ABTS Radical Cation Scavenging Activity Research Articles

Solvent Effects on the Phenolic Compounds and Antioxidant Activity Associated with Camellia polyodonta Flower Extracts.

Camellia polyodonta flowers contain limited information available regarding the composition of their bioactive compounds and activity. The objective of this study was to identify phenolic compounds and investigate the effect of different solvents (ethanol and methanol) on the phenolic content and antioxidant activity in C. polyodonta flowers. The analysis using UPLC-Q-TOF-MS/MS revealed the presence of 105 phytochemicals and the most common compounds were flavonols, procyanidins, and ellagitannins. Interestingly, flavonol triglycosides were identified for the first time in these flowers. The study demonstrated that the concentration of the solvent had a significant impact on the total phenolic compound (TPC), total flavonoid compound (TFC), and total proanthocyanidin content (TPAC). The TPC, TFC, and TPAC showed a remarkable increase with the increasing concentration of the solvent, reaching their maximum levels (138.23 mg GAE/g DW, 421.62 mg RE/g DW, 60.77 mg PB2E/g DW) at 70% ethanol. However, the total anthocyanin content reached its maximum at low concentrations (0.49 mg CGE/g DW). Similar trends were observed in the antioxidant activity, as measured by the DPPH· assay (DPPH radical scavenging activity), ABTS·+ assay (ABTS radical cation scavenging activity), and FRAP assay (Ferric reducing antioxidant power). The maximum antioxidant activity was observed at 100% solvents and 70% methanol. Among the 14 individual phenolic compounds, 70% methanol yielded the highest content for 8 (cyanidin-3-O-glucoside, procyanidin B2, procyanidin B4, epicatechin, rutin, kaempferol-3-O-rutinoside, astragaline and quercitrin) out of the 14 compounds. Additionally, it was found that epicatechin was the most abundant phenolic compound, accounting for approximately 20339.37 μg/g DW. Based on these findings, it can be concluded that 70% methanol is the most effective solvent for extracting polyphenols from C. polyodonta flowers. These results provided chemical information and potential antioxidant value for further research in C. polyodonta flowers.

Phenylethanoid glycosides from Michelia champaca leaves

Chemical investigation on the leaves of Michelia champaca L. (Magnoliaceae) led to the isolation of five previously undescribed phenylethanoid glycosides (PhGs), 4-O-β-d-glucopyranosyl-acteoside (1), 4‴-O-(6-O-E-caffeoyl)-β-d-glucopyranosyl-acteoside (2), 4‴-O-(6-O-E-caffeoyl)-β-d-glucopyranosyl-isoacteoside (3), 6""-O-E-feruloyl-echinacoside (4), and 6""-O-p-E-coumaroyl-echinacoside (5), together with eighteen known PhGs. Their structures were determined by spectroscopic and chemical methods. All the known PhGs except acteoside (8) were not previously reported in the genus. Twenty-one PhGs exhibited more potent DPPH radical scavenging activity and FRAP than l-ascorbic acid (l-AA), and twenty-two PhGs showed better ABTS radical cation scavenging activity than l-AA. In addition, twelve PhGs displayed more potent cellular reactive oxygen species scavenging activity than curcumin. The results revealed that the leaves of M. champaca are a rich source of phenylethanoid glycosides and antioxidants.

CYTOTOXICITY SCREENING AND ANTIOXIDANT CAPACITY ASSESSMENT OF THE INNER PERIANTH SEGMENTS OF 14 RUMEX SPECIES GROWN IN TÜRKİYE

Objective: Breast cancer is one of the most prevalent cancer types worldwide. Antioxidant sources may prevent the occurrence of cancer. Natural sources rich in phenolics, thus, may provide alternate agents in the management of breast cancer. Rumex species are widely distributed in Turkish flora. Emerging evidence has pointed out the antitumoral property of Rumex species on a variety of cancer cells. In the present study, we propose to test the ethanolic extracts of the inner perianth segments of 14 Rumex species on four breast cancer cells with different origins. We also demonstrated their toxicity on healthy cells. Material and Method: We performed the resazurin reduction assay to examine the cytotoxicity and toxicity. Furthermore, we determined the phenolic contents of the extracts as an indicator of their antioxidant profile and ascertained their antioxidant activities by DPPH radical, ABTS radical cation scavenging activity and cupric ion-reducing antioxidant capacity assays. Result and Discussion: The ethanolic extracts of the inner perianth segments of Rumex species exhibited remarkable cytotoxicity profiles neither on breast cancer cells nor on healthy H9c2 rat myoblastoma cells. However, they usually displayed strong antioxidant activities due to possessing high phenolic content.

