Phenolic compounds of Sorghum vulgare in response to Sclerotium rolfsii infection

Abstract

Identification of individual phenolic acids of Sorghum vulgare Pers. cv. M.P. after interaction with Sclerotium rolfsii Sacc. using high performance liquid chromatograph (HPLC) showed the presence of phenolics namely tannic, gallic, ferulic, chlorogenic and cinnamic acids in varying amounts. After 72 h inoculation with S. rolfsii, a maximum amount of ferulic acid (166.6 µg g^?1 fresh wt) was present in the collar of inoculated plants, followed by leaves and roots and its level decreased gradually with time. Similarly, the presence of chlorogenic acid was traced after 48 h, while that of cinnamic acid was traced after 72 h of inoculation. Reddish-brown pigmentation at the collar region of inoculated plants was also observed along with the high content of tannic acid. Among other phenolics, the presence of gallic acid was recorded consistently and maximum accumulation (139.3 µg g^?1 fresh wt) was noticed at the zone of interaction (collar region) after 72 h of inoculation. In contrast, maximum lignin deposition was observed at collar region after 96 h of inoculation. Induction of phenolic acids in S. vulgare along with the lignin deposition and red pigmentation at collar region is considered a key biomarker in the non-host-pathogen interaction in the S. valgare–S. rolfsii pathosystem.     

Phytochemical analysis and antioxidant activity of Tamarix africana,Arthrocnemum macrostachyum and Suaeda fruticosa,three halophyte species from Algeria

Abstract

Extracts and fractions using six solvents of increasing polarities from Northwest Algeria (Tamarix africana, Arthrocnemum macrostachyum and Suaeda fruticosa) were studied for phytochemical analysis and in vitro antioxidant properties. Methanol and water fractions were found to be the more suitable solvents used for extraction of polyphenolic compounds. Aqueous leaf fraction of T. africana showed the highest content of phenolics (61.06?±?0.40?mg GAE/g DW) and condensed tannins (118.43?±?11.79?mg CE/g DW). Dichloromethane stem fraction of T. africana had the highest 2,2-diphenyl-1-picrylhydrazil radical scavenging ability (0.34?±?0.00?mg/ml). Methanol leaf fraction of the same plant exhibited the highest antioxidant power against the inhibition of β-carotene bleaching, while the maximum total antioxidant capacity was recorded in the leaf extract of S. fruticosa. Phenolic content was not influenced by the species but very affected by the extraction solvent, while antioxidant activities were not influenced by these two parameters. High-performance liquid chromatography with a diode-array detector analysis of methanol and aqueous leaf fractions of T. africana revealed the presence of six phenolic acids; chlorogenic and gallic acids were predominant and 10 flavonoid compounds among which rutin and quercetin-3-O-arabonoside were the major constituents. These findings suggest that these species may be considered as an interesting source of antioxidants.     

Biochemical Investigations of Sclerotial Exudates of Sclerotium rolfsii and their Antifungal Activity

Exudates from sclerotia of two Sclerotium rolfsii isolates (one causing collar rot in Cicer arietinum, isolate VC971, and the other leaf spots in Rauvolfia serpentina, isolate VL016) were assayed for their antifungal activity against 26 fungi consisting of plant parasites as well as saprophytes. Spore germination of all the test fungi was affected by the exudates reaching 100% in some cases. Foliar spray with exudates of isolate VL016 significantly reduced disease incidence of balsam (Impatiens balsamina) powdery mildew caused by Erysiphe cichoracearum and pea (Pisum sativum) powdery mildew caused by Erysiphe pisi, under field conditions. Characterization of exudates from 25 isolates of S. rolfsii revealed pH ranging from 3.8 to 5.3 and colour from light yellow to deep yellow. Among the phenolic acids found in the exudates were tannic, gallic, caffeic, vanillic, ferulic, chlorogenic and cinnamic acids. Oxalic acid was also found in varied amounts. Among the phenolic acids, ferulic acid was found to be present at high concentration in exudates of most isolates (3.9–153.4 μg/ml). The antioxidant properties of phenolics, which generally inhibit fungal morphogenesis including spore germination along with the antifungal nature of some phenolics are chiefly attributed to the inhibitory effect of sclerotial exudates of S. rolfsii. Additionally, both the isolates VC971 and VL016 showed almost similar antifungal activities despite they are of different origin and thereby demonstrate the antifungal nature of sclerotial exudates.     

