Isolation of alkaloids

The isolation of alkaloids from plants is reviewed in the August 1991 issue of the Journal of Chemical Education pp 700-703... 

Scott and co-workers have also reported on the isolation of alkaloids from C. roseus cell suspension cultures 126). The cell line used, identified as CRW, afforded akuammicine (49), catharanthine (4), and strictosi-dine (33), and feeding experiments with labeled tryptophan led to incorporation into ajmalicine (39), akuammicine (49), catharanthine (4), and vindoline (3). The ability to produce alkaloids was carried through 8 successive generations. 

A problem of great importance is the isolation of alkaloids. Traditionally, very strong solvents have been used. This presents some difficulties connected with the confidence with which the results can be treated. The isolation of all alkaloids from the sample, and the purity of this isolation, is also a significant problem. 

Gharbo, S. A., Beal, J. L., Doskotch, R. W. and Mitscher, L. A. 1973. Alkaloids of Thalictrum. XIV. Isolation of alkaloids having antibacterial activity from Thalictrum polyganum. Lloydia, 36 349-351. 

In the earlier literature there arc reports of the detection in or isolation of alkaloids from 46 species, 24 of which had been included in Mesembryanthemum. Some of these are now recognized... 

The photochemical reaction of tertiary amines with C6o can be used to synthesize alkaloid-C6o derivatives [269], Irradiation of alkaloids bearing a tertiary amino group such as tazettine, gramine, scandine, or 10-hydroxyscandine with C6o led to the isolation of alkaloid-C6o adducts. Use of tazettine and gramine in the reaction yielded the expected [6,6] adduct. In addition to the pyrrolidinofullerene 94a-b, a new type of monoadduct 95a-b with a bis-[6,6] closed structure characterized by UV-vis, FT-IR, II-NMR, 13C-NMR, II- II-COSY, ROESY, HMQC, and HMBC spectroscopy was obtained from the reaction with scandine 93a and its 10-hydroxy derivative 93b (Scheme 38). 

Table 1 Isolation of alkaloids of the lupinine-cytisine-sparteine-matrine group...

The first extractions performed on different parts of the yew (leaves, bark, roots, or wood) employed the usual techniques for the isolation of alkaloids 1% sulfuric acid applied directly to the leaves or after their extraction with methanol (12). This rather rough treatment did not allow isolation of the very labile substances present in this plant. However, the use of petroleum ether for the wood (13) and alcohol for the trunk bark (2) or leaves (14) led to the isolation of several interesting products such as the baccatin derivatives. These observations explain why a certain number of taxanes have been identified only by way of their derivatives, artifacts of the extraction process. 

Chadwick, L.R. Wu, C.D. Kinghom, A.D. Isolation of alkaloids from goldenseal Hydrastis canadensis rhizomes) using pH-zone-refming countercurrent chromatography. J. Liq. Chromatogr. Relat. Technol. 2001, 24 (16), 2445-2453. 

Reviews have appeared on the distribution and systematic significance of alkaloids of the Rutaceae and of the Papaveraceae and on the taxonomic significance of benzyltetrahydroisoquinoline-derived alkaloids in particular. The isolation of alkaloids from plants in the Soviet Union has been discussed. In addition to continued alkaloid screening studies, surveys encompassing detection of alkaloids have been carried out on plants from Argentina, India, and Morelos State, Mexico. ... 

The isolation of alkaloids bearing the 8-hydroxyquinoline moiety prompted postulation (17) of a biosynthetic pathway to 1 from the amino acid tryptophan, for which chemical analogies are known (22) (Scheme 2). It should be noted, however, that, in general, quinolines are biosynthesized from anthranilic acid (14). Biosynthesis of broussonetine (4) would involve condensation of two molecules of 1 with a molecule of acetyl-CoA followed by cyclization, as depicted in Scheme 3. 

The isolation of alkaloids named fumariline, fumarilicine, and narceimine has also been reported I Stamens cf. Table 7, ref. a. 

Continuing their work on the isolation of alkaloids of Vinca minor Dopke et al. (10) obtained a new amorphous / -anilinoacrylate alkaloid... 

Continuing with the isolation of alkaloids from the fruits of Alstonia venenata, Majumder et al. have obtained two unusual /3-anilinoacrylate bases, echitoserpine (34) (24) and echitoserpidine (35) (25). Because these alkaloids are so closely related they will be discussed together, although the main emphasis will be on echitoserpidine. The UV and IR spectra, and the characteristic chromogenic reaction with ceric ammonium sulfate, indicated the presence of the anilinoacrylate chromophore, but the IR spectrum also indicated the presence of an ester carbonyl (1720 cm-1). Six aromatic protons were discerned, but the pattern was too complex for... 

---