Antioxidant activity, anti-tyrosinase activity, molecular docking studies, and molecular dynamic simulation of active compounds found in nipa palm vinegar.

Tyrosinase is a key enzyme in melanogenesis and its inhibitors have become increasingly because of their potential activity as hypopigmenting agents which have less side effects. Nipa palm vinegar is an aqueous product that is normally used as a food supplement. The aim of this study was to study the determination of antioxidant activity and tyrosinase inhibitory activities of aqueous extract of original nipa palm vinegar (AE O-NPV), nipa palm vinegar powder (NPV-P) and aqueous extract of nipa palm vinegar powder (AE NPV-P) were examined. Nipa palm vinegars were evaluated the phenolic and flavonoid content, and the active compounds which were submitted to molecular docking and molecular dynamic simulation, chemoinformatics, rule of five, skin absorption and toxicity. The highest phenolic and flavonoid contents in the AE O-NPV were 2.36 ±0.23 mg gallic acid equivalents/g extract and 5.11 ±0.59 mg quercetin equivalents/g, and the highest ABTS radical cation scavenging activity was also found. The AE O-NPV, NPV-P and AE NPV-P showed anti-mushroom tyrosinase activity. The HPLC analysis showed that there were vanillic acid and three flavonoids (catechin, rutin and quercetin). The molecular docking study revealed that the binding of the vanillic acid and three flavonoids occurred in the active site residues (histidine and other amino acids). Moreover, the number of hydrogen bond acceptors/donors, solubility, polar surface area and bioavailability score of the vanillic acid and three flavonoids were acceptable compared to Lipinski's Rule of Five. The molecular dynamic simulation showed that vanillic acid interacts with HIS284 through π-π stacking hydrophobic interactions and forms a metal-acceptor interaction with the copper molecule at the tyrosinase active site. All compounds revealed good skin permeability and nontoxicity. Nipa palm vinegar could be a promising source of a new ingredient for tyrosinase inhibition for cosmetics or pharmaceutical products.

Widely targeted metabolomics analysis of the main bioactive compounds of Ganpu tea processing through different drying methods

The flavor and biological components of Ganpu tea are largely affected by the drying process. In this study, Ganpu tea was selected as the research object, and the effects of different drying methods, including drying by sunlight, low temperatures and hot air, on the antioxidant activities, α-glucosidase and acetylcholinesterase activities and metabolite profiles of Ganpu tea were investigated. The results suggested that the DPPH free radical scavenging activities of low temperature-dried Ganpu tea (GPTL), sunlight-dried Ganpu tea (GPTS) and hot air-dried Ganpu tea (GPTH) were 46.8%, 56.2% and 47.1%, respectively. The ABTS radical cation scavenging activity of GPTL, GPTS and GPTH were 45.2%, 51.4% and 46.3%, and the T-AOC activities among them were 14.3, 21.4 and 12.5 U/g, respectively. In addition, compared with GPTS and GPTH, GPTL increased α-glucosidase inhibition and acetylcholinesterase inhibition activities. The widely targeted metabolomics analysis showed that low-temperature drying significantly increased corilagin and strictinin levels, which played an important role in the antioxidant activities of Ganpu tea. The results provide a novel method for drying Ganpu tea and help promote the quality control of Ganpu tea during processing.

식물성 유지 및 수중유적형 유화계에서 육두구 종자 에탄올 추출물의 항산화활성 평가

The antioxidant ability of 80% ethanolic extract of nutmeg seed (NM80) was evaluated using in vitro assays and bulk oil and oil-in-water (O/W) emulsion matrices. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation radical scavenging, and oxygen radical antioxidant capacity (ORAC) in vitro assays were used to evaluate the antioxidant ability of the extract. The DPPH radical scavenging activities of 25, 50, 100, and 200 μg/mL NM80 were 12.5, 20.9, 35.1, and 62.8%, respectively, while the ABTS cation radical scavenging activities were 2.7, 6.5, 30.5, and 29.8%, respectively, demonstrating a dose-dependent effect. The ORAC value was significantly higher at an NM80 concentration of 25 μg/mL than the positive control (p<0.05). The conjugated dienoic acid (CDA), ρ-anisidine, and tertiary butyl alcohol values in 90-min-heated corn oil containing 200 ppm of NM80 were significantly reduced by 3.26, 16.94, and 17.34%, respectively, compared to those for the sample without NM80 (p<0.05). However, the headspace oxygen content and CDA value in the O/W emulsion containing 200 ppm of NM80 at 60°C had 6.29 and 82.85% lower values, respectively, than those for the sample without NM80 (p<0.05). The major volatile compounds of NM80 were allyl phenoxyacetate, eugenol acetate, and eugenol. NM80 could be an effective natural antioxidant in lipid-rich foods in bulk oil or O/W emulsion matrix.

