Ultrasound-assisted extraction, HPLC analysis, and antioxidant activity of polyphenols from unripe apple

The polyphenols were extracted from the unripe apple assisted by a highly efficient and simple method of the ultrasound. Response surface methodology was used to investigate the effects of processing parameters, including ultrasound power, extraction time, temperature, and ethanol concentration on total polyphenols yield and polyphenols composition was analyzed by HPLC. Antioxidant activity of the polyphenols was evaluated as 2, 2-diphenyl-1-picrylhydracyl scavenging activity and inhibition activity of lipid peroxidation. The results showed that 10-100 times higher total polyphenols yield was obtained from the unripe apple than those from the reported apple pomace. The optimum extraction conditions were ultrasonic power of 519.39 W, extraction time of 30 min, extraction temperature 50°C, ethanol concentration of 50% gave the total polyphenols yield of 13.26 ± 0.56 mg GAE/g. HPLC analysis indicated that (-)-epicatechin, procyanidin B2, chlorogenic acid, and procyanidin B1 were the predominant polyphenols in unripe apple, which contributed to the higher antioxidant activity to 2, 2-diphenyl-1-picrylhydracyl of unripe apple polyphenols than other apple polyphenols. The extracted polyphenols had higher ability to inhibit lipid peroxidation than butylated hydroxy toluene, which demonstrated that the unripe apple polyphenols have the potential to be used as a substitute of some synthetic antioxidants.     

Composition and antioxidant activity of Thymus vulgaris volatiles: Comparison between supercritical fluid extraction and hydrodistillation

Supercritical fluid extraction (SFE) of the volatile oil from Thymus vulgaris L. aerial flowering parts was performed under different conditions of pressure, temperature, mean particle size and CO₂ flow rate and the correspondent yield and composition were compared with those of the essential oil isolated by hydrodistillation (HD). Both the oils were analyzed by GC and GC‐MS and 52 components were identified. The main volatile components obtained were p‐cymene (10.0–42.6% for SFE and 28.9–34.8% for HD), γ‐terpinene (0.8–6.9% for SFE and 5.1–7.0% for HD), linalool (2.3–5.3% for SFE and 2.8–3.1% for HD), thymol (19.5–40.8% for SFE and 35.4–41.6% for HD), and carvacrol (1.4–3.1% for SFE and 2.6–3.1% for HD). The main difference was found to be the relative percentage of thymoquinone (not found in the essential oil) and carvacryl methyl ether (1.0–1.2% for HD versus t?0.4 for SFE) which can explain the higher antioxidant activity, assessed by Rancimat test, of the SFE volatiles when compared with HD. Thymoquinone is considered a strong antioxidant compound.     

Versatile synthesis of epicatechin series procyanidin oligomers, and their antioxidant and DNA polymerase inhibitory activity

Proanthocyanidins, known as condensed tannins or oligomeric flavonoids, exist in many edible plants and show various interesting biological activities. We have developed a simple and versatile method of synthesizing procyanidin oligomers consisting of (−)-epicatechin and (+)-catechin. This method is applicable to the synthesis of various 3-O-substituted oligomers. We report here the stereoselective and length controlled synthesis of [4-8]-condensed (−)-epicatechin series procyanidin oligomers. We described the details of the synthesis of an two tetramers, (−)-epicatechin-(−)-epicatechin-(−)-epicatechin-(−)-epicatechin and (−)-epicatechin-(−)-epicatechin-(−)-epicatechin-(+)-catechin (arecatannin A1), (−)-epicatechin pentamer and two 3,3″,3?-tri-O-galloyl trimers, (−)-epicatechin-(−)-epicatechin-(−)-epicatechin-3,3″,3?-tri-O-gallate and (−)-epicatechin-(−)-epicatechin-(+)-catechin-3,3″,3?-tri-O-gallate with the condensation method using TMSOTf as a catalyst. The ability of DPPH radical scavenging activity and DNA polymerase inhibitory activity of these oligomeric compounds were investigated.     

北虫草多糖的理化特征及抗氧化和免疫活性研究

采取超高压提取,DEAE-Sepharose Fast Flow和Sephadex G-100柱层析分离纯化得到虫草多糖(CMP),通过高效凝胶色谱(HPGPC)、气相色谱(GC)和傅里叶红外光谱(FT-IR)对其理化特征进行了表征,并对CMP抗氧化及免疫调节活性进行了测定.结果显示CMP是纯度较高杂多糖,由鼠李糖、甘露糖、葡萄糖和半乳糖4个单糖组成,结果表明超高压是一种高效的菌多糖提取技术,提取得到的CMP可以探索作为天然的抗氧化和免疫调节剂应用于功能食品和药品.     

