Karakterizacija sirodezmina izolovanih iz fitopatogene gljive Leptosphaeria maculans

The pathogenicity of phytopathogenic fungi is associated with phytotoxins, especially with their chemical nature and quantity. Sirodesmins are phytotoxins from the epipolythiodioxopiperazines group, produced by the fungus Leptosphaeria maculans, which are a cause of blackleg and stem canker in oilseed rape (Brassica napus L.). The aim of this work was to obtain a detailed chemical profile of sirodesmins in five fungal isolates (four from Vojvodina, Serbia, and one from the Centre for Agricultural Research, Rothamsted, UK). Sirodesmins showing different phytotoxicity on treated cotyledons of cv. Quinta were separated and detected by thin layer chromatography in all analysed isolates (L.m, C-3, St-5 and S-11) except K-113, which neither contained sirodesmin congeners nor did it exhibit activity. By use of high performance liquid chromatography coupled with tandem mass spectrometer, it was possible to identify total of 10 sirodesmins, together with their precursor-phomamide. It was found that the dominant epipolythiodioxopiperazines of the investigated L. maculans isolates were sirodesmin PL, sirodesmin C, and their de-acetylated derivatives.Patogenost fitopatogenih gljiva povezana je sa fitotoksinima, a naročito sa njihovom hemijskom prirodom i količinom. Sirodezmini su fitotoksini iz grupe epipolitiodioksopiperazina, koje proizvodi gljiva Leptosphaeria maculans, uzročnik suve truleži korena i raka stabla uljane repice. Cilj ovog rada bila je detaljna hemijska karakterizacija sirodezmina u pet izolata gljiva (četiri iz Vojvodine i jedan iz Velike Britanije, Centar za poljoprivredna istraživanja, Rothamsted). Kod svih ispitivanih izolata (L. maculans, C-3, St-3, S-11), osim K-113 (koji nije sadržao sirodezmine niti pokazivao aktivnost) tankoslojnom hromatografijom su razdvojeni i detektovani sirodezmini koji su pokazali različitu fitotoksičnost na tretiranim kotiledonima sorte Quinta. Primenom tečne hromatografije visoke efikasnosti, kuplovane sa tandemskim masenim spektrometrom, bilo je moguće identifikovati ukupno 10 sirodezmina, kao i njihov prekursor - fomamid. Utvrđeno je da su dominantni epipolitio-dioksopiperazini ispitivanih izolata L. maculans sirodezmin PL, sirodezmin C i njihovi deacetilovani derivati

Determination of residues of sulfonylurea herbicides in soil by using microwave-assisted extraction and high performance liquid chromatographic method

A modified method for the analysis of nicosulfuron, rimsulfuron and prosulfuron was developed and validated by using microwave-assisted extraction (MAE) and ultra-performance liquid chromatography with diode array detection in the ultraviolet region (HPLC-UV-DAD). The most important experimental parameters of extraction procedure and HPLC-UV-DAD technique were optimised in respect to those sulfonylurea herbicides. High recoveries of the microwave-assisted extraction were obtained by using a dichloromethane-acetonitrile mixture (2:1 volume ratio) acidified with acetic acid (0.8 vol.%) with the addition of urea. The mean recoveries at three spiking levels ranged from 97.47 to 98.76% for nicosulfuron, 97.88 to 99.17% for rimsulfuron and from 97.91 to 99.83% for prosulfuron. The limits of detection of nicosulfuron, rimsulfuron and prosulfuron were 0.95, 0.91 and 0.89 mu g kg(-1), respectively. The accuracy of the developed method was confirmed by HPLC coupled with tandem mass spectrometry parallel analyses. The developed method was used to investigate the dissipation dynamics of sulfonylurea herbicides in the real field trials in Vojvodina Province, Serbia. The obtained half-lives were 0.05, 0.23 and 0.15 days for recommended dose application of nicosulfuron, rimsulfuron and prosulfuron, respectively. Low residues and short half-life in soil suggested that the risk to sensitive rotational crops after application of those sulfonylurea herbicides is low when they are used in the appropriate dosages

Antioxidant activity relationship of phenolic compounds in Hypericum perforatum L.

<p>Abstract</p> <p>Background</p> <p>The St John's Wort (<it>Hypericum perforatum</it>; Clusiaceae) has been used in traditional and modern medicine for a long time due to its high content of biologically active phenolics. The purpose of this work was to develop a method for their fractionation and identification, and to determine the most active antioxidant compounds in plant extract.</p> <p>Results</p> <p>An LC-MS method which enables fast qualitative and semiquantitative analysis was developed. The composition determined is in agreement with the previous results, where 6 flavonoids, 4 naphthodianthrones and 4 phloroglucinols have been identified. Significant antioxidant activity was determined for most of the fractions by DPPH assay (the lowest IC₅₀of 0.52 μg/ml), NO scavenging (6.11 μg/ml), superoxide scavenging (1.86 μg/ml), lipid peroxidation (0.0079 μg/ml) and FRAP (the highest reduction capacity of 104 mg Fe equivalents/g) assays.</p> <p>Conclusion</p> <p>LC-MS technique has been successfully applied for a quick separation and identification of the major components of <it>H. perforatum </it>fractions. Majority of the fractions analyzed have expressed a very high antioxidative activity when compared to synthetic antioxidants. The antioxidant activity could be attributed to flavonoids and phenolic acids, while phloroglucinols and naphthodianthrones showed no significant activity. It is demonstrated that it is possible to obtain, by fractionation, <it>H. perforatum </it>preparations with significantly increased phloroglucinols-to-naphthodianthrones ratio (up to 95:5).</p

