Bis benzylisoquinoline Alkaloids

The emetine alkaloids and their derivatives from Uragoga species are the object of renewed medical interest. Stahl [228] recommends double development with chloroform-methanol (85 + 15) on silica gel G, using chamber saturation, for separating these alkaloids. He found the most sensitive detection to be spraying with about 10 ml of a 0.5% solution of iodine in chloroform, followed by heating 15 min at 60° C ( ) the alkaloids then fiuoresce intensely yellow or blue in UV light (365 nm). 

Machovi ova [128] has compared PC and TLC for testing the stability of emetine hydrochloride solutions for injection. She showed amongst other things that TLC is far better than PC for determining the purity of the emetine. 

Stahl [228] describes a rapid test for distinguishing between Rio-and Cartagena-ipecacuanha  

100 mg of the finely powdered drug in a small test tube are treated with one drop of concentrated ammonium hydroxide solution 5.0 ml chloroform are then added and the mixture left 3—4 h, mixing vigorously from time to time with a glass rod. The mixture is then filtered and 5 pi amormts of filtrate used for TLC. 5 pi of a 

Alkaloid hR/. value Colour of the iodine-reaction Limit of detection 

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Kwan CY, Achike FI (2002) Tetrandrine and related bis-benzylisoquinoline alkaloids from medicinal herbs cardiovascular effects and mechanisms of action. Acta Pharmacol Sin 23(12) 1057-1068... 

Nakaoji, K., Nayeshiro, H., Tanahashi, T., Su, Y. and Nagakura, N. 1997. Bis-benzylisoquinoline alkaloids from Stephania cepharantha and their effects on proliferation of cultured cells from the Murine Hair apparatus. Planta Medica, 63 425 28. 

A large number of alkaloids have been converted to quaternary salts and examined pharmacologically. The quaternary derivatives of certain bis-benzylisoquinoline alkaloids, which are closely related structurally to one class of curare alkaloids, are potent curarizing agents. Quaternary salts of cinchona alkaloids are effective and have been used in clinical investigations. Quaternary salts of many other alkaloids have been shown to exhibit curariform activity. 

This group of alkaloids is formed in the plant (Faltis theory) by a double enzymatic dehydrogenation of two molecules of norcoclaurine (II). It is necessary to perform this bimolecular dehydrogenation in three different ways in order to provide correct skeletal structures for the known bis-benzylisoquinoline alkaloids of this group. First, the two diphenyl ether linkages may be formed by the dehydrogenation occurring between the... 

D-( — )-Armepavine and l-( -t )-armepavine have been obtained by reductive cleavage with sodium-liquid ammonia of a number of bis-benzylisoquinoline alkaloids (11, 12). A similar treatment of the pro-aporphine alkaloid pronuciferine has produced d-( — )-armepavine, a method which permits the correlation of its configuration with the aporphine alkaloids (79). 

Takahashi K, Mitchell MJ, Cava MP (1976) Sciadenine, a new bis-benzylisoquinoline alkaloid from Sciadotenia toxifera. Heterocycles 4 471-474 Takhtajan A (1973) The chemical approach to plant classification with special reference to the higher taxa of Magnoliophyta. In Bendz G, Santesson J (eds) Chemistry in botanical classification. Nobel Symp (Med Nat Sci) 25 17-29... 

Table XXI. Sub-type II.c.1.4 - Bi benzylisoquinoline Alkaloids Bonded Head to Head, Tail to Tail and Bearing Three Joints...

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