ABTS Radical Cation Scavenging Research Articles

Towards a better understanding of commonly used medicinal plants from Turkiye: Detailed phytochemical screening and biological activity studies of two Teucrium L. species with in vitro and in silico approach

Ethnopharmacological relevanceSince ancient times, Teucrium L. species have been among the most commonly used traditional medicinal plants mainly in the Mediterranean region. From tackling gastrointestinal problems to maintaining the healthy functioning of endocrine glands, and from treating malaria to severe dermatological disorders, Teucrium species are known to have extensive therapeutic applications. Teucrium polium L. and Teucrium parviflorum Schreb. are the two members of the genus that have been used in Turkish folk medicine for various medicinal purposes. Aim of the studyTo determine the phytochemical compositions of the essential oils and ethanol extracts of Teucrium polium and Teucrium parviflorum collected from different locations in Turkiye along with the investigation of in vitro antioxidant, anticancer, antimicrobial activities, and both in vitro and in silico enzyme inhibitory activities of the extracts. Materials and methodsEthanol extracts of Teucrium polium aerial parts and roots, and aerial parts of Teucrium parviflorum were prepared. Volatile profiling of the essential oils by GC-MS, phytochemical profiling of the ethanol extracts by LC-HRMS, antioxidant activity by DPPH radical scavenging, ABTS cation radical scavenging, CUPRAC, and metal chelating activity assays, anticholinesterase, antityrosinase, antiurease, activities by different enzyme inhibitory activity assays, anticancer activity by SRB cell viability assay, and antimicrobial activity against a standard panel of bacteria and fungi by the microbroth dilution technique. Molecular docking studies were performed by Autodock Vina (Ver. 1.1.2). ResultsThe studied extracts were found to be quite rich in various biologically important volatile and phenolic compounds. (−)-Epigallocatechin gallate, which is a molecule renowned for having great therapeutic potential, was the major compound of all extracts. Teucrium polium aerial parts extract was revealed as a great source for naringenin with 16327 ± 685.23 μg/g extract. All extracts exerted significant antioxidant activity by different methods. All extracts demonstrated antibutrylcholinesterase, antityrosinase, and antiurease activities by in vitro and in silico assays. Teucrium polium roots extract stood out with remarkable tyrosinase and urease inhibitory and cytotoxic activities. ConclusionThe obtained results from this multi-disciplinary study proves that the traditional use of these two Teucrium species is justified, and the mechanisms behind are enlightened.

PHYTOCHEMICAL INVESTIGATION AND EVALUATION OF ANTIOXIDANT, AND ANTI-INFLAMMATORY ACTIVITY OF AERIAL PARTS OF Lindernia antipoda

Plant species always remain a backbone for the discovery of active biomolecules required for public health. The existing scrutiny is outlined to dissect the chemical nature and explore the antioxidant and anti-inflammatory strength of methanol extract of aerial parts of Lindernia antipoda by in vitro methods. The basic phytochemical evaluation of the extract reflected the existence of essential nitrogenous and phenolic bio-compounds. UV-visible and FTIR (Fourier Transform-Infrared Spectroscopy) spectral analysis supported the chemical nature of reflected compounds. The antioxidant capability was noticed through nitric oxide scavenging assay and ABTS [2,2’-azinobis-(3- ethylbenzothiazoline-6-sulfonic acid)] radical cation scavenging assay while anti-inflammatory competence was examined through the stabilization approach of human erythrocytes membrane against heat-induced membrane lysis. The methanol extract showed nitric oxide scavenging and ABTS radical cation scavenging by IC50 values of 398.38 μg/mL and 513.30 μg/mL respectively while anti-inflammatory activity was observed with the IC50 value of 573.01 μg/mL. The outcomes of each activity of methanol extract are presumably linked to the essential bioactive chemical substances in the extract

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.

