Phenolic composition and antioxidant properties of some traditionally used medicinal plants affected by the extraction time and hydrolysis

Introduction – Polyphenolic phytochemicals in traditionally used medicinal plants act as powerful antioxidants, which aroused an increasing interest in their application in functional food development. Objective – The effect of extraction time (5 and 15 min) and hydrolysis on the qualitative and quantitative content of phenolic compounds and antioxidant capacity of six traditionally used medicinal plants (Melissa officinalis L., Thymus serpyllum L., Lavandula officinalis Miller, Rubus fruticosus L., Urtica dioica L., and Olea europea L.) were investigated. Methodology – The content of total phenols, flavonoids, flavan‐3‐ols and tannins was determined using UV/Vis spectrophotometric methods, while individual phenolic acids, flavones and flavonols were separated and detected using HPLC analysis. Also, to obtain relevant data on the antioxidant capacity, two different assays, (2,2‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulphonic acid) (ABTS) radical scavenging and ferric reducing/antioxidant power (FRAP) assays were used. Results – The extraction efficiency of phenolics, as well as the antioxidant capacity of plant extracts, was affected by both prolonged extraction and hydrolysis. The overall highest content of phenolic compounds was determined in hydrolyzed extract of blackberry leaves (2160 mg GAE/L), followed by the non‐hydrolyzed extract of lemon balm obtained after 15 min of extraction (929.33 mg GAE/L). The above extracts also exhibited the highest antioxidant capacity, while extracts of olive leaves were characterized with the lowest content of phenolic compounds, as well as the lowest antioxidant capacity. The highest content of rosmarinic acid, as the most abundant phenolic compound, was determined in non‐hydrolyzed extract of lemon balm, obtained after 15 min of extraction. Although the hydrolysis provided the highest content of polyphenolic compounds, longer extraction time (15 min) was more efficient to extract these bioactives than shorter extraction duration (5 min). Conclusion – The distribution of detected phenolic compounds showed a wide variability with regard to their botanical origin. Examined medicinal plants showed to be a valuable supplement to a daily intake of bioactive compounds. Copyright © 2010 John Wiley & Sons, Ltd.     

Establishment of a plant regeneration system for wheatgrasses (Thinopyrum,Agropyron and Pascopyrum)

Wheatgrasses (Thinopyrum, Agropyron and Pascopyrum spp.) are a ubiquitous group of cool-season grasses used throughout much of the semiarid temperate world. In order to explore the potential of biotechnology to accelerate conventional breeding efforts, we developed an efficient plant regeneration system for different wheatgrass species: tall wheatgrass [Thinopyrum ponticum (Podp.) Liu and Wang], intermediate and pubescent wheatgrass [Thinopyrum intermedium (Host) Barkw. and D.R. Dewey], crested wheatgrass [Agropyron cristatum (L.) Gaertner], and western wheatgrass [Pascopyrum smithii (Rydb.) Löve]. Embryogenic callus was induced from mature and immature embryos and immature inflorescence with an induction frequency in the range of 0.5–8.3% for the different wheatgrass species tested. Individual embryogenic calluses were then used to establish single genotype-derived suspension cultures. Efficient plant regeneration was achieved from the established em-bryogenic suspensions with regeneration frequencies in the range of 20–65% for tall wheatgrass, 21–40% for intermediate and pubescent wheatgrasses, 32–51% for crested wheatgrass, and 25–48% for western wheatgrass. The cell suspension-derived wheatgrass plants were fertile and phenotypically normal in the field. The efficient plant regeneration system provides a solid basis for genetic transformation of wheatgrasses.     

