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  • Author: Mirosława Krauze-Baranowska x
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Loretta Pobłocka-Olech, Piotr Migas and Mirosława Krauze-Baranowska

Abstract

Flavonoids in the buds of eight Populus species and hybrids were detected and compared with the aid of an optimized TLC method. Separation of 17 flavonoid aglycones belonging to different groups, namely, flavones, flavonols, flavanones and flavanonols, previously described as constituents of poplar buds, was performed on silica gel plates using a hexane/ethyl acetate/formic acid (60:40:1.3, V/V/V) mixture as the mobile phase. Pinocembrin and pinostrobin were found in the majority of analyzed poplar buds. For quantitative analysis of both compounds, two TLC evaluation modes, densitometric and videodensitometric, were compared and the established methods were validated. Concentrations of flavanones in some extracts differed slightly or significantly due to the analyzed plant matrix complexity and the TLC evaluation mode applied. Poplar buds rich in flavanones originated from P. × canadensis ‘Robusta’ (1.82 and 2.23 g per 100 g, resp.) and P. balsamifera (1.17 and 2.24 g per 100 g, resp.).

Open access

Loretta Pobłocka-Olech, Daniel Głód, Maria E. Żebrowska, Małgorzata Sznitowska and Miroslawa Krauze-Baranowska

Abstract

This study comprises the optimization and validation of a new TLC method for determination of flavonols in the bulbs of seven cultivars of onions and shallots. Separation was performed on RP-18 plates with the solvent mixture tetrahydrofuran/water/formic acid (40+60+6, V/V/V) as a mobile phase. The method was evaluated for precision, linearity, LOD, LOQ, accuracy and robustness. Chromatographic analysis of the extracts revealed the presence of three main flavonols, quercetin, quercetin-4′-O-glucoside and quercetin-3,4′-O-diglucoside in the majority of analyzed cultivars. The content of flavonols in the analyzed extracts of onion bulbs varied from 123 (‘Exihibition’) to 1079 mg kg-1 fresh mass (fm) (‘Hybing’) in edible parts, and from 1727 (‘Hyline’) to 28949 mg kg-1 fm (‘Red Baron’) in outer scales. The bulbs of two shallot cultivars contained 209 (‘Ambition’) and 523 mg kg-1 fm (‘Matador’) of flavonols in edible parts and 5426 and 8916 mg kg-1 fm in outer scales, respectively.

Open access

Barbara Król-Kogus, Khenifi Mohammed Lamine, Piotr Migas, Messaoud Boudjeniba and Mirosława Krauze-Baranowska

Abstract

A new HPTLC-densitometric method for diosgenin determination in fenugreek seeds was established after optimization of the conditions for efficient saponin extraction and acid hydrolysis. Several procedures were tested, the best of which was a three-step Soxhlet extraction, followed by hydrolysis of the obtained methanolic extract with 2 mol L-1 H2SO4. Best diosgenin separation from other hydrolysis products was obtained on HPTLC Si60F254 plates u sing a mixture of n-heptane/ethyl acetate (7:3, V/V) and modified anisaldehyde as a spraying reagent. The method was preliminarily validated and the determined amounts of diosgenin in fenugreek seeds of Polish and African origin were found to be similar and ranged from 0.12-0.18 %.