Bioreactor type affects the accumulation of phenolic acids and flavonoids in microshoot cultures of Schisandra chinensis (Turcz.) Baill.

Microshoots of the East Asian medicinal plant species Schisandra chinensis (Chinese magnolia vine) were grown in bioreactors characterized by different construction and cultivation mode. The tested systems included two continuous immersion systems—a cone-type bioreactor (CNB) and a cylindric tube bioreactor (CTB), a nutrient sprinkle bioreactor (NSB), and two temporary immersion systems (TIS)—RITA® and Plantform. Microshoots were grown for 30 and 60 days in the MS medium enriched with 1 mg l^?1 NAA and 3 mg l^?1 BA. The accumulation of two groups of phenolic compounds: phenolic acids and flavonoids in the bioreactor-grown S. chinensis biomass, was evaluated for the first time. In the microshoot extracts, seven phenolic acids: chlorogenic, gallic, p–hydroxybenzoic, protocatechuic, syringic, salicylic and vanillic, and three flavonoids: kaempferol, quercitrin and rutoside, were identified. The highest total amount of phenolic acids (46.68 mg 100 g^?1 DW) was recorded in the biomass maintained in the CNB for 30 days. The highest total content of flavonoids (29.02 mg 100 g^?1 DW) was found in the microshoots maintained in the NSB for 30 days. The predominant metabolites in all the tested systems were: gallic acid (up to 10.01 mg 100 g^?1 DW), protocatechuic acid (maximal concentration 16.30 mg 100 g^?1 DW), and quercitrin (highest content 21.00 mg 100 g^?1 DW).

     

Antioxidant activity and phenolic compounds of 112 traditional Chinese medicinal plants associated with anticancer

Cancer prevention and treatment using traditional Chinese medicines have attracted increasing interest. This study characterizes antioxidant activity and phenolic compounds of traditional Chinese medicinal plants associated with anticancer, comprising 112 species from 50 plant families. The improved ABTS(*+) method was used to systematically assess the total antioxidant capacity (Trolox equivalent antioxidant capacity, TEAC) of the medicinal extracts. The TEAC values and total phenolic content for methanolic extracts of herbs ranged from 46.7 to 17,323 micromol Trolox equivalent/100 g dry weight (DW), and from 0.22 to 50.3 g of gallic acid equivalent/100 g DW, respectively. A positive, significant linear relationship between antioxidant activity and total phenolic content (all R(2) values>/=0.95) showed that phenolic compounds were the dominant antioxidant components in the tested medicinal herbs. Major types of phenolic compounds from most of the tested herbs were preliminarily identified and analyzed, and mainly included phenolic acids, flavonoids, tannins, coumarins, lignans, quinones, stilbenes, and curcuminoids. These medicinal herbs exhibited far stronger antioxidant activity and contained significantly higher levels of phenolics than common vegetables and fruits. Traditional Chinese medicinal plants associated with anticancer might be potential sources of potent natural antioxidants and beneficial chemopreventive agents.     

Polyphenols,flavonoids, antioxidant activity in leaves and flowers of Tunisian Globularia alypum L. (Globulariaceae)

Leaves and flowers from Tunisian Globularia alypum were assessed for their phenolic and flavonoid contents and antioxidant activity. Phenolic (15.5–22.30 mg GAE g^?1 DW) and flavonoid (3.63–4.72 mg RE g^?1 DW) contents varied according to plant part. Globularia alypum leaves exhibited the highest phenol and flavonoid contents, and displayed the highest antioxidant activity, based on radical‐scavenging activity (295 μmol TEAC g^?1 DW) and ferric reducing power (24.27 mmol Fe2+/l). The obtained results demonstrated that some of the isolated compounds play an important role for the antioxidant activity of G. alypum and give a scientific basis to the use of this plant in traditional medicine. The methanolic extract of G. alypum could be considered as a source of potential antioxidants and will promote the reasonable usage of this plant in food technology and processing as well as for medical use.     

