Xanthones from Halenia corniculata. 2. Quantitative Determination of Total γ-Pyrone Content in the Aerial Part

Abstract

581.192+582.936 L. M. Tankhaeva, and G. G. NikolaevaA method for quantitative determination of total γ-pyrone content in the aerial part of Halenia corniculata was developed. Their total content in various samples of the aerial part was investigated.We previously established that the principal active compounds from Halenia corniculata (L.) Cornaz (Gentianaceae) are xanthones and flavones [1].The development of objective methods for quantitative determination of the content of biologically active compounds in starting material and medicinal preparations is an important step in the development of medicinal preparations. Therefore, our task was to develop a method for quantitative determination of the total γ-pyrone content in the aerial part of Halenia corniculata.The present article also includes results from a study of the total γ-pyrone content in various samples of the aerial part of this plant.We used a chromato-spectrophotometric method for quantitative determination of the γ-pyrone content. The standard was 1-hydroxy-2,3,4,5-tetramethoxyxanthone (1), the dominant component of the total γ-pyrones. Its absorption maximum in the UV spectrum (260 ± 1) is close to those of the second dominant xanthone, 1-hydroxy-2,3,5-trimethoxyxanthone (257 ± 3), and luteolin (253 ± 1) and to that of the alcohol extract of the hydrolyzed raw material (254 ± 1) (Fig. 1). The analytical wavelength was 254 nm, which is situated between the peaks in the UV spectra of the xanthones, flavone, and the alcohol extract. It has been found that the optical density as a function of concentration for 1 is linear in the range 1.2·10 -6 -12.0·10 -6 g/mL.The optimal conditions for the extraction became clear during development of the quantitative determination method: extractant, 60% ethanol; extraction temperature, 90°C; particle size of raw material, 0.5-1 mm; raw-material/extractant ratio, 1/60; time and repetition of extraction: I, 60 min; II, 60 min; III, 45 min.The extract was purified of accompanying substances by chromatographic separation over a column of polyamide sorbent. Ballast substances (blue band in UV light) were eluted by water; γ-pyrones (absorbing band in UV light), by 95% ethanol. However, it was noted that preliminary elution with water gave effluents containing O-glycosides of γ-pyrones (TLC monitoring). In order to avoid these losses (up to 4%), the plant material was extracted with 60% ethanol containing HCl (5%). The glycoside bonds were completely destroyed in 1 h (TLC).A correction factor was introduced into the formula for quantitative determination of total γ-pyrones in the aerial part of Halenia corniculata. This took into account incomplete desorption from the column of the eluted substances. This coefficient (K elu ), equal to 1.093, was determined experimentally for 1 in a series of ten independent determinations. Table 1 gives the metrological parameters of the quantitative method for determining the total γ-pyrone content in the aerial part of Halenia corniculata (calculated for 1-hydroxy-2,3,4,5-tetramethoxy...

Iridoids and Flavonoids of Four Siberian Gentians: Chemical Profile and Gastric Stimulatory Effect

“…These herbs are given uncomplicated names, like white or blue bitter herbs (plants with white or blue flowers), and their derivative beverages are referred to as bitter teas ( гашуун ундан , Buryatian; аhыы утах , Yakutian; йдарйичу умивўн , Evenkian) [4]. Ethnopharmacological investigations allow us to identify the “bitter herbs” as various species of the genera Halenia [5,6,7,8], Gentianopsis [9], Anagallidium [10] and Gentiana . As part of an ongoing study of the chemistry and pharmacology of gentianaceous bitter teas, we present the results of analysis of the herbs of the four most frequently used gentians, including G. algida Pall.…”