EFFECT OF LIGHT QUALITY AND INTENSITY ON GLYCEROL CONTENT IN DUNALIELLA TERTIOLECTA (CHLOROPHYCEAE) AND THE RELATIONSHIP TO CELL GROWTH/OSMOREGULATION1

Dunaliella tertiolecta Butcher was grown at two intensities (33, 150μEin · m^?2· s^?1) of blue light and white light at 0.25, 0.50 and 1.00 M NaCl. Growth rates were used as an indication of the relative osmoregulatory ability of cells in the various treatments. There was no significant effect on growth rate due to various NaCl molarities. No significant difference in growth rate was found between blue- and white-light cultures at the high intensity, the average growth constant being 2.07 divisions/day. However, at the low intensity illumination, blue light produced a significant increase in growth rate; 1.42 vs. 0.93 divisions/day for blue light and white light grown cells respectively. The average glycerol content of exponentially dividing cells grown at 0.25, 0.50 and 1.00 M NaCl was 0.12, 0.41 and 1.12 mg/10⁸ cells, respectively, as measured by gas chromatography. The intracellular glycerol content was significantly reduced by blue light at both light intensities and at each NaCl molarity. However, high light intensity reduced cellular glycerol content more than the reduction effected by blue light. Glycerol accumulated in the medium throughout culture growth. Intracellular glycerol content also increased with cellular aging reaching 2.72 mg/10⁸ cells in stationary phase, low intensity 1.00 M NaCl cultures. A negative correlation between glycerol content and growth rate was found. Total inhibition of glycerol production could not be obtained by treatment with blue light. However, this negative correlation possibly indicates that D. tertiolecta expends energy producing an excess amount of glycerol over that required for osmoregulation, leading to a reduction in the growth rate for the organism.     

Pharmacological properties and preliminary phytochemical analysis of Pseudocaryopteris foetida (D.Don) P.D. Cantino leaves

Medicinal plants have significant contribution in pharmaceutical industries being producers of compounds utilized as precursors for drug development. A plant of Lamiaceae family; Pseudocaryopteris foetida had not been investigated for its biomedical potential. Current research was aimed to investigate phytochemical analysis, cytotoxic potential and antioxidant activity of crude methanolic extract and fractions of Pseudocaryopteris foetida (leaves). The preliminary phytochemical analysis of crude methanolic extracts and fractions of Pseudocaryopteris foetida revealed that plant is rich in phenolic and flavonoid classes of secondary metabolites while presence of tannin was observed only in crude methanolic extract. The cytotoxicity was determined using brine shrimp lethality test. Different concentrations (25, 50, 100, 150, 200 and 250 µg/mL) of crude methanolic extract and fractions exhibited dose dependent cytotoxicity. However, The LD₅₀ for all the extracts was more than 200 µg/mL indicating weak cytotoxic potential of Pseudocaryopteris foetida. The antioxidant capabilities of crude methanolic extract and fraction of Pseudocaryopteris foetida were analyzed by in vitro bio assays including DPPH, ABTS, Reducing power and phosphomolybdate antioxidant assays using ascorbic acid as standard. The crude methanolic extract showed IC₅₀ (256.38 ± 0.6 and 314.95 ± 1.1 µg/mL) for DPPH and ABTS respectively, while total antioxidant capacity was calculated as 55.79 ± 0.5 µg/mL for crude methanolic extract of Pseudocaryopteris foetida while ascorbic acid indicated total antioxidant capacity of 71.89 ± 2.3 µg/mL. Study concluded that leaves of Pseudocaryopteris foetida were the rich source of antioxidant phytochemicals. Based on preliminary investigations further research should be focused to isolate bioactive phytochemicals as leading source of clinical medicines in future.     

Protective Role of Selenium on Pepper Exposed to Cadmium Stress During Reproductive Stage