Farklı Tekniklerle Ekstrakte Edilen Propolisin Polifenol İçerikleri Ve Antioksidan Aktivitelerinin Değerlendirilmesi

Propolis is classified as an opotherapeutic medicine due to the botanical origin of the resins. The chemical composition of propolis is greatly influenced by the honeybee species, botanical source and extraction techniques. Within this frame, we compared the same propolis’ polyphenol contents and antioxidant activities prepared with different techniques. Four types of extracts were prepared. The first type was prepared classically by ethyl alcohol (POH). The second and third types were extracted by sterile distilled water kept as both sterilised (PS) and non-sterilized (PN). The fourth one was prepared with full vacuumed and dried propolis with honey (PH). The antioxidant activity of extracts was evaluated with DPPH radical scavenging, ABTS radical cation scavenging, Cupric ion reducing antioxidant capacity. Also total phenolic and flavonoid content of extracts were investigated. POH extract showed significantly high content of total phenol and flavonoids which followed by PN, PS and PH. POH showed approximately two times higher activity on DPPH radical (IC50=4,39μg/mL) compared with quercetin as references. The highest activity on DPPH is shown by POH with 4,39 μg/mL of IC50 value which was followed by aqueous extracts 18,08. The lowest activity was shown by PS with 4,39 μg/mL of IC50 value. The highest scavenging activity against ABTS radical cation was shown by POH (73,37 mg TE/g extract) and the lowest activity was shown by PS (34,21 mg TE/g extract). According to the results, the new aqueous extraction technique is promising with relatively high polyphenol contents and antioxidant activities. Also honey with propolis can be an alternative product, although it has relatively lower values of antioxidant activity.

Anti-aging and Antioxidant Activities of Ethanol and Three-phase Partitioned Extracts of Inula viscosa

Inula viscosa is a plant commonly used to treat inflammation, germicide, expectorant, cough reducer, diuretic, anemia, and cancer. In addition to its medicinal effect, this plant has been preferred because it is thought to be a free radical scavenger and anti-aging effect due to its phenolic compounds. The aim of the study was to determine whether the plant has antioxidant and anti-aging potential. The plant was extracted with both the traditional solvent extraction method with ethanol and the novel three-phase partitioned (TPP) system, and the two methods were compared. The methods of DPPH free radical scavenging, ABTS cation radical scavenging, superoxide anion radical scavenging, and reduction of copper and iron ions were used to determine the antioxidant effects of the obtained extracts. In addition, elastase enzyme inhibition was studied to investigate the anti-aging potential. TPP method (23.9% yield) was performed at a higher yield than the solvent extraction (8.99% yield). The ethanolic extract and TPP extract of plant inhibited the DPPH free radical with IC50=0.27 µg/mL and IC50=0.026 µg/mL, and ABTS cation radical with IC50=0.28 µg/mL and IC50=0.13 µg/mL, and superoxide anion radical with IC50=3.53 µg/mL and IC50=2.43 µg/mL, respectively. According to the elastase inhibition results, IC50=3.11 µg/mL for ethanol extract and IC50=3.05 µg/mL for TPP extract were obtained. Both extracts of I. viscosa showed antioxidant and anti-aging effects at levels close to the standards. In addition, according to the results, TPP extract was found to be more effective than ethanol extract.

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.

Compositional Analysis and Antioxidant Activities of Thymus pubescens Essential Oil from Iran.

The genus Thymus is one of the well-known members of the Lamiaceae, comprising about 215 species. It is a polymorphic genus in this family. Therefore, possible differences in chemical composition among polymorphs may result in differences in their biological activities. This study was designed to specify chemical composition in order to assess antioxidant activities and to characterize active constituents of essential oil of Thymus pubescens. Essential oil was collected by hydrodistillation and was analyzed using GC-MS and GCFID. Antioxidant activities were evaluated by ABTS radical cation scavenging and β-carotene bleaching inhibition methods. Detection and identification of antioxidant components were performed by TLC-bioautography assay using ABTS•+ reagent. GC analyses indicated the presence of 39 components, accounting for 96.64% of total constituents, with thymol (38.67%), γ-terpinene (7.46%), and p-cymene (5.54%) as the main components. The IC50 values for antioxidant activities were equal to 1.15 (1.05 - 1.25) μg/mL and 0.45 (0.33 - 0.62) μg/mL for ABTS•+ scavenging and β-carotene bleaching inhibition tests, respectively. TLC-bioautography of oil resulted in the identification of thymol as the major antioxidant compound. Essential oil exhibited very potent and significant antioxidant activities correlated well with increasing dose in vitro.

