As anticancer compounds

Bathaie, SK, A Bolhasan, R Hoshyar, B Ranjbar, F Sabouni, and A-A Moosavi-Movahedi. 2007. Interaction of saffron carotenoids as anticancer compounds with ctDNA, Ohgo (dG.dC)15, and Oligo (dA.dT)15. DNA Cell Biol 26(8) 533-540. 

As mentioned in the introduction, metallocene-type complexes based on the early transition metals were evaluated as anticancer compounds shortly after the discovery of cisplatin. While the biological activity of each of the metallocene dihalides is unique, titanocene dichloride 7 has been the subject of a number of studies and even entered clinical evaluation, although evaluation was discontinued (not due to its anti-proliferative properties), principally due to formulation problems, despite showing superior activity to certain cancers than other established drugs. This class of compound continues to be modified and studied for anticancer activity, for example, the titanocene-type derivative of tamoxifen 1, described above, and other developments described below. 

Bradford PG, Awad AB (2007) Phytosterols as anticancer compounds. Mol Nutr Food Res 51(2) 161-170... 

Bryostatins are another class of compounds that bind to the Cl domain and result in acute activation of PKC. However, unlike phorbol esters, these marine natural products have antitumor effects. Bryostatins are currently in phase II clinical trials and show promise as anticancer drugs, particularly when combined with other adjuvant therapy. 

Many complexes and coordination compounds exist as isomers, compounds that contain the same numbers of the same atoms but in different arrangements. For example, the ions shown in (13a) and (13b) differ only in the positions of the Cl ligands, but they are distinct species, because they have different physical and chemical properties. Isomerism is of more than academic interest for example, anticancer drugs based on complexes of platinum are active only if they are the correct isomer. The complex needs to have a particular shape to interact with DNA molecules. 

Bis(thiosemicarbazones) [89-97] and AT-heterocyclic thiosemicarbazones comprise two interesting series of experimental chemotherapeutic agents. 2-formylpyridine thiosemicarbazone, the first of the latter series to be examined for biological activity, showed mild antileukemic activity against 1-1210 tumor in mice [98]. However, it was found to be toxic at the therapeutic dose levels which led to synthesis of other aromatic and heterocyclic thiosemicarbazones as potential agents [80, 99, 100]. However, the only active anticancer compounds besides glyoxal bis(thiosemicarbazones) were the iV-heterocyclic thiosemicarbazones [101], 2 formyl-3-hydroxypyridine thiosemicarbazone [102] and... 

Nazarov, A. A. et al. Anthracene-Tethered Ruthenium(II) Arene Complexes as Tools To Visualize the Cellular Localization of Putative Organometallic Anticancer Compounds. Inorg. Chem. 51, 3633-3639 (2012). 

These phytochemicals are common in the Asteraceae (Compositae) and Apiaceae (Umbelliferae) (Chitwood, 1992 Zidom et al., 2005). There is considerable interest in these compounds because of their potential as anticancer agents and therapeutic agents (e.g. Zheng et al., 1999 Kobaek-Farsen... 

Figure 12 Traw -platinum compounds as potential anticancer compounds.

There are natural targets whose syntheses have important practical applications. For example, paclitaxel (marketed as Taxol by Bristol-Myers Squibb) is an anticancer compound originally isolated from the bark of a species of yew tree, but for a long time it seemed that natural sources would not be sufficient to meet the need. Consequently, many chemists developed synthetic approaches to paclitaxel from readily available materials, although these are not yet fully practical for manufacturing. The quest continues, and a semisynthetic route has been developed starting with a compound isolated from yew needles that can be harvested without destroying the tree. An alternative approach has employed plantcell cultures in bioreactors to produce paclitaxel from yew needles (see Chapter 7 for discussion of related matters). 

Combretastatins are a class of compounds originally derived from the African Willow tree (Combretum caffrum) and are powerful reversible inhibitors of tubulin polymerization. This class of molecules has been shown to bind to the colchicine binding site of tubulin, by the same mode of action as mentioned above (Sect. 1.2). Combretastatins consist of a ris-slilbcnc core structure. To date, there have been several compounds that have shown promise as potential anticancer drugs. However, development of these compounds as anticancer agents is limited by issues of chemical stability, bioavailibilty, toxicity, and solubility. 

Selman Waksman s commitment to the isolation and screening of soil bacteria in the search for bioactive small molecules, especially potential antibiotics, was validated by the discovery of streptomycin. This led to the creation of the modem biopharmaceutical industry and the subsequent isolation of tens of thousands of bioactive small molecules from soil bacteria and other environments. A proportion of these compounds have become highly successfnl therapeutics, not only for all types of infectious diseases, but also in the treatment of many other human and animal ailments and as anticancer, immnno-modnlatory, and cardiovascular agents. Waksman and Fleming could be considered the fathers of chemical biology (Figure 1.1). 

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