The aim of the present study was to examine the effects of exogenous selenium (Se) supplementation on the tolerance of pepper (Capsicum annuum L.) cv. Suryamukhi Cluster plants to cadmium (Cd) phytotoxicity at the reproductive stage. The pepper plants were supplied with Cd (0, 0.25 or 0.50 mM) and Se (0, 3 or 7 μM), individually or simultaneously, three times during the experiment. The obtained results show that Cd had deleterious effect on pepper plants at the reproductive stage. However, Se supplementation improved the flower number, fruit number and fruit diameter in plants exposed to 0.50 mM Cd. Moreover, both Se concentrations used in 0.25 mM Cd-treated plants and 3 μM Se in 0.50 mM Cd-treated plants enhanced fruit yield per plant as compared to Cd-alone treatment. The chlorophyll concentrations significantly increased in the fruits of Cd-exposed plants after Se addition. However, Se supplementation reduced total carotenoids and total soluble solid (TSS) concentrations in the pepper fruits exposed to Cd. Selenium also generally enhanced the total antioxidant activity of pepper fruits subjected to Cd. Both Se concentrations used increased mean productivity (MP), stress tolerance index (STI) and yield stability index (YSI) in plants grown in the medium containing 0.25 mM Cd. At low concentration (3 μM), Se significantly increased geometric mean productivity (GMP), STI and YSI of plant exposed to 0.50 mM Cd. The highest Cd concentration in the fruits was achieved at 0.50 mM Cd and Se application significantly reduced Cd accumulation in the Cd-exposed plants. Our results indicate that application of Se can alleviate Cd toxicity in pepper plants at the reproductive stage by restricting Cd accumulation in fruits, enhancing their antioxidant activity and thus improving the reproductive and stress tolerance parameters.     

Enzyme Inhibition and Antioxidant Activities of Asparagus officinalis L. and Analysis of Its Phytochemical Content by LC/MS/MS

In the study, water, ethanol, methanol, dichloromethane, and acetone extracts of Asparagus officinalis L. were obtained by maceration. DPPH⋅, ABTS⋅⁺, FRAP, and CUPRAC methods determined the antioxidant capacities of all extracts. Moreover, the in vitro effects of extracts on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carbonic anhydrase (CA)-I, CA-II and α-Glycosidase were investigated. At a 10 μg/ml concentration, the extract with the highest Fe³⁺ reduction capacity was ethanol (AE), and the extract with the highest Cu²⁺ reduction capacity was acetone (AA). AE for AChE (IC₅₀=21.19 μg/ml) and α-Glycosidase (IC₅₀: 70.00 μg/ml), methanol (AM) for BChE (IC₅₀=17.33 μg/ml), CA−I and II (IC₅₀=79.65 and 36.09 μg/ml, respectively) showed the most potent inhibition effect. The content analysis of acetone extract was performed with LC/MS-MS, the first three phytochemicals found most were p-Coumaric acid, rutin, and 4-hydroxybenzoic acid (284.29±3.97, 135.39±8.19, and 102.06±5.51 μg analyte/g extract, respectively).     

褪黑素抑制雌二醇诱致的垂体PRL瘤生长与血浆PRL和过氧化脂质含量的关系

雄性大鼠皮下埋置17-β雌二醇(17-β-estradiol,E2)药泵诱发垂体催乳素PRL)瘤,并每日皮下注射褪黑素(melatonin,MLT)观察MLT对E2诱发PRL瘤生长的影响.另外,采用放免法和紫外分光光度法测定大鼠血浆PRL和过氧化脂质(peroxidativelipid,PL)浓度,观察PRL瘤重量与大鼠血浆浓度间的相关关系.实验结果显示,在对照组、0.05、0.25、0.50、1.00和2.00mgMLT组,PRL瘤重量分别为115.0±71.0、85.2±41.0、58.9±24.1、72.7±23.6、79.3±56.1、74.5±46.8mg;血浆PRL浓度分别为493.46±33.3、373.78±26.5、125.13±13.3、201.79±11.2、418.88±41.3、281.94±36.4ng/ml;血浆PL水平分别为1.21±0.23、0.89±0.32、0.92±0.27、0.64±0.24、0.41±0.14、0.43±0.21△D233/ml.相关性分析表明,PRL瘤重量与血浆PRL浓度间的相关系数为0.8738(P＜0.05),与血浆PL水平间的相关系数为0.5550(P＞0.05),血浆PRL浓度与血浆PL水平间的相关系数为0.2141(P＞0.05).该结果提示,(1)0.25(P＜0.01)、0.50(P＜0.05)mgMLT能有效抑制E2诱致的PRL瘤生长和PRL分泌,所有剂量的MLT均能抑制血浆PL的形成;(2)PRL瘤重量与血浆PRL浓度间呈正相关关系,PRL瘤重量与血浆PL水平间、以及血浆PRL浓度与血浆PL水平间均无相关关系.因此,我们认为,MLT抑制E2诱致的PRL瘤生长可能与MLT抑制PRL表达性分泌有关,但与MLT抗氧化作用无关.     