Antiviral, Cytotoxic, and Antioxidant Activities of Three Edible Agaricomycetes Mushrooms: Pleurotus columbinus, Pleurotus sajor-caju, and Agaricus bisporus.

In this study, we investigated aqueous extracts of three edible mushrooms: Agaricus bisporus (white button mushroom), Pleurotus columbinus (oyster mushroom), and Pleurotus sajor-caju (grey oyster mushroom). The extracts were biochemically characterized for total carbohydrate, phenolic, flavonoid, vitamin, and protein contents besides amino acid analysis. Triple TOF proteome analysis showed 30.1% similarity between proteomes of the two Pleurotus spp. All three extracts showed promising antiviral activities. While Pleurotus columbinus extract showed potent activity against adenovirus (Ad7, selectivity index (SI) = 4.2), Agaricus bisporus showed strong activity against herpes simplex II (HSV-2; SI = 3.7). The extracts showed low cytotoxicity against normal human peripheral blood mononuclear cells (PBMCs) and moderate cytotoxicity against prostate (PC3, DU-145); colorectal (Colo-205); cecum carcinoma (LS-513); liver carcinoma (HepG2); cervical cancer (HeLa); breast adenocarcinoma (MDA-MB-231 and MCF-7) as well as leukemia (CCRF-CEM); acute monocytic leukemia (THP1); acute promyelocytic leukemia (NB4); and lymphoma (U937) cell lines. Antioxidant activity was evaluated using 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging, 2,2′-Azinobis-(3-Ethylbenzthiazolin-6-Sulfonic Acid) ABTS radical cation scavenging, and oxygen radical absorbance capacity (ORAC) assays. The three extracts showed potential antioxidant activities with the maximum activity recorded for Pleurotus columbinus (IC50 µg/mL) = 35.13 ± 3.27 for DPPH, 13.97 ± 4.91 for ABTS, and 29.42 ± 3.21 for ORAC assays.

Proteome Analysis and In Vitro Antiviral, Anticancer and Antioxidant Capacities of the Aqueous Extracts of Lentinula edodes and Pleurotus ostreatus Edible Mushrooms.

In this study, we examined aqueous extracts of the edible mushrooms Pleurotus ostreatus (oyster mushroom) and Lentinula edodes (shiitake mushroom). Proteome analysis was conducted using LC-Triple TOF-MS and showed the expression of 753 proteins by Pleurotus ostreatus, and 432 proteins by Lentinula edodes. Bioactive peptides: Rab GDP dissociation inhibitor, superoxide dismutase, thioredoxin reductase, serine proteinase and lectin, were identified in both mushrooms. The extracts also included promising bioactive compounds including phenolics, flavonoids, vitamins and amino acids. The extracts showed promising antiviral activities, with a selectivity index (SI) of 4.5 for Pleurotus ostreatus against adenovirus (Ad7), and a slight activity for Lentinula edodes against herpes simplex-II (HSV-2). The extracts were not cytotoxic to normal human peripheral blood mononuclear cells (PBMCs). On the contrary, they showed moderate cytotoxicity against various cancer cell lines. Additionally, antioxidant activity was assessed using DPPH radical scavenging, ABTS radical cation scavenging and ORAC assays. The two extracts showed potential antioxidant activities, with the maximum activity seen for Pleurotus ostreatus (IC50 µg/mL) = 39.46 ± 1.27 for DPPH; 11.22 ± 1.81 for ABTS; and 21.40 ± 2.20 for ORAC assays. This study encourages the use of these mushrooms in medicine in the light of their low cytotoxicity on normal PBMCs vis à vis their antiviral, antitumor and antioxidant capabilities.

