Antioxidant activities of extracts and fractions from Lysimachia foenum-graecum Hance

The antioxidant activities of water extract, methanol extract, ethyl acetate, and n-BuOH fractions of methanol extract from Lysimachia foenum-graecum Hance were investigated in this study. Various methods, such as the total antioxidant capacity measured by phosphomolybdenum method, scavenging activities towards 1,1-diphenyl-2-picryhydrazyl (DPPH) radical, superoxide anion radical, and hydroxyl radical, were established in in vitro systems. The amounts of total phenolics and total flavonoids in the extracts and fractions were also determined by spectrophotometric methods. The results showed that all the extracts and fractions exhibited antioxidant and radical-scavenging activities at different magnitudes of potency. The decreasing order of antioxidant and radical-scavenging activities among the extracts assayed through all the four methods were found to be ethyl acetate fraction>n-BuOH fraction>methanol extract>water extract. This similar order of the amounts of total phenolics and total flavonoids shows that the extent of antioxidant and radical-scavenging activities is in accordance with the amounts of phenolics and flavonoids present in extracts and fractions. The extracts of L. foenum-graecum Hance might be valuable antioxidant natural sources and seemed to be applicable in both healthy medicine and food industry.     

油菜蜂花粉抗氧化活性研究

采用回流提取、大孔吸附树脂分离,得到8个油菜蜂花粉提取部位;利用H2O2诱导PC12细胞氧化损伤模型,评价各提取部位对PC12细胞氧化损伤的保护作用。在此基础上,采用HPLC法初步分析最佳抗氧化部位活性物质基础。结果表明,8个油菜蜂花粉提取部位中,部位B处理组细胞存活率最高,为90.0%,显著高于模型组53.6%(P<0.001),且高于VE阳性对照组85.0%(P<0.05)。通过对乙酸乙酯各提取部位进行HPLC分析,并用对照品标定色谱图中色谱峰,表明部位B含有3种主要黄酮:山奈酚-3,4’-双-O-β-D-葡萄糖苷(KMG)、山奈酚-3-O-β-D-(2-O-β-D-葡萄糖基)吡喃葡萄糖苷(KMP)和山奈酚-3-O-β-D-葡萄糖苷(KMC)。     

香露兜叶的抗氧化活性(英文)

本文评价了香露兜叶的乙醇提取物以及石油醚、乙酸乙酯、正丁醇和水相组分的抗氧化活性。在体外测定了提取物和组分的总抗氧化活性,二苯代苦味肼基(DPPH)自由基清除活性,超氧阴离子自由基清除活性和铁离子还原能力,并利用分光光度法测定了其总酚和总黄酮的含量。结果表明,所有的提取物和组分均表现出抗氧化和自由基清除活性。抗氧化活性的大小如下:正丁醇部分>乙酸乙酯部分>乙醇提取物>水部分>石油醚部分。总酚含量的顺序和其相似,说明提取物和组分中的酚类化合物使其具有抗氧化活性。香露兜叶提取物可能会成为有价值的天然抗氧化资源,并将在保健品和食品中得到应用。     

Antitermitic and antioxidant activities of heartwood extracts and main flavonoids of Hymenaea stigonocarpa Mart.

Hymenaea stigonocarpa, is an endemic tree from the Brazilian cerrado (savannah) and popularly known as jatobá-do-cerrado. The wood of this species is resistant to biodegradation and is used in naval and civil construction. Cuttings from heartwood of this species showed resistance to fungi and termites. In this paper, we report the antitermitic and antioxidant activities of H. stigonocarpa heartwood ethyl acetate extract and its main flavonoids constituents, hultenin (1), taxifolin (2), quercetin (3) and 7-methoxycathequin (4). The structure elucidation of the isolated flavonoids was performed by spectroscopic methods. The ethyl acetate extract possesses highest antitermitic and antioxidant activity when compared with isolated flavonoids.     