LC-MS characterization of bioactive metabolites from two Yemeni Aloe spp. with antioxidant and antidiabetic properties

Two Yemeni Aloe(s) have been investigated; the resin from A. perry Baker (APR, Socotran Aloe), and the gel from A. vera (AVG, Saber Yamaniis). LC-MS for APR identified aloin B, aloinoside B/A, homonataloin B and microdontin B/A as the major components, constituting 67.7% w/w of the extract. AVG showed the same pattern of anthrones (19.5% w/w), in addition to the chromones aloesin, aloeresin A, aloeresin D and aloeresin E. Dihydro-isocoumarin glucoside was identified in both Aloe species. Aloe extracts showed high antioxidant activity: DPPH (0.09 & 0.05 mM/g TE), ABTS (0.06 & 0.03 mM/g TE), and FRAP (20.5 & 15.5 mM Fe⁺²E), for APR & AVG, respectively. The antidiabetic properties was evaluated through inhibition of α-glucosidase enzyme. APR showed inhibitory activity with IC₅₀ 0.76 μg/mL higher than AVG (IC₅₀ 0.76 mg/mL). Aloin A showed the highest inhibitory activity with IC₅₀ 0.34 mg/mL that was higher than acarbose (0.54 mg/mL) the positive control, indicating that the activity of Aloe extract is linked to the aloin and other anthrone compounds. These findings highlight the phytochemical profile, antioxidant and potential antidiabetic activity of the Yemeni Aloe species and draw attention to their potential application in food, medicine and cosmetic products.     

Optimization of polysaccharides extraction from quince peels: partial characterization,antioxidant and antiproliferative properties

Abstract

In this study, Box-Behnken Design was used to optimize the ultrasonic extraction of polysaccharides from quince peels (QPPs) by ascorbic acid and the effect of extraction temperature, extraction time and pH was evaluated. Under optimized conditions of temperature 90?°C, 60?min sonication time and pH?=?3.26, the extraction yield, the galacturonic acid yield and the concentration of sample required to scavenge 50% of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic) acid (ABTS) values of QPPs were respectively 10.25%, 3.86% and 1.35?mg/mL. The QPPs extracted under optimum conditions was characterized by Fourier transform infrared spectroscopy (FTIR), Nuclear magnetic resonance (^1?H NMR) and Size exclusion chromatography (SEC/MALS/VD/DRI). The monosaccharide analysis revealed that arabinose was the most abundant, followed by galactose, glucose, mannose and xylose. Moreover, QPPs showed significant antioxidant activities (2,2-diphenyl-1-picrylhydrazyl (DPPH) and Ferric- reducing antioxidant power (FRAP)) and reduced viability of human Caco-2 and murine B-16 cell lines in a dose-dependent manner. Hence QPPs could be used as antitumor agent in functional foods andpharmaceutical industries.     

Synthesis,spectral characterization,antioxidant, anticancer in vitro,and DNA cleavage studies of a series of ruthenium(II) complexes bearing Schiff base ligands

Ruthenium(II) complexes with 2-acetylpyridine-thiosemicarbazones (L¹–L⁴) were synthesized and characterized by analytical and spectral (FT-IR, UV–vis, NMR [¹H, ¹³C and ³¹P], and ESI-Mass) methods. Systematic biological investigations, free radical scavenging, anticancer activities, and DNA cleavage studies, were carried out for the complexes. Antioxidant studies showed that the complexes have significant antioxidant activity against DPPH, hydroxyl, nitric oxide radicals and hydrogen peroxide assay. The in vitro cytotoxicity of complexes against breast cancer (MCF-7) cell line was assayed showing high cytotoxicity with low IC₅₀ values indicating their efficiency in destroying the cancer cells even at very low concentrations. The DNA cleavage studies showed that the complexes efficiently cleaved DNA.     

