Co-carcinogenic activity

Phorbol (14) was isolated from the oil of Croton tiglium (Euphorbiaceae) seeds " ". The presence of a system containing both the cyclopropanol and the cyclopropylcarbinol functionalities at the C/D ring moiety is quite unusual. Various fatty acid esters of phorbol have been shown to be the active components responsible for the co-carcinogenic activity of croton oil. Esterification usually occurs at C(11) and C(12) with a pair of long chain and short chain fatty acids, as in the potent co-carcinogenic tetradecyl phorbol acetate (TPA). 

Tetrachoroethylene (perchloroethylene, PCE) is the only chlorinated ethene that resists aerobic biodegradation. This compound can be dechlorinated to less- or nonchlorinated ethenes only under anaerobic conditions. This process, known as reductive dehalogenation, was initially thought to be a co-metabolic activity. Recently, however, it was shown that some bacteria species can use PCE as terminal electron acceptor in their basic metabolism i.e., they couple their growth with the reductive dechlorination of PCE.35 Reductive dehalogenation is a promising method for the remediation of PCE-contaminated sites, provided that the process is well controlled to prevent the buildup of even more toxic intermediates, such as the vinyl chloride, a proven carcinogen. 

In 1954, Kotin and co-workers reported the carcinogenicity of atmospheric extracts of Los Angeles air. Subsequently, in 1956, they reported the carcinogenic activity of oxidation products of aliphatic hydrocarbons and, in 1958, of ozonized gasoline. Concurrently, Falk and co-workers (1956) published results... 

Tigliane (G5 C7 C61 C3) diterpenes include the highly irritant, toxic, co-carcinogenic, PKC activating phorbol esters from Euphorbiaceae plants. While not being activated by the parent compound phorbol, PKC is activated by plant-derived esters of phorbol, 4-deoxyphor-bol and 12-deoxyphorbol (e.g. 12-0-palmitoyl-16-hydroxy-phorbol 13-acetate, 12-deoxyphorbol 13-benzoate, 12-deoxyphorbol 13-phenylacetate, 12-deoxyphorbol 13-phenylacetate-20-acetate, sapintoxin A (4-deoxyphorbol 12-(2-methylamino)benzoate-l3-acetate) and 12-tetradecanoylphorbol 13-acetate (TPA)), as well as by synthetic phorbol esters. 

The biogenetic structural relationships and structure-activity relationships of the diterpenoid skin irritants and co-carcinogens of the Euphorbiaceae and Thymelaceae have been described in a number of reviews.Baliospermum montanum (Euphorbiaceae) contains the orthoester montanin (111) and baliospermin (112) together with some 12-deoxyphorbol-13-esters. A number of new highly irritant 1-alkyl-daphnane orthoester derivatives [(113) and the corresponding 3-ketone] have been obtained from the Thymelaceae. The Chinese... 

A topic closely related to enumeration and construction of benzenoid hydrocarbons is enumeration and construction constrained by specific structural requirements. An example is enumeration of benzenoid hydrocarbons having a bay region. According to Jerina and co-workers, " the presence of a bay region is critical for the carcinogenic activity of benzenoid hydrocarbons. Let us first define a bay region, following Balasubramanian et al. ... 

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