Antioxidant Activity Of Plant Extracts Research Articles

Simultaneous Analytical Efficiency Evaluation Using an HPTLC Method for the Analysis of Syringic Acid and Vanillic Acid and Their Anti-Oxidant Capacity from Methanol Extract of Ricinus communis L. and Euphorbia hirta L.

The well-known medicinal plants Ricinus communis L. and Euphorbia hirta L. have been traditionally used to treat a variety of ailments in the India and other countries. In the present research, a simple, rapid, reliable, and accessible HPTLC technique has been established for concurrent quantification of phenolic compounds (syringic acid and vanillic acid) and evaluation of their anti-oxidant capacity. The chromatographic separation was conceded on pre-coated silica gel plates 60 F254 as the stationary phase. The appropriate mobile phase combination of toluene-ethyl acetate-formic acid (7:2.5:0.5, v/v/v) were developed to expand the plates which separated components according to the marker compounds. Further, the anti-oxidant potential of methanol extract of R. communis (MERC) and E. hirta (MERH) were also assessed with 1,1-diphenyl-2-picrylhydrazyl (DPPH) by using UV spectrophotometry. Densitometric scanning was performed with a Camag V scanner and measured at two different wave lengths, 272 and 318 nm. The marker compounds were practically resolved with RF 0.5 ± 0.04 for syringic acid and 0.6 ± 0.06 for vanillic acid. The results obtained in the study of anti-oxidant activity of MERC and MERH showed significant free radical scavenging capacity against DPPH-generated free radicals. The developed HPTLC method was validated for accuracy, linearity, precision, and specificity. Both the extracts revealed considerable antioxidant activity. The reported existing phenolic and flavonoids compounds are responsible for antioxidant activity of plant extracts.

Effect of Traditional Preparation Processing on the Total Phenol Content and Antioxidant Activity of Fallopia multiflora Thunb.

This study evaluates the effects of traditional preparation on the total phenol content and in vitro antioxidant activity of Fallopia multiflora Thunb.. The experimental results show that the total phenol content calculated with gallic acid (GAE) of Fallopia multiflora Thunb. increased during preparation processing. The Fallopia multiflora Thunb. after preparation had a total phenol content of 22.73 ± 0.21 mg GAE/g, about 3% higher than the raw sample (22.03 ± 0.40 mg GAE/g). The preparation processing also significantly increased the antioxidant activity of Fallopia multiflora Thunb.. The concentration of extract, which could neutralize 50% of the free radicals generated from 2.2-diphenyl-1-picrylhydrazyl of medicinal materials, after processing was 53.71 ± 0.44 µg/ml, about 2.3 times lower when compared to raw pharmaceutical materials (124,38 ± 0,56 µg/ml).
 Keywords
 Fallopia multilflora Thunb., processing, antioxidant, total phenol, neutralized free radicals.
 References
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Screening of Antimicrobial and Antioxidant Activity of Acetone Extracts of Heritiera fomes Whole Plant against Pathogens

Background: Phytochemicals are well known to have many important pharmaceutical properties. Heritiera fomes grows in low saline environments. The present study was initiated to explore the biologically beneficial properties of H. fomes. Methods: The crude extracts of H. fomes were extracted in acetone by orbital shaker and concentrated using rota evaporator. Total flavonoid content and Total phenolic content were estimated spectrophotometrically and the in-vitro antioxidant capacity was estimated by DPPH (2,2-diphenyl-1-picrylhydrazyl), Ferric Reducing Antioxidant Power (FRAP) and Hydrogen peroxide (H2O2) Scavenging Assays. Anti-microbial activity was determined by Disc diffusion method. Results: Phytochemical screening of acetone extract of H. fomes showed the presence of major classes of phytochemicals like alkaloids, glycosides, flavonoids, saponins, carbohydrates, phenols and sterols in considerable quantity. The total amount of phenolic and flavonoid content was found to be 75.3 mg GAE/g dry weight and 61.3 mg QE/g dry weight respectively. Antioxidant activity of plant extract determined by using different assays like H2O2 radical scavenging, DPPH and FRAP. A positive correlation between all the pairs of antioxidant assays was observed. Further, antimicrobial activity against various pathogens was evaluated by disc diffusion method where the zone of inhibitions were found to be in range from 5± 0.35 to 12 ± 0.50 mm. Conclusion: The study concludes that the plant Heritiera fomes has its effect in scavenging free radicals and has a potential to be a power antioxidant. Several in-vitro studies possess significant antioxidant, antimicrobial activities. The present study plays an important tool for new drug discovery.