Bioguided Isolation of Secondary Metabolites from Salvia cerino-pruinosa Rech. f. var. cerino-pruinosa

In the current study, the ethanol extracts prepared from the aerial parts and roots of an endemic species, Salvia cerino-pruinosa Rech. f. var. cerino-pruinosa were fractionated on silica gel columns and tested for determination of their antioxidant activity using DPPH free radical and ABTS cation radical scavenging, and cupric reducing antioxidant capacity (CUPRAC) test assays. Twenty known secondary metabolites were isolated from the active antioxidant fractions; rosmarinic acid (1), chlorogenic acid (2), caffeic acid (3), 4-hydroxybenzoic acid (4), benzoic acid (5), luteolin 7-O-glucoside (6), bis-(2-ethylhexyl)benzene-1,2-dicarboxylate (7), salvianolic acid A (8), salvianolic acid B (9), 7-acetylroyleanone (10), 6,7-dehydroroyleanone (11), ferruginol (12), inuroyleanol (13), 12-hydroxy-6,7-secoabieta-8,11,13-triene-6,7-dial (14), ursolic acid (15), oleanolic acid (16), taraxasterol (17), lupenone (18), β-sitosterol (19), and stigmasterol (20). Rosmarinic acid, which was obtained from the aerial parts, was found to be the best antioxidant compound among the isolated secondary metabolites in DPPH free radical and ABTS cation radical scavenging, and CUPRAC assays (IC50: 1.20±0.04 µg/mL, IC50: 1.74±0.06 µg/mL, A0.5: 1.22±0.02 µg/mL, respectively). Chlorogenic and caffeic acids, luteolin 7-O-glucoside, salvianolic acids A and B, and inuroyleanol exhibited also high antioxidant activity in the mentioned assays.

Antioxidant and cytoprotective effects of synthetic peptides identified from Kluyveromyces marxianus protein hydrolysate: Insight into the molecular mechanism

Antioxidant peptide obtained from Kluyveromyces marxianus protein hydrolysate, VLSTSFPPK (VL-9) and peptide analogues were synthesized chemically and analyzed for in vitro and cellular antioxidant activity. VLSTSFCPK (VCK-9), VLSTSFYPK (VYK-9), VLSTSFPPY (VY-9) and VLSTSFPPW(VW-9) showed the highest DPPH radical, ABTS radical cation scavenging and ferric reducing activities. VCK-9, VYK-9 and STSFPPK (SK-7) showed cytoprotective effects against Caco2 cells under H2O2-induced oxidative stress. The positive role of peptides in the protection of cells was shown to be due to scavenging free radicals, activation of Keap1-Nrf2 signaling pathway that may lead to overexpression of antioxidant enzyme genes and also increasing the activity of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPX) due to direct interaction with enzymes and changing their conformation. Altogether, pretreatment of cells under oxidative stress with VCK-9, VYK-9 and SK-7 led to decreasing the level of lipid and protein oxidation and cell apoptosis and increasing the cell viability.

Cytotoxic Activity-Guided Isolation from Achillea monocephala, and Biological Activities of its Different Extracts

Background: The genus Achillea is one of the most important genus of the Asteraceae family and many species of Achillea are used in traditional medicine to treat several ailments. Aim: The aim of the current research was to evaluate in vitro cytotoxic activities of n-hexan, chloroform, ethyl acetate and methanol extracts and to isolate the active compounds from the extract showing the strongest cytotoxic activity. In addition to this, it was aimed to evaluate the biological activities (cytotoxic, antioxidant, anti-urease, anticholinesterase, antimicrobial) of different extracts and active compounds from Achillea monocephala. Methods and Materials: The in vitro antioxidant, cytotoxic, anti-urease, anticholinesterase and antimicrobial activities of different extracts from A. monocephala aerial parts were examined. The structures of the active compounds were determined by NMR techniques, UV, IR and LC-MS/MS analysis and their biological potential was examined. Results: The chloroform extract showed strong and selective cytotoxic activity on the cancer cell lines (MDA-MB-231, MCF-7). Besides, this extract exhibited stronger antimicrobial activity than other extracts. Therefore, through activity-guided procedures, luteolin, naringenin and 8-hydroxy-salvigenin compounds were isolated from this extract. The methanol extract showed stronger antioxidant (DPPH, ABTS, CUPRAC) and anticholinesterase activity than other extracts. The n-hexan extract exhibited the highest anti-urease activity. In this study, it was determined that the isolated compounds had a strong biological activity. Naringenin compound had stronger ABTS radical cation scavenging and ferric reducing/antioxidant power, cytotoxic and antimicrobial activity than other compounds. 8-hydroxy-salvigenin compound showed the highest urease and acetylcholinestease enzyme inhibition. Conclusion: The results of this study suggest that the extracts and isolated compounds from the A. monocephala may be used as antioxidant, cytotoxic, anti-urease, anticholinesterase and antimicrobial agents in the future.

