Antioxidant and free radical scavenging activity of flavonol glycosides from different Aconitum species

Bioassay-guided fractionation by 1,1-diphenyl-2-dipicrylhydrazyl (DPPH) radical scavenging test of polar extracts of some Italian Aconitum species (A. napellus subsp. tauricum, A. napellus subsp. neomontanum, A. paniculatum, A. vulparia) led to the isolation of 13 flavonol glycosides: quercetin 3-O-(6-trans-caffeoyl)-beta-glucopyranosyl-(1-->2)-beta-glucopyranoside-7-O-alpha-rhamnopyranoside (1), kaempferol 3-O-(6-trans-caffeoyl)-beta-glucopyranosyl-(1-->2)-beta-glucopyranoside-7-O-alpha-rhamnopyranoside (2), quercetin 3-O-(6-trans-p-coumaroyl)-beta-glucopyranosyl-(1-->2)-beta-glucopyranoside-7-O-alpha-rhamnopyranoside (3), kaempferol 3-O-(6-trans-p-coumaroyl)-beta-glucopyranosyl-(1-->2)-beta-glucopyranoside-7-O-alpha-rhamnopyranoside (4), quercetin 7-O-(6-trans-caffeoyl)-beta-glucopyranosyl-(1-->3)-alpha-rhamnopyranoside-3-O-beta-glucopyranoside (5), kaempferol 7-O-(6-trans-caffeoyl)-beta-glucopyranosyl-(1-->3)-alpha-rhamnopyranoside-3-O-beta-glucopyranoside (6), kaempferol 7-O-(6-trans-p-coumaroyl)-beta-glucopyranosyl-(1-->3)-alpha-rhamnopyranoside-3-O-beta-glucopyranoside (7), kaempferol 3-O-beta-(2"-acetyl)galactopyranoside (8), kaempferol 3-O-beta-(2"-acetyl)galactopyranoside-7-O-alpha-arabinopyranoside (9), quercetin 3-O-beta-(2"-acetyl)galactopyranoside-7-O-alpha-arabinopyranoside (10), quercetin 3,7-di-O-alpha-rhamnopyranoside (11), kaempferol 3,7-di-O-alpha-rhamnopyranoside (12) and quercetin 3-O-beta-glucopyranoside-7-O-alpha-rhamnopyranoside (13). Their antioxidant activity (AA) was determined by measuring free radical scavenging activity by DPPH test and the coupled oxidation of beta-carotene and linoleic acid assay. The results showed that 5 is the most active compound in the DPPH free-radical scavenging test (IC(50) 1.9 microM) while in the coupled oxidation of beta-carotene and linoleic acid assay compound 1 has the highest inhibitory ratio after 1h (58.9%). Some structure-activity relationships on the AA were obtained.     

Quinic acid esters from Pluchea indica with collagenase, MMP-2 and MMP-9 inhibitory activities

Investigation of collagenase inhibitory natural components afforded two quinic acid esters (1 and 2) and quercetin (3) from the leaves of Pluchea indica (Compositae). Of these, compounds 1 and 2 exhibited collagenase inhibitory activity (IC(50)) at a concentration of less than 10 microm, and 1 showed matrix metalloproteinase (MMP)-2 and -9 inhibitory activity (IC(50)) at 2.5 and 6.4 microm, respectively.     

Flavimycins A and B, dimeric 1,3-dihydroisobenzofurans with peptide deformylase inhibitory activity from Aspergillus flavipes

Flavimycins A (1) and B (2), novel dimeric 1,3-dihydroisobenzofurans, were isolated as inhibitors of peptide deformylase from cultures of Aspergillus flavipes. Their chemical structures were established by NMR and MS data analysis. Compounds 1 and 2 exist as epimeric mixtures at C-1 through fast hemiacetal-aldehyde tautomerism. Compounds 1 and 2 inhibited Staphylococcus aureus peptide deformylase with IC?? values of 35.8 and 100.1 μM, respectively. Consistent with their PDF inhibition, 1 showed two times stronger antibacterial activity than 2 on S. aureus including MRSA, with MIC values of 32-64 μg/mL.     

Flavonol glycosides from the leaves of Eucommia ulmoides O. with glycation inhibitory activity

Eucommia ulmoides leaves have been used as a folk remedy for the treatment of diabetes in Korea. The aim of this study was to isolate and identify the compounds which inhibited advanced glycation end-product formation, one of main molecular mechanisms implicated in diabetic complications. A new flavonol glycoside, quercetin 3-O-alpha-L-arabinopyranosyl-(1-->2)-beta-D-glucopyranoside (1), and known flavonols kaempferol 3-O-beta-D-glucopyranoside (astragalin) (2), quercetin 3-O-beta-D-glucopyranoside (isoquercitrin) (3) were isolated from the leaves of Eucommia ulmoides. These compounds exhibited glycation inhibitory activity comparable to that of aminoguanidine, a known glycation inhibitor. The results suggest that the flavonol glycosides with glycation inhibitory activity could be attributed to the anti-diabetic action of Eucommia ulmoides leaves.     

