Preparative Separation Of Alkaloids Research Articles

Preparative Separation of Alkaloids from Stem of Euchresta tubulosa Dunn. by High-Speed Counter-Current Chromatography Using Stepwise Elution.

Euchresta tubulosa Dunn. is a Chinese herbal medicine with biological activity, but there are few studies on its components at present. Alkaloids in the stem of Euchresta tubulosa Dunn. were isolated and purified by high-speed counter-current chromatography (HSCCC) using stepwise elution. First of all, liquid-liquid extraction (methylene chloride-methanol-water, 5:1:4, v/v) was used for the preliminary enrichment. According to the partition coefficient (K) of a target compound in a series of different two-phase solvents, the final result was that carbon tetrachloride-methylene chloride-methanol-water (2:3:3:2, v/v) (1) and methylene chloride-methanol-water (5:3:2, v/v) (2) were suitable for the HSCCC using stepwise elution. As a result, the purity was all higher than 93% and matrine (1), oxymatrine (2), N-formyl cytisine (3), and N-acetyl cytisine (4) can be eluted at one time by this mode. Cytisine-type alkaloids were isolated for the first time in this plant. Finally, the applicability of the mode was verified.

Preparative separation of alkaloids from Litsea cubeba using combined applications of pH-zone-refining and high-speed counter-current chromatography

pH-zone-refining counter-current chromatography and high-speed counter-current chromatography are used for separation of alkaloids from the extract of Litsea cubeba.

Preparative separation of alkaloids from Picrasma quassioides (D. Don) Benn. by conventional and pH-zone-refining countercurrent chromatography.

Two high-speed countercurrent chromatography (HSCCC) modes were compared by separation of major alkaloids from crude extract of Picrasma quassioides. The conventional HSCCC separation was performed with a two-phase solvent system composed of petroleum ether–ethyl acetate–methanol–water (5:5:4.5:5.5, v/v/v/v) with 200 mg loading. pH-Zone-refining CCC was performed with two-phase solvent system composed of petroleum ether–ethyl acetate–n-butanol–water (3:2:7:9, v/v/v/v) where triethylamine (10 mM) was added to the upper organic stationary phase and hydrochloric acid (5 mM) was added to the lower aqueous phase with 2 g loading. From 2 g of crude extract, 87 mg of 5-methoxycanthin-6-one (a), 38 mg of 1-methoxy-β-carboline (b), 134 mg of 1-ethyl-4,8-dimethoxy-β-carboline (c), 74 mg of 1-ethoxycarbonyl-β-carboline (d), 56 mg of 1-vinyl-4,8-dimethoxy-β-carboline (e) and 26 mg of 1-vinyl-4-dimethoxy-β-carboline (f) were obtained with purities of over 97.0%. The results indicated that pH-zone-refining CCC is an excellent separations tool at the multigram level.

PREPARATIVE SEPARATION OF TERTIARY ALKALOIDS FROM CORYDALIS YANHUSUO W. T. WANG BY pH-ZONE-REFINING COUNTER-CURRENT CHROMATOGRAPHY

Preparative separation of alkaloids from the crude extract of Corydalis yanhusuo by pH-zone-refining counter-current chromatography was successfully performed, The method used a biphasic solvent system composed of methyl-tert-butyl ether-acetonitrile-water (2:2:3, v/v), in which the organic phase containing 10 mM of triethylamine was used as a retainer in the stationary phase, while the aqueous phase containing 5 mM of hydrochloric acid as an eluter was used as the mobile phase. In the present study, 80 mg of glaucine, 41 mg of tetrahydropalmatine, and 67 mg of corydaline were separated from 1.16 g of the crude sample of C. yanhusuo with purity of 91.4%, 84.3%, and 98.2%, respectively. The structures of alkaloids were identified by 1H NMR and 13C NMR.