Green Synthesis of Silver Nanoparticles from Allium cepa L. Peel Extract, Their Antioxidant, Antipathogenic, and Anticholinesterase Activity

The present work deals with the green synthesis and characterization of silver nanoparticles (AgNPs) using Allium cepa (yellowish peel) and the evaluation of its antimicrobial, antioxidant, and anticholinesterase activities. For the synthesis of AgNPs, peel aqueous extract (200 mL) was treated with a 40 mM AgNO3 solution (200 mL) at room temperature, and a color change was observed. In UV-Visible spectroscopy, an absorption peak formation at ~439 nm was the sign that AgNPs were present in the reaction solution. UV-vis, FE-SEM, TEM, EDX, AFM, XRD, TG/DT analyses, and Zetasizer techniques were used to characterize the biosynthesized nanoparticles. The crystal average size and zeta potential of AC-AgNPs with predominantly spherical shapes were measured as 19.47 ± 1.12 nm and -13.1 mV, respectively. Pathogenic microorganisms Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were used for the Minimum Inhibition Concentration (MIC) test. When compared to tested standard antibiotics, AC-AgNPs demonstrated good growth inhibitory activities on P. aeuruginosa, B. subtilis, and S. aureus strains. In vitro, the antioxidant properties of AC-AgNPs were measured using different spectrophotometric techniques. In the β-Carotene linoleic acid lipid peroxidation assay, AC-AgNPs showed the strongest antioxidant activity with an IC50 value of 116.9 µg/mL, followed by metal-chelating capacity and ABTS cation radical scavenging activity with IC50 values of 120.4 µg/mL and 128.5 µg/mL, respectively. The inhibitory effects of produced AgNPs on the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were determined using spectrophotometric techniques. This study provides an eco-friendly, inexpensive, and easy method for the synthesis of AgNPs that can be used for biomedical activities and also has other possible industrial applications.

Investigation of antioxidant properties of olive leave extracts from Hatay by different extraction methods

In this study, it was aimed to compare the antioxidant properties of the extracts obtained from the extraction of olive leaves in Hatay province prepared with different solvents. For this purpose, olive leaves were extracted using pure methyl alcohol with soxhlet and also by maceration using 60% ethanol, 70% methanol, 90% acetone (v/v) and distilled water. Total Flavonoid Content (TFC), Total Phenolic Content (TPC), Ferric Antioxidant Reducing Power (FRAP), DPPH radical scavenging avctivity, ABTS Cation Radical Scavenging activity and total sulfydryl groups by Ellman methods were used to determine the antioxidant properties of the extracts. As a result of the study, the highest TFC values per g leaf and g extract were obtained for 70% methanol maceration and soxhlet-methanol extract, respectively, while the highest TPC observed per leaf and g extract were determined in the extracts obtained with 90% acetone. In the FRAP method, the extract obtained with 60% Ethanol showed the highest activity per g leaf and g extract. Extracts obtained with Soxhlet showed the highest activity for both ABTS activity and Ellman method. In the DPPH method, the lowest EC50 value was determined in the extract obtained using 70% methanol, and it was determined that the extracts obtained with water showed the lowest performance in all antioxidant activity methods.

Correlation between metabolites of lactic acid bacteria isolated from dairy traditional fermented Tunisian products and antifungal and antioxidant activities.

