Alkaloid separation

Fig. 13.2 Ephedrine alkaloids separated using a pentafluorophenylpropyl-based HPLC column.

Halogen-containing organic solvents, such as chloroform and dichloromethane, have been widely used in alkaloid separation because of their relatively strong... 

Fig. 1 Chromatograms of the crude alkaloids from C. chinensis Franch by analytical HSCCC. Nine chromatograms are arranged in such a way that the effects of methanol and HCl concentrations on the alkaloid separation are each clearly visualized. Experimental conditions apparatus analytical HSCCC instrument equipped with a multilayer coil of 0.85 mm I.D. and 30 mL capacity sample 2.5 mg of crude alkaloid extract of C. chinensis Franch solvent system shown above each chromatogram mobile phase lower organic phase flow rate 1 mL/min revolution 1500 rpm. Retention of the stationary phase was as follows CHCI3-MeOH-(0.1-0.3 M HCl) (4 3 2), 77% CHCI3-MeOH-(0.1-0.3 M HCl) (4 2 2), 80% and CHCl3-MeOH-(0.1-0.3 M HCl) (4 1.5 2), 77%.

Calystegines, in common with other classes of polyhydroxy alkaloids, are highly water-soluble and cannot be isolated by conventional alkaloid separation techniques which employ add-base pardoning methods with non-hydroxylic organic solvents [20], Ion-exchange chromatography is therefore extensively employed for separation of the alkaloid fraction from neutral and addic compounds present in the extract [21,22]. 

Two octadecyl columns were coupled in series and the alkaloids separated with a gradient of an increasing amount of acetonitrile in a triethylamine - phosphoric acid buffer (Fig.3.1). The influence of the pH on the separation of the alkaloids was studied optimum results were obtained at pH 7.56. The results were compared with a GLC and a spectrophotometric method. 

Ergot alkaloids Separation with straight phase ion-pair HPLC (Tables 9.9, 9.10) ifiondapak CN 300x3.9 Hexane-CHCl -ACN-di-(2-ethyl -hexyl)phospnoric acid in various ratios 61... 

Solanum and veratrum alkaloids Separation steroidal alka-loids(Fig.10.1 and 10.2) Zorbax Sil 6 Mm 250x4.6 n-Hexane-Me0H-Me,C0(18 1 1) n-Hexane-EtOH-Me CO(18 1 1) 4... 

Jarvie et al. used a microparticulate silica gel column for the determination of colchicine in plasma. Iorio et al. isolated and identified some impurities of colchicine by means of HPLC, TLC and MS. Alkaloid separation was performed on silica gel with a gradient system of chloroform - methanol. 

Fig. 5-30. Separation of epinephrine, ephedrine, and opium alkaloids. - Separator column IonPac NS1 (10 pm) eluent 0.005 mol/L sodium octanesulfonate + 0.05 mol/L KH2P04 (pH 4.0) / acetonitrile (89 11 v/v) flow rate 1 mL/min detection UV (220 nm) injection volume 50 pL solute concentrations 10 mg/L epinephrine, 10 mg/L morphine sulfate, 20 mg/L ephedrine hydrochloride, and 20 mg/L codeine phosphate.

The residue obtained on evaporation of the more rapidly traveling zone weighs 32 mg. On taking up in 4 cc. of methanol, 20 mg. of a very sparingly soluble alkaloid separate out. This melts at 235-240° (decomp.) and exhibits a specific rotation of [a]20°/D= +365° (+5°) in chloroform), which identifies it as ergotaminine. In all other properties this alkaloid also agrees with authentic ergotaminine. 

Figure 6 The CZE separation of quaternary alkaloid standards (right) compared to the alkaloids separated from a sample prepared from plant tissue (left). Peaks (1) benzyltrimethylammonium chloride (internal standard) (2) coptisine (3) berberine (4) epiberberine ...