Agaricus bisporus compost improves the potential of Salix purpurea × viminalis hybrid for copper accumulation

The aim of the study was to determine the ability of spent mushroom compost (SMC) from the production of Agaricus bisporus (A. bisporus) to stimulate the growth and efficiency of copper (Cu) accumulation by Salix purpurea × viminalis hybrid. Roots, shoots and leaves were analysed in terms of total Cu content and selected biometric parameters. Due to the absence of information regarding the physiological response of the studied plant, low molecular weight organic acids (LMWOAs), phenolic compounds and salicylic acid (SA) contents were investigated. The obtained results clearly demonstrate the effectiveness (usefulness) of SMC in promoting the growth and stimulation of Cu accumulation by the studied Salix taxon. The highest Cu content in roots and shoots was found at the 10% SMC addition (507±22 and 380±11 mg kg^?1 DW, respectively), while there was a reduction of the content in leaves and young shoots (109±8 and 124±7 mg kg^?1 DW, respectively). In terms of physiological response, lowered secretion of LMWOAs, biosynthesis of phenolic compounds and SA, as well as accumulation of soluble sugars in Salix leaves was observed with SMC addition. Simultaneously, an elevation of the total phenolic content in leaves of plants cultivated with SMC was observed, considered as antioxidant biomolecules.     

Influence of thidiazuron on callus induction and crocin production in corm and style explants of <Emphasis Type="Italic">Crocus sativus</Emphasis> L.

Crocus sativus L., mostly famous as saffron, has gained more attention due to its crocin (crocetin ester) pigment responsible for its extensive pharmaceutical properties. In this study, we established two different callus cultures from corm and style explants of saffron to find out the best explant as a suitable source for crocin production. Comparative analyses of total phenolic, flavonoid, carotenoid and anthocyanin contents were also performed in the two callus cultures. For callus induction, different combinations of MS medium with name thidiazuron (TDZ), benzylaminopurine (BA), 1-naphthaleneacetic acid (NAA), and 2,4-dichlorophenoxyacetic acid (2,4-D) alone or in combination were tested. Of the used media, all the combinations containing TDZ and NAA gave 100% callus induction. HPLC-DAD and HPLC–ESI-MS analysis were used for identification of crocin esters in established callus cultures. The highest amount of 0.35 mg g^?1 DW crocin was detected in style originated calli grown on the medium containing 3 mg L^?1 NAA?+?1 mg L^?1 TDZ while the corm calli showed the most abundant total carotenoid (0.73 mg g^?1 DW), phenolic (15.04 mg gallic acid equivalent g^?1 DW) and flavonoid (0.76 mg rutin equivalent g^?1 DW) contents. In general, style-derived calli showed longer time survival with a fine texture and good quality compared to corm-derived calli.     