The Interactions among the Heavy Metals in Soils and in Weeds and Their Antioxidant Capacity under the Mining Activities in Thai Nguyen Province, Vietnam

In this study, the relationship between heavy metals (HMs) concentrations in soils and several weeds including Cyclosorus parasiticus, Dicranopteris linearis, Pityrogramma calomelanos, and Pteris vittata in three mining sites (Cam Gia (Thai Nguyen city), Tan Long (Dong Hy district), and Ha Thuong (Dai Tu district)) in Thai Nguyen province, Vietnam, have been investigated. The levels of HMs varied among soil origins and showed the contaminations of As, Cu, and Pb in soil samples collected in Dong Hy and Dai Tu districts. In addition, the HM distribution and cocontamination phenomena in different soils significantly affected the HM residues and transportation abilities into different species as well as tissues. Moreover, based on the analysis of bioaccumulation factor (BF) and translocation factor (TF), C. parasiticus and D. linearis were found potentially for phytoextraction by roots, while P. calomelanos and P. vittata were suitable for hyperaccumulation in shoots and leaves. Consequently, the strongest antioxidant property by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion (SRSA) radical scavenging assays were demonstrated in the methanol root extracts of C. parasiticus and P. vittata, respectively. In conclusion, the correlation among HM in soils and tissues with antioxidant property allows us to hypothesize that the presence of these elements can enhance the antioxidant activity of plant extracts, suggesting to apply the weeds in phytoremediation as well as in phytomedicine.

DETERMINATION OF ANTIOXIDANT ACTIVIY Salvia sclarea L. AND Rosmarinus officinalis L. (LAMIACEAE) SPECIES FROM ESKİŞEHİR, TURKEY

Salvia sclarea L. and Rosmarinus officinalis L. are an important medicinal and aromatic plants of Lamiaceae. The plant materials were collected from Eskişehir and the collected samples were macerated with 70% MeOH. In this study, antioxidant activity of plant extracts was evaluated using 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, Trolox equivalent antioxidant capacity (TEAC assay) and β-carotene bleaching method. The in vitro antioxidant results, DPPH radical scavenging assay and β-carotene bleaching method, it is seen that R. officinalis extract shows a more effective antioxidant activity compared to S. sclarea extract, and in the TEAC assay, S. sclarea extract shows a more effective antioxidant activity than R. officinalis extract.

IN VITRO BIOLOGICAL STUDY OF SEVEN NEPALESE MEDICINAL PLANTS AND ISOLATION OF CHEMICAL CONSTITUENTS FROM CISSAMPELOS PAREIRA

