The development of methods for determination the total flavonoids in buds of Populus alba L.

Abstract

White poplar (Populus alba L.,  family Saliaceae ) has a similar chemical composition with other species of the genus Populus L. and it can consider as a promising source of raw materials containing phenolic compounds, in particular flavonoids. The pharmacological activity of the buds of pharmacopeial species of genus Populus L., and also of the white poplar is caused by biologically active compounds, mainly of a phenolic nature, including flavonoids (pinostrobin, piriocembrin, quercetin, etc.), phenylpropanoids (caffeic acid, etc.) and simple phenols (salicin).. One of the most well-known biologically active compounds of white poplar is quercetin, for which an antihistamine, anti-inflammatory action has been demonstrated. Differential spectrophotometry carried out in accordance with the OFS was used as a research method.1.2.1.1.0003.15 "Spectrophotometry in the ultraviolet and visible regions". Spectral characteristics of water-alcohol extracts were evaluated on a Specord 40 spectrophotometer (Analytik Jena AG, Germany) in cuvettes with a layer thickness of 10 mm. It was determined that in all electronic spectra of the water-ethanolic extractions from the buds of the white poplar there are two absorption maxima  in the area of 290 nm and 370 nm, due to flavanones and flavonols, respectively. It was established that in the electronic spectra of the water-ethanolic extractions from the buds of the white poplar, a  significant bathochromic shift of the long-wavelength band in the presence of aluminum chloride is observed, which confirms the presence of flavonoids. Under the conditions of differential spectrophotometry UV spectrum of the water-ethanolic extractions from the buds of the white poplar, an absorption maximum is observed at wavelength of 430 nm, which indicates the expediency of using quercetin in the analysis technique, which has an absorption maximum at a wavelength of 430±2 nm. As a result of the study, the method  has been developed for the quantitative determination of the amount of flavonoids in the buds of white poplar using differential spectrophotometry calculated on quercetin at an analytical wavelength of 430 nm. The optimal parameters of extraction of raw materials were determined: extractant – 90% ethyl alcohol, the ratio of "raw material-extractant" – 1:30, extraction time – 60 minutes. The content of the total flavonoids calculated on quercetin in the buds of the white poplar is varied from 0,45±0,02 %  to 0.69 ± 0.03%