Arjunic acid, a strong free radical scavenger from Terminalia arjuna

This study was designed to investigate the antioxidant and free radical scavenging capacities of arjunic acid, an aglycone obtained from the fruit of medicine Terminalia Fruit. Liver microsomes, mitochondria, and red blood cells (RBCs) were prepared from Wistar rats. The antioxidant capacity was determined by the inhibitory effect on lipid peroxidation, hydrogen peroxide induced RBCs hemolysis, and RBCs autoxidative hemolysis. The free radical scavenging activity was tested by DPPH method and 2',7'-dichlorodihydrofluoresc in diacetate (DCFH(2)-DA) assay. Ascorbic acid was chosen as the positive controls. Results showed that arjunic acid was a strong antioxidant and a free radical scavenger, more potent than ascorbic acid, in microsomes lipid peroxidation, DPPH, hydrogen peroxide induced RBCs hemolysis, and (DCFH(2)-DA) assay (p < 0.05). However, no significant difference was observed in the RBCs autoxidative hemolysis assay (p > 0.05).     

Scytonemides A and B, cyclic peptides with 20S proteasome inhibitory activity from the cultured cyanobacterium Scytonema hofmanii

Two cyclic peptides, scytonemides A (1) and B (2), were isolated from the cultured fresh water cyanobacterium Scytonema hofmannii (UTEX 1834) by bioassay-guided fractionation using a proteasome inhibition assay. The planar structures of the compounds were determined by a combination of MS and 1D and 2D NMR spectroscopy. The advanced Marfey's method was used to determine the absolute configuration of both peptides. Scytonemide A possesses an unusual imino linkage, while scytonemide B is a depsipeptide containing 3-hydroxyoctanoic acid in the macrocycle. Both isolates were evaluated for their inhibition of the 20S proteasome, and scytonemide A displayed an IC(50) value of 96 nM, while scytonemide B was inactive at 50 μM.     

Flavonoid glycosides from the stem bark of Margaritaria discoidea demonstrate antibacterial and free radical scavenging activities

One new flavonoid glycoside, along with three known flavonoid glycosides were isolated from the stem bark of Margaritaria discoidea, which is traditionally used in the management of wounds and skin infections in Ghana. The new flavonoid glycoside was elucidated as hydroxygenkwanin‐8‐C‐[α‐rhamnopyranosyl‐(1 → 6)]‐β‐glucopyranoside (1) on the basis of spectroscopic analysis. The isolated compounds demonstrated free‐radical scavenging as well as some level of antibacterial activities. Microorganisms including Staphylococcus aureus are implicated in inhibiting or delaying wound healing. Therefore, any agent capable of reducing or eliminating the microbial load present in a wound as well as decreasing the levels of reactive oxygen species may facilitate the healing process. These findings therefore provide some support to the ethnopharmacological usage of the plant in the management of wounds. Copyright © 2013 John Wiley & Sons, Ltd.     

Secoiridoid glucosides with free radical scavenging activity from the leaves of Syringa dilatata

Activity-guided fractionation of the EtOAc and MeOH extract of the leaves of Syringa dilatata NAKAI furnished one free radical scavenger, the secoiridoid glucoside oleuropein together with ligstroside and an iridoid glucoside, syringopicroside. Oleuropein interacted with the stable free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and showed an IC(50) value of 40.4 microM. L-Ascorbic acid as a positive control showed an IC(50) value of 50.3 microM.     

Phthalides from Pittosporum illicioides var. illicioides with inhibitory activity on superoxide generation and elastase release by neutrophils

Six new phthalides, (S)-3-ethyl-7-hydroxy-6-methoxyphthalide (1), (S)-3-ethyl-7-hydroxy-5,6-dimethoxyphthalide (2), (S)-3-ethyl-5,6,7-trimethoxyphthalide (3), (R)-3-ethyl-7-hydroxy-6-methoxyphthalide (4), (Z)-3-ethylidene-7-hydroxy-6-methoxyphthalide (5), and (Z)-3-ethylidene-6,7-dimethoxyphthalide (6), have been isolated from the root of Pittosporum illicioides var. illicioides, together with seven known compounds. The structures of these new compounds were determined through spectroscopic and MS analyses. Compounds 1-4 exhibited inhibition (IC50相似文献   

Hyalodendrosides A and B, antifungal triterpenoid glycosides from a lignicolous hyphomycete, Hyalodendron species

Two antifungal triterpenoid glycosides, hyalodendrosides A and B (1 and 2), were isolated from a solid matrix fermentation of a lignicolous hyphomycete, Hyalodendron sp. Their structures were determined based upon extensive examination of spectral parameters, particularly NMR and MS data. Both compounds have beta-linked glucose moieties. Compounds 1 and 2 show weak to moderate antifungal activity against some clinically relevant fungi.     