Evaluation of flavonoids from <Emphasis Type="Italic">Zostera asiatica</Emphasis> as antioxidants and nitric oxide inhibitors

Zostera asiatica is one of the five members of the genus Zostera that can be found in Korea. Studies have reported the phytochemical properties and bioactivities of Zostera species. Current study focused on the antioxidant effects of Z. asiatica as a part of ongoing research for bioactive substances from marine resources. Results indicated that a crude extract of Z. asiatica not only scavenged on peroxynitrite in vitro and on intracellular reactive oxygen species (ROS) but also inhibited production of nitric oxide (NO). The crude extract was subjected to solvent fractionation for bioactivity-based separation using aforementioned three bioassay systems. From the active n-butanol fraction, two flavonoids were isolated and characterized as luteolin (1) and luteolin-3’-sulfate (2). Both flavonoids showed significant antioxidant effects. In conclusion, Z. asiatica was demonstrated to possess antioxidant effect partly attributed to isolated flavonoids, the first such effect reported from Z. asiatica, to the best of our knowledge.     

Evaluation of cytotoxic compounds from calligonum comosum L. growing in Egypt

Calligonum comosum (Polygonaceae), an Egyptian desert plant, was extracted and fractionated using petroleum ether, methylene chloride, and ethyl acetate. The total methanolic extract and other fractions were tested for their anticancer activity using Ehrlich ascites, brine shrimp and antioxidant assays. Ethyl acetate fraction proved to be the most active in all assays. Eight compounds were isolated, purified, and identified from this fraction as (+)-catechin (1), dehydrodicatechin A (2), kaempferol-3-O-rhamnopyranoside (3), quercitrin (quercetin-3-O-rhamnopyranoside) (4), beta-sitosterol-3-O-glucoside (5), isoquercitrin (quercetin-3-O-glucopyranoside) (6), kaempferol-3-O-glucuronide (7), and mequilianin (quercetin-3-O-glucuronide) (8). All isolated compounds were tested for their cytotoxicity and antioxidant activity. Compound 2 showed the best cytotoxic and antioxidant activity.     

Antioxidant properties ofErigeron annuus extract and its three phenolic constituents

The antioxidant activity of the extract ofErigeron annuus was assessed by means of two differentin vitro tests: bleaching of the stable 1,1-diphenyl-2-picrylhydrazyl radical (DPPH test) and the scavenging of authentic peroxynitrite in company with peroxynitrite generation from 3-morpholinosydnonimine (SIN-1). In both tests, the 85% aq. MeOH andn-BuOH soluble fractions of the crude extract showed a significant scavenging effect on peroxynitrite and DPPH radical in comparison to L-ascorbic acid. And bioassay-guided fractionation of then-BuOH soluble fraction led to the isolation of three compounds: Apigenin (1), quercetin-3-O-glucoside (2), and caffeic acid (3). The structures of the isolated compounds were elucidated on the basis of their spectroscopic data and their antioxidant activities were measured by determining their capacity to scavenge peroxynitrite and the DPPH radical.     

Red Mexican grapefruit: a novel source for bioactive limonoids and their antioxidant activity