The objective of this study is to identify and investigate the antifungal and antioxidant potential of lactic acid bacteria (LAB) isolated from traditional fermented products. In this work, a collection of LAB was isolated from traditional fermented products collected in four Tunisian regions. After first screening using the overlay method, seven bacterial strains were retained due to their high antifungal effect. Four strains of Limosilactobacillus fermentum were identified, one strain of Lacticaseibacillus paracasei, one strain of Lacticaseibacillus rhamnosus and one strain of Enterococcus faecium. The antifungal and the antioxidant potential of these bacteria were then evaluated. Bacterial strains were effective against six fungal strains with minimum inhibitory concentrations ranging from 25 to 100 mg/ml and minimum fungicidal concentrations ranging from 50 to 200 mg/ml. Cell-free supernatants of LAB were analysed by HPLC-DAD and LC-MS-qTOF-MS analysis. Results showed significant production of organic acids as well as several phenolic compounds. Correlation analysis confirmed that PLA and 1,2-dihydroxybenzene were positively correlated with antifungal potential. The results of the antioxidant activity highlighted an ABTS radical cation scavenging activity ranging from 49% to 57% and a DPPH trapping percentage ranging from 80% to 97%. Therefore, due to these characteristics, identified lactic acid bacteria strains have shown their effectiveness to perform as antifungal and antioxidant agents. Since microbial contamination is at the root of extensive losses in the food sector, the identified strains or their metabolites can potentially be used as additives to limit micro-organism spoilage in food products and increase their shelf life.

Phytochemical Compounds, Antioxidant, and Digestive Enzymes Inhibitory Activities of Different Fractions from Ginkgo biloba L. Nut Shells

This study was designed to investigate the phytochemical compounds, antioxidant, and digestive enzymes inhibitory activities of the free (F), esterified (E), and insoluble-bound (IB) fractions from Ginkgo biloba L. nut shells. Results showed that a total of twelve compounds were detected in G. biloba nut shells by using UHPLC-ESI-HRMS/MS, including two kinds of organic acids, three kinds of phenolic acids, three kinds of flavonoids, and four kinds of terpene lactones. The F fraction contained all identified compounds and had the highest contents of the total phenolics and total flavonoids. All of the three different fractions exhibited good DPPH radical and ABTS radical cation scavenging activities and strong inhibitory effects on the generation of intracellular reactive oxygen species (ROS). Moreover, these three fractions also had good inhibitory effects towards α-glucosidase and pancreatic lipase. Among the three fractions, the F fraction possessed the strongest bioactivities. The findings obtained in the current study may provide some insights and bases for the further investigation and application of G. biloba nut shells in clinical medicine or the nutraceutical industry.

Antioxidant and skin health-enhancing activities of wild indigo (Baptisia tinctoria) root extracts

This study aimed to investigate the effects of wild indigo (Baptisia tinctoria) root extract as a functional food material, in terms of antioxidant and skin health-related activities. Both water and ethanol (50/50, v/v) extracts showed high phenol content. They were evaluated for antioxidant activity, such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), antioxidant protection factor (PF), and thiobarbituric acid reactive substances (TBARS). While the DPPH radical scavenging activities of water and ethanol extracts were 84.23% and 89.30%, respectively, at 200 μg/mL total phenol content (TPC), the ABTS radical cation scavenging activities were 51.39% and 48.10%, respectively. The water and ethanol extracts also showed desirable antioxidant PF levels of 1.18 and 1.16, respectively. Furthermore, the antioxidant effects on TBARS significantly increased by 37.31% and 51.43%, respectively, in 200 μg/mL of water and ethanol extracts. Both the extracts showed high dose-dependent collagenase inhibitory activities, up to 27.60% and 77.39%, respectively. The ethanol extract showed an elastase inhibitory activity of 37.21%; the tyrosinase inhibitory effect (which facilitates natural skin-whitening) was 59.26% at 200 μg/mL TPC. The hyaluronidase activity inhibition, related to anti-inflammatory activity, was 20.02% for the water extract and 14.30% for the ethanol extract, at 200 μg/mL TPC. Therefore, B. tinctoria extract has potential applications in cosmetics and food supplements due to its antioxidant and skin health promoting activities.

Evaluation of the medicinal potential of a traditionally important plant from Turkey: Cerinthe minor L.