Optimization of extraction conditions for secondary biomolecules from various plant species

Extraction of plant secondary metabolites is an essential step in isolation of natural products. Non-optimized extraction conditions can lead to losses, degradation and modification of the biomolecules. In this paper, the influence of different solvent mixtures, solvent amounts, temperature, extraction time, and procedures for defatting on yield and profile of various classes of secondary metabolites was investigated. Rumex alpinus was used for the extraction of anthraquinones, Glycine max for isoflavonoids, Chaerophyllum bulbosum for flavonoids and phenolic acids, Anthriscus sylvestris for lignans and coumarins, alkaloids were extracted from Lupinus albus and sesquiterpene lactones from Artemisia absinthium. Extraction efficiency was evaluated by use of LC-DAD-ESI-MS/MS. The compromise extraction solvent for all of the examined compounds is 80 % methanol, mixed in ratio 13 : 1 with plant material. Maceration should last for six hours, repeated four times with fresh solvent. Defatting of the extracts does not lead to significant losses of the compounds of interest. It is acceptable to use extraction and evaporation temperature of 60ºC, while the extracts should be stored in the dark, on -20ºC. [Projekat Ministarstva nauke Republike Srbije, br. 172058

Phenolic profile, antioxidant and anti-inflammatory potential of herb and root extracts of seven selected legumes

Herb and root parts of legumes are not commonly used in human consumption, since they are traditionally considered waste material. Although inedible, these plant parts have a complex chemical composition, with potential biological activities. They are especially rich in polyphenols, such as flavonoids, isoflavonoids and phenolic acids. In this paper, phenolic profile of the seven selected legumes (soybean (Glycine max L.), common bean (Phaseolus vulgaris L), pea (Pisum sativum L.), broad bean (Vida faba L.), chickpea (Cicer arietinum L), white lupin (Lupinus albus L) and grass pea (Lathyrus sativus L)) was examined using LC-MS/MS method. In the examined herb and root extracts 33 phenolic compounds were identified and quantified. High levels of isoflavones genistein and daidzein were found in G. max, P. vulgaris and L. albus root extracts (1.02-1.53, 0.309-0.648 and 2.81 mg/g, respectively). C. arietinum, L. albus and P. vulgaris herb extracts were found to be the richest sources of flavonoid compounds (13.1-19.4, 5.98 and 2.36-3.64 mg/g, respectively). Since polyphenols have redox properties, antioxidant activity of the abovementioned plants was investigated using DPPH center dot, NO center dot, and FRAP assay. All samples demonstrated the ability to scavenge both DPPH center dot and NO center dot radical, and exhibited a good FRAP reducing power. V. faba exhibited the highest antioxidant activity (DPPH center dot IC50 11.7-20 mu g/mL, NO center dot IC30 0.080-0.34 mg/mL, FRAP 32.6-66.9 AAE/g dw). Anti-inflammatory potential was examined using in vitro COX-1/12-LOX pathway inhibition assay, resulting in moderate activity of all samples (IC50 2.09-8.00 for all metabolites). The obtained results indicate a strong potential of waste legume material as a promising source for isolation of bioactive antioxidant and anti-inflammatory compounds for their use as therapeutic and dietary supplements in pharmaceutical and food industry

Photocatalytic decomposition of selected biologically active compounds in environmental waters using TiO 2 /polyaniline nanocomposites: Kinetics, toxicity and intermediates assessment

A comprehensive study of the removal of selected biologically active compounds (pharmaceuticals and pesticides) from different water types was conducted using bare TiO2nanoparticles and TiO2/polyaniline (TP-50, TP-100, and TP-150) nanocomposite powders. In order to investigate how molecular structure of the substrate influences the rate of its removal, we compared degradation efficiency of the initial substrates and degree of mineralization for the active components of pharmaceuticals (propranolol, and amitriptyline) and pesticides (sulcotrione, and clomazone) in double distilled (DDW) and environmental waters. The results indicate that the efficiency of photocatalytic degradation of propranolol and amitriptyline was higher in environmental waters: rivers (Danube, Tisa, and Begej) and lakes (Moharač, and Sot) in comparison with DDW. On the contrary, degradation efficacy of sulcotrione and clomazone was lower in environmental waters. Further, of the all catalysts applied, bare TiO2and TP-100 were found to be most effective in the mineralization of propranolol and amitriptyline, respectively, while TP-150 appeared to be the most efficient in terms of sulcotrione and clomazone mineralization. Also, there was no significant toxicity observed after the irradiation of pharmaceuticals or pesticides solutions using appropriate catalysts on rat hepatoma (H-4-II-E), mouse neuroblastoma (Neuro-2a), human colon adenocarcinoma (HT-29), and human fetal lung (MRC-5) cell lines. Subsequently, detection and identification of the formed intermediates in the case of sulcotrione photocatalytic degradation using bare TiO2and TP-150 showed slightly different pathways of degradation. Furthermore, tentative pathways of sulcotrione photocatalytic degradation were proposed and discussed. Kinetics, toxicity and intermediates assessment of biologically active compounds (pesticides and pharmaceuticals) in environmental waters