Objective: This study aimed to investigate the phytochemical analysis and biological activities of methanol extracts of seven medicinal plants such as Anisomeles indica, Achyranthes bidentata, Sphenomeris chinensis, Cleistocalyx operculatus, Malvaviscus arboreus, Cissampelos pareira, and Tectaria coadunate collected from Tanahun district of Nepal.
 Methods: Phytochemical analysis was performed by color differentiation methods adopting the standard protocol. Antioxidant activity of plant extracts was evaluated by 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. Flavonoid content was estimated by aluminum chloride colorimetric method. Antidiabetic activity was evaluated by α-amylase inhibition assay where acarbose was used as standard. Toxic effect was studied by brine shrimp bioassay.
 Results: Phytochemical analysis showed the presence of alkaloids, polyphenols, flavonoids glycoside, and terpenoid in most of the extracts. T. coadunate and C. pareira exhibited high antioxidant activity with IC50 41.84 and 52.03 μg/ml, respectively. Whereas, the plant extracts of Malvaviscus arboretum, S. chinensis, and A. bidentata exhibited moderate antioxidant activity with IC50 76.07, 81.05, and 89.93 µg/ml, respectively. The result of flavonoid content showed the values ranged A. indica (1.84 mg quercetin equivalent per gram [mg QE/g]) to A. bidentata (5.93 mg QE/g). C. pareira and S. chinensis exhibited the highest α amylase inhibition activity with IC50 471.68 and 517.59 µg/ml, respectively. Whereas, A. indica and M. arboreus showed moderate activity with IC50 626.12 and 952.39 μg/ml, respectively. C. pareira exhibited against Staphylococcus aureus (ATCC 25923) with a zone of inhibition 12 mm/well, and Escherichia coli (ATCC 25922) 9 mm/well but, T. coadunate showed 14 mm/well against S. aureus. The plant extracts of A. bidentata and C. operculatus showed toxic effect against newly hatched brine shrimp larvae. The chemical compounds isolated from C. pareira indicated by gas chromatography-mass spectrometry analysis were 3-isopropoxy-1,1,1,7,7,7-hexamethyl-3,5,5-tris(trimethylsiloxy) tetrasiloxane, alpha-tocopherol, pentadecanoic acid, and 4,22-stigmastadiene-3-one. The major compound was indicated by percent peak area and base m/z value as alpha-tocopherol.
 Conclusion: Present study revealed that plant extracts are the potential source of antioxidant, antidiabetic, and antibacterial agents showing different biological activities. The results of this study provide partial scientific support for the traditional application of medicinal plants to cure diabetes and infectious diseases, although further studies are needed to assess the mechanism of action.

Borate suppresses the scavenging activity of gallic acid and plant polyphenol extracts on DPPH radical: A potential interference to DPPH assay

The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay is commonly applied for appraising antioxidant activity of plant extracts. To test the potential interference of borate on DPPH assay, the effects of borates (0–16 mM sodium tetraborate) on the DPPH radical scavenging ability of gallic acid (GA, at 10, 20 and 40 mg/L) were studied. The presence of borate led to a remarkable reduction of DPPH inhibition of GA, and its DPPH radical scavenging ability can be suppressed contingently on borate content. This interference was interpreted to be resulted from the autoxidation of GA as well as the formation of GA-borate ester complex under alkaline pH (~9.50) of borate. Natural polyphenol extracts from apple peels, parsley and lettuce leaves (as boron-enriched representatives) also exhibited a reduced ability in eliminating DPPH radicals when spiked with borates. In order to avoid this limitation, the utilization of acetate buffer at pH 5.50 for sample preparation is proposed. This work pointed to the possible underestimation of antioxidant properties of polyphenol extracts originated especially from boron-enriched or borate pretreated plants by DPPH assay.

Cytotoxicity and antioxidant activity of plant extracts from Vietnam

Traditional medicine plays an important role in treatment of human diseases. Extracts from medicinal plants exhibit many valuable biological activities. However, the exploitation and application of the extracts requires knowlege on the mechanism of action. In this study, cytotoxic and antioxidant activites of the methanol and hexane extracts of 09 Vietnamese plants have been studied in vitro on keratinocyte HaCaT cell line. The results showed that all plant extracts had a cytotoxyc effect on HaCaT cells. The hexane extracts showed more potent than the methanol extract. Garcinia mangostana exhibited the best cytotoxicity with IC50 values of 14.42 mg/ml (for hexane extract) và 14.27 mg/ml (for MeOH extract). All tested extracts resulted in the generation of intracellular reactive oxygen radicals in HaCaT cells. Mangifera indica, Cleistocalyx operculatus and Terminalia catappa had the best DPPH radical scavenging activity with EC50 values of 23.0 mg/ml, 27.4 mg/ml and 23.73 mg/ml, respectively. Besides, G. mangostana and T.catappa exhibited capacity of eliminating active oxygen radicals (iROS). The test extracts significantly reduced the number of cells in phase G1 and increased the number of cells in S and G2/M phases. The data obtained in this study are the preliminary results for further studies on the mechanisms of action and therapeutic applications of these plants.