Voltammetric Detection of Oxidative DNA Damage Based on Interactions between Polymeric Dyes and DNA

Oxidative damage of DNA was assessed with glassy carbon electrode (GCE) coated with electropolymerized Methylene Blue (MB). For this purpose, DNA solution was first mixed with an oxidant (Fenton reagent, H₂O₂ alone and in the presence of Cu(II) ions) and then placed on the polymeric film surface. After washing, the cyclic voltammogram was recorded in buffer solution and the anodic peak potential measured against that before the contact with DNA. Oxidative DNA damage resulted in remarkable decrease of the anodic peak potential which depended on the oxidant nature and incubation period. Specificity of the DNA – MB interactions was confirmed by surface plasmon resonance (SPR) measurements. Similar experiment performed with polymerized Methylene Green (MG) and Neutral Red (NR) showed lower selectivity of the response toward various sources of reactive oxygen species. The protocol of the DNA damage detection was tested on the estimation of antioxidant properties of green tea extract and red table wine.     

Impedimetric Detection of DNA Damage with the Sensor Based on Silver Nanoparticles and Neutral Red

Novel electrochemical DNA‐sensor based on glassy carbon electrode (GCE) modified with Ag nanoparticles, Neutral red covalently attached to its surface and native DNA adsorbed on modifier coating was developed for the estimation of DNA damage on example of model system based on Fenton reagent. As was shown, the oxidation process resulted in synchronous increase of electron transfer resistance and capacitance measured by electrochemical impedance spectroscopy (EIS). The contribution of each sensor component on the signal was specified and sensitivity estimated against similar surface coatings. The shift of EIS parameters was found to be higher than that of similar biosensors reported. The DNA sensor was tested on the estimation of antioxidant capacity of green tea infusions again the results of coulometric titration with electrogenerated bromine.     

Hydroxyethyl curdlan as a novel water soluble derivative: Synthesis,characterization, and antioxidant capacity

In this study, hydroxyethyl curdlans (HeCDs) with different molecular weights were successfully fabricated. The structure and properties of the synthesized HeCDs were measured by FTIR, ¹³C nuclear magnetic resonance (NMR), and Raman spectroscopy and compared with curdlan. The degree of crystallinity of HeCDs was measured with X-ray diffractometry (XRD). Differential scanning calorimetry and thermogravimetric analysis were performed to determine thermal properties of HeCs. Solubility of HeCDs was tested in water, common organic solvents, and NaOH solution. Antioxidant activities of HeCs were investigated using various in vitro assay systems. The HeCDs exhibited a dose-dependent free radical scavenging activity as shown by their DPPH radical, ABTS radical and superoxide anion radical inhibition, and ferrous chelating ability and reducing power. The improved water solubility property and antioxidant activity of these curdlan derivatives could have a wide range of applications, particularly its use as an antioxidant in food, food packaging, biomedical, and pharmaceutical industries.     

Preparation,characterization and antioxidant activity of a novel polysaccharide-iron (III) from Flammulina velutipes scraps

In the present study, a novel polysaccharide from Flammulina velutipes scraps (FVSP) was extracted and purified from Flammulina velutipes scraps. FVSP was chemically chelated to synthesize FVSP-iron (III) complex. Based on single factor experiments, preparation process of FVSP- iron (III) was optimized by response surface methodology. The characterization and antioxidant activity of FVSP-iron (III) were investigated. The results showed that the optimal preparation process of FVSP-iron (III) was reaction temperature of 50 °C, reaction time of 4.7 h and the mass ratio of FVSP/sodium citrate - of 2:1. The relative molecular weight of FVSP-iron (III) was 36.25 kDa. FVSP-Iron (III) was composed of glucose, galactose, mannose and xylose in a molar ratio of 65.1:20.5:5.2:9.2.The results of UV–vis absorption spectrum, FI-IR spectrum and X-ray diffraction showed that both hydroxyl and carboxyl groups in FVSP participated in the coordination reaction and the iron core of FVSP-Iron(III) was a polymerized β-FeOOH structure. FVSP-iron (III) had better thermal stability and stronger antioxidant activities than FVSP. The results indicated that FVSP-iron (III) could be potentially used in food industry as a new food additive and iron supplement.     

Synthesis,characterization, and antioxidant activity of a new Gd(III) complex

A new gadolinium(III) complex of 5-aminoorotic acid (HAOA) was synthesized by reaction of the respective inorganic salt in molar ratio of 1:3 to ligand. The structure of the complex was determined by elemental analysis, FT-IR, and FT-Raman spectroscopies. Significant differences in the IR and Raman spectra of the complex were observed as compared to the spectra of the free ligand. Detailed vibrational analysis of HAOA and Gd(III)-AOA systems revealed that the binding mode in the complex was bidentate through the carboxylic oxygens. The newly synthesized gadolinium(III) complex of 5-aminoorotic acid (GdAOA) showed antioxidant properties. The antioxidant activity of both HAOA and GdAOA was related with their electron donor properties.     

