Ajmalicin

Ajmalicine Circulatory agent Low/bigb Cathai anthusi oseus... 

Crystd from EtOH, and dried to remove EtOH of crystn. For Y-Yohimbine see ajmalicine on p. 

R. serpentina Benth. Ajmalicine, ajmaline, ajmalinine, serpentine, serpentinine (Siddiqui and Siddiqui ). From a geographical variety of the species, Moajmaline, neoajmaline and unnamed alkaloids, m.p. 220° and m.p. 234 (S. Siddiqui ). From the same species van Itallie and Steenhauer isolated alkaloids B, C and A (rauwolfine) which may be identical with Siddiqui s serpentine, aimalinine and ajmaline respectively. 

R. vomitoria Afz. (sample from French Guinea). Ajmaline, iso-ajmaline, ajmalicine, ajmalinine and possibly serpentinine, cf. R. serpentina (Paris ). 

Further elaboration of tetracycle 159c resulted in the syntheses of the racemate of indole alkaloids of the ajmalicine (61JA2594), tetrahydroalstunine (56JOC1315, 71JA5907), and akuammigine type (ajmalicinoid alkaloids). Similarly, 159d can be converted into yohimboid alkaloids (79JA5370). 

On the other hand, oxymercuration of demethylcorynantheine (593), followed by sodium borohydride reduction, gave 1 -abeo-( 17- 16)-yohimbane derivative 596 as the major product besides small quantities of ajmalicine (597) and 19-epiajmalicine (598) (287). 

Microbial transformations of four heteroyohimbine stereoisomers [ajmalicine (81a) tetrahydroalstonine (81b), isoajmalicine (81c), and akumigine (81d)] yielded mixtures of 10- and 11-hydroxylation products (786) (Scheme 21). Microorganisms known for their abilities to metabolize indole alkaloids, steroids, and antibiotics were intitially screened, and seven cultures were further used for preparative-scale incubations with alkaloid substrate. The microorganisms used and yields (by HPLC) of metabolites obtained from 81a-81d are shown in Table HI. 

Air-water flow regimes, 22 773 Air-water interface, molecular recognition at, 26 799-800 AISI 403 alloys, 23 511 AISI alloy steels, 23 299-300 Ajmalicine, 2 94, 95, 96, 100 Ajmaline, 2 94, 95, 96-97 AK-UFVE contactor, 20 768 A1203 surface scale, 23 507-508 Alabaster, 4 583... 

This overall biosynthetic scheme is summarized in Scheme 7, and it is well to remember that C. roseus is almost alone as a plant in which this whole pathway can be viewed in its entirety, for most indole alkaloid-containing plants produce only one or two of the major alkaloid classes, and not all four. In addition, C. roseus is without doubt the most economically important of the indole alkaloid-containing plants, and thus studies were, and continue to be, driven by the goal of increasing the availability of the commercially significant alkaloids ajmalicine (39), vinblastine (1), and vincristine (2). 

Leaf organ cultures of C. roseus have also been described 118). A typical 2.5-g fresh weight inoculum produced 29 g fresh weight of leaf material after 35 days dedifferentiated tissue was absent. The alkaloids found included ajmalicine (39), sitsirikine (48), tetrahydroalstonine (39), serpentine (40), and vindoline (3). 

Goodbody and co-workers (7/9) have examined the production of alkaloids in root and shoot cultures induced from seedlings of C. roseus. The pattern of alkaloids in the root cultures was similar to that of the roots from intact plants. Thus ajmalicine (39) and catharanthine (4) were produced, but no vindoline (3), a major leaf alkaloid, and no bisindole alkaloids. Similarly, the pattern of the alkaloid content of the shoot cultures was like that of the leaves of the intact plant, showing the presence of vindoline (3), catharanthine (4), and ajmalicine (39), with 3 predominating. A search for the bisindole alkaloids in the cultures indicated the presence of anhydrovinblastine (8) and leurosine (11) in the shoot cultures (2.6 and 0.3 xg/g fresh weight, respectively), but no vinblastine (1) or vincristine (2). 

The effect of light on alkaloid production in these cultures was also evaluated (7/9). More catharanthine was produced in the light than in the dark, and the same observation was made for ajmalicine (39). Knobloch et al. 120) examined the production of anthocyanins, ajmalicine (39), and serpentine (40) in cell suspension cultures and found that although serpentine levels increased 18-fold in the light, ajmalicine levels decreased 50%. In the work of Goodbody et al. 119) the biosynthesis of vindoline (3)... 

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. 

Mitraphylline 7-Hydroxyindolenine ajmalicine (66) Serpentine (40) Sitsirikine (48) Isositsirikine (58) + + ... 

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