Reticulin and

Methylarmepavine has been found in Annona squamosa.23 Reticuline and its N-oxide (a new natural product) have been isolated from Pachygone ovata24 and another new base, the quaternary hydroxide zanoxyline, has been isolated from the stem bark of Zanthoxylum oxyphyllum, its structure being... 

Ghedira I, Sghiri R, Ayadi A, Sfar MT, Harbi A, Essoussi AS, et al. Anti endomysium, anti-reticulin and anti-gliadin antibodies, value in the diagnosis of celiac disease in the child. Pathol Biol (Paris) 2001 49 47-52. 

Other important mammalian benzylisoquinolines which thus far have escaped detection in mammals are (5)-reticuline and its (R) enantiomer TIQ 121b, shown in Fig. 29. The latter compound is required for the biosynthesis of morphinandienones in the opium poppy, and its possible role in biosynthesis of mammalian morphine is discussed in Section IV. 

Personal communication, 1992, by Dr. Xiao-shu He, NIDDK, National Institutes of Health, Bethesda, Maryland. Reductive N-methylation of norreticulines with formaldehyde in methanol over Pd/C catalyst at pH 7 afforded 2 products which were on TLC clearly different from reticuline, and most likely based on MS are berbines. 

Feeding of + )-aryl-3H-reticuline (absolute configuration as in XCVII) and ( —)-aryl-3H-reticuline to H. canadensis in separate experiments resulted in the former being incorporated into berberine fifteen times more efficiently than the (— )-isomer. Corroboration that (+)-reticuline is the true precursor was obtained from the results of administering a mixture of (— )-aryl-3H-reticuline and ( + )-reticuline-3-i4C to H. canadensis. 

It is noteworthy that protosinomenine (XCVIII), despite being so similar to reticuline, and possessing the necessary C-8 hydroxyl group (protoberberine numbering) to permit cyclization, is not incorporated into berberine in H. canadensis. 

Reticuline and (— )-reticuline, containing tritium at C-1 and multiple labels at the positions shown (see Chart VIII), when administered to C. majus plants resulted in the significant incorporation of the ( + )-isomer into protopine (Cl), chelidonine (CII), and ( —)-tetrahydrocoptisine [(— )-stylopine] (LXXVIII). 

A study was undertaken in order to understand the effect of reticuline and coclaurine on conflict and learning behavior. The results were not available in the abstract [320]. 

Hemangiopericytoma is a highly cellular and mitotically active neoplasm that is rich in pericellular reticulin and stainable with anti-type IV collagen. Eighty percent of these tumors recur, and 23% metastasize. > 8i... 

The major alkaloids of the bark of species T.O.H., 13077, were identified as (+ )-l-(4-hydroxylbenzyl)-6,7-methylenedioxy-l,2,3,4-tet-rahydroisoquinoline (noroinnamolaurine), (— )-cinnamolaurine, ( + )-reticuline, and + )-corydine. The structure of noroinnamolaurine was elucidated by spectroscopic methods and confirmed by conversion into cinnamolaurine and by a synthesis of its racemate (49). 

The stereochemical relationship between (— )-reticuline and morphine during biosynthesis has already been dealt with in connection with the promorphinane bases (52). The intermediates of the biosynthesis of morphine have the same R-configuration on the tertiary C-9 atom to which nitrogen is attached. Consequently, the biosynthesis of morphine proceeds along the following pathway (see Scheme 3) ... 

Figure 12.13. The biosynthetic pathway for L-tyrosine derived tetrahydrobenzylisoquinoline alkaloids. The core production of (5)-reticuline and the branch points for berberine, macarpine, and morphine production. Reprinted with permission from Chou and Kutchan (I998)" .

The biosynthesis of papaverine (85) and laudanosine (86) in P. somniferum, has received attention. ( )-[3- " C]Nor-reticuline (as 80) was specifically and efficiently incorporated into papaverine, and so was [6-0-Mc- C]nor-reticu-line, this latter result indicating that incorporation was not via norlaudanosoline (87). Reticuline itself was poorly utilized and 1,2-dehydronor-reticuline, perhaps surprisingly, not at all. Therefore, 1,2-dehydronor-reticuline was not reduced to nor-reticuline, and its incorporation into morphine must be by N-methylation... 

Analyses of P. orientate from natural habitats showed that the dried latex contained 20% of oripavine (195) and 9% of thebaine (192) (92). Traces of isothebaine (122) were found in plants collected from Khaikhala in northwest Iran. Six different chemotypes of P. orientate were reported (64,93), namely, oripavine, oripavine-thebaine, oripavine-isothebaine, oripavine-aipinigenine, oripavine-thebaine-alpinigenine, and mecambridine-orientalidine-salutari-dine. In all of them, with the exception of one, oripavine was the major alkaloid (82). Feeding experiments in P. orientate with radioactively labeled reticuline and thebaine have demonstrated that oripavine is derived from reticuline and thebaine (93a). Reticuline undergoes racemization in this plant as has been earlier shown for P. somniferum and P. bracteatum. 

Laudanidine, reticuline, and N-methylcoclaurine have been isolated from Thal-ictrum revolutum Two new bases, yuziphine (16 R = H) and yuzirine (17), have... 

The second syndrome resembled active chronic hepatitis, which was confirmed by demonstrating confluent areas of lobular collapse with condensation of reticulin and an intense inflammatory cell infiltrate which contained plasma cells. Many of the individual liver cells showed ballooning degeneration and the presence of Con-citma bodies. 

Fujii, N., Inui, T., Iwasa, K., Morishige, T., and Sato, F. (2007) Knockdown of berberine bridge enzyme by RNAi accumulates (S)-reticuline and activates a silent pathway in cultured California poppy cells. Transgenic Res., 16, 363-375. 

The first reaction in the direction of the protoberberines is the formation of the berberine bridge (Fig. 2), catalyzed by the berberine bridge enzyme (abbreviated BBE), which specifically only accepts (S)-reticuline and not the (R)-enantiomer as substrate (ref. 23). As a next step a methylation at C-9 follows to form (S)-tetrahydrocolumbamine catalyzed by a methyltransferase with a much higher substrate specificity than the methyltransferases described before (ref. 24). In the genus Berberis (S)-tetrahydrocolumbamine is then oxidized by an enzyme called (S)-tetrahydroprotoberberine oxidase (abbreviated STOX) (ref. 25) and finally the methylene dioxy bridge is formed by the so called berberine synthase (ref. 26). 

The lack of strict specificity for the enzymes involved in the initial conversion to (5)-reticuline (20) suggests that stereochemical control does not occur at this stage of biosynthesis (Zenk, 1985). The use of plant cell cultures (both callus and suspension types) from different species of plants that produce benzylisoquinoline alkaloids has proven to be a powerful approach for the isolation of enzymes and intermediates in the pathways leading to these compounds (Zenk et al., 1985). For example, the use of cell-free extracts of Berberis cultures permitted Zenk and co-workers to isolate and characterize all eight enzymes involved in the conversion of dopamine (22) and 4-hydroxyphenylacetaldehyde (19) to (5)-reticuline and, subsequently, to berberine. 

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