Miscellaneous alkaloid separations Dansyl derivatives of cephaeline, emetine, ephedrine and morphine obtained by direct deriva-tization of syrups and aqueous slurries of capsules having a complex excipient and drug composition Adsorption Silica gel Di-isopropyl ether/isopropanol/ cone, ammonia (48 2 0.3)... 

There are about 20 alkaloids separated from the herb. Most of them are three-ring sesquctcrpcnes linked with a pyridine through two ester groups. Many of these alkaloids have immunosuppressive activities (c.f. table 2 fig. 2) [45-55]. 

Several important alkaloids have been isolated from Catharanthus roseus plants ajmalicine (34) and serpentine (35) from the root, and the dimeric alkaloids vinblastine (36) and vincristine (37) from the leaves. Therefore, much research has been done on production of these alkaloids by means of plant cell culture. Catharanthus roseus is, in fact, one of the most widely studied plants for the production of secondary metabolites in cell culture systems. We here discuss the two types of alkaloids separately. Table XXIX summarizes patents concerning the production of alkaloids by means of cell cultures of C. roseus. 

Brochmann-Hanssen E, Furuya T (1964) Opium alkaloids - separation and identification by gas, thin layer and paper chromatography. J Pharm Sci 53 1549-1550 Chalmers RA, Wadds GA (1970) Spectrofluorimetric analysis of mixtures of the principal opium alkaloids. Analyst 95 234-241... 

The combination of preparative high-speed countercurrent chromatography with other separation methods, such as HPLC, and TLC, will enable chemists to isolate minor components of complex alkaloid mixtures more efficiently. This technique is not limited to alkaloid separations and, in theory, other complex mixtures of compounds having only minor differences in their partition coefficients should be efficiently separated by high-speed countercurrent chromatography. 

Fig. 2 Densitogram and videoscan from 2D-TLC of isoquinoline alkaloids separated on silica layer by use of aqueous methanol (8%) with 1% ammonia as the first direction eluent and multicomponent non-aqueous eluent with 0.1 M DBA as the second direction eluent. N—noscapine, Na—narcotine, Nc—narceine, G—glaucine, E—emetine, C—codeine, P—papaverine, Pr— protopine, T— tubocurarine. Source From the effect of chromatographic conditions on the separation of selected alkaloids on silica layers, in J. Planar Chromatogr. ...

Broad application of Cinchona alkaloids in medicine, food industry, as well as in academic research has stimulated very early the development of both qualitative and quantitative methods for their analysis. Currently, chromatographic TLC [98, 99], HPTLC [99, 100], HPLC [76, 101-104], and LC-MS [105, 106] and electrochromatographic methods [107] are preferred for Cinchona alkaloid separation, identification, and quantitative analysis. Older analytics from this field is the subject of a review [23]. 

CE possesses higher separatimi efficiency and could supply complementary information to HPLC. The LOD expressed as concentration in CE is higher than GC and HPLC because of the small sample volumes and the relatively low concentration for Catharanthus alkaloids. Using nonaqueous solvents, CE can be coupled to MS easily and would provide a powerful means for alkaloids separation and identification in the near future. 

Fig. 6-30. Separation of epinephrine, ephedrine, and opium alkaloids. — Separator column lonPac NSl (10-pm) eluant ...

This plant yielded three alkaloids, separated largely by chromatographic methods daphniphylline, C32H49O5N (mp 240° [aju -t-108°), and two other bases, neodaphniphylline (mp 240°) and yuzurimine (mp 200°) (68). An X-ray analysis of the hydrobromide of daphniphylline showed that it had structure XXI (69). 

Alkaloid fractions were obtained by Extrelut chromatography of methanolic extracts (Roberts et al. 1983). Concentrations were estimated by peak height analysis of alkaloids separated by HPLC with UV detection at 280 nm. Resolution was achieved on a 5 jum silica gel column eluting with n4iexane-chloroform-methanol-diethylamine (88.5 8.6 2.9 0.03). 

---