Stepwise elution by high-speed counter-current chromatography combined with a modified macroporous resin to isolate and purify antioxidant phenolics from discarded jackfruit (Artocarpusheterophyllus Lam.) peels

Marine Polyphenol Phlorotannins as a Natural Sleep Aid for Treatment of Insomnia: A Review of Sedative-Hypnotic Effects and Mechanism of Action

Insomnia is a common sleep disorder. Natural sleep aids are gaining worldwide popularity as alternatives to prescription drugs for improving sleep. Recently, numerous studies have investigated the sedative-hypnotic effects of the polyphenols of terrestrial plants. The hypnotic effects of marine polyphenols have also been studied in recent years. Phlorotannins are marine polyphenols that are found only in brown algae. Phlorotannins exert sedative-hypnotic effects via the gamma-aminobutyric acid type A-benzodiazepine receptor. In addition, the brown seaweed Ecklonia cava supplement containing phlorotannins has been approved by the Ministry of Food and Drug Safety as a health-functional ingredient that helps improve sleep quality. Currently, it is meaningful to deal with the sedative-hypnotic effects of phlorotannins as natural sleep aids. The current review comprehensively presents the sedative-hypnotic effects in animal models and human clinical trials as well as their mechanism of action, extraction, purification, and safety.

Separation of chemical constituents in Bidens pilosa Linn. var. radiata Sch. Bip. by elution-extrusion counter-current chromatography using two new three-phase solvent systems

Two new three-phase solvent systems combined with elution-extrusion counter-current chromatography mode were used to study the chemical constituents in Bidens pilosa Linn. var. radiata Sch. Bip. The first novel solvent system consisted of n-hexane, acetonitrile, chloroform, and water in a ratio of 5:5:1:5, which was selected for elution-extrusion counter-current chromatography to separate the n-hexane extraction part. A total of six constituents were obtained from this part in the up phase as the stationary phase and the middle phase as the mobile phase. The second novel solvent system, composed of n-hexane-butyl acetate-acetonitrile-water (3:1:4:3, v/v/v/v), was used for separating ethyl acetate extract of Bidens pilosa Linn. var. radiata Sch. Bip. Eight compounds were successfully isolated using elution-extrusion counter-current chromatography elution-extrusion mode. Fourteen chemical constituents were identified as 2-β-D-glucopyranosytoxy-1-hydroxy-5(E)-tridecene-7,9,11-triyne (Y1), 3-β-D-glucopyranosyloxy -1-hydroxy-6(E)-tetradecene-8,10,12-triyne (Y2), 1, 2-dihydroxy-5(E)-tridecene-7,9, 11-triyne (Y3), isorhamnetin (Y4), kaempferol (Y5), icthyothereolacetate (Y6), quercetin-3-O-β-D- galactopyranosyl-7-O-β-D-glucopyranoside (W1), quercetin 3-O-β-L-rhamnopyranoside (W2), neosperidin dihydrochalcone (W3), quercetin (W4), quercetagetin-3,6,4' -trimethoxyl- 7-O-β-D-glucopyranoside (W5), taxifolin (W6), luteolin (W7), and apigenin (W8) by spectra of ¹ H-NMR and ¹³ C-NMR data. Among them, compounds Y1, Y2, Y3, and Y6 belong to polyacetylene compounds, and the rest were flavonoids. In addition, counter-current chromatography has been used to separate polyacetylene compounds for the first time. All compounds in this method were isolated from Bidens pilosa Linn. var. radiata Sch. Bip. for the first time.

A strategy based on isocratic and linear-gradient high-speed counter-current chromatography for the comprehensive separation of platycosides from Platycodi radix

Platycosides, the generally recognized main active constituents of Platycodi radix, have been studied extensively for their wide pharmacological activities. Herein, we have successfully developed an efficient method for the enrichment and comprehensive isolation of platycosides from Platycodi radix by MCI resin column chromatography (CC) and two different modes of high-speed counter-current chromatography (HSCCC). MCI resin CC was the preferable enrichment operation for platycosides from the 70%-ethanol extract of Platycodi radix and rendered target platycosides when eluted by 60% aqueous methanol solution. As for the separation, two different modes, including isocratic HSCCC and linear-gradient HSCCC, were applied together to separate the platycosides using a mixture of ethyl acetate, n-butanol and water coupled with evaporative light scattering detection, for the first time. Isocratic HSCCC was applied to separate crude platycosides from Platycodi radix using ethyl acetate-n-butanol-water (1 : 1 : 2, v/v), yielding seven pure platycosides (compounds 1-6, 8) and two fractions of enriched mixtures of compounds 7, 9, 10, and 11. Linear-gradient HSCCC was employed to rapidly separate compounds 7, 9, 10, and 11 by constantly changing the proportions of ethyl acetate and n-butanol in the ethyl acetate-n-butanol-water solvent system. Finally, platycoside E (1), deapio-platycodin D₃ (2), platycodin D₃ (3), deapio-platycodin D₂ (4), platycodin D₂ (5), platycodin D (6), polygalacin D₂ (7), polygalacin D (8), and three tautomers, namely 2''-O-acetylplatycodin D (9) and 3''-O-acetylplatycodin D (9'), 2''-O-acetylpolygalacin D₂ (10) and 3''-O-acetylpolygalacin D₂ (10'), and 2''-O-acetylpolygalacin D (11) and 3''-O-acetylpolygalacin D (11'), were obtained from 300 mg of crude platycosides from Platycodi radix.