Tumour-inhibiting activity

For the tumour-inhibiting activity of amides from Piper novaehollandiae (Piperaceae) see ref. 128. Tumour-inhibiting extracts have also been obtained from Brugueria spp. (Rhizophoraceae), but it is not clear whether this activity is partly associated with tannins or with tannin-free compounds. 

No conclusions as to any structure-activity relationship can be made in the field of tumour inhibitory alkaloids, in spite of the enormous amount of work that has been carried out. Structures and origin of alkaloids vary widely and it does not seem to be the prerogative of a few plant families to elaborate tumour inhibiting alkaloids. Two Catharanthus alkaloids and a few colchicine derivatives have become commercial products, but they certainly do not represent a final solution to the enormously complicated cancer problem. 

The apparent rationale for study of the metallocene dihalides was that the cis geometry, Figure 6.4, was reminiscent of that of cisplatin, with a c chloride separation of 3.470 A for Ti, for example, in contrast to that in cisplatin, 3.349 A [102]. However, it is clear from studies of the hydrolysis of the cyclopentadienyl complexes that the aqueous chemistry is very different from that of platinum and no structural analogies should be drawn. In general, the complexes inhibit Ehrlich ascites tumours and solid growths of this tumour, are active in Lewis Lung, but are only very... 

Betulin (lup-20(29)-ene-3,28-diol) is an abundant naturally occurring triterpene, and it is found predominantly in bushes and trees forming the principal extractive (up to 30% of dry weight) of the bark of birch trees. Betulin and its derivatives such as betulinic acid have many interesting pharmacological properties, such as cytotoxic activity against many tumour cell lines and anti-HIV activity with a new mechanism of action. Several synthetic betulin derivatives that have been chemically modified at the positions C-3 and C-28 of the lupane skeleton were produced, and the anti-leishmanial inhibition activity of compounds was evaluated at 50 pM against Leishmania donovani and Leishmania tropica. Betulonic acid had the best anti-leishmanial activity with... 

Type I interferons induce a vims-resistant state in human cells, whereas Type II are more active in inhibiting growth of tumour cells. 

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