低海拔地区黑苦荞酚类物质含量、组成及抗氧化活性研究

为探究黑苦荞的市场利用价值,该研究选择种植于湖北江汉平原低海拔地区的川荞1号和九江苦荞作为材料,分析苦荞籽粒中游离酚、结合酚、总酚、游离黄酮、结合黄酮和总黄酮的含量,利用DPPH自由基法、ABTS自由基法和铁离子还原抗氧化法(FRAP)三种抗氧化测试模型综合评价其体外抗氧化活性,并运用高效液相色谱(HPLC)技术对其酚类物质的组成进行鉴定。结果表明:(1)川荞1号籽粒的总酚和总黄酮含量显著高于九江苦荞,分别为27.38 mg GAE·g~(-1)DW、31.46 mg RE·g~(-1)DW和12.71 mg GAE·g~(-1)DW、14.68 mg RE·g~(-1)DW;其中游离酚与游离黄酮含量显著高于结合酚与结合黄酮含量,均占总酚和总黄酮含量的79%以上,且九江苦荞中结合酚和结合黄酮的含量高于川荞1号。(2)苦荞籽粒中酚类物质主要由芦丁、槲皮素、表儿茶素、山奈酚、山奈酚-3-芸香糖苷和槲皮素-3-O-芸香糖苷-3'-O-吡喃葡萄糖苷等黄酮类化合物组成,其中游离酚以芦丁和槲皮素为主,结合酚以表儿茶素和芦丁为主。(3)苦荞籽粒提取物均具有一定的抗氧化活性,黑苦荞川荞1号游离态DPPH、ABTS和FRAP抗氧化能力值分别为30.14、11.03、18.84 mg TE·g~(-1)DW,高于九江苦荞,而结合态三种抗氧化能力值低于九江苦荞,但黑苦荞川荞1号总抗氧化能力显著高于九江苦荞。在低海拔地区江汉平原,种植的黑苦荞川荞1号籽粒具有较高含量的酚类物质,符合后续的食品加工的生产要求,市场开发前景广阔。     

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.     

In vitro antioxidant activity and phenolic contents in methanol extracts from medicinal plants

Antioxidant activities and phenolic contents of 26 species extracts from 20 botanical families grown in north-western Himalaya were investigated. Antioxidant activities were determined using DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging and ferric reducing antioxidant power (FRAP) assays. Total phenolic content (TPC) was determined using a Folin-Ciocalteu assay. Quantitative and qualitative analysis of phenolic compounds was also carried out by reverse phase high performance liquid chromatography (RP-HPLC) using diode array detector (DAD). Major phenolics determined using RP-HPLC in analyzed species were gallic acid, chlorogenic acid, p-hydroxy benzoic acid, caffeic acid, vanillic acid, syringic acid, p-coumaric acid and ferulic acid. Antiradical efficiency (1/EC₅₀) determined using DPPH radical scavenging assay ranged from 0.13 to 5.46. FRAP values ranged from 8.66 to 380.9 μmol Fe(II)/g dw. Similarly, the total phenolic content in the analyzed species varied from 3.01 to 69.96 mg of gallic acid equivalents (GAE)/g dry weight. Gallic acid was found in the majority of the samples, being most abundant compound in Syzygium cumini bark (92.64 mg/100 g dw). Vanillic acid was the predominant phenolic compound in Picrorhiza kurroa root stolen (161.2 mg/100 g dry weight). The medicinal plants with highest antioxidant activities were Taxus baccata and Syzygium cumini. A significant positive correlation, R ²?=?0.9461 and R ²?=?0.9112 was observed between TPC determined using Folin-Ciocalteu method and antiradical efficiency and FRAP values respectively, indicating that phenolic compounds are the major contributor of antioxidant activity of these medicinal plants.     

Antioxidant activity and phenolic profile in filamentous cyanobacteria: the impact of nitrogen

In the present study, ethanolic extracts of ten cyanobacterial strains cultivated under different nitrogen conditions were assessed for the phenolic content and antioxidant activity. The amount of detected phenolic compounds ranged from 14.86 to 701.69 μg g^?1 dry weight (dw) and HPLC-MS/MS analysis revealed gallic acid, chlorogenic acid, quinic acid, catechin, epicatechin, kaempferol, rutin and apiin. Only catechin, among the detected phenolics, was present in all the tested strains, while quinic acid was the most dominant compound in all the tested Nostoc strains. The results also indicated the possibility of increasing the phenolic content in cyanobacterial biomass by manipulating nitrogen conditions, such as in the case of quinic acid in Nostoc 2S7B from 70.83 to 594.43 μg g^?1 dw. The highest radical scavenging activity in DPPH assay expressed Nostoc LC1B with IC₅₀ value of 0.04?±?0.01 mg mL^?1, while Nostoc 2S3B with IC₅₀ =?9.47?±?3.61 mg mL^?1 was the least potent. Furthermore, the reducing power determined by FRAP assay ranged from 8.36?±?0.08 to 21.01?±?1.66 mg AAE g^?1, and it was significantly different among the tested genera. The Arthrospira strains exhibited the highest activity, which in the case of Arthrospira S1 was approximately twofold higher in comparison to those in nitrogen-fixing strains. In addition to this, statistical analysis has indicated that detected phenolics were not major contributor to antioxidant capacities of tested cyanobacteria. However, this study highlights cyanobacteria of the genera Nostoc, Anabaena, and Arthrospira as producers of antioxidants and phenolics with pharmacological and health-beneficial effects, i.e., quinic acid and catechin in particular.     

