ABSTRACT
A switchable deep eutectic solvent-based liquid-phase microextraction was proposed and applied to the preconcentration and determination of liposoluble quality-markers of diterpenoid quinones (dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone IIA) in traditional Chinese medicine coupled with high performance liquid chromatography-ultraviolet detection. In the procedure, the hydrophilic deep eutectic solvent of diethanolamine-hexanoic acid (molar ratio 1:1) was prepared and added into the sample phase as an extractant, and a homogeneous solution was formed under slight vortex stirring. After the addition of HCl solution, the deep eutectic solvent miscible with the sample phase was converted to hydrophobic form, and a cloudy solution was generated. Then, the upper hydrophobic layer enriching the target analytes was collected through centrifugation for high performance liquid chromatography analysis. Several critical parameters affecting the extraction performance including the composition and consumption of switchable deep eutectic solvent, the type and amount of acid, salt amount and extraction time were investigated and optimized. Moreover, the structures of the deep eutectic solvent and the recovered hydrophobic layer were both characterized using Fourier transform infrared spectroscopy, further demonstrating the switching mechanism of the extractant during the extraction process. Under the optimal conditions, enrichment factors of diterpenoid quinones ranged from 59 to 274. Good linearities (r≥0.9963), low detection limits (0.5-0.7 ng/mL), satisfactory precisions (relative standard deviations 0.5%-8.6%) and accuracies (recoveries 94.6%-104.6%) were also obtained. Comparing the proposed switchable deep eutectic solvent-based liquid-phase microextraction with other published methods, the characteristics of the procedure were summarized. The developed method was successfully applied for the preconcentration of four liposoluble diterpenoid quinones from a traditional Chinese herbal medicine of Salvia Miltiorrhiza.
Subject(s)
Liquid Phase Microextraction , Salvia miltiorrhiza , Deep Eutectic Solvents , Furans , Limit of Detection , Liquid Phase Microextraction/methods , Phenanthrenes , Quinones , Solvents/chemistryABSTRACT
OBJECTIVE: To investigate the liposoluble constituents of Urticae Rhizoma. METHODS: The compounds were isolated and purified by silica gel, Sephadex LH-20, ODS gel column chromatographies, and semi-preparative HPLC. The structures were elucidated on the basis of spectral data and physiochemical properties. RESULTS: Twenty-one compounds were isolated from the ethyl acetate fraction of Urticae Rhizoma, and identified as(-)-urticol(1),(-)-secoisolariciresinol(2), 23-hydroxybetulinic acid(3), 2α,3β, 24-trihydroxy-12-oleanen-28-oic acid(4), cleomiscosin A (5), dihydro-4-hydroxy-5-hydroxymethyl-2(3H)-furanone(6), methyl chlorogenate(7), kaempferol(8), pinoresinol monomethyether-4'-O-β-D-glucopyranoside(9), martairesinol-4'-O-β-D-glucopyranoside(10), cycloolivil-6-O-β-D-glucopyranoside(11), stigmasterol-3-O-β-D-glucopyranoside(12), nicotinamide(13), trans-caffeic acid-4-O-β-D-glucopyranoside(14), esculin(15), 5-hydroxyl-7-methoxycoumarin-8-O-β-D-glucopyranoside(16), 6-oxymethyluteolin-7-O-β-D-glucopyranoside(17), luteolin-7-O-β-D-glucopyranoside(18), quercetin-3-O-(4″-methoxy)-α-L-rhamnopyranoside(19), 2'-deoxy uridine(20), and apigenin-6, 8-di-C-β-D-glycoside(21), respectively. CONCLUSION: All the compounds, except 8 and 12, are isolated from U. fissa for the first time. Meanwhile, compounds 5, 6, 9, 10, 11, 14, 16, 17, and 19 are all found in Urticaeae plants for the first time.
ABSTRACT
OBJECTIVE: To investigate the liposoluble constituents from the herb of Pothos chinensis (Raf.) Merr. of Araceae. METHODS: The compounds were isolated and purified by silica gel, Sephadex LH -20, semi-preparative HPLC and recrystallization methods. Their structures were identified on the basis of spectral analysis, physicochemical characteristics and comparison of their spectral data with those in the literature. RESULTS: Seventeen compounds were isolated and identified respectively as honokiol(1), hinokinin(2), racemosol(3), 24-propylcholest-7-en-3-ol(4), β-sitosterol(5), daucosterol (6), hentriacontane(7), palmitic acid (8), oleic acid(9), linoleic acid(10), 9, 12, 15-ocatadecatrienoic acid(11), 13-phenyltridecanoic acid(12), 13-(3', 4'-methyl -enedioxyphenyl)-tridecanoic acid(13), 1-monostearin(14), 1-monopalmitin(15), benzoic acid(16), and vanillic acid(17). CONCLUSION: Compounds 1-16 are isolated for the first time from this plant.