Isolation and characterization of free radical scavenging flavonoid glycosides from the flowers of Spartium junceum by activity-guided fractionation

Spartium junceum L. (Fabaceae) flowers are used for the treatment of peptic ulcers in Turkish folk medicine. The possible superoxide dismutase-like activity of the extracts, fractions and constituents obtained through activity-guided fractionation were studied by using in vitro electron spin resonance spectrometry, in order to explain the role of antioxidant principles in the potent antiulcerogenic activity of the extract. Despite the fact that the triterpene, spartitrioside, which was previously reported as the active antiulcerogenic constituent of the flowers was found almost inactive, the flavonoid-rich fractions showed potent antioxidant activity. Five flavonoid glycosides bearing catechol structure in ring B were isolated from the butanol extract and their structures were elucidated using 1H- and 13C-NMR techniques as isoquercitrin (quercetin 3beta-glucoside) (1,); luteolin 4'beta-glucoside (2); quercetin 3, 4'-diglucoside (3); azaleatin 3beta-glucoside (quercetin 5-methylether 3beta-glucoside) (4), quercetin 4'beta-glucoside (5). Flavonoids (2) and (4) showed the highest in vitro antioxidant activity with 22.59 and 19.08 U/ml, respectively.     

Cypellocarpins A-C, phenol glycosides esterified with oleuropeic acid, from Eucalyptus cypellocarpa

Three new phenol glycosides acylated with (+)-oleuropeic acid, cypellocarpins A (1), B (2), and C (3), along with seven known compounds, were isolated from the dried leaves of Eucalyptus cypellocarpa. Structures of the new compounds were determined on the basis of spectroscopic methods, including 2D NMR experiments and chemical degradation. These new compounds and a known related glucoside (7) showed potent in vitro antitumor-promoting activity in a short-term bioassay evaluating the inhibitory effect on Epstein-Barr virus early antigen activation induced by 12-O-tetradecanoyl phorbol 13-acetate (TPA). These compounds also suppressed an in vivo two-stage carcinogenesis induced with nitric oxide and TPA on mouse skin.     

吴茱萸化学成分清除DPPH自由基的活性研究

[目的]研究吴茱萸中分离得到的17个化合物清除1,1-二苯基-2-三硝基苯肼(DPPH)自由基的活性。[方法]采用DPPH薄层生物自显影法(TLC-DPPH)快速筛选17个化合物的清除DPPH自由基活性,并采用微孔板定量法测定其中4个具有较强活性化合物清除50%DPPH自由基的浓度(IC50)。[结果]TLC-DPPH生物自显影法结果显示金丝桃苷、咖啡酸、儿茶酚、绿原酸具有较强的清除DPPH自由基的活性,其IC50值分别为(108.06±5.96),(248.18±0.72),(122.33±16.80),(156.28±0.93)μmol/L(DPPH终浓度0.19 mmol/L)。[结论]吴茱萸中金丝桃苷、咖啡酸、儿茶酚、绿原酸清除自由基的活性较强,为进一步的吴茱萸药效物质研究奠定了基础。     

Flavonoid glycosides from Adina racemosa and their inhibitory activities on eukaryotic protein synthesis

From the dried leaves, flowers, and twigs of Adina racemosa, five new flavonoid glycosides, quercetin 3-O-alpha-l-rhamnopyranosyl(1-->6)-(3-O-trans-p-coumaroyl)-beta-d-galactopyranoside (1), quercetin 3-O-alpha-l-rhamnopyranosyl(1-->6)-[(4-O-trans-p-coumaroyl)-alpha-l-rhamnopyranosyl(1-->2)]-(4-O-trans-p-coumaroyl)-beta-d-galactopyranoside (2), kaempferol 3-O-alpha-l-rhamnopyranosyl(1-->6)-[(4-O-trans-p-coumaroyl)-alpha-l-rhamnopyranosyl(1--> 2)]-(4-O-trans-p-coumaroyl)-beta-d-galactopyranoside (3), quercetin 3-O-alpha-l-rhamnopyranosyl(1-->6)-[(4-O-trans-p-coumaroyl)-alpha-l-rhamnopyranosyl(1-->2)]-(3-O-trans-p-coumaroyl)-beta-d-galactopyranoside (4), and quercetin 3-O-alpha-l-rhamnopyranosyl(1-->6)-[(4-O-trans-caffeoyl)-alpha-l-rhamnopyranosyl(1-->2)]-(3-O-trans-p-coumaroyl)-beta-d-galactopyranoside (5), and eight known compounds were isolated. The structures of the new compounds were determined by spectroscopic and chemical means. Their inhibitory activities on protein synthesis were assessed. The new glycosides were found to be inhibitors of eukayrotic, but not prokaryotic, protein synthesis.     