Investigation of the inhibitory properties of some phenolic standards and bee products against human carbonic anhydrase I and II

Abstract

Polyphenols are important secondary products of plants with the potential to inhibit carbonic anhydrases. The aim of this study was to investigate the inhibition effects of various phenolic standards, honey, propolis, and pollen species on human carbonic anhydrase I and II. The inhibition values (IC₅₀) of the phenolics (gallic acid, protocatechuic acid, quercetin, catechin, tannic acid, and chrysin) ranged from 0.009 to 0.32?μg/mL, tannic acid emerging as the best inhibitor. The inhibition values of three different types of honey, heather, rhododendron, and chestnut ranged between 2.32 and 25.10?μg/mL, the chestnut honeys exhibiting the best inhibition. The ethanolic extracts of pollen and propolis exhibited good inhibitory properties, with IC₅₀ values between 0.486 and 3.320?μg/mL. In order to evaluate the phenolic composition of bee products, phenolic profiles and total phenolic contents (TFC) were also measured. The inhibition ranking among the natural products studied was phenolic standards?>?propolis?>?pollen?>?honeys, and inhibition was related to TFC.     

Quantitative analysis of phenolics in selected crop species and biological activity of these compounds evaluated by sensitivity of Echinochloa crus-galli

The purpose of this study was to determine the content of selected phenolic compounds in white mustard, buckwheat, spring barley, oat and rye grown under field conditions. Moreover, the allelopathic efficiency of these compounds was evaluated by sensitivity of Echinochloa crus-galli. The aromatic acids: trans-cinnamic, salicylic, ferulic, chlorogenic, p-hydroxybenzoic, protocatechuic, p-coumaric and vanillic were separated from crop plants by TLC and determined spectrophotometrically. Differences in concentrations of analysed compounds were observed for most of the examined plant species. The highest concentration was noticed for cinnamic acid and ranged from 360 μg·g⁻¹ DW in rye to 2770 μg·g⁻¹ DW in spring barley. The relatively high concentration was noticed for ferulic acid (from 73.8 μg·g⁻¹ DW in buckwheat to 1046 μg·g⁻¹ DW in spring barley) and p-coumaric acid (from 50 μg·g⁻¹ DW in oat to 1499 μg·g⁻¹ DW in buckwheat). The observed differences in the phenolics content between two successive vegetation seasons can reflect the effect of abiotic and biotic environmental factors on the phenolics level in studied plants. In the greenhouse experiment the effect of particular compounds on the growth of Echinochloa crus-galli was also studied. It has been found that the examined phenolics, and especially trans-cinnamic acid and mixture of phenolic compounds, significantly inhibit the growth of Echinochloa crus-galli. The obtained results may contribute to the explanation of the biological activity of some phenolic compounds.     