In-vitro antibacterial,antioxidant potentials and cytotoxic activity of the leaves of Tridax procumbens

The present study explored the phytochemicals, antibacterial, antioxidant and cytotoxic effect of Tridax procumbens leaves. The leaves were dried and extracted with various organic solvents. The leaves contained the phytochemicals such as alkaloids, carbohydrates, polyphenols and tannins respectively. Antimicrobial potentials of the extracts were determined by performing the disc diffusion techniques. Results revealed that different organic solvents extracts namely methanol, ethanol and ethyl acetate extracts documented comparatively good activity against the studied microbial strains. The methanol extract of leaves of T. procumbens showed combatively better antioxidant potential. The tested plant leaf extract showed high activity against human lung cancer cells than breast cancer cell lines. 250 µg/ml plants extract showed 84 ± 2.8% toxicity against human lung cancer cells.     

Lichenochemical Screening and Antioxidant Capacity of Four Tunisian Lichen Species

The phenolic composition and antioxidant capacity of four Tunisian lichen species, Cladonia rangiformis, Flavoparmelia caperata, Squamarina cartilaginea and Xanthoria parietina, were determined in order to provide a better understanding of their lichenochemical composition. Powdered material of F. caperata was the richest in total phenolic content (956.68 μg GAE g⁻¹ DW) and S. cartilaginea in proanthocyanidin content (77.31 μg CE g⁻¹ DW), while the acetone extract of X. parietina showed the highest flavonoid content (9.56 μg CE g⁻¹ DW). The antioxidant capacity of all lichen extracts and crude material was evaluated by DPPH^. scavenging, iron-chelating, and iron-reducing powers. Results showed that methanol extracts of S. cartilaginea had the highest DPPH^. antioxidant capacity (IC₅₀=0.9 μg mL⁻¹) and the highest iron-reducing power was attributed to the acetone extract of this species. All extracts of all species were further screened by Fourier-transform infrared spectroscopy (FT-IR) and nuclear resonance spectroscopy (NMR); results showed an abundance of phenols, aromatic compounds, and fatty acids. Overall, our results showed that the investigated species are a rich source of potentially bioactive compounds with valuable properties.     

Variations in the Components and Antioxidant and Tyrosinase Inhibitory Activities of Styphnolobium japonicum (L.) Schott Extract during Flower Maturity Stages

Styphnolobium japonicum (L.) S chott is widely cultivated in China, and its flowers and flower buds (FFB‐SJ) are commonly used as traditional Chinese medicine. This work aimed to assess variations in the chemical components and antioxidant and tyrosinase inhibitory activities of S. japonicum extract during five flower maturity stages (ES1–ES5). The results showed that the contents of total flavonoids, rutin, and narcissin were highest at ES1, whereas the contents of quercetin and isorhamnetin were highest at ES3. ES1 presented considerable antioxidant activities in terms of reducing power (RP) and 1,1‐diphenyl‐2‐picrylhydrazyl radical (DPPH^.) and hydroxyl radical (^.OH) scavenging capacity, whereas ES3 showed excellent tyrosinase inhibitory activity and 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) radical (ABTS^.+)‐ and O₂^.?‐scavenging capacity. Rutin and quercetin are the main bioactive components of FFB‐SJ with antioxidant and tyrosinase inhibition, and the immature flower buds of S. japonicum (S2 and S3) with excellent biological activities and relatively high extract yields were the best for product development.     