Quantification of the Antioxidant Activity of Plant Extracts: Analysis of Sensitivity and Hierarchization Based on the Method Used.

Plants have a large number of bioactive compounds with high antioxidant activity. Studies for the determination of the antioxidant activity of different plant species could contribute to revealing the value of these species as a source of new antioxidant compounds. There is a large variety of in vitro methods to quantify antioxidant activity, and it is important to select the proper method to determine which species have the highest antioxidant activity. The aim of this work was to verify whether different methods show the same sensitivity and/or capacity to discriminate the antioxidant activity of the extract of different plant species. To that end, we selected 12 species with different content of phenolic compounds. Their extracts were analyzed using the following methods: 2,2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, ferric reducing (FRAP) assay, Trolox equivalent antioxidant capacity (ABTS) assay, and reducing power (RP) assay. The four methods selected could quantify the antioxidant capacity of the 12 study species, although there were differences between them. The antioxidant activity values quantified through DPPH and RP were higher than the ones obtained by ABTS and FRAP, and these values varied among species. Thus, the hierarchization or categorization of these species was different depending on the method used. Another difference established between these methods was the sensitivity obtained with each of them. A cluster revealed that RP established the largest number of groups at the shortest distance from the root. Therefore, as it showed the best discrimination of differences and/or similarities between species, RP is considered in this study as the one with the highest sensitivity among the four studied methods. On the other hand, ABTS showed the lowest sensitivity. These results show the importance of selecting the proper antioxidant activity quantification method for establishing a ranking of species based on this parameter.

Comparative pharmacologic profiles of leaves and hypocotyls of a mangrove plant: Bruguiera gymnorrhiza

Ethanolic extracts of leaves and hypocotyls of a mangrove plant, Bruguiera gymnorrhiza (Family Rhizophoraceae), were investigated to identify the presence of different phytochemicals and to assess the antihyperglycemic, antidiarrheal, analgesic and antioxidative activity in the current study. Oral glucose tolerance test (OGTT) was performed to investigate the in vivo antihyperglycemic activity and leaves extract (LE) was found to possess significant antihyperglycemic property compared to hypocotyl extract (HE). Therefore, the leaves extract was considered for α-Glucosidase enzyme inhibitory activity test and substantial α-glucosidase enzyme inhibitory property was observed with an IC50 (concentration required to inhibit 50% enzyme) value of 2.670. Antioxidative activity of plant extracts was tested in vitro by evaluating their ability to scavenge DPPH, hydrogen peroxide and hydroxyl radical as well as superoxide anions. In all cases, LE showed greater activity than HE. In addition, LE demonstrated higher amount of total phenolics, flavonoids and tannins indicating higher antioxidant effect compared to HE. For the evaluation of antidiarrheal effect in castor oil induced diarrheal mice, both extracts showed significant inhibition of defecation at doses 250 and 500 mg/kg body weight. Finally, for acetic acid-induced writhing method to evaluate the analgesic activity, significant percentage inhibition of writhing (P < 0.05 vs. control) was observed for both extracts at lower and higher doses. Altogether, these studies justified the plant’s usage in folklore medication.

