究其结构特性、理化性质和抗氧化活性.采用紫外分光光度计、傅里叶红外光谱仪和元素分析仪对乌鳖肌肉黑色素结构特性进行分析,并进行了颜色检测、溶解性试验、稳定性试验、总抗氧化能力试验、羟基自由基清除能力试验、DPPH自由基清除能力试验、超氧阴离子自由基清...     

Organochalcogen compounds from glycerol: Synthesis of new antioxidants

We describe here a simple method for the synthesis of glycerol derivatives containing an organochalcogen unit (Se, Te and S) using NaBH₄ and PEG-400 as a solvent. The new methodology was used to synthesize a range of new organochalcogen compounds in good yields. Furthermore, four of synthesized compounds were evaluated for their antioxidant activity using different assays, such as 2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, nitric oxide (NO) and hydroxyl radical (OH) scavenging, ferric ion reducing antioxidant power (FRAP), ferrous ion chelating, superoxide dismutase-like activity and inhibition of linoleic acid lipid peroxidation. The new organotellurium 2,2-dimethyl-4-(phenyltellanylmethyl)-1,3-dioxolane 3j showed antioxidant activity and was more effective in inhibition of induced lipid peroxidation compared to solketal 4. Selenium and sulfur analogs 3a and 3m and solketal 4 did not present antioxidant effect. These findings suggest that 2,2-dimethyl-4-(phenyltellanylmethyl)-1,3-dioxolane 3j is a promising antioxidant and that its activity is influenced by the presence of the tellurium atom on the structure.     

基于ORAC评价多酚类化合物抗氧化活性

采用氧自由基清除能力(ORAC)方法考察20种多酚类化合物的抗氧化活性。结果表明,该方法具有较优的线性关系(R2=0.997）;检测限(LOD）和定量限(LOQ）为0.5～3.1 μmol·L-1,精密度＜18%,准确度91%～105%。比较20种多酚类化合物抗氧化活性,对羟基苯甲酸类化合物中,鞣花酸和没食子酸具有较强的抗氧化活性;对羟基肉桂酸类以咖啡酸及其衍生物抗氧化活性最高;在类黄酮组分中,黄烷-3-醇表现出优良的抗氧化特性,黄酮醇次之。ORAC可作为评价多酚类化合物抗氧化的简便、高效的标准化检测方法。     

Naphthalene Derivatives and Quinones from Ventilago denticulata and Their Nitric Oxide Radical Scavenging,Antioxidant, Cytotoxic,Antibacterial, and Phosphodiesterase Inhibitory Activities

New naphthalene derivatives ( 1 and 2 ) and a new isomer ( 3 ) of ventilagolin, together with known anthraquinones, chrysophanol ( 4 ), physcion or emodin 3‐methyl ether ( 5 ), and emodin ( 6 ), were isolated from vines of Ventilago denticulata. The isolated compounds exhibited cytotoxic activity with IC₅₀ values of 1.15 – 40.54 μg/ml. Compounds 1 – 3 selectively exhibited weak antibacterial activity (MIC values of 200.0 – 400.0 μg/ml), while emodin ( 6 ) displayed moderate antibacterial activity with MIC value of 25.0 μg/ml. The isolated compounds showed nitric oxide and DPPH radical scavenging activities. Compounds 1 – 3 and 6 exhibited weak xanthine oxidase inhibitory activity, while emodin ( 6 ) acted as an aromatase inhibitor with the IC₅₀ value of 10.1 μm . Compounds 1 and 2 exhibited phosphodiesterase 5 inhibitory activity with IC₅₀ values of 8.28 μm and 6.48 μm , respectively.     

Synthesis and Antioxidant Capacity of Some Derivatives of Sesamol at the C-6 Position

Several synthetic approaches (aminomethylation, alkylation, condensation, etc.) have been used to synthesize derivatives based on the sesamol ( 1 ), natural phenol. The set of methods, including the study of antioxidant activity (AOA) by the ability to inhibit the initiated oxidation of animal lipids, radical scavenging activity, Fe²⁺-chelation ability, as well as a comparative assessment of membrane-protective activity under the conditions of H₂O₂-induced hemolysis of mice red blood cells (RBCs), was used to analyze the antioxidant potential of the synthesized compounds. The synthesized derivatives have demonstrated different activity in the listed test systems, and we have identified compounds which appear to be most promising for a detailed study of their pharmacological properties.     

Identification of structure and antioxidant activity of a fraction of polysaccharide purified from Dioscorea nipponica Makino

A large number of polysaccharides are present in boiling-water extraction of Dioscorea nipponica Makino. A DEAE-Sepharose CL-6B column chromatography was used to isolate the major polysaccharides from D. nipponica Makino. The largest amount of fraction of polysaccharide was subjected to further purification by gel-filtration on Sephadex G-100. The purified fraction was a neutral polysaccharide and a single peak in HPLC with Sugar KS-804 column, with a molecular weight of 38,000, and comprised mainly of glucose and fructose (45:1). Analysis by Periodate oxidation–Smith degradation indicated that there were 5.9%(1→)-glycosidic linkages, 4.94% (1 → 2)-glycosidic linkages, 61.16% (1 → 4)-glycosidic linkages, and 28% (1 → 3)-glycosidic linkages. On the basis of superoxide radical assay, hydroxyl radical assay, and self-oxidation of 1,2,3-phentriol assay, its antioxidant activity was investigated. This purified fraction of polysaccharide exhibited equivalent inhibiting power for self-oxidation of 1,2,3-phentriol to Vc, a little higher scavenging activity of superoxide radical and hydroxyl radical than Vc, and should be explored as a novel potential antioxidant.     