Method validation of 15 phytochemicals in Hypericum lysimachioides var. spathulatum by LC–MS/MS, and fatty acid, essential oil, and aroma profiles with biological activities

The aim of the present study was to develop and validate a LC–MS/MS method for quantification of 15 phytochemicals in Hypericum species. The developed method was fully validated in terms of repeatability (inter-day and intra-day precision), limits of detection and quantification, linearity, recovery and relative standard uncertainty. The developed and validated LC–MS/MS method was applied to determine 15 phytochemicals in the ethanol extracts of H. lysimachioides var. spathulatum aerial parts (HLS-A) and roots (HLS-R). Hyperoside was found to be the major compound in HLS-A and HLS-R ethanol extracts (16,560.3 and 3561.6 µg analyte/g extract, respectively). According to the results of GC–MS analyses, cis-13,16-docosadienoic acid (35.0%), caryophyllene oxide (24.33%) and undecane (28.21%) were determined as the major components in fatty acid, essential oil and aroma compositions of H. lysimachioides var. spathulatum, respectively. HLS-A and HLS-R ethanol extracts showed moderate activity in ABTS cation radical decolorization assay. The major components (hyperoside, astragalin, and quercetin) present in HLS-A and HLS-R ethanol extracts were found to have also the highest antioxidant effect in ABTS cation radical scavenging method. The extracts, main constituents in the extracts and essential oil had no toxic-cytotoxic potential against PDF, MCF-7 and HT-29 cell lines. HLS-A ethanol extract and essential oil exhibited high butyrylcholinesterase inhibitory activity. Quercetin showed the highest inhibitory effect against acetyl- and butyryl-cholinesterase, urease and tyrosinase among the tested samples. According to biological activity studies, H. lysimachioides var. spathulatum and their major components might be promoted as promising sources of natural agents and used in the development of nutraceuticals, functional food ingredients and pharmaceutical industry.

Antioxidant Potential and Stabilization Studies of Sunflower Oil Using Sorbaria tomentosa Extract and its Cu(II)/Zn(II) Chelates

Sorbaria tomentosa,, commonly known as “Berre” is native to Himalaya and Hindukush range in Pakistan. Qualitative phytochemical screening as well as quantitative antioxidant potential of its ethanolic extract was evaluated. Antioxidant potential of the extract was determined using standard methods like DPPH, FRAP, total phenolics, total flavonoids, ABTS radical cation scavenging assay and β-carotene linoleic acid emulsion system. Cu(II) and Zn(II) chelates of ,,Sorbaria tomentosa,, were also prepared and their antioxidant potential was compared with the extract as well as with synthetic antioxidants (BHT and BHA). It was observed that ,,Sorbaria tomentosa,, is a good source of natural antioxidant that worked efficiently compared to respective chelates. Keeping in view less efficiency of chelated extracts, stabilization studies of sunflower oil were conducted with ethanolic extract (250, 500, 1000 ppm) of ,,Sorbaria tomentosa,,. Various parameters like PV, FFA and IV were estimated to evaluate stabilization of oil. ,,Sorbaria tomentosa,, extract (1000 ppm) showed almost same role during stabilization like BHA at ambient condition during a storage period of 45 days. Keywords: Sorbaria tomentosa, phytochemicals, antioxidant potential, chelation, stabilization

Identification of hydroxycinnamic acid derivatives of selected canadian and foreign commercial beer extracts and determination of their antioxidant properties