Citrus limonoids have shown to inhibit the growth of cancer in colon, lung, mouth, stomach and breast in animal and cell culture studies. For the first time in the present study, an attempt has been made to isolate antioxidant fractions and five limonoids from red Mexican grapefruit seeds. Defatted seed powder was successively extracted with hexane, ethyl acetate (EtOAc), acetone, methanol (MeOH) and MeOH/water and the extracts were concentrated under vacuum. Radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and total phenolic content were also measured for comparison with the antioxidant capacity in the phosphomolybdenum method for the above extracts. Acetone and MeOH extracts, respectively, showed the highest (85.7%) and lowest (53.3%) radical scavenging activity, at 500 ppm. The total phenolic contents were found to be highest in the acetone extract (15.94%) followed by the MeOH extract (5.92%), ethyl acetate extract (5.54%) and water extract (5.26%). Antioxidant capacity of the extracts as equivalents to ascorbic acid (micromol/g of the extract) was in the order, EtOAc extract > acetone extract > water extract > methanol extract. Furthermore, the EtOAC and acetone extracts were loaded onto silica gel columns to obtain four limonoid aglycons. MeOH fraction was loaded onto a dowex-50 and sepabeads resin column to obtain a limonoid glucoside. The purity of the isolated five compounds was analyzed by HPLC using a C18 column and UV detection at 210 nm. Finally, the structures of the compounds were identified as obacunone, nomilin, limonin, deacetylnomilin (DAN) and limonin-17-beta-D-glucopyranoside (LG) using 1H and 13C NMR studies.     

Evaluation of terrestrial plants extracts for uranium sorption and characterization of potent phytoconstituents

Sorption capacity of four plants (Funaria hygrometrica, Musa acuminata, Brassica juncea and Helianthus annuus) extracts/fractions for uranium, a radionuclide was investigated by EDXRF and tracer studies. The maximum sorption capacity, i.e., 100% (complete sorption) was observed in case of Musa acuminata extract and fractions. Carbohydrate, proteins, phenolics and flavonoids contents in the active fraction (having maximum sorption capacity) were also determined. Further purification of the most active fraction provided three pure molecules, mannitol, sorbitol and oxo-linked potassium oxalate. The characterization of isolated molecules was achieved by using FTIR, NMR, GC-MS, MS-MS, and by single crystal-XRD analysis. Of three molecules, oxo-linked potassium oxalate was observed to have 100% sorption activity. Possible binding mechanism of active molecule with the uranyl cation has been purposed.     

The antioxidant activity of aqueous spinach extract: chemical identification of active fractions

In previous studies we have elucidated the presence of powerful, natural antioxidants (NAO) in water extracts of spinach leaves and demonstrated their biological activity in both in vitro and in vivo systems. In the present study, the chemical identity of several of these antioxidant components is presented. Spinach leaves were extracted with water and the 20,000 g supernatant which contained the antioxidant activity was extracted with a water:acetone (1:9) solution. The 20,000 g supernatant obtained was further purified on reverse phase HPLC using C-8 semi-preparative column. Elution with 0.1% TFA resulted in five hydrophilic peaks. Elution with acetonitrile in TFA resulted in seven additional hydrophobic peaks. All the peaks were detected at 250 nm. All the fractions obtained showed antioxidant activity when tested using three different assays. Based on 1H and 13C NMR spectroscopy four of the hydrophobic fractions were identified as glucuronic acid derivatives of flavonoids and three additional fractions as trans and cis isomers of p-coumaric acid and others as meso-tartarate derivatives of p-coumaric acid. The present study demonstrates for the first time the presence of both flavonoids and p-coumaric acid derivatives as antioxidant components of the aqueous extract of spinach leaves.     

Cholinesterase inhibitory and antioxidant properties of Verbascum mucronatum Lam. and its secondary metabolites

The aqueous extract of Verbascum mucronatum Lam. along with its fractions and secondary metabolites were assessed for their antioxidant, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) inhibitory activities. The antioxidant activity was evaluated by three methods: as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, ferrous ion-chelating effect, and ferric-reducing antioxidant power (FRAP) tests. The AChE activity was determined by the Ellman method using an ELISA microplate reader. Phytochemical investigations revealed the presence of four iridoid glucosides, ajugol (1), aucubin (2), lasianthoside I (3) and catalpol (4), two saponins, ilwensisaponin A (5) and C (6), and a phenylethanoid glycoside, verbascoside (7), in Verbascum mucronatum. Their structures were elucidated by spectral techniques. The aqueous extract and fractions including the phenylethanoid glycoside 7 showed DPPH scavenger effect and had the best FRAP. Besides these results, one of the phenylethanoid fractions displayed the highest ferrous ion-chelating effect. While only 7 was found to possess moderate AChE inhibition, the extract, fractions, and all other tested compounds did not inhibit AChE and BChE.     