Background and Aims: Cerinthe minor L. has been used for both culinary and medicinal purposes in Turkey. Since the plant has remained uninvestigated pharmacognostically, this study aims to provide data on the phytochemical profile and in vitro biological activities of the ethanol extract prepared from the aerial and root parts of Cerinthe minor L. Methods: The phytochemical profile of the extract was determined by LC-MS/MS. Total phenolic and total flavonoid contents of Cerinthe minor ethanol extract were determined as pyrocatechol, and quercetin equivalents, respectively. Antioxidant activity of the extract was investigated by DPPH, and ABTS cation radical scavenging activity, and CUPRAC activity assays. Enzyme inhibitory activity assays were used to investigate anticholinesterase, antityrosinase, and antiurease activities. Cytotoxic potential of the plant was clarified by using the XTT method, and antimicrobial activity of the extract was established by the microbroth dilution technique. Results: According to the LC-MS/MS results, 11 different constituents were present in the extract, and the major compounds were, malic acid (5392.18±60.93 μg/g extract), fumaric acid (4730.99±58.66 μg/g extract), and rosmarinic acid (2470.07±176.12 μg/g extract). Total phenolic and flavonoid contents were found as 10.39±0.73 μg PEs/mg extract, and 0.75±0.07 μg QEs/mg extract, respectively. The extract demonstrated moderate antioxidant activity, whereas no enzyme inhibitory activity was exerted against the tested enzymes. No cytotoxic activity was observed on human renal (A498, UO-31) or human colon (COLO205, KM12) cancer cell lines. The extract was shown to possess low-moderate antimicrobial activity against C. tropicalis with a MIC value of 78.12 µg/mL. Conclusion: Having several pharmacologically valuable compounds, and not causing any toxicity on studied cell lines, Cerinthe minor is a plant that requires attention with its medicinal potential.

Synthesis, characterization and effect of alkyl chain unsaturation on the antioxidant activities of chlorogenic acid derivatives

Chlorogenic acid (CGA), a hydrophilic polyphenolic compound, is difficult to use in lipophilic systems. Accordingly, to improve its lipophilicity and explore the effect of alkyl chain unsaturation on antioxidant activity, CGA was acylated with fatty acids of the same chain length, but an increasing degree of unsaturation, namely, stearic acid [C18:0], oleic acid [C18:1], linoleic acid [C18:2], and linolenic acid [C18:3]. The major products were monoesters, as confirmed by ESI-MS, 1H NMR, 13C NMR, and Fourier transform infrared spectra (FT-IR) analysis. The lipophilicity of CGA derivatives was enhanced by acylation, and decreased with an increasing degree of fatty acid unsaturation. All CGA derivatives showed a high level of antioxidant activity. In detail, CGA-C18:0, CGA-C18:1, and CGA-C18:2 showed similar antioxidant activities, while CGA-C18:3 had the lowest antioxidant activity. The DPPH radical and ABTS radical cation scavenging activities of CGA-C18:3 were equivalent to 66.9% and 62.0% of those of CGA, respectively. The results of peroxide value (PV) indicated that the oxidative stability of CGA derivatives was enhanced. These results indicated that CGA derivatives could serve as potential sources of antioxidants for lipophilic food systems.

Chemical Composition, Total Phenolic Content, and Antioxidant Activity of the Essential Oils Extracted from the Needle of Ten Pinus Taxa

This study investigated the chemical compositions of essential oils (EOs) from ten taxa belonging to the Pinus genus. The studied taxa that grow wildly in China, and the EOs were extracted by steam distillation; the chemical compositions were isolated and characterized by GC-MS. Eighty-one components, representing over 92.10% of the EOs, were identified. The main constituents of EOs were α-pinene (6.44%–53.00%), β-caryophyllene (2.43%–24.64%), β-pinene (0.00%–22.32%), δ-cadinene (2.56%–17.56%), germacrene D (0.74%–11.38%), and camphene (0.78%–10.48%). Furthermore, we determined the total phenolic content (TPC) of the EOs, with the values from 26.50 to 60.01 mg eq GAE/mL EO. DPPH free radical scavenging activity (DPPH), ferric reducing antioxidant power (FRAP), and ABTS radical cation scavenging activity (ABTS) were used to evaluate the antioxidant capacity of the EOs, and the obtained values were ranged from 499.15 to 1,272.75 mmol eq Trolox/mL EO, 1,255.67 to 3,857.93 mmol eq Trolox/mL EO, and 370.81 to 1,677.19 mmol eq Trolox/mL EO, respectively. The results showed that all of the EOs studied had strong antioxidant activity, and these pine plants could be used as natural antioxidants in functional food and pharmaceutical industries.