Phenolic compounds in beer are derived from grains and hops during processing and production. Thus, the total phenolic content (TPC) of beer extracts, from selected Canadian and foreign commercial, and laboratory produced beers were examined and ranged from 3.72 ± 0.23 to 13.73 ± 0.49 mg GAE/100 mL beer. The total flavonoid content (TFC) of the same beer extracts varied from 0.82 ± 0.02 to 5.28 ± 0.04 mg CE/100 mL beer. Of particular interest were the hydroxycinnamic acids (HCAs) and derivatives in beer extracts because of their antioxidant properties. Main HCAs and a key derivative of ferulic acid, 4-vinylguaiacol (4-VG), were identified in beer extracts by high performance liquid chromatography (HPLC). Significant variations in TPC, TFC, HCAs and 4-VG content were observed among the beer extracts. Antioxidant activities of beer extracts, determined by radical scavenging and ferric-reducing assays, were positively correlated (p < 0.05) with TPC, TFC, and 4-VG but observed negative correlation with individual HCAs (p > 0.05). The positive correlation of 4-VG with ABTS radical cation scavenging and reducing power assays is reported first time. These findings suggest that phenolic compounds and a key derivative of the hydroxycinnamic acid, 4-VG, may have the protective role in the beer as an antioxidant.

Evaluation of in vitro biological activities of three Hypericum species (H. calycinum, H. confertum, and H. perforatum) from Turkey

Hypericum species have been used since ancient times for medicinal purposes due to their important pharmacological properties. As the most abundant species of the genus Hypericum, Hypericum perforatum is unquestionably one of the best-known and most consumed medicinal plants in the world. The aim of this current study is to evaluate antioxidant, anticholinesterase, and antiurease activities of the methanol extracts of flowering aerial parts of Hypericum calycinum L. Hypericum confertum Choisy, and Hypericum perforatum L. from Turkey. In this study, total phenolic and total flavonoid contents were determined as pyrocatechol and quercetin equivalents, respectively. Antioxidant activities of the species were carried out by using DPPH free radical scavenging, ABTS cation radical scavenging, metal chelate, and CUPRAC activity methods.Among the species that were investigated, it was determined that H. calycinum had the highest total phenolic content (141.12±2.40 μg PEs/mg), whereas H. confertum had the highest total flavonoid content (70.61±0.51 μg QEs/mg). The biochemical results in this study showed that all three species exerted strong antioxidant activity. H. calycinum appeared the most active in all antioxidant activity assays which is mainly due to its rich phenolic content. Additionally, H. calycinum showed the highest acetylcholinesterase inhibitory activity, while H. perforatum had the best inhibition towards butyrylcholinesterase. According to the urease inhibitory activity assay results, only H. calycinum showed low antiurease activity, whereas the other species did not show any activity against urease. The obtained results suggest that the studied three Hypericum species, especially H. calycinum could be promising sources for the treatment of several diseases because of their antioxidant and anticholinesterase properties.

Matrix effect evaluation and validation of the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical cation scavenging assay, as well as its application using a tejate, an ancient beverage in Mexico

Nowadays, consumers, food industries, and researchers have a great interest in evaluating the total antioxidant value of foodstuffs and plasma samples. The 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation scavenging assay is one of the most common antioxidant evaluations. However, this assay shows a great variability in its methodology, e.g., the use of a phosphate buffered saline (PBS) matrix. Moreover, all prior assays did not describe a complete validation procedure. This study demonstrated that the matrix of calibration standards had a significant effect on the accuracy of antioxidant measurements, under the ABTS radical cation scavenging assay. A PBS matrix should only be used in this assay during plasma analysis due to a negative matrix effect on calibration curves. Meanwhile, a PBS-free matrix should be used during analyses of water-based beverages. Our analytical validation showed that the current assay had an inverse lineal relationship, acceptable range, sensitivity, precision, accuracy, short and long-term stability, selectivity, identity, and short time of analysis. Additionally, this study showed that a traditional Southern Mexico beverage (tejate) had antioxidant properties (inhibition of the ABTS radical cation and ability to reduce the ferric ion) due to the presence of polyphenol compounds. The biological relevance was supported by a high plasma antioxidant activity in rats after a 7-day period of tejate consumption.

