Drugs: A review of promising novel corrosion inhibitors

Novel nanocomposite materials for efficient and selective mercury ions capturing from wastewater

Food and feed laboratories share several similarities when facing the implementation of liquid-chromatographic analysis. Using the experience acquired over the years, through application chemistry in food and feed research, selected analytes of relevance for both areas were discussed. This review focused on the common obstacles and peculiarities that each analyte offers (during the sample treatment or the chromatographic separation) throughout the implementation of said methods. A brief description of the techniques which we considered to be more pertinent, commonly used to assay such analytes is provided, including approaches using commonly available detectors (especially in starter labs) as well as mass detection. This manuscript consists of three sections: feed analysis (as the start of the food chain); food destined for human consumption determinations (the end of the food chain); and finally, assays shared by either matrices or laboratories. Analytes discussed consist of both those considered undesirable substances, contaminants, additives, and those related to nutritional quality. Our review is comprised of the examination of polyphenols, capsaicinoids, theobromine and caffeine, cholesterol, mycotoxins, antibiotics, amino acids, triphenylmethane dyes, nitrates/nitrites, ethanol soluble carbohydrates/sugars, organic acids, carotenoids, hydro and liposoluble vitamins. All analytes are currently assayed in our laboratories.

Liquid Chromatography Analysis of Common Nutritional Components, in Feed and Food.

Among natural substances widespread in fruits, vegetables, spices, and medicinal plants, flavonoids and organic acids belong to the promising groups of bioactive compounds with strong antioxidant and anti-inflammatory properties. The aim of the present work was to evaluate the antibacterial activity of 13 common flavonoids (flavones, flavonols, flavanones) and 6 organic acids (aliphatic and aromatic acids). The minimal inhibitory concentrations (MICs) of selected plant substances were determined by the micro-dilution method using clinical strains of four species of pathogenic bacteria. All tested compounds showed antimicrobial properties, but their biological activity was moderate or relatively low. Bacterial growth was most strongly inhibited by salicylic acid (MIC = 250–500 μg/mL). These compounds were generally more active against Gram-negative bacteria: Escherichia coli and Pseudomonas aeruginosa than Gram-positive ones: Enterococcus faecalis and Staphylococcus aureus. An analysis of the antibacterial effect of flavone, chrysin, apigenin, and luteolin showed that the presence of hydroxyl groups in the phenyl rings A and B usually did not influence on the level of their activity. A significant increase in the activity of the hydroxy derivatives of flavone was observed only for S. aureus. Similarly, the presence and position of the sugar group in the flavone glycosides generally had no effect on the MIC values.

https://www.mdpi.com/2077-0383/9/1/109/pdf

Antibacterial Activity of Some Flavonoids and Organic Acids Widely Distributed in Plants.

Pistacia lentiscus leaves as a source of phenolic compounds: Microwave-assisted extraction optimized and compared with ultrasound-assisted and conventional solvent extraction

A high-performance liquid chromatographic method with gradient elution and diode-array detection was developed to quantify free phenolic acids (gallic, vanillic, chlorogenic, caffeic, syringic, p-coumaric, ferulic, sinapic, salycilic, elagic and trans-cinnamic), flavonoids (catechin, epicatechin, rutin, myricetin and quercetin) and juglone in walnut leaves. Chromatographic separation was performed on a Hypersil Gold C18 column (5 mm particle size, 250 3 4.6 mm) and detection was conducted at three different wavelengths (254, 278 and 300 nm) according to the absorption maxima of the analyzed compounds. Validation procedures were conducted and the method was proven to be precise, accurate and sensitive. The developed method has been applied to analyze walnut leaves samples from nine different cultivars, with the same agricultural, geographical and climatic conditions. The experimental results revealed high concentrations of myricetin, catechin hydrate and rutin, and low concentrations of quercetin and epicatechin aglycones. Ellagic acid was established as the dominating phenolic acid of walnut leaves, followed by trans-cinnamic, chlorogenic and caffeic acids. Juglone content varied between 44.55 and 205.12 mg/100 g fresh weight. Significant differences were detected among cultivars for the concentration levels of phenolics.