Target-guided isolation and purification of antioxidants from Selaginella sinensis by offline coupling of DPPH-HPLC and HSCCC experiments

Selaginella sinensis (Selaginellaceae) is used extensively in traditional Chinese medicine (TCM) for the treatment of many kinds of chronic diseases. In this study, fractionation of the methanol extract of S. sinensis by different polarity solvents indicated the ethyl acetate fraction exhibited an potent 1,1-diphenyl-2-picryhydrazyl (DPPH) radical scavenging activity with the IC(50) value of 44.9 μM. In order to evaluate the scientific basis, antioxidant peaks were firstly screened using DPPH spiking test through high performance liquid chromatography (DPPH-HPLC). Under the target-guidance of DPPH-HPLC experiment, two flavonoids and six biflavonoids, quercetin (1), apigenin (2), amentoflavone (3), robustaflavone (4), 2,3-dihydroamentaflavone (5), hinokiflavone (6), 4'-O-methyl-robustaflavone (7) and ginkgetin (8) were separated by high-speed counter-current chromatography (HSCCC) method using n-hexane-ethyl acetate-methanol-water (8:8:9:7) as the solvent system with purities 98.2%, 97.6%, 99.4%, 92.3%, 98.5%, 98.9% and 99.6%, respectively. The structures were identified by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) analysis. Antioxidant activity of eight isolated compounds was assessed by the radical scavenging effect on DPPH radical, compound 1 showed strongest antioxidant activities with IC(50) values of 3.2 μM, while compounds 2-8 showed weak antioxidant activities. This is the first report on simultaneous separation of eight antioxidant compounds from S. sinensis by HSCCC, moreover, apigenin and 4'-O-methyl-robustaflavone were first identified from this plant. Results of the present study indicated that the combinative method using DPPH-HPLC and HSCCC could be widely applied for rapid screening and isolating of antioxidants from complex TCM extract.     

Antiproliferative activities of isolated flavone glycosides and fatty acids from Stachys byzantina

From the aerial parts of Stachys byzanthina C. Koch., a new flavone glycoside, was isolated for the first time in addition to known two flavone glycosides. Structures were established by conventional methods of analysis and confirmed by ¹H, ¹³C NMR and mass spectral analysis. Antiproliferative activities of isolated compounds, crude extract and fractions, fatty acids (extracts of hexane and hexane:ethyl acetate, 9:1) of aerial parts of S. byzantina were investigated against Vero (African green monkey kidney), HeLa (human uterus carcinoma) and C6 (rat brain tumor) cells in vitro and compared with 5-fluorouracil (5-FU). Antiproliferative effect of the extract, isolated flavonoids and fatty acids were tested at 100, 250, 500 and 1000 μg/mL using BrdU cell proliferation ELISA.     

Evaluation of Antioxidant,Antibacterial and Enhancement of Antibiotic Action by Punica granatum Leaves Crude Extract and Enriched Fraction against Multidrug-Resistant Bacteria

The aim of this study was to evaluate the phytochemical composition, antioxidant, and antimicrobial potential of crude extract and fractions of Punica granatum leaves. The extract was produced by turbo extraction, after which hexanic, ethyl acetate, and aqueous fractions were obtained by partitioning. The chemical analyses were performed by thin layer chromatography and high-performance liquid chromatography, and the antioxidant activities were assayed by DPPH^. and ABTS^.+. Minimal inhibitory and bactericidal concentrations (MIC/MBC) were applied to twenty-two bacteria. Most strains susceptible to extract/fractions and resistant to antibiotics were selected, and ampicillin, azithromycin, ciprofloxacin, and gentamicin were associated with the ethyl acetate fraction (EAF) against multidrug-resistant strains in modulatory and checkboard models. The data from chromatographic analyses showed flavonoids and tannins in the extract, as well as the enrichment of EAF in phenols, mainly flavonoids. The flavonoids were connected to the electron transfer activity demonstrated in the DPPH^. and ABTS^.+ assays. Gram-positive strains are more susceptible to EAF. The subinhibitory concentrations of P. granatum enhanced the antimicrobial activity of the agents and reduced the EAF individual MIC, and the combination of EAF and antibiotics demonstrated a synergistic effect. These results present a promising approach for developing a therapy in which antioxidant extracts and fractions can be used in combination with antibiotics.     

