Salah M. A. D. Zayed

Dietary cancer risk conditional cancerogens in produce of livestock fed on species of spurge (Euphorbiaceae)

Abstract The hypothesis was proposed that there is a risk of dietary cancer from conditional cancerogens in produce of livestock polluted with irritants of the diterpene ester type, picked up by feeding on species of Euphorbiaceae ( spurge). To challenge this, several herbaceous plants of the genus Euphorbia, widespread as weeds and contaminants of livestock fodder, were identified botanically and extracts of their aerial parts were tested for irritancy on the mouse ear. As compared to a standard probe of croton oil, the extracts of E.␣peplus, E. nubica and E. helioscopia displayed irritancy. The most active extract (that from E. peplus) was investigated by a fractionation procedure monitored by the mouse ear assay, and five molecularly uniform irritant Euphorbia factors Pe1–Pe5 were identified as diterpene ester-type toxins. Together these factors comprise at least 11 ppm in the aerial parts. They were characterized individually to␣carry the diterpene parent alcohols ingenol, 20-deoxyingenol, and 20-deoxyingenol-6 α, 7α-epoxide. The irritancy of the aerial plant parts was shown to be caused mainly by the Euphorbia factors Pe1 and Pe2 together. Upon chronic administration of these irritants and hyperplasiogens as principal cancerogenic risk factors in the mouse skin initiation/promotion bioassay, Pe1 and Pe2 were established as tumor promoters. These findings together support the␣initial hypothesis and suggest the need for further investigations to determine whether there is a consequent risk of dietary cancer.

Distribution and degradation of tetrachlorvinphos on stored faba beans and soya beans

The distribution and degradation of [CH3-14C]tetrachlorvinphos in stored fabe beans and soya beans were studied for 30 weeks at moisture contents and temperatures similar to those prevailing under normal storage conditions. Tetrachlorvinphos penetrated the seed coat and the insecticide residues inside the beans increased with storage time. A considerable portion of radioactivity, amounting to about 20–30% of the applied dose in faba beans and 30–40% in soya beans, was present in a non-extractable form. Residues on the seed coat consisted mainly of unchanged insecticide. The internal extract contained both unchanged insecticide and desmethyltetrachlorvinphos which was present in a free and a conjugated form. Dimethyl phosphate and monomethyl phosphate were identified as hydrophilic 14C-degradation products. The degradation of tetrachlorvinphos proceeded mainly via cleavage of methoxy groups. The nature and percentage of metabolites varied slightly with storage period. A scheme for possible degradation routes of tetrachlorvinphos on stored beans is suggested.

Reactions with substituted xanthones—VI : Infrared spectra of hydroxy-9-xanthones, hydroxy-10-thiaxanthones and some related compounds

Abstract Synthesis of 6′-substituted-4′-pyrono (2′,3′-1,2)-(IIa and IIb), 4′,5′-dihydro-4′-4-oxofurano (2′,3′-1,2)-(IIIb and IIIc), 4′,5′-dihydro-5′-methylfurano (2′,3′-2,1)-(VI) and 4′,5′-dihydro-5′-methylfurano (2′,3′-4,3)-9-xanthones (VII) is described. The infrared absorption spectra of a number of hydroxy-9-xanthones, hydroxy-10-thiaxanthones and new extended xanthone systems are briefly discussed.

Dietary cancer risk from conditional cancerogens (tumor promoters) in produce of livestock fed on species of spurge (Euphorbiaceae)

Abstract The feeding of lactating goats on usual green fodder, contaminated with Euphorbia helioscopia or E. nubica, results in poisoning of the dams as well as their suckling kids. General signs of toxicity were emaciation, depression, shedding of body hair, arching of back, and possible death. Post-mortem changes of dams and dead suckling kids included congestion and hemorrhage in cardiac muscle, lung, liver, and kidneys. Blood analyses of goats exposed to these contaminants showed an increased level of serum alanine amino transferase compared to control samples, indicating cellular destruction in the liver. The latter was confirmed by histopathological changes in the organ which include severe congestion, necrosis, and degenerative changes. The goats also suffered from deterioration of renal function as indicated by increased blood urea nitrogen and creatinine levels. In histopathologic inspections of kidney, severe congestion, hemorrhage in the cortex and medulla, as well as necrosis of epithelial cells of kidney tubules were noticed. Considerable degenerative changes were also observed in heart and lung. The pathophysiological appearances indicate that by feeding on the Euphorbia species mentioned above, the goats are poisoned in a way similar to the case of E. peplus reported previously. Such intoxication most likely is due to irritant and hyperplasiogenic diterpene ester (DTE) toxins, usually present in the aerial parts of Euphorbia species and well known as tumor promoters in mouse skin. After ingestion of the toxic plant parts by the goats, the DTE toxins might be metabolized and thereby partially detoxified. Yet, at least in part, they may show up in the milk of the goats, as indicated by severe poisoning of their suckling kids. As discussed previously in lactating goats fed on fodder contaminated with E. peplus, tumor promoters of the DTE type may enter the human food chain via this source of milk. Such milk may be considered a valuable etiologic model for the investigation of economic, ecologic, and public health problems raised by human diet polluted with tumor promoters, i.e., conditional (non-genotoxic) cancerogens.