Polymeric emulgel carrying Cinnamomum tamala extract: promising delivery system for potential topical applications

Currently, the use of natural compounds obtained from plants tremendously increased due to their promising therapeutic properties. The aim of this study was to formulate a stable emulgel formulation loaded with Cinnamomum tamala (CT) extract. The antioxidant activity of plant extract was determined by DPPH inhibition assay. The extract was successfully loaded into an emulgels using different concentrations of carbopol-940, liquid paraffin, emulsifying agents and preservatives. Preliminary stability study was performed of 17 CT emulgel formulations at accelerated temperature of 50 °C for 2-months. Organoleptic evaluation, centrifugation, globule size, pH, electrical conductivity and rheological studies were performed for a period of 90-days at different temperature including 8, 25, 40 and 40 °C ±75% RH. The CT extract showed promising antioxidant activity of about 81%. On the other hand, the CT loaded emulgel formulation displayed high physical stability at all tested conditions of temperature and time. However, slight decrease in pH and minimum increase in conductivity was observed at 40 and 40 °C±75% RH. The rheological examination of CT emulgel indicated the flow index values of all the samples kept at different temperatures were less than 1, demonstrated non-newtonian and pseudo-plastic nature of CT emulgel. Taken together, the CT emulgel formulation has been evinced to be an excellent addition in the field of topical formulations.

The Effect of the Antioxidant Activity of Plant Extracts on the Properties of Gold Nanoparticles.

Synthesis of gold nanoparticles (phyto-AuNPs) with the use of leaf extracts (phytosynthesis) is based on the concept of Green Chemistry. The present study is conducted to discuss how antioxidant activity (AOA) of extracts from plant leaves impacts on the kinetics of phytosynthesis, the size of the formed nanoparticles, and the stability of their nanosuspensions. Results show that the formation rate of phyto-AuNPs suspensions accelerate due to the increase in the AOA of the extracts. Accompanying the use of transmission electron microscopy (TEM), UV-Vis-spectrophotometry and dynamic light scattering (DLS), it also has been found that higher AOA of the extracts leads to a decrease in the size of phyto-AuNPs, an increase in the fraction of small (d ≤ 5 nm), and a decrease in the fraction of large (d ≥ 31–50 nm) phyto-AuNPs, as well as an increase in the zeta potential in absolute value. Phyto-AuNPs suspensions synthesized with the use of extracts are more resistant to destabilizing electrolytes and ultrasound, as compared to suspensions synthesized using sodium citrate. Thus, the AOA of the extract is an important parameter for controlling phytosynthesis and predicting the properties of phyto-AuNPs. The proposed approach can be applied to the targeted selection of plant extract that will be used for synthesizing nanoparticles with desired properties.

OxiCyan®, a phytocomplex of bilberry (Vaccinium myrtillus) and spirulina (Spirulina platensis), exerts both direct antioxidant activity and modulation of ARE/Nrf2 pathway in HepG2 cells

• OxiCyan® is a phytocomplex based on bilberry and spirulina extracts. • The bilberry anthocyanin moiety exerts a direct effect on ROS quenching on HepG2 cells. • The constituents of spirulina induce ARE/Nrf2 pathway on HepG2 cells. • OxiCyan® is a strong antioxidant at the cellular level and triggers the natural antioxidant cell defense. The antioxidant activity of plant extracts requires compelling evidence of the physiological functions of antioxidants at the cellular level. In order to assess the antioxidant power of the phytocomplex OxiCyan®, a bilberry extract functionalized on spirulina, traditional chemical methods (DPPH and ABTS) were compared to in vitro cellular responses by using HepG2 human hepatocyte carcinoma 85011430 cell lines. OxiCyan® was found to act on HepG2 cells in a dual mode: with a direct effect on ROS scavenging and as a cytoprotective agent via induction of ARE/Nrf2 pathway. Direct ROS scavenging activity of OxiCyan® depended on the anthocyanin moiety provided by bilberry, whereas the gene activation of the ARE/Nrf2 pathway was triggered by spirulina chemical constituents. The comparative analysis of chemical and cellular assays indicated contrasting results. OxiCyan® showed a high antioxidant activity at the cellular level by both scavenging ROS and inducing the gene expression of natural antioxidant cell defense.