Preparative separation of alkaloids from Gelsemium elegans Benth. using pH-zone-refining counter-current chromatography

Alkaloids in Gelsemium elegans possess a variety of therapeutic properties, including tumor suppression, analgesic and anti-inflammatory effects. In China, G. elegans has been used for centuries to treat a variety of medical conditions, including chronic pain and skin ulcer. Methods currently used to separate the active components of G. elegans are time-consuming and have low recovery. In the present study, we used pH-zone-refining counter-current chromatography to separate major alkaloids from a crude extract of G. elegans. The two-phase solvent system was methyl tert-butyl ether (MtBE)/acetonitrile/water (3:1.5:4, v/v). Triethylamine (20 mM) was added to the upper organic stationary phase as a retainer. Hydrochloric acid (10 mM) was added to the lower aqueous phase as an eluter. From 1.5 g of crude extract, we obtained 312 mg gelsemine, 420 mg koumine and 195 mg gelsevirine, with purities at 94.8%, 95.9% and 96.7%, respectively, which were determined by HPLC at 256 nm. The chemical identity of the isolated compounds was verified by electrospray ionization-mass spectrometry (ESI-MS), 1H NMR and 13C NMR. These results demonstrated that pH-zone-refining counter-current chromatography is an effective method to separate and purify major alkaloids from G. elegans.

Preparative separation of alkaloids from Nelumbo nucifera leaves by conventional and pH-zone-refining counter-current chromatography

Two modes of high-speed counter-current chromatography (HSCCC) were successfully applied to the separation of alkaloids from crude extract of Nelumbo nucifera leaves. The conventional HSCCC separations were performed with a two-phase solvent system composed of tetrachloromethane–CHCl 3–methanol–0.1 M HCl at a volume ratio of 1:3:3:2 (v/v/v/v), and 120 mg crude extract could be successfully separated. pH-Zone-refining CCC was performed with a two-phase solvent system composed of petroleum ether (60–90 °C)–ethyl acetate–methanol–water (5:5:2:8, v/v/v/v) where triethylamine (10 mM) was added to the upper organic stationary phase as a retainer and hydrochloric acid (5 mM) to the aqueous mobile phase as an eluent. From 4.0 g of the crude extract, 120 mg N-nornuciferine, 1020 mg nuciferine and 96 mg roemerine were obtained in a single run each with a purity of over 98% as determined by HPLC. The structures of the isolated compounds were identified by ESI-MS, 1H NMR and 13C NMR.

Preparative separation of alkaloids from Nelumbo nucifera Gaertn by pH‐zone‐refining counter‐current chromatography

Preparative separation of alkaloids from embryo of the seed of Nelumbo nucifera Gaertn has been successfully performed for the first time using pH-zone-refining counter-current chromatography. Two kinds of two-phase solvent systems were applied to preparative CCC isolation. The first was the system composed of MtBE-water (1:1, v/v), 10 mM triethylamine in organic stationary phase and 5 mM HCl in aqueous mobile phase, which could only separate neferine partly from the crude extract. The second was the system composed of n-hexane-ethyl acetate-methanol-water (5:5:2:8, v/v), 10 mM triethylamine in organic stationary phase and 5 mM HCl in aqueous mobile phase, which was the optimum for large-scale CCC isolation. 2.5 g of the crude alkaloid was purified in one-step separation of 7 h, yielding 151 mg of liensinine, 118 mg of isoliensinine and 572 mg of neferine with the purities of 93.0, 95.1 and 97.0%, respectively.

Preparative Separation of Alkaloids from Green Tea by pH‐Zone‐Refining Countercurrent Chromatography

pH‐Zone‐refining countercurrent chromatography was applied to the separation of alkaloids from a crude extract of green tea using a multilayer coil planet centrifuge. After methyl tert‐butyl ether and water were equilibrated, triethylamine (10 mM) was added to the organic phase as a retainer and hydrochloric acid (10 mM) was added to the aqueous phase as an eluter. The separation was performed by eluting the aqueous phase while the organic phase was used as the stationary phase. From 3 g of the extract, 2.2 g caffeine and 0.07 g theophylline were separated within about 4 h.

Preparative separation of alkaloids from the root of Sophora flavescens Ait by pH-zone-refining counter-current chromatography

pH-Zone-refining counter-current chromatography was applied to the separation of alkaloids from a crude extract of the root of Sophora flavescens Ait using a multilayer coil planet centrifuge. After methyl tert.-butyl ether and water were equilibrated, triethylamine (10 m M) was added to the organic phase as a retainer and hydrochloric acid (5–10 m M) to the aqueous phase as an eluter. The separation was performed by eluting the aqueous phase while the organic phase was used as the stationary phase. From 1.0 g of the crude extract, sophocarpine (170 mg) and matrine (600 mg) were separated within 4.5 h at high purity of over 98%.

On-plate injection in the preparative separation of alkaloids and glycosides using overpressured layer chromatography

On-plate injection in the preparative separation of alkaloids and glycosides using overpressured layer chromatography