Tag Archives: spectrophotometry

The Analysis of Flavonoids from Inula helenium L. Flowers and Leaves

Objective: In this study we investigated the flavonoids in the leaves and flowers of Inula helenium L..
Material and method: Flowers and leaves were harvested from the Medicinal Plant Garden of the University of Medicine and Pharmacy of Tîrgu Mureș. Dried vegetable product was extracted with methanol and in order to investigate aglycones we prepared hydrolised extracts. We screened the vegetable product for flavonoids using a TLC method, then we determined the total flavonoid content by a spectrophotometric method. HPLC-MS and HPLC-UV methods were used to determine polyphenols in methanolic and hydrolised extracts.
Results: Flavonoid content varies from 1.83% in leaves to 1.43% in flowers, equivalent in hyperoside. We identified the flavonols quercetin and kaempferol and the glycosides isoquercitrin, quercitrin and rutoside. Isoquercitrin is the major compound, in a concentration of 0.898 mg/g dry vegetable product.
Conclusions: Our study shows that the leaves and flowers of Inula helenium L. contain a high percentage of flavonoids with pharmacological activities.

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Indirect Determination of Gentamicin by Derivative Spectrophotometry

Introduction: Gentamicin sulfate is an aminoglycosidic antibiotic, used in severe infections caused by Gram-negative bacteria. UV-Vis spectrophotometry, a simple, high speed and accessible analytical method, is generally suitable for the quantitative determination of pharmaceutical active ingredients in raw materials. In the case of gentamicin, a drug that presents low absorbances on the UV-Vis domain, direct determination by UV-Vis spectrophotometry would not assure adequate detection and quantitation limits.
The aim of this study was to develop a new indirect spectrophotometric method, based on the capacity of gentamicin to form in the presence of Cu2+ ions complex combinations with increased UV-Vis light absorbing capacity.
Material and method: Optimised experimental conditions which assure formation of a stable complex was found to take place in the pre-sence of CuCl2.6H2O 0.1 mg/mL, while 1 mM NaOH was used as solvent. All readings were performed at 291 nm on the first derivative of the absorbance spectrum.
Results: The developed method was validated, and proved to be linear on the 0.051–0.261 mg/mL concentration range (r = 0.99935).
Conclusions: The developed method is fast, accessible and can be used for the determination of gentamicin in raw materials.

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Botanical Investigation Of Fallopia Dumetorum (L.) Holub (Polygonaceae) And Qualitative And Quantitative Assessment Of Its Polyphenolic Compounds

DOI: 10.2478/amma-2014-0015

Background: Considering the continuous need to find new sources of polyphenolic compounds, we performed a pharmacognostical examination of the species Fallopia dumetorum (L.) Holub sin. Polygonum dumetorum L. (Polygonaceae). The plant is common in the plain regions of Romania and has not been exploited therapeutically.
Materials and method: Microscopic examination was performed on cross-sections, surface preparations and on powder obtained from the aerial parts of the flowering plant. Qualitative chemical analysis was realized by phytochemical screening and thin layer chromatography (TLC). Phenolic compounds were assayed by spectrophotometric methods: flavonoids expressed as rutin (with aluminium chloride), phenol-carboxylic acids expressed as chlorogenic acid (Arnow’s method) and proanthocyanidins expressed as cyanidin chloride (in acidic medium, by conversion to anthocyanins).
Results: The species has the following microscopic characters: anomocytic stomata, druses of calcium oxalate, sessile, pluricellular glandular hairs and pollen grains with smooth exine. Polysaccharides, reducing compounds, coumarins, sterols/triterpenes, phenol-carboxylic acids, flavones, proanthocyanidins, tannins and carotenoids were identified by phytochemical screening; chlorogenic acid, caffeic acid, quercetin and stigmasterol/beta-sitosterol were detected by TLC. F. dumetori herba has a content of 1.49 ± 0.105 g% polyphenol-carboxylic acids, 0.40 ± 0.087g% flavonoids and 0.18 ± 0.002 g% proanthocyanidins.
Conclusions: We have characterized pharmacognostically the native species F. dumentorum. Due to its content in phenolic compounds it might serve as a source of polyphenols.

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