Effect of Heat on Antioxidant Capacity of Black Radish (<i>Raphanus sativus</i> L. var <i>niger</i>) Root

The aim of this study was to identify the influence of drying temperature on total phenolic content and antioxidative efficacy of black radish root and to investigate heat stability of antioxidant capacity of its juice. Hot water extracts from the roots dried at four different temperatures were rich in total phenolics and characterized for DPPH free radical and ABTS radical cation scavenging activity, and reducing power. The best oven drying temperature corresponding to maximum value of total phenolic content and antioxidant potential was 70C. Antiradical activity and reducing power of the juice remained after pasteurization at 95C for 2 min.

Cytotoxic activity of Indigofera aspalathoides (Vahl.) extracts in cervical cancer (HeLa) cells: Ascorbic acid adjuvant treatment enhances the activity

The folkloric use of Indigofera aspalathoides (Vahl) in anti-inflammatory and anti-cancer treatment dates back to circa 300 BC. However, reports on scientific validation for folkloric usage are not available yet. The objective of the study is to assess the cytotoxic potential of I. aspalathoides and to provide a rationale for its ethnopharmacological use with lime juice (ascorbic acid) as an adjuvant. Using Soxhlet, the active principles of I. aspalathoides were extracted using methanol and ethanol as solvent and studied using gas chromatography coupled with mass spectrometry (GC–MS). We assessed the in vitro antioxidant efficacy by studying the DPPH radical scavenging activity, ferrous reducing antioxidant capacity (FRAC), and ABTS cation radical scavenging activity. Using MTT assay, the cytotoxic activity of SV-ME and EE against human cervical cancer (HeLa) and normal murine fibroblast (L929) cells were evaluated. The cytotoxicity and apoptosis induction was studied by dual acridine orange/ethidium bromide (AO/EB) fluorescent probe and Hoechst dye. Mitochondria membrane potential (Δψm) was assessed using JC1. Ascorbic acid (AA) additive/synergism was studied by co-treating HeLa cells with AA along with SV-ME and SV-EE at IC50 concentration. SV-ME and EE exert higher DPPH radical scavenging at 200 μg/mL. Both the extracts showed effective ABTS radical cation scavenging activity and ferrous reducing antioxidant capacity. Further, SV-ME and SV-EE treatment affected the cell viability and induced apoptosis, reduced cell viability with a concomitant increase in nuclear condensation and DNA fragmentation in a dose-dependent manner in cancer (HeLa) cells, but not in normal (L929) cells. Both the extracts increased the mitochondria membrane potential (Δψm) depolarization and altered the cellular redox state in HeLa cells. In addition, adjuvant ascorbic acid (AA) treatment increased the cytotoxic efficacy of the SV-ME and SV-EE in HeLa cells. I. aspalathoides used in the Siddha medicine for antitumor treatment have a very potent cytotoxic effect against cervical cancer cells (HeLa) in vitro. The cytotoxic and antitumor effect may have plausible involvement of Nrf2-ARE signaling pathway by restoration of cellular redox homeostasis.

Effect of organosolv extraction on the structure and antioxidant activity of eucalyptus kraft lignin

In this study, three lignin fractions F1, F2, and F3 were obtained from eucalyptus kraft lignin (EKL) by solvent extraction with ethyl acetate, acetone, and acetone/water. The antioxidant activity of these lignin fractions were measured and evaluated by using the DPPH radical scavenging activity, ABTS radical cation scavenging activity and ferric reducing antioxidant power analysis. These lignin fractions were also characterized by applying Gel permeation chromatography, Fourier transform infrared, 31P NMR and 2D HSQC NMR techniques. The three different lignin fractions had rather different average molecular sizes, as well as different phenolic and methoxy functional contents. The ethyl acetate fraction (F1) with the lowest average molecular weight (2342 g/mol) and the highest phenolic hydroxyl content (4.2457 mmol/g) and methoxy groups (6.2714 mmol/g) showed high homogeneity and the highest antioxidant activity. Its DPPH scavenging activity, ABTS+ scavenging activity, and ferric reducing the antioxidant power were 68.67%, 75.57%, and 91.89 μmol/g, respectively. Moreover, the antioxidant activity of F1 and F2 was found to be higher than that of butylated hydroxytoluene. Therefore, solvent extraction was shown to be an effective way to separate lignin fractions with high homogeneity, high antioxidant activity, which could lead to application of lignin with higher value.