不同实验方法检测常用有机溶剂对细菌活性的影响及其安全使用限量

【目的】采用不同实验方法测定常用有机溶剂二甲基亚砜(DMSO)、丙酮和乙醇对细菌活性的影响,以指导抗菌类药物体外抑菌实验所用溶剂的选择和添加限量。【方法】采用常规体外抑菌实验方法(纸片扩散法、肉汤稀释法),并参照生长曲线法检测有机溶剂DMSO、丙酮和乙醇对大肠杆菌(Escherichia coli)及金黄色葡萄球菌(Staphylococcus aureus)的抑菌作用,采用扫描电子显微镜(SEM)观察溶剂作用后的细菌形态变化。【结果】3种溶剂对E.coli和S.aureus抑菌率达到20%时,在肉汤稀释法下,DMSO、丙酮、乙醇的浓度(体积比)分别为1.00%、0.25%、2.00%和1.00%、1.00%、0.50%;在生长曲线法下,溶剂浓度(体积比)分别为0.50%、1.00%、0.50%和1.00%、0.50%、0.50%;而在纸片扩散法下,32%(体积比)DMSO和32%(体积比)乙醇对E.coli产生明显抑菌圈,但3种溶剂对S.aureus均无抑菌圈出现。3种方法比较后得出:当3种溶剂的抑菌率达到20%时,溶剂浓度(体积比)均低于0.5%,对细菌整体生长活性影响较小。SEM结果表明控制溶剂使用限量可有效减少其对E.coli生长过程的影响。【结论】相对于DMSO和丙酮,乙醇对微生物生长繁殖能力的影响更加明显;采用相同浓度有机溶剂时,液态条件下(肉汤稀释法和生长曲线法)微生物受到有机溶剂的影响较大。     

Chemical Composition and Biological Activities of Trans-Himalayan Alga Spirogyra porticalis (Muell.) Cleve

The freshwater alga Spirogyra porticalis (Muell.) Cleve, a filamentous charophyte, collected from the Indian trans-Himalayan cold desert, was identified on the basis of morpho-anatomical characters. Extracts of this alga were made using solvents of varying polarity viz. n-hexane, acetonitrile, methanol and water. The antioxidant capacities and phenolic profile of the extracts were estimated. The methanol extract showing highest antioxidant capacity and rich phenolic attributes was further investigated and phytochemical profiling was conducted by gas chromatography-mass spectrometry (GC/MS) hyphenated technique. The cytotoxic activity of methanol extract was evaluated on human hepatocellular carcinoma HepG2 and colon carcinoma RKO cell lines. The anti-hypoxic effect of methanol extract of the alga was tested on in vivo animal system to confirm its potential to ameliorate oxidative stress. The antioxidant assays viz. ferric reducing antioxidant power (FRAP), 2,2''-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide (NO) radical scavenging capacities, β-carotene-linoleic acid bleaching property and lipid peroxidation exhibited analogous results, wherein the algal extracts showed significantly high antioxidant potential. The extracts were also found to possess high content of total proanthocyanidin, flavonoid and polyphenol. GC/MS analysis revealed the presence of thirteen chemotypes in the methanol extract representing different phytochemical groups like fatty acid esters, sterols, unsaturated alcohols, alkynes etc. with substantial phyto-pharmaceutical importance. The methanol extract was observed to possess anticancer activity as revealed from studies on HepG2 and RKO cell lines. In the present study, S. porticalis methanol extract also provided protection from hypoxia-induced oxidative stress and accelerated the onset of adaptative changes in rats during exposure to hypobaric hypoxia. The bioactive phytochemicals present in this trans-Himalayan alga are of enormous interest and can be utilized sustainably for discovery of novel drugs against oxidative stress.     

Pre-treatment with salicylic acid induces phenolic responses of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis>) bark to bark beetle (<Emphasis Type="Italic">Ips typographus</Emphasis>) attack

Keymessage

The temporal gradations of the investigated phenolics in Norway spruce bark after bark beetle (Ips typographus) attack followed the general eco-physiological concept. Treatment with salicylic acid inhibits bark beetle colonisation, alleviates the phenolic responses and activates the synthesis of condensed tannins on later sampling dates.