Effect of nitrogen on herb production, secondary metabolites and antioxidant activities of Hypericum pruinatum under nitrogen application

The optimization of growing conditions using germplasm potentials is an effective way to manage the production and quality of medicinal plant raw materials. The present study aimed to evaluate the effect of mineral nitrogen on the Hypericum pruinatum plant yield, the accumulation of secondary metabolites and their antioxidant activities. Mineral nitrogen fertilizer containing 33% ammonium was applied at five rates, which corresponded to 0, 30, 60, 90 and 120 kg N/ha. The results showed that the yield of herb material increased with increasing doses of nitrogen. Application of nitrogen enhanced the accumulation of naphtodianthrones and emodin, and did not have any effect on phloroglucinol derivatives. Meanwhile, the increased nitrogen supply significantly reduced the accumulation of major phenolics, such as catechin, chlorogenic acid, hyperoside, quercitrin, isoquercitrin and total phenolic content. The results of the antioxidant capacity assay using the HPLC cupric-ion reducing antioxidant capacity (CUPRAC) method with post-column detection indicated that hydroxycinnamic acids and flavonoids, such as quercetin, isoqercitrin and hyperoside, were responsible for most of the antioxidant activity of plant extracts. Overall, antioxidant activity was reduced from non-fertilized samples to samples exposed to high nitrogen dose, although it was variable for individual compounds. Samples with a greater abundance of phenolics had the highest antioxidant capacity. Application of medium rates of nitrogen (60–90 kg N/ha) should be considered as the optimal mode for reconciling the sufficient yield and high quality of herb material. The results of this study emphasize the importance of controlled growth conditions as an effective means of optimizing the accumulation of secondary metabolites and expressing their biological activities.

Antioxidant capacity of plant raw material of Scutellaria baicalensis Georgi

The aim of this study was to evaluate antioxidant capacity of Scutellaria baicalensis Georgi from two regions of Ukraine: Kyiv city (M. M. Gryshko National Botanical Garden of NAS of Ukraine (NBG)) and Kherson region (Experimental Facility “Novokakhovska” of Rice Research Institute of Ukrainian Academy of Agrarian Sciences (EFN of RRI)). Observation of plants and biochemical analyses conducted with plants collected in the stage of flowering. In study investigated and compared above-ground part of plants and separated organs: inflorescences, stems, leaves. Measured morphometric parameters (height of plants, length, and width of leaves, length, and diameter of inflorescence, the diameter of the stem) showed that the most variable was the length of inflorescence (12.79%) for NBG sample and diameter of the stem (33.33%) for EFN of RRI sample. Ethanolic extracts were screened for the antioxidant capacity. As standards were used gallic acid for polyphenol content (GAE), quercetin for flavonoids (QE), caffeic acid for phenolic acids (CAE), Trolox for antioxidant capacity (TE). The total content of polyphenol compounds was 42.43 – 86.13 mg GAE.g-1 DW (dry weight) (NBG sample) and 28.06 – 96.76 mg GAE.g-1 DW (EFN of RRI sample). The content of flavonoids was9.39 – 62.97 mg QE.g-1 DW (NBG sample) and 10.64 – 66.07 mg QE.g-1 DW (EFN of RRI sample). The concentration of phenolic acids was 2.60 – 16.13 mg CA.g-1 DW (NBG sample) and 12.02 – 30.12 CA.g-1 DW (EFN of RRI sample). Antioxidant activity of plant extracts was measured by DPPH assay and reducing power method. The first method indicated an antioxidant ability 8.24 – 8.56 mg TE.g-1 DW (NBG sample) and 7.63 – 8.83 mg TE.g-1 DW (EFN of RRI sample). Reducing power of extracts was 51.48 – 306.09 mg TE.g-1 DW (NBG sample) and 63.33 – 260.24 mg TE.g-1 DW (EFN of RRI sample). Very strong positive correlation identified between total polyphenol content, total flavonoid content and reducing power. Scutellaria baicalensis is a rich source of antioxidants and potential raw of further pharmacological study in Ukraine as well as in other regions for improving and enrichment of relevant production.