Bioactive Phytochemicals and Antioxidant Capacity of Wheatgrass Treated with Salicylic Acid under Organic Soil Cultivation

This study was undertaken to determine the influence of salicylic acid (SA) on the bioactive phytochemicals and antioxidant capacity of wheatgrass extract in the organic growing medium. Wheatgrass was cultivated in SA-enriched organic growing medium, obtained from acetylsalicylic acid (aspirin) of various concentrations (0 [control], 0.25, 0.50, 1.00, and 2.00 mM) in a plant growth chamber by controlling atmosphere (20/15 °C, day/night), light (14/10 h, light/dark; light intensity 150 μmol m⁻² s⁻¹, using quantum dot light-emitting diodes), and atmospheric moisture (60 %) for 10 d. The 0.25 mM SA-treatment showed the highest impact on germination rate, wheatgrass length, weight, yield, and chlorophyll content. Levels of bioactive phytochemicals, mainly phenolic compounds, flavonoids, β-carotene, and vitamin C, were the highest in the 1.00 mM SA-treated wheatgrass extract. The DPPH radical and nitrite-scavenging capacities were the highest in the 1.00 mM SA-treated wheatgrass extract. The 0.50 mM SA-treated wheatgrass extract showed the highest superoxide dismutase-like capacity, whereas the 2.00 mM SA-treated wheatgrass extract showed the highest anthocyanin content and ABTS radical-scavenging capacity. Therefore, it might be suggested that the appropriate levels of SA-treatment were between 0.5 and 1.0 mM to enhance the bioactive phytochemicals and antioxidant capacity of wheatgrass.     

Flavonoids from Lysidice rhodostegia Hance

A novel flavonoid named mopanolchin (1), together with seven known flavonoids, was isolated by various chromatographic techniques and spectroscopic methods from the EtOAc extract of the roots of Lysidice rhodostegia Hance. The structure of the new compound was elucidated as 1"-(4-hydroxy-3, 5-dimethoxy)phenyl-2"-hydroxymethyl-dioxino [4', 5',1", 2"]mopanol (1) on the basis of spectral analysis.The known compounds were identified as (-)-epicatechin-3-O-gallate (2), epicatechin (3), naringenin (4),eriodictyol (5), luteolin (6), 7, 3', 4'-trihydroxyflavone (7) and (-)-robinetinidol (8).     

Evaluation of antioxidant and anticancer activities of chemical constituents of the Saururus chinensis root extracts

Evaluation of antioxidant and anticancer activities were screened by various Saururus chinensis root extracts. Four solvents (ethyl acetate, methanol, ethanol, and water) extracts were investigated for their total flavonoids, phenol contents and their antioxidant activity of DPPH (2,2-diphenyl-1-picrylhydrazyl), NO (nitric oxide), H₂O₂ (hydrogen peroxide), ABTS 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonicacid)diammonium assays, FRAP (ferric reducing ability of plasma) assays and anticancer activity. The total phenolic and flavonoid content of extracts were determined by using FC (Folin–Ciocalteu) and AlCl₃ colorimetric assay method. Total flavonoid content in these plants ranged from 24.7 to 72.1 mg g^?1 and amount of free phenolic compounds was between 11.2 and 67.1 mg g^?1 extract. The all extracts have significant levels of phenolics and flavonoids content. Anticancer activity was screened for MCF-7 breast cancer cell line. Ethanol extract shows significant of antioxidant activity and water extract shows significant of anticancer activity compared with standard (BHT) butylated hydroxy toluene. These ethanol and water extracts could be considered as a natural source for using antioxidant, and anticancer agents compared to commercial available synthetic drugs.     