盾叶木中具蛋白酪氨酸磷酸酶1B抑制活性的三萜类成分

目的研究盾叶木Macaranga adenantha枝的化学成分并进行蛋白酪氨酸磷酸酶1B(PTP1B)抑制活性和人肿瘤细胞毒活性筛选。方法用硅胶和凝胶色谱分离化合物,用波谱学等方法鉴定结构;分别以体外酶学方法和MTT法测定化合物PTP1B抑制活性和细胞毒活性。结果从盾叶木乙醇提取物中分离得到8个化合物,分别鉴定为:齐墩果酸(Ⅰ)、3β-乙酰基齐墩果酸(Ⅱ)、3β-乙酰基齐墩果酸甲酯(Ⅲ)、3β,28-二羟基-12-烯-齐墩果烷(Ⅳ)、2α,3β-二羟基齐墩果酸(Ⅴ)、3β-乙酰氧基-11-烯-齐墩果烷-28,13-内酯(Ⅵ)、3β-乙酰氧基-11α,12α-环氧-齐墩果烷-28,13-内酯(Ⅶ)、3β-O-乙酰基木油醇酸(Ⅷ)。化合物Ⅰ, Ⅳ, Ⅴ抑制PTP1B酶的IC50分别为(7.2±0.3)、(12.4±5.5)、(6.2±0.9)、(7.6±1.7)μg/mL,所有化合物抑制几种肿瘤细胞的IC50均大于10μg/mL。结论8个化合物均为首次从该属植物中得到。化合物、、、为PTP1B酶抑制剂,所有化合物均无细胞毒活性。     

Four glycosides from the leaves of Abeliophyllum distichum with inhibitory effects on angiotensin converting enzyme

The bioassay-guided fractionation of the n-BuOH extract of Abeliophyllum distichum afforded acteoside (1), isoacteoside (2), rutin (3), and hirsutrin (4). Compounds 1-3 moderately inhibited the angiotensin I converting enzyme activity in a dose-dependent manner. Compounds 1-3 showed the 50% inhibitory concentration values of 228 micro g/mL, 290 micro g/mL, and 278 micro g/mL, respectively.     

Ipomotaosides A-D, resin glycosides from the aerial parts of Ipomoea batatas and their inhibitory activity against COX-1 and COX-2

Four new resin glycosides, namely, ipomotaosides A-D (1-4), were isolated from the dried aerial parts of Ipomoea batatas. The structures of 1-4 were elucidated by analysis of their spectroscopic data and by chemical derivatization and were tested for their anti-inflammatory activity against cyclooxygenase (COX)-1 and -2.     

瓜馥木总黄酮提取纯化及其清除自由基活性研究

目的:研究瓜馥木总黄酮最佳提取工艺,并将总黄酮进行富集纯化,测试其清除自由基活性。方法:采用正交实验,考察乙醇浓度、提取温度、固液比及提取时间4个因素对该工艺的影响;利用AB-8大孔吸附树脂分离纯化总黄酮粗品;采用清除DPPH自由基初步评价瓜馥木提取物及总黄酮的抗氧化能力。结果:确立了瓜馥木总黄酮的最佳提取工艺为:提取时间3 h,乙醇浓度90%,固液比1∶10,提取温度为70℃。黄酮粗品经AB-8大孔树脂纯化以后,含量可达到55%以上。结论:优选出的最佳提取工艺条件及纯化总黄酮的方法对进一步的工艺开发有较好的参考价值,瓜馥木富集纯化的总黄酮部位具有较强的清除自由基能力,为开发成为中药保健品提供了一定的依据。     

Crypthophilic acids A, B, and C: resin glycosides from aerial parts of Scrophularia crypthophila

The water-soluble part of the methanolic extract from the aerial parts of Scrophularia crypthophila, through chromatographic methods, yielded three new resin glycosides, crypthophilic acids A - C (1-3). Compounds 1-3 are tetraglycosides of (+)-3S,12S-dihydroxypalmitic acid. The structures of these and 10 known compounds were elucidated by spectroscopic and chemical means. All natural resin glycosides known so far have been obtained from Convolvulaceae plants; this is the first report of such glycosides from another, taxonomically unrelated family (Scrophulariaceae).