Effect of salinity stress on the physiological characteristics, phenolic compounds and antioxidant activity of Thymus vulgaris L. and Thymus daenensis Celak

Salinity stress is one of the most important challenges in agriculture systems. The present work was aimed to evaluated the effects of saline irrigation, using different NaCl concentrations (0, 30, 60, and 90 mM), on growth, physiological characteristics, phenolic compounds, and antioxidant activity of Thymus vulgaris and Thymus daenensis, that are two of the most important medicinal and aromatic plants in Iran. An analytical method based on HPLC-DAD has been developed to identify the main metabolites (mainly phenolic compounds) in thyme extracts. The results indicated that concentrations of 60 and 90 mM NaCl significantly decreased the plant dry matter production by about 28 and 40% in T. vulgaris and 34 and 39% in T. daenensis, respectively, compared with untreated plants. Application of NaCl also induced an increase in Na+content in shoots and leaves while the K+ and Ca2+contents decreased with the salinity stress. Total phenolic content increased by around 20% after the application of 60 mM NaCl, compared with control plants. Also, an increase in leaf flavonoid content by 38.6% and 36.6% was observed in plants grown under salt stress conditions after the application of 60 and 90 mM NaCl, respectively. Both investigated species were rich in phenolic acids, flavonoids, and phenolic monoterpenes. Cinnamic acid was the major constituent in both species. This compound increased by 31.4% in T. vulgaris treated with 60 mM NaCl compared with the control. Concentrations of 60 and 90 mM NaCl increased significantly the amount of gallic and rosmarinic acids in T. vulgaris (25 and 31.6%, respectively) and T. daenensis (20.4 and 27.6%, respectively). On the other hand, the mentioned NaCl concentrations did not significantly change the content of caffeic, syringic, and vanillic acids in T. vulgaris. Interestingly, the higher amount of chlorogenic acid (increase of 4.4%) in T. vulgaris was found under control condition, whereas in T. daenensis this compound increased when salinity stress intensified. The main outcome of the present study was the enhancement of thyme phenolic content under salt stress treatments. Furthermore, salinity stress significantly influenced the antioxidant activities of plant extracts and may be recommended as an appropriate approach to enhance the antioxidant capacity of medicinal plants. In conclusion, the obtained data demonstrated that salinity stress decreased significantly the yield of both species, whereas improved the phenolic contents and antioxidant capacity of thyme plants.

Polyphenolic Composition of Rosa canina, Rosa sempervivens and Pyrocantha coccinea Extracts and Assessment of Their Antioxidant Activity in Human Endothelial Cells.

The aim of the present study was the investigation of the antioxidant activity of plant extracts from Rosa canina, Rosa sempervivens and Pyrocantha coccinea. The results showed that the bioactive compounds found at higher concentrations were in the R. canina extract: hyperoside, astragalin, rutin, (+)-catechin and (-)-epicatechin; in the R. sempervirens extract: quinic acid, (+)-catechin, (−)-epicatechin, astragalin and hyperoside; and in the P. coccinea extract: hyperoside, rutin, (−)-epicatechin, (+)-catechin, astragalin, vanillin, syringic acid and chlorogenic acid. The total polyphenolic content was 290.00, 267.67 and 226.93 mg Gallic Acid Equivalent (GAE)/g dw, and the total flavonoid content 118.56, 65.78 and 99.16 mg Catechin Equivalent (CE)/g dw for R. caninna, R. sempervirens and P. coccinea extracts, respectively. The extracts exhibited radical scavenging activity in DPPH and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS)•+ assays and protection from ROO•-induced DNA damage in the following potency order: R. canina > R. sempervirens > P. coccinea. Finally, treatment with R. canina and P. coccinea extract significantly increased the levels of the antioxidant molecule glutathione, while R. canina extract significantly decreased Reactive Oxygen Species (ROS) in endothelial cells. The results herein indicated that the R. canina extract in particular may be used for developing food supplements or biofunctional foods for the prevention of oxidative stress-induced pathological conditions of endothelium.