Co-production of tannase and gallic acid by a novel Penicillium rolfsii (CCMB 714)

Abstract

A novel tannase and gallic acid-producing Penicillium rolfsii (CCMB 714) was isolated from cocoa leaves from the South of Bahia. The influence of nutritional sources and the simultaneous effect of parameters involved in the fermentation process were available. Tannase (9.97 U?mL^?1) and gallic acid (9?mg mL^?1) production were obtained in 48?h by submerged fermentation in non-optimized conditions. Among the carbon sources, tested gallic acid and tannic acid showed the highest tannase production (p<.05) when compared with methyl gallate and glucose. After optimization using the temperature and tannic acid concentration as variables with the Central Compound Rotational Design (CCRD), the maximal tannase production (25.6?U mL^?1) was obtained at 29.8?°C and 12.7%, respectively, which represents an increase of 2.56 times in relation to the initial activity. The parameters optimized for the maximum production of gallic acid (21.51?mg mL^?1) were 30?°C and 10% tannic acid. P. rolfsii CCMB 714 is a new strain with a high tannase and gallic acid production and the gallic acid produced is very important, mainly for its applications in the food and pharmaceutical industry.     

Characterization of saponins and phenolic compounds: antioxidant activity and inhibitory effects on α-glucosidase in different varieties of colored quinoa (Chenopodium quinoa Willd)

ABSTRACT

This study investigated the contents of saponins and phenolic compounds in relation to their antioxidant activity and α-glucosidase inhibition activity of 7 colored quinoa varieties. The total saponin content was significantly different among 7 varieties and ranged from 7.51 to 12.12 mg OAE/g DW. Darker quinoa had a higher content of phenolic compounds, as well as higher flavonoids and antioxidant activity than that of light varieties. Nine individual phenolic compounds were detected in free and bound form, with gallic acid and ferulic acid representing the major compounds. The free and bound phenolic compounds (gallic acid and ferulic acid in particular) exhibited high linear correlation with their corresponding antioxidant values. In addition, the free phenolic extracts from colored quinoa exhibited higher inhibitory activity against α-glucosidase than the bound phenolic extracts. These findings imply that colored quinoa with abundant bioactive phytochemicals could be an important natural source for preparing functional food.     

Polyphenol Characterization,Antioxidant and Skin Whitening Properties of Alnus cordata Stem Bark

In this study, we investigated the phenolic composition of the crude extract (MeOH 80 %) of Alnus cordata (Loisel .) Duby stem bark (ACE) and its antioxidant and skin whitening properties. RP‐LC‐DAD analysis showed a high content of hydroxycinnamic acids (47.64 %), flavanones (26.74 %) and diarylheptanoids (17.69 %). Furthermore, ACE exhibited a dose‐dependent antioxidant and free‐radical scavenging activity, expressed as half‐maximal inhibitory concentration (IC₅₀): Oxygen radical absorbance capacity (ORAC, IC₅₀ 1.78 μg mL^?1)>Trolox equivalent antioxidant capacity (TEAC, IC₅₀ 3.47 μg mL^?1)>2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH, IC₅₀ 5.83 μg mL^?1)>β‐carotene bleaching (IC₅₀ 11.58 μg mL^?1)>Ferric reducing antioxidant power (FRAP, IC₅₀ 17.28 μg mL^?1). Moreover, ACE was able to inhibit in vitro tyrosinase activity (IC₅₀ 77.44 μg mL^?1), l ‐DOPA auto‐oxidation (IC₅₀ 39.58 μg mL^?1) and in an in vivo model it exhibited bleaching effects on the pigmentation of zebrafish embryos (72 h post fertilization) without affecting their development and survival. In conclusion, results show that A. cordata stem bark may be considered a potential source of agents for the treatment of skin disorders due to its bleaching properties and favorable safety profiles, associated to a good antioxidant power.     

Comprehensive Study of Mediterranean (Croatian) Propolis Peculiarity: Headspace,Volatiles, Anti‐Varroa‐Treatment Residue,Phenolics, and Antioxidant Properties