HPLC Determination of Phenolic Acids, Flavonoids and Juglone in Walnut Leaves

A reversed phase HPLC method for separation and quantification of organic acids (oxalic, citric, tartaric, malic, ascorbic and lactic acids) in fruit juices was developed. The chromatographic separation was performed with a Surveyor Thermo Electron system at 10C by using potassium dihydrogen orthophosphate buffer (pH 2.8) as mobile phase, an Hypersil Gold aQ Analytical Column and diode array detection at ?=254 nm for ascorbic acid and ?=214 nm for the other organic acids. Organic acid profiles of ten species of Citrus: sweet orange, minneola, clementine, mandarin orange, pomelo, lemon, lime, sweetie, white and pink grapefruit were established. Species significantly affect the organic acid distribution of citrus fruit juices. In all citrus juices, the most abundant organic acid was citric acid, ranging from 6.88 to 73.93 g/l. Citrus juices are good sources of ascorbic acid (0.215-0.718 g/l). Average ascorbic acid was the highest in lemon juice followed by sweet orange juice, sweetie and white grapefruit.

HPLC organic acid analysis in different citrus juices under reversed phase conditions.

Mesoporous silica functionalized with 1-furoyl thiourea urea for Hg(II) adsorption from aqueous media.

Fifteen apple cultivars grown in Valcea Research Station, Romania were evaluated in terms of fruit quality. Some selected compositional characteristics such as dry matter, total soluble solids, total sugar, titratable acidity, malic, citric and ascorbic acids and minerals content were investigated. Malic, citric and ascorbic acids were determined by a reversed-phase HPLC method. Sodium, calcium, magnesium, phosphorus, iron, manganese, copper, aluminium, chromium, zinc and strontium contents were determined by inductively coupled plasma-mass spectrometry following a microwave digestion while potassium content was determined by flame atomic absorption spectrometry. Large differences between cultivars were found for the contents of particular biochemical and mineral compounds. The dry matter content ranged between 12.49% (Prima) and 20.09% (Red Boskoop) while the total sugar content varied between 9.5% (Cadel) and 15.03% (Red Boskoop). The highest titratable acidity was found in Red Boskoop (0.771%), while in Starkrimson the titratable acidity was only 0.101%. The respective ranges of malic and citric acid contents of the tested samples were: 522.2-1993.7 mg/100 g and 3.5-49.1 mg/100 g. The ascorbic acid content was on average 6.18 mg/100 g. Potassium was the most accumulated nutrient in fruits. The potassium content was comprised between 82.25 mg/100 g (Mutzu) and 160.85 mg/100 g (Florina). Calcium follows, with variation limits between 1.70 mg/100 g (Starkrimson) and 8.74 mg/100g (Prima) while iron content varied between 0.19 mg/100 g (Ionagold) and 0.40 mg/100 g (Cadel and Early Red). The observed differences in composition are of such magnitude that they may affect both nutritional and sensory properties.

Compositional Characteristics of Fruits of several Apple (Malus domestica Borkh.) Cultivars

Introduction. Red and black currants are a valuable component of a healthy diet because they are an excellent source of ascorbic acid, anthocyanins and minerals. Materials and methods. Three red currant cultivars and eight black currant cultivars were evaluated in terms of fruit quality. Some selected physicochemical characteristics such as berry weight, dry matter, soluble solids, total sugars, titratable acidity and total anthocyanins were investigated. Total anthocyanin content was measured with the pH differential absorbance method while citric, malic, tartaric and ascorbic acid were quantified by a reversed-phase HPLC method. Sodium, calcium, magnesium, iron, manganese, chromium and zinc were determined by ICP- MS following a microwave digestion, while potassium content was determined by FAAS. Results. Significant differences in the physicochemical and mineral content were detected among the cultivars. The range of total anthocyanins of the tested samples was 12.14- 22.06 mg·100 g -1 (red currants) and 116.17-287.78 mg·100 g -1 (black currants). Ascorbic acid content varied between 23.23-44.62 mg·100 g -1 (red currants) and 161.58-284.46 mg·100 g -1 (black currants). Citric acid was predominant in all studied black and red currant cultivars, fol- lowed by malic and tartaric acids. Black and red currants have rich mineral composition, espe- cially potassium, calcium and magnesium. Black currant fruits were superior to red currants with regard to calcium and magnesium content. Romania/Ribesrubrum/Ribesnigrum/softfruits/redcurrants/blackcurrants / proximate composition / anthocyanins / organic acids / mineral content

/pdf/ascorbic-acid-anthocyanins-organic-acids-and-mineral-content-32o95k97lp.pdf

Ion Trandafir

Papers

HPLC Determination of Phenolic Acids, Flavonoids and Juglone in Walnut Leaves

HPLC organic acid analysis in different citrus juices under reversed phase conditions.

Mesoporous silica functionalized with 1-furoyl thiourea urea for Hg(II) adsorption from aqueous media.

Compositional Characteristics of Fruits of several Apple (Malus domestica Borkh.) Cultivars

Ascorbic acid, anthocyanins, organic acids and mineral content of some black and red currant cultivars