오레가노 종자 에탄올 추출물의 항산화 특성 및 유지 산화안정성에 미치는 영향

This study aimed to evaluate the antioxidant ability and inhibitory effects of oregano seed ethanol extract (OSEE). In vitro antioxidant assays including DPPH radical scavenging and ABTS cation radical scavenging were conducted, and, ORAC, total phenolic content, and FRAP value were determined. In addition, headspace oxygen, conjugated dienoic acid (CDA) value, and ρ-anisidine value (ρ-AV) for exploring oxidative stability were examined in an oil system with 100 ppm OSEE. The radical scavenging activities of 125 μg/mL OSEE using DPPH and ABTS were 84.6% and 32.2%, respectively. ORAC was significantly higher at a concentration of 100 μg/mL of OSEE as compared with the control without OSEE (p&lt;0.05). The antioxidant ability of the sample was concentration dependent manner. Additionally, the total phenolic content and FRAP value of OSEE were 264.64 μg/mL tannic acid equivalent/g extract and 339.78 μg/mL ascorbic acid equivalent/g extract, respectively. CDA and ρ-AV were significantly reduced to 56.3% and 76.5%, respectively, in 7 h of oil oxidation in OSEE, as compared with the control oil. OSEE exhibited excellent in vitro antioxidant ability and oxidative stability in the oil matrix. Furthermore, the major volatile compounds of OSEE were limonene, linalool, o-cymene, thymol, α-pinene, and γ-terpinene. Therefore, it is evident that oregano seed can be used as a functional ingredient in the natural antioxidant market.

In vitro antioxidant capacity of Euphorbia retusa Forssk. from Algerian desert

Context: Euphorbia retusa Forssk. is a medicinal plant, which traditionally is used in Algerian Sahara for treatment of infantile eczema, warts and trichiasis. Aims: To evaluate phenolic composition and antioxidant capacity of methanolic extracts from stems, leaves and seeds of Euphorbia retusa. Methods: Total phenolic and flavonoids were analyzed by Folin-Ciocalteu and aluminum chloride assays, respectively using gallic acid (GA) and quercetin (Q) as standard compounds. Antioxidant capacity was studied in vitro by using DPPH and ABTS cation radical scavenging, cupric-reducing antioxidant capacity (CUPRAC) and reducing power assays, followed by identification of phenolic compounds of seeds by mean of high-performance liquid chromatography (HPLC-DAD). Results: Methanolic extracts of E. retusa seeds had the highest total phenolic and flavonoid contents with 315.50 ± 1.41 µg GA equivalent/mg dry extract and 91.83 ± 8.18 µg Q equivalent/mg dry extract, respectively. Identification of phenolic compounds from seeds revealed that epigallocatechin 3-O- gallate was the major flavonoid. This organ showed the highest activity in the assays of DPPH (IC50 = 7.20 ± 0.25 µg/mL), ABTS (IC50 &lt; 6.25 µg/mL), CUPRAC (A0.5 = 10.64 ± 0.99 µg/mL) and reducing power (A0.5 = 11.84 ± 1.72 µg/mL). Conclusions: Euphorbia retusa seeds have an antioxidant capacity that could be useful in pharmacological and medicinal fields

Chemical Composition, Antioxidant, Anticholinesterase and Anti-Tyrosinase Activities of Essential Oils of Two Sideritis Species from Turkey.

Sideritis species have been known as medicinal plants since ancient times, and used as tea in Mediterranean countries such as Turkey, Greece, and Spain. They are also used for the treatment of several ailments such as a cough, common cold, and gastrointestinal disorders. The aim of the present study was to perform the chemical composition, antioxidant, anticholinesterase, and anti-tyrosinase activities of the essential oils of Sideritis albiflora and S. leptoclada. β-caryophyllene (21.2%) and Germacrene D (17.9%) were identified as the major compounds in S. albiflora and S. leptoclada essential oils, respectively. The essential oil of S. albiflora showed the highest lipid peroxidation inhibitory (IC50: 73.8 ± 0.8 µg/mL), DPPH free radical scavenging (28.3±0.1%), ABTS cation radical scavenging (IC50: 50.6 ± 1.0 µg/mL), reducing power (A0.05: 181.7 ± 0.6 µg/mL), acetylcholinesterase (22.1 ± 0.4%), butyrylcholinesterase (IC50: 157.2 ± 0.9 µg/mL) and tyrosinase (15.2 ± 0.4%) inhibitory activities. Moreover, S. albiflora essential oil had rich total phenolic and flavonoid contents indicating 41.5 ± 0.8 µg PEs/mg and 21.4 ± 1.0 µg QEs/mg respectively. This study suggests that consumption of Sideritis species as tea may protect one against melanogenesis, amnesia, and oxidative stress without any observable side effect.