Eight propolis samples from Croatia were analyzed in detail, to study the headspace, volatiles, anti‐Varroa‐treatment residue, phenolics, and antioxidant properties. The samples exhibited high qualitative/quantitative variability of the chemical profiles, total phenolic content (1,589.3–14,398.3 mg GAE (gallic acid equivalent)/l EtOH extract), and antioxidant activity (11.1–133.5 mmol Fe²⁺/l extract and 6.2–65.3 mmol TEAC (Trolox^® equivalent antioxidant capacity)/l extract). The main phenolics quantified by HPLC‐DAD at 280 and 360 nm were vanillin, p‐coumaric acid, ferulic acid, chrysin, galangin, and caffeic acid phenethyl ester. The major compounds identified by headspace solid‐phase microextraction (HS‐SPME), simultaneous distillation extraction (SDE), and subsequent GC‐FID and GC/MS analyses were α‐eudesmol (up to 19.9%), β‐eudesmol (up to 12.6%), γ‐eudesmol (up to 10.5%), benzyl benzoate (up to 28.5%), and 4‐vinyl‐2‐methoxyphenol (up to 18.1%). Vanillin was determined as minor constituent by SDE/GC‐FID/MS and HPLC‐DAD. The identified acaricide residue thymol was ca. three times more abundant by HS‐SPME/GC‐FID/MS than by SDE/GC‐FID/MS and was not detected by HPLC‐DAD.     

EFFECT OF INDOLE-3-ACETIC ACID,KINETIN, AND ETHYLENEDIAMINETETRAACETIC ACID ON PLANT GROWTH AND UPTAKE AND TRANSLOCATION OF LEAD,MICRONUTRIENTS, AND MACRONUTRIENTS IN ALFALFA PLANTS

Alfalfa plants germinated and grown for 15 d in soil containing 80 mg Pb kg^?1 were treated with ethylenediaminetetraacetic acid (EDTA) at 0.8 mM and indole-3-acetic acid-kinetin (IAA-KN) at 100 μM. Fifteen days after the treatment application, the concentration of lead (Pb), macronutrients, and micronutrients was determined using inductively coupled plasma/optical emission spectroscopy. The chlorophyll content and plant growth were also measured. Roots of plants exposed to Pb alone, Pb–EDTA, and Pb–EDTA-IAA-KN had 160, 140, and 150 mg Pb kg^?1 DW, respectively. Pb was not detected in the stems of plants exposed to Pb alone; however, stems of plants treated with EDTA and EDTA–IAA-KN had 78 and 142 mg Pb kg^?1 DW, respectively. While the Pb concentration in leaves of plants treated with EDTA and EDTA–IAA-KN was 92 and 127 mg kg^?1 DW, respectively. In addition, EDTA and EDTA–IAA-KN significantly increased the translocation of zinc and manganese to leaves. The x-ray absorption spectroscopic studies demonstrated that Pb(II) was transported from roots to leaves without a change in the oxidation state.     

Variability of phenolic composition and biological activities of two Tunisian halophyte species from contrasted regions

The present study consists in evaluating the inter- and intraspecific variability of phenolic contents and biological capacities of Limoniastrum monopetalum L. and L. guyonianum Boiss. extracts. Ultimately, they were subjected to HPLC for phenolic identification. Results showed a great variation of phenolic content as function of species and localities. In fact, L. guyonianum extracts (El Akarit) contained the highest polyphenol (57 mg GAE g^?1 DW), flavonoid (9.47 mg CE g^?1 DW) and condensed tannin contents (106.58 mg CE g^?1 DW). These amounts were accompanied by the greatest total antioxidant activity (128.53 mg GAE g^?1 DW), antiradical capacity (IC₅₀ = 4.68 μg/ml) and reducing power (EC₅₀ = 120 μg/ml). In addition, L. monopetalum and L. guyonianum extracts exhibited an important and variable antibacterial activity with a diameter of inhibition zone ranging from 6.00 to 14.83 mm. Furthermore, these extracts displayed considerable antifungal activity. L. monopetalum extracts (Enfidha) showed the strongest activity against Candida glabrata and C. krusei with a diameter exceeding 12 mm. The phytochemical investigation of these extracts confirmed the variability of phenolic composition, since the major phenolic compound varied as a function of species and locality. These findings suggest that these two halophytes may be a new source of natural antioxidants that are increasingly important for human consumption, as well as for agro-food, cosmetic and pharmaceutical industries.