Abstract

Conifer bark is the target of numerous organisms due to its assimilated transport and nutrient storage functions. In the presented study, 100 mM salicylic acid (SA) was applied onto Norway spruce stems prior to being infested with bark beetles (Ips typographus L.), to study the temporal gradation of changes in condensed tannins (CT) and total phenolics (tPH) and their significance for mediating stress-tolerance. A significant accumulation of CT was monitored in untreated trees in response to progressive bark beetle infestation occurring from May onwards. In SA-treated infested trees, the CT values remained at control levels until May, but after the re-treatment of infested trees in June, the concentrations of CT rose significantly in comparison to the controls. The tPH values dropped 16 days after SA-treatment, independent of infestation, and later on remained at control level until July. In contrast, tPH contents accumulated in untreated infested trees in May, eased in June and increased again in July, when the trees were affected by the second generation of bark beetles. To sum up, in May and July when the highest beetle-flight activity was monitored the metabolic shift of phenolics within untreated infested trees differed significantly from the response of SA-treated trees. In addition, on SA-treated trees less entrance holes were monitored over the whole period of sampling when compared to untreated infested trees. These results provide evidence that SA-treatment alleviates the phenolic responses, activates the synthesis of condensed tannins and inhibits bark beetle colonisation.

     

Control of Staphylococcus aureus methicillin resistant isolated from auricular infections using aqueous and methanolic extracts of Ephedra alata

In the current study the potential use of aqueous and methanolic extracts of Ephedra alata aerial parts as biological control agent against pathogenic bacteria and especially Staphylococcus aureus methicillin resistant isolated from auricular infections was evaluated. Chemical tests and spectrophotometric methods were used for screening and quantification of phytochemicals. The assessment of the antioxidant activity was accomplished by DPPH and ABTS radicals scavenging assays. Extracts were evaluated for their antibacterial efficacy by diffusion and microdilution methods. Biofilm inhibition was tested using XTT assay and the cytotoxicity of extracts was carried out on Vero cell line. The GC-FID analysis revealed that E. alata was rich in unsatured fatty acids. In addition, the aqueous extract had the highest flavonoid and protein contents (30.82 mg QE /g dry extract and 98.92 mg BSAE/g dry extract respectively). However, the methanolic extract had the highest phenolic, sugars and tannins. The antioxidant activity demonstrated that the aqueous extract exhibited the strong potency (IC50 ranged between 0.001 and 0.002 mg/mL).Both extracts displayed antimicrobial activity on Gram negative and positive strains. They were effective against S. aureus isolated from auricular infections. The tested extracts were able to inhibit biofilm formation with concentration-dependent manner.Moreover, no cytotoxic effect on Vero cells line was demonstrated for the extracts. Overall, our findings highlight the potential use of E. alata extract as a novel source of bioactive molecules with antioxidant, antibacterial and antiobiofilm effects for the control of infectious disease especially those associated to S. aureus methicillin resistant.     

Phenolic production and antioxidant properties of some Macedonian medicinal plants

Investigations have been made to study the production of phenolic compounds (total phenolics, flavonoids and phenylpropanoids) and total antioxidant capacity in 27 Macedonian traditional medicinal plants to improve its potential as a source of natural antioxidants. Antioxidant potential of plant extracts was analyzed by five different assays: cupric reducing antioxidant capacity (CUPRAC), phosphomolybdenum method (PM), reducing power (RP), 2,2-diphenyl-1-picrylhydrazyl (DPPH^·) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS^·+) radical scavenging activity. Origanum vulgare extract consistently exhibited the highest content of phenolic compounds and the strongest antioxidant capacity based on the tests performed, and can be proposed as a promising source of natural antioxidants. Melissa officinalis and Salvia ringens were also identified as valuable sources of antioxidant compounds. A positive linear correlation between antioxidant activity and total phenolics, flavonoids and phenylpropanoids indicates that these compounds are likely to be the main antioxidants contributing to the observed activities of evaluated plants. These findings suggest that the medicinal plants studied in this paper are good sources of bioactive compounds for the food and pharmaceutical industries.     