Four new depsides in Origanum dictamnus methanol extract

We herein describe the identification of four new depsides present in methanol extract of Origanum dictamnus. O. dictamnus’ (dittany) aerial parts methanol extract was subjected to semi-preparative RP-HPLC fractionation followed by identification of individual compounds in each fraction using 1D/2D NMR, MS approaches and DFT calculations. The structural data revealed that 4 of the compounds were novel hitherto unidentified molecules, whereas the other 6 corresponded to known structures belonging to the groups of monoterpenes, phenolic acids and depsides. We have additionally estimated the antioxidant capacity of the methanol extract and individual fractions using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) in vitro assay. Methanol extract exhibited significant scavenging activity, which was attributed predominantly to the depside group of phytochemicals. The scavenging activity of the new compounds is reported herein for first time. Moreover, the antimitotic activities of the methanol extract as well as that of rosmarinic acid were examined and appeared to be several fold weaker comparing to their scavenging capacity.     

Antioxidant activity of flavonoids from Sideritis javalambrensis.

Five flavonoid glycosides, 4'-O-methylisoscutellarein 7-O-[6"'-acetylallopyranosyl(1----2)glucopyranoside], 4'-O-methylisoscutellarein 7-O-allopyranosyl(1----2)glucopyranoside, 3'-hydroxy-4'-O-methylisoscutellarein 7-O-[6"'-acetylallopyranosyl(1----2) glucopyranoside], and hypolaetin-8-glucoside have been isolated from Sideritis javalambrensis aerial parts and identified by standard methods. These glycosides have been tested for their antioxidant properties alongside other 7,8-substituted flavonoids using FeSO4/cysteine-induced microsomal lipid peroxidation. Superoxide scavenging activity was assessed in the nitroblue tetrazolium test. Among this series of flavonoids, hypolaetin-8-glucoside is the most potent inhibitor of nonenzymic lipid peroxidation. The antiperoxidative activity of these flavonoids may be related to their superoxide scavenging ability.     

Non-phenolic antioxidant compounds from Buddleja asiatica

The methanol extract of the leaves of Buddleja asiatica Lour. (Loganiaceae) showed antioxidant activity toward the well known in vitro antioxidant tests such as total antioxidant capacity by the phosphomolybdenum method, free radical scavenging activity by the 1,1-diphenyl-2-picrylhydrazyl scavenging assay (DPPH assay) and hydrogen peroxide scavenging methods. Due to the high scavenging activity of the n-butanol successive fraction toward DPPH and H2O2 (SC50 = 11.99 and 18.54 microg/ml, respectively), this extract was subjected to chromatographic separation and isolation. Four non-phenolic compounds were isolated and identified on the basis of spectroscopic and chemical analyses: 1-O-beta-D-glucopyranosyl-2-methoxy-3-(2-hydroxy-triaconta-3,12-dienoate)-glycerol (1), 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-[beta-D-glucopyranosyl-(1-->2)]-beta-D-fucopyranosyl-olean-11,13(18)-diene-3 beta,23,28-triol (2), 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-beta-D-fucopyranosyl-olean-11,13(18)-diene-3,23,28-triol (3), and 3-O-[alpha-L-rhamnopyranosyl-(1-->4)-beta-D-glucopyranosyl-(1-->3)]-[beta-D-xylopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl-acid-olean-11,13(18)-diene-3 beta,23,28-triol (4). The four compounds were evaluated as antioxidant agents using the three antioxidant bioassay tests.