Organophosphorus compounds—VIII : The reaction of alkyl phosphites and diphenylphosphino-dithioic acid with 2-benzylidene-3(2H)-thianaphthenone-1,1-dioxides

Abstract The reaction of 2-benzylidene-3(2 H )-thianaphthenone-1,1-dioxides (VI) with trialkyl phosphites depends upon the reaction medium. In phenol, compounds having structure VII are produced. In benzene, the 1:1 adducts isolated, wre believed to have a structure similar to X or the corresponding cyclic oxy-phosphorane (XI) which is readily converted into VII by the action of phenol. Dialkyl phosphites react with VI to give the 1:1 adducts (VII) and diphenylphosphinodithioic acid adds to the 2-benzylidenes (VI) in molar ratios to give compounds assigned structure XIV. The IR and NMR spectra of the adducts are recorded.

Deltamethrin degradation and effects on soil microbial activity

Deltamethrin [(S)-cyano-3-phenoxybenzyl-cis-(1R,3R)-2,2-dimethyl) cyclo–propane carboxylate),1] labelled at gem-dimethyl groups of the cyclopropane ring was applied on two Egyptian soils at a level of 10 mg/kg soil for a laboratory incubation experiment under aerobic and anaerobic conditions. A steady decrease of soil extractable14C-residues, accompanied by a corresponding increase of non- extractable bound 14C-residues was observed over a 90-day incubation period. The percentage of evolved 14CO2 increased with time under aerobic and anaerobic conditions in both soils. The effect of deltamethrin on soil microorganisms as well as the counter effect of microorganisms on the insecticide was also investigated. As the incubation period increased, the inhibitory effect of the insecticide on the microorganisms decreased and the evolution of carbon dioxide depended on the applied dose. The nature of soil methanol soluble residues was determined by chromatographic analysis which revealed the presence of the parent insecticide as the main product in addition to four metabolites: 3-(2′,2′-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (II); 3-phenoxybenzaldehyde (III); 3-phenoxybenzoic acid (IV); 3-phenoxybenzyl alcohol (V).

Impact of repeated pesticide applications on the binding and release of methyl 14C-monocrotophos and U-ring labelled 14C-carbaryl to soil matrices under field conditions

The dissipation of (O-methyl-14C) monocrotophos and U-ring labelled 14C-carbaryl was monitored for over two years in absence and presence of other insecticides using in situ soil columns. The dissipation of 14C-monocrotophos from soil treated with methomyl and carbaryl showed a faster rate of downward movement than in a control column tagged with the labelled insecticide alone. The same trend was observed in experiments with 14C-carbaryl that dissipated more readily in soil treated with non-labelled monocrotophos and methomyl. In the presence of other insecticides the percentage of bound residues was generally lower than in control experiments. The bound residues at the top of the column are released at a low rate under conditions prevailing in the field. The overall time required for dissipation of 50% of monocrotophos and carbaryl (t50) as estimated from control experiment was approximately 20 and 24 weeks, respectively. The data indicate that repeated applications of pesticides might enhance the release of 14C-bound residues.

Spaltungsreaktionen mit organischen Disulfiden

Triphenylarsin reagiert mit aktiven organischen Disulfiden in siedendem Xylol oder im Sonnenlicht unter Bildung der entsprechenden Monosulfide und von Triphenylarsinsulfid. Die Entmethylierung von Khellin und Visnagin durch Einwirkung von organischen Disulfiden im Sonnenlicht wird diskutiert.

γ-Hexachlorocyclohexane の貯蔵ソラマメ中での挙動

[14C] γ-Hexachlorocyclohexane の乳濁液を, 貯蔵状態のソラマメに噴霧し, 26週間にわたってその浸透経過を調べたところ, 4週間で全薬量の37～55%が, また22週間で65～82%が浸透した. 95%メタノールで抽出されない部分は全薬量の1.6～3.2%であった. 抽出物中に見いだされる基質以外の14C量は2%以下であり, ペンタクロロベンゼン, 2, 4, 5-トリクロロフェノールならびにジクロロフェノール類を含んでいた.