Synthesis, spectral characterization of Schiff base transition metal complexes: DNA cleavage and antimicrobial activity studies

A new series of transition metal complexes of Cu(II), Ni(II), Co(II), Mn(II), Zn(II), VO(IV), Hg(II) and Cd(II) have been synthesized from the Schiff base (L) derived from 4-aminoantipyrine, 3-hydroxy-4-nitrobenzaldehyde and o-phenylenediamine. Structural features were obtained from their elemental analyses, magnetic susceptibility, molar conductance, mass, IR, UV-Vis, ¹H NMR and ESR spectral studies. The data show that these complexes have composition of ML type. The UV-Vis, magnetic susceptibility and ESR spectral data of the complexes suggest a square-planar geometry around the central metal ion except VO(IV) complex which has square-pyramidal geometry. The redox behaviour of copper and vanadyl complexes was studied by cyclic voltammetry. Antimicrobial screening tests gave good results in the presence of metal ion in the ligand system. The nuclease activity of the above metal complexes shows that Cu, Ni and Co complexes cleave DNA through redox chemistry whereas other complexes are not effective.     

Anti-Alzheimer,antidiabetic and antioxidant potential of Satureja cuneifolia and analysis of its phenolic contents by LC-MS/MS

Many chronic diseases such as diabetes and Alzheimer’s disease are related to the type and quality of foods, which are consumed. Particularly, various plant origin products are stated as beneficial against such kind of chronic diseases with secondary metabolites such as their phenolic structures. Satureja cuneifolia is a plant, which is consumed as an herbal tea in some regions of Turkey and that’s why investigate of its biological activity is important. In our study, the anti-diabetic and anti-Alzheimer potentials of the methanol and water extracts of S. cuneifolia plant were measured via some enzymes inhibition experiments as in vitro. The antioxidant ability of the same extracts was measured via radical scavenging and reducing power methods. Also, the total phenolics and flavonoids of the plant were identified. Finally, the extracts were analyzed by the LC-MS/MS analysis and the phenolic content of S. cuneifolia was clarified.     

Separation and characterization of antioxidants from Spirulina platensis microalga combining pressurized liquid extraction, TLC, and HPLC-DAD

A new procedure has been developed to separate and characterize antioxidant compounds from Spirulina platensis microalga based on the combination of pressurized liquid extraction (PLE) and different chromatographic procedures, such as TLC, at preparative scale, and HPLC with a diode array detector (DAD). Different solvents were tested for PLE extraction of antioxidants from S. platensis microalga. An optimized PLE process using ethanol (generally recognized as safe, GRAS) as extraction solvent has been obtained that provides natural extracts with high yields and good antioxidant properties. TLC analysis of this ethanolic extract obtained at 115 degrees C for 15 min was carried out and the silica layer was stained with a DPPH (diphenyl-pycril-hydrazyl) radical solution to determine the antioxidant activity of different chromatographic bands. Next, these colored bands were collected for their subsequent analysis by HPLC-DAD, revealing that the compounds with the most important antioxidant activity present in Spirulina extracts were carotenoids, as well as phenolic compounds and degradation products of chlorophylls.     

High resolution LC-MS characterization of phenolic compounds and the evaluation of antioxidant properties of a tropical purple radish genotype

This study reports qualitative profiling of the phenolic compounds in an indigenously developed purple radish genotype VRRAD-151 using ultra performance liquid chromatography with quadrupole time of flight mass spectrometry. The root and leaf samples were harvested at the horticultural maturity stage of the genotype. Roots were divided into the periderm, and xylem, and the leaf samples were divided into petiole, and lamina, and these were separately extracted with methanol before the LC-MS analysis. A total of 66 compounds, including 23 flavonols, 1 dihydroflavonols, 4 flavonones, 4 flavones, 28 anthocyanins, 2 isoflavonoids, 3 phenolic acids, and 1 hydroxybenzaldehyde were putatively identified based on high resolution accurate mass analysis with the data processing through UNIFI®, which is a comprehensive compound identification software solution. An in-house developed database comprising the secondary metabolites of polyphenols was used for the screening purpose, and each phenolic compound was identified based on the detection of the precursor ion, and at least one characteristic fragment ion, each with less than 5 ppm of mass error. Anthocyanins were the most abundant type of phenolics exhibiting 59% in leaf petiole, 80% in root periderm, and 90% in root xylem. The relative concentration of anthocyanins was lower (11%) in the leaf lamina. Cyanidins were the most predominant anthocyanins accounting for 54, 100, 90 and 65%, in leaf lamina, leaf petiole, root periderm and root xylem, respectively. Eight anthocyanins and 25 flavonols (except kaempferol-3-O-p-coumaryl-shophoroside-7-O-glucoside) are tentatively new identifications and reported for the first time in radish. Flavonols were found to be the predominant group of phenolic compounds in the leaf lamina, and interestingly, the gradient of antioxidant activity followed the (relative) concentration gradient of flavonols in the samples. The relative antioxidant activity of various fractions when compared with each other, followed the trend: leaf lamina > root periderm > leaf petiole ≈ root xylem. Based on the results it can be reflected that this genotype can be utilized as a functional food for management of various human and animal diseases. Since the detected anthocyanins were mostly present in acylated forms, this genotype can function as a potential source of stable natural colorants.     