Antimicrobial, DPPH scavenging and tyrosinase inhibitory activities of Thymus vulgaris, Helichrysum arenarium and Rosa damascena mill. ethanol extracts by using TLC bioautography and chemical screening methods

Antimicrobial, DPPH scavenging and tyrosinase inhibitory activities of Thymus vulgaris, Helichrysum arenarium and Rosa damascena Mill. ethanol extracts by using TLC bioautography and chemical screening methods. The ethanol extracts of Thymus vulgaris (Tv), Helichrysum arenarium (Ha) and Rosa damascena Mill. (Rm) (red) were screened for their antimicrobial, 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and tyrosinase inhibitory activities. The test microorganisms included bacteria of Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923). Thin Layer Chromatography (TLC) - bioautography, disk diffusion and well diffusion methods were used for the antimicrobial activity assays. Rosa damascena Mill. extract was effective against E. coli and all plant extracts showed antimicrobial activity against S. aureus. The phenolic acids in the structure of the extracts were also identified by LC-MS analysis. Human blood agar well diffusion method and TLC-DPPH assays were used to identify the hemolytic and antioxidant activity of plant extracts, respectively, along with 10 compounds including phenolic acids as a standard. Among these compounds, caffeic acid (Rf = 0.68) was detected in all extracts while vanillic acid (Rf = 0.75), and gallic acid (Rf = 0.51) was found in Tv extract. Kojic acid (Rf = 0.36), on the other hand, was detected in Rm extract as a tyrosinase inhibitor. All plant extracts presented tyrosinase inhibitory activities on TLC-bioautography assay.

Comparison of Phenolic Compounds and Antioxidant Activities of the Extracts of Grape Seed, Rosemary, Green Tea and Olive Leaf

Objective: Total antioxidant activities and phenolic compounds of ethanol extract of grape seed, rosemary, green tea and olive leaf were investigated in this study.Material and Methods: The total antioxidant activities of plant extracts were analyzed by two different methods, including 2.2-diphenyl-1-picrylhydrazyl hydrate (DPPH) radical scavenging activity and trolox equivalent antioxidant capacity (TEAC). Carnosic acid, rosmarinic acid in rosemary extract (RE), total catechins in green tea extract (GTE) and oleuropein in olive leaf extract (OLE) were identified by high performance liquid chromatography (HPLC) method. Condensed tannins of grape seed extract (GSE) was analyzed by butanol-HCl method.Results: The total phenolic contents of plant extracts determined by the Folin-Ciocalteu method ranged from 141.7 to 315.56 mg of gallic acid equivalents (GAE) g-1. According to results obtained this study, RE exhibited the highest DPPH radical scavenging activity, and GTE exhibited highest TEAC activity. Additionally, obtained data revealed high linear correlation (r=0.82) between total phenolic contents and TEAC values and low linear correlation (r=0.47) between total phenolic contents and DPPH values.Conclusion: The potent antioxidant activity of plant extracts provided from agro-industrial by-products, medicinal and aromatic plants makes it possible used them as natural sources of antioxidants in feed, food and pharmaceutical industries.

Anticonvulsant and GABAnergic Activity of Nigella sativa oil in Mice

Several experimental studies have described neuroprotective and antioxidant activity of plant extracts and its oil as Nigella sativa. The existing study was conducted to investigate the anticonvulsant activity of Nigella sativa oil. Fifty five male albino mice were used through three experiments; each experiment was taken 1 week. The experiments were pentylenetetrazole induced convulsion, maximal electric shock induced convulsion and neurotoxicity tests. Mice were treated with Nigella sativa oil 10 ml/kg; using sodium valproate (100 mg/kg) and phenytoin sodium (25 mg/kg) orally as standard drugs. In pentylenetetrazole induced convulsion, onset of seizure and generalized seizures were measured, beside the gamma aminobutyric acid and antioxidant enzymes levels assessments. In maximal electric shock, mice were observed for hind limb tonic convulsion. Nigella sativa oil significantly delayed seizure onset after pentylenetetrazole induced convulsion but had no effect on electric shock induced convulsion. Nigella sativa showed a good antioxidant activity and increased gamma amino butyric acid level in brain and had neuroprotective effects.