Accumulation of anthocyanin in callus cultures of red-pod okra [<Emphasis Type="Italic">Abelmoschus esculentus</Emphasis> (L.) Hongjiao] in response to light and nitrogen levels

Nitrogen and light are critical determinants of biomass accumulation and secondary metabolite production under in vitro culture conditions. In this study, we analyzed the effects of varied concentrations of total nitrogen in Murashige and Skoog (MS) medium and light intensity on the production of biomass, anthocyanin pigments, and bioactive antioxidants in callus cultures of Abelmoschus esculentus cv. ‘Hongjiao’. Maximum callus biomass accumulation (3 g FW) was achieved when calluses were cultured on MS medium containing 60 mM nitrogen under 40 μmol m^??2 s^??1 light intensity. In contrast, maximum values of total anthocyanin accumulation (TA; 7.3 CV/g FW), total phenolic content (TP; 12.07 mg/100 g FW), total flavonoid content (TF; 2.47?±?0.15 mg/100 g FW), and total antioxidant activity (TAA; 56.10 μmol Trolox/g FW) were observed when calluses were cultured on MS medium containing 40 mM total nitrogen under 80 μmol m^??2 s^??1 light intensity. In addition, callus grown under same culture condition exhibited high flavonoid content along with increased phenolic content and antioxidant activity. High performance liquid chromatography (HPLC) was performed for qualitative and quantity analysis of callus cultures. Most of the pigments from the callus extracts were identical with pod anthocyanins, and appeared on the ODS-column HPLC with lower concentration than the main pigments of the pod tissues. These findings indicate that callus cultures of red-pod okra represent a potential source of bioactive compounds with antioxidant properties for industrial applications.     

Changes in western wheatgrass foliage quality following defoliation: consequences for a graminivorous grasshopper

We determined the effects of defoliation by a graminivorous grasshopper on the foliage quality of the C3 plant, western wheatgrass (Pascopyrum smithii [Rydb] A. Love). Additionally, we determined the effects of this defoliation upon the subsequent feeding of the graminivorous grasshopper Phoetaliotes nebrascensis Thomas (Orthoptera: Acrididae). In field and greenhouse studies, graminivorous grasshopper herbivory altered the quality of remaining western wheatgrass foliage. In the greenhouse, severe (50% foliage removal) grasshopper grazing (638 grasshoppers/m² for 72h) resulted in decreased foliar nitrogen (–12%), carbohydrate (–11%) and water (–2.5%) concentrations, and increased phenolic concentrations (+43%). These changes were associated with decreased adult female grasshopper mass gain, consumption rate, approximate digestibility, and food conversion efficiencies. In the field, moderate (14% foliage removal) grasshopper grazing (20 grasshoppers/m² for 20 days) led to a 10% reduction in foliar nitrogen concentrations. Foliage quality changes in the field were not associated with any reductions in grasshopper mass gain, consumption rates, food digestibility, or conversion efficiencies. The results presented here are consistent with the hypothesis that defoliation leads to a reallocation of carbon and nitrogen compounds within the plant such that foliage quality for P. nebrascensis is reduced.     

Salicylic acid increased aldose reductase activity and sorbitol accumulation in tomato plants under salt stress

