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.
Subject(s)
Antioxidants/analysis , Chemistry, Pharmaceutical/methods , Crops, Agricultural/chemistry , Flavonoids/analysis , Onions/chemistry , Plant Roots/chemistry , Shallots/chemistry , Antioxidants/isolation & purification , Calibration , Chromatography, Reverse-Phase , Chromatography, Thin Layer , Densitometry , Flavonoids/isolation & purification , Glucosides/analysis , Glucosides/isolation & purification , Limit of Detection , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Poland , Quality Control , Quercetin/analogs & derivatives , Quercetin/analysis , Quercetin/isolation & purification , Reproducibility of Results , Species Specificity , Spectrophotometry, UltravioletABSTRACT
CONTEXT: Keloids and hypertrophic scars are hyperproliferative skin disorders resulting in abnormal wound healing. In the prevention and treatment of keloids and hypertrophic scars, ointments containing heparin and onion extract are very popular. Their therapeutic effects, however, are still controversial and the mechanism of action is not fully understood. OBJECTIVE: The aim of this study was to assess the effect of enoxaparin and dry onion extract on proliferation, apoptosis and ß1 integrin expression in human fibroblasts. MATERIALS AND METHODS: Fibroblast human cell lines (46 BR.1 N) were treated for 48 h with various concentrations of enoxaparin sodium (20, 100, 500 µg/mL) and/or onion [Allium cepa L. (Alliaceae)] extract (50, 250, 1000 µg/mL). The cell proliferation was evaluated by [(3)H]-thymidine incorporation assay. Furthermore, the expression of ß1 integrin and apoptosis was determined by flow cytometry. RESULTS AND DISCUSSION: The results demonstrate that enoxaparin and onion extract inhibited the proliferation of human fibroblasts. Almost complete inhibition of cell proliferation was achieved by enoxaparin in 500 µg/mL concentration (91.5% reduction). The onion extract at a concentration of 250 µg/mL also strongly inhibited the proliferation of cells (50.8% reduction). Depending on concentration, enoxaparin and onion extract induced apoptosis (500 and 1000 µg/mL, respectively) and, depending on concentration, downregulated the expression of ß1 integrin on human fibroblasts. CONCLUSION: This work points at possible mechanism of action of enoxaparin and onion extract, when administered in the treatment of patients with keloids and hypertrophic scars.