Di- and Triterpenoids Isolation and LC-MS Analysis of Salvia marashica Extracts with Bioactivity Studies

In this study, dichloromethane, acetone, and methanol extracts of the aerial parts of the Salvia marashica plant which is an endemic species to Anatolia, were investigated. The total phenolic amounts of these extracts were determined as pyrocatechol equivalent and total flavonoids as quercetin equivalent. Antioxidant activity was determined by four complementary methods including inhibition of lipid peroxidation (by β-carotene color expression), DPPH free radical scavenging activity, ABTS cation radical scavenging activity and CUPRAC methods. Anticholinesterase activity of the extracts was investigated by the Ellman method against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Viability and cytotoxic activity tests were carried out on the fibroblast L929 cells and cytotoxic A549 lung cancer cells, respectively. The triterpenoids and diterpenoids constitute the major secondary metabolites of the S. marashica acetone and methanol extracts isolated by chromatographic methods. Their structures were determined based on spectroscopic methods, namely NMR and mass analyses. Ten terpenoids were obtained from either acetone or methanol extracts of the S. marashica. Seven of them were triterpenoids, elucidated as lupeol, lupeol-3-acetate, lup-12, 20(29)-diene, lup-20(29)-ene, α-amyrin-tetracosanoate, oleanolic acid and ursolic acid besides a steroid β-sitosterol. Two abietane diterpenes, abieta-8,11,13-triene (1) and 18-acetoxymethylene-abieta-8,11,13-triene (2), were obtained from the acetone extract which were isolated from a Salvia species for the first time in the present study. The methanol extract was found to be very rich in rosmarinic acid determined by LC-MS/MS analysis.

Identification and molecular docking of antioxidant peptides from hemp seed protein hydrolysates

The aim of this study was to assess the antioxidant activities of hemp seed protein hydrolysates (HPH) and identify antioxidant peptides. In vitro chemical-based assays indicated that HPH (0.4 mg/mL) possessed high ABTS radical cation scavenging activity (52.3 ± 0.1%), Fe2+-chelating activity (52.9 ± 0.9%) and hydroxyl radical scavenging activity (50.9 ± 1.3%). HPH (0.4 mg/mL) significantly elevated the cell viability (from 55.7 ± 1.2% to 80.0 ± 2.0%), and prevented the production of reactive oxygen species accompanied by increasing the antioxidant enzyme activities in HepG2 cells with H2O2-induced oxidative stress. After separation with gel filtration chromatography and reversed-phase high-performance liquid chromatography, two potential antioxidant peptides were firstly identified as Tyr-Gly-Arg-Asp-Glu-Ile-Ser-Val (YGRDEISV) and Leu-Asp-Leu-Val-Lys-Pro-Gln (LDLVKPQ) by liquid chromatography-tandem mass spectrometry. Molecular docking showed that the putative antioxidant mechanism of both peptides was attributed to their blockage of the entrance to myeloperoxidase active cavity. The (−) CDOCKER energy was 114.6 kcal/mol for peptide YGRDEISV, and 82.8 kcal/mol for peptide LDLVKPQ. Additionally, both of the peptides had good water-solubility and stability, no allergenicity or toxicity according to in silico prediction. Our findings suggest the potential for the development of HPH as an antioxidant.

Antioxidative Properties and Chemical Changes of Quercetin in Fish Oil: Quercetin Reacts with Free Fatty Acids to Form Its Ester Derivatives.

In this research, we studied the antioxidative properties and chemical changes of quercetin in fish oil during accelerated storage at 60 °C for 5 days. Gas chromatography (GC) analysis showed that quercetin inhibited aldehyde formation and unsaturated fatty acid oxidation in fish oil significantly; however, the inhibitory effects decreased gradually with prolonged heating time. Moreover, quercetin was consumed with increasing heating time. Some new phenolic derivatives were discovered in the fish oil with quercetin, with their structures fully elucidated by LC-MS/MS and comparison with newly synthesized ones (characterized by MS and NMR spectroscopy). Based on their chemical structures, we proposed that quercetin reacted with EPA and DHA to form the corresponding quercetin fatty acid esters in fish oil. In addition, the newly formed quercetin-3-O-eicosapentaenoate and quercetin-3-O-docosahexaenoate showed weaker DPPH and ABTS radical cation scavenging activity but much improved lipophilicity, higher cell membrane affinity, and hence enhanced cellular antioxidant activity compared with the parent quercetin. Overall, quercetin could be used as a safe dietary polyphenol to inhibit lipid oxidation. The newly formed quercetin-polyunsaturated fatty acid esters may render improved bioactivity to humans, which needs further investigation.