Hydroxytyrosol lipophilic analogues: enzymatic synthesis, radical scavenging activity and DNA oxidative damage protection

The olive oil phenol hydroxytyrosol (3), as well its metabolite homovanillic alcohol (4), were subjected to chemoselective lipase-catalysed acylations, affording with good yield 10 derivatives (5-14) bearing C(2), C(3), C(4), C(10) and C(18) acyl chains at C-1. Hydroxytyrosol (3) and its lipophilic derivatives showed very good DPPH. radical scavenging activity. Compounds 3, 4 and their lipophilic analogues 5-14 were subjected to the atypical Comet test on whole blood cells: 3 and its analogues 5 and 6, with little hydrophobic character (logP相似文献   

Antioxidant,antimicrobial and cytotoxicity potential of n-hexane extract of Cayratia trifolia L

It is of interest to analyze the antioxidant, antimicrobial and cytotoxicity activity of n-hexane extract of Cayratia trifolia L. (C. trifolia). The antimicrobial activity of n-hexane extract of C. trifolia was determined using disc diffusion method against six selected pathogenic microorganisms. The cytotoxicity potential of n-hexane plant extract was also studied against A2780 cell lines by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Results, n-hexane extract of C. trifolia possess significant antioxidant activity with significant IC50 values in radical scavenging assays. In antimicrobial studies, the maximum zone of inhibition was found in the range of 19.0 ± 0.1 to 22.0 ± 0.1 mm. In MTT assay, inhibition of cell growth with minimal IC50 values of 46.25±0.42μg/mL against A2780 cell lines was observed. Thus, n-hexane extract of C. trifolia is a possible antioxidant, antimicrobial and cytotoxicity agent.     

Chemical Composition and in vitro Biological Activities of the Essential Oil of Vepris macrophylla (Baker) I.Verd. Endemic to Madagascar

Vepris macrophylla is an evergreen tree occurring in sub‐humid forest of Madagascar and traditionally used in the Island to treat several complaints as well as to prepare aromatic teas and alcoholic drinks. In the present work, the essential oil distilled from the leaves was analyzed for the first time by gas chromatography (GC‐FID) and gas chromatography/mass spectrometry (GC/MS). The major compounds were citral (56.3%), i.e., mixture of neral (23.1%) and geranial (33.2%), citronellol (14.5%), and myrcene (8.3%). The essential oil exhibited antimicrobial activity against S. aureus, P. aeruginosa, and C. albicans as determined by vapor‐diffusion assay, supporting the traditional use of the plant for preparing steam bath for the treatment of infectious diseases. The essential oil was evaluated for cytotoxic activity on human tumor cell lines by MTT (=3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide) assay, showing inhibitory effects comparable to those of cisplatin, notably on MDA‐MB 231 (human breast adenocarcinoma) and HCT116 (human colon carcinoma) cell lines. Finally, the essential oil was also subjected to screening for its antioxidant activity and the free radical scavenging capacity.     

向日葵籽壳黑色素的分离提取及生物活性研究*

目的:天然黑色素安全性高,兼具多种生物活性,深受消费者青睐,发展前景十分广阔。研究向日葵籽壳黑色素制备条件,以及抗氧化和吸附重金属生物活性,为其进一步应用提供理论基础。方法: 采用热碱提取、酸水解、有机溶剂洗涤和反复沉淀法,结合单因素与响应面分析法实现了黑色素的高效制备,利用氯化硝基四氮唑蓝还原法、分光光度法和静态吸附法进行抗氧化活性和吸附活性测定。结果: 成功制备了向日葵籽壳黑色素。提取结果表明最优工艺为氢氧化钠浓度0.11 mol/L、提取温度75.19℃、提取时间181.16 min、料液比为15.77∶1,向日葵籽壳黑色素得率为2.95%,与预测值相近,说明模型拟合良好,该优化工艺准确可行。抗氧化活性测定结果表明,向日葵籽壳黑色素清除超氧阴离子自由基、DPPH自由基的能力和还原力都高于合成型黑色素。吸附活性测定结果表明,向日葵籽壳黑色素对Pb²⁺、Cu²⁺和Cr³⁺的吸附效率高于合成型黑色素。结论: 与其合成型黑色素相比,天然黑色素既可作为着色剂,又兼抗氧化剂和吸附剂,且不亚于合成型黑色素的效果,可用于代替合成型黑色素开发的重要候选。     

Chemical composition and antimicrobial,antioxidant, and anti-inflammatory activities of Lepidium sativum seed oil

Lepidium sativum (garden cress) seed oil was examined for its antimicrobial, antioxidant, and anti-inflammatory activities. The oil was obtained by hydrodistillation, where gas chromatography coupled with mass spectrometry that utilized to study its chemical composition. Microdilution method was used to test the antimicrobial effect of oil against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, Klebsiella pneumoniae, and Candida albicans. The antioxidant activity was assessed by radical scavenging activity assay using 2,2-diphenyl-1-picrylhydrazyl radical. The major constituents found in the oil were 7,10-hexadecadienoic acid, 11-octadecenoic acid, 7,10,13-hexadecatrienoic acid, and behenic acid. The minimum inhibitory concentration (MIC) against all pathogens was 47.5 mg/ml, except for Salmonella enterica, which showed MIC of 90 mg/ml. The oil demonstrated antioxidant activity in a dose dependent pattern, with a half maximal inhibitory concentration (IC₅₀) value of 40 mg/ml, and exerted anti-inflammatory activity, wherein 21% protection was shown at a concentration of 300 μg/ml. Thus, L. sativum seed oil shows antimicrobial, antioxidant, and anti-inflammatory properties.