DNA cleavage,cytotoxic and antioxidant properties of Cistus laurifolius L. extracts

In this study, extracts of the root, branch and leaf parts of Cistus laurifolius L. were prepared using hexane, methylene chloride and ethanol solvents. DNA cleavage, cytotoxic and antioxidant properties of the prepared extracts were then investigated. The cytotoxic properties of the extracts were investigated in A549, DU-145, PNT-1A, MDA-MB231, CRL-4010 and HCT-116 cell lines. Among all prepared extracts, T4 (seed–methylene chloride) extract showed cytotoxic effects on more cancer cell lines compared to other extracts. Antioxidant tests were performed by DPPH (2,2-diphenyl-1-picrylhydrazil) radical scavenging and Folin-Ciocalteu methods. In both tests, it was determined that T7 (seed–ethanol) extract has a very strong antioxidant effect (IC₅₀ = 0,000015 μg/ml for the DPPH method). In DNA cleavage studies, the results obtained confirm the protection of DNA from hydroxyl radical damage in the presence of methanolic plant extracts. Consequently, we determined that some of the Cistus laurifolius L. extracts have significant biological properties on the studied cell lines.     

GC/MS and LC-MS/MS phytochemical evaluation of the essential oil and selected secondary metabolites of Ajuga orientalis from Jordan and its antioxidant activity

The current investigation aimed to shed light in the volatile and non-volatile secondary metabolites of Ajuga orientalis L. from Jordan. GC/MS and GC/FID analysis of the hydrodistilled essential oil obtained from aerial parts of the plant revealed tiglic acid (18.90 %) as main constituent. Each of the methanol and butanol fractions of A. orientalis were screened for their total phenol content (TPC), total flavonoid content (TFC), and antioxidant activity determined by DDPH and ABTS methods. The extracts were then analyzed by LC-ESI-MS/MS to unveil their chemical constituents, especially phenols and flavonoids. Results showed that the AO-B extract had the highest TPC (217.63 ± 2.65 mg gallic acid/g dry extract), TFC (944.41 ± 4.77 mg quercetin /g dry extract), highest DPPH and ABTS antioxidant activity ((4.00 ± 0.20) × 10^-2; (3.00 ± 0.20) × 10^-2 mg/mL, respectively) as compared to the AO-M extract. LC-ESI-MS/MS analysis of both extracts revealed the presence of several phenolics, flavonoids and nonphenolic acids.     

Biosynthesis and characterization of lead selenide semiconductor nanoparticles (PbSe NPs) and its antioxidant and photocatalytic activity

The current study fabricated novel lead selenide nanoparticles (PbSe NPs) by a simple biological benign process with Trichoderma sp. WL-Go. Ultraviolet–visible spectroscopy (UV–vis), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transfer infra-red (FTIR) spectroscopic analysis, Raman spectroscopy and Photoluminescence (PL) were used to characterize the physicochemical properties of the fabricated NPs. Synthesis at pH 8 with 0.5 g biomass of strain WL-Go and (1:1) mM of SeO₂: Pb(NO₃)₂ were the optimal synthesis conditions to achieving 10–30 nm cubic faced centered NPs. The PbSe NPs served as catalyst for investigating the antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and photodegradation ability of rhodamine B dye (10 mg/L). The results indicated that the NPs could eliminate up to 88.60% of free radicals after adding 600 g/mL NPs and could photodegrade 82% of rhodamine B in 30 min. Thus, this study provides new knowledge and strategies for the future use of an environmentally benign bio- catalytic PbSe NPs to efficiently eliminate free radicals and in treatment of persistent organic pollutants in wastewaters.