Increased aldose reductase (ALR) activities were detected in the leaf tissues of tomato plants grown for 3 weeks in culture medium containing 10^?7 or 10^?4 M salicylic acid (SA), and in the roots after the 10^?4 M SA pretreatment. The ALR activity changed in parallel with the sorbitol content in the leaves of the SA-treated plants. Salt stress elicited by 100 mM NaCl enhanced the accumulation of sorbitol in the leaves of control plants and as compared with the untreated control the sorbitol content in the SA-pretreated leaves remained elevated under salt stress. DEAE cellulose anionexchange column purification of the protein precipitated with 80 % (NH₄)₂SO₄ revealed two enzyme fractions with ALR activity in both the leaf and the root tissues. The fraction of the leaf extract that was not bound to the column reacted with glucose and glucose-6-P as substrates, whereas glucose was not a substrate for the bound fraction or for root isoenzymes. The root enzyme was less sensitive to salt treatment: 50 mM NaCl caused 30 % inhibition in the leaf extract, whereas the enzyme activity of the root extract was not affected. It is suggested that increased ALR activity and sorbitol synthesis in the leaves of SA-treated tomato plants may result in an improved salt stress tolerance.     

Enhancement of stilbene compounds and anti-inflammatory activity of methyl jasmonate and cyclodextrin elicited peanut hairy root culture

A highly stable and productive hairy root culture from peanut cultivar Tainan9 (T9-K599) was established using Agrobacterium rhizogenes strain K599 (NCPPB 2659)-mediated transformation. Valuable phenolic compounds with antioxidant activity and stilbene compounds were produced and secreted into the culture medium after elicitation with 100 µM methyl jasmonate (MeJA) and 6.87 mM cyclodextrin (CD). The antioxidant activity of the culture medium was increased to the highest Trolox equivalent antioxidant capacity (TEAC) value (28.30?±?2.70 mM Trolox/g DW) in the group treated with CD. The group co-treated with MeJA and CD exhibited the highest phenolic content, with a gallic acid equivalent (GAE) value of 10.80?±?1.00 µg gallic acid/g DW. The CuZn-SOD (CuZn superoxide dismutase) and APX (ascorbate peroxidase) antioxidant enzyme gene were up-regulated in the treatment with CD alone while the CuZn-SOD, GPX (glutathione peroxidase) and APX gene expression were down-regulated in the co-treatment with MeJA plus CD. The stilbene compounds resveratrol, trans-arachidin-1 and trans-arachidin-3 were detected by analysing the culture medium treated with CD alone and after co-treatment with MeJA and CD via HPLC. The LC-MS/MS results confirmed the presence of resveratrol, trans-arachidin-1, trans-arachidin-3, 4-Isopentadienyl-3,5,3′,4′-tetrahydroxystilbene (IPP), trans-3′-Isopentadienyl-3,5,4′-trihydroxystilbene (IPD) and arahypin-7. The results indicate that elicited peanut hairy roots can produce beneficial stilbene compounds that have antioxidant properties and anti-inflammatory activity. This peanut hairy root system could be applied as an experimental model to enhance the production of stilbene and other polyphenolic bioactive compounds.     

Effect of a novel aromatic cytokinin derivative on phytochemical levels and antioxidant potential in greenhouse grown Merwilla plumbea

In an attempt to elucidate the carry-over effect of cytokinins (CKs) on phytochemical and antioxidant activity of acclimatized plants, tissue culture-derived Merwilla plumbea supplemented with three CK types at four (0.25, 0.5, 1 and 2 µM) concentrations were grown for 6 months ex vitro. Phenolic acids including the hydroxybenzoic and hydroxycinnamic acid derivatives in M. plumbea were quantified using ultra performance liquid chromatography while the antioxidant activity was evaluated using oxygen radical absorbance capacity (ORAC). Different concentrations of gallic acid, protocatechuic acid, p-hydroxybenzoic acid and salicylic acid were observed with all the treatments with the exception of non-treated plants. Most phytochemicals (for example, gallic acid, ferulic acid protocatechuic acid and caffeic acid) were highest in plants obtained from 0.25 µM meta-topolin riboside (mTR). Likewise, plants derived from 2 µM mTR had the highest ORAC (684 µmol g^?1 trolox equivalents) activity. Bearing in mind that therapeutic effects of medicinal plants are often associated to their phytochemical content, the current results are an indication on how the intricate in vitro environment (CK type and concentration in this case) affects the growth and general physiology of micropropagated plants especially after acclimatization.