Sesamex

Sesamex [51-14-9] (Sesoxane) (30) is a synergist oflow toxicity, acute oral LD q (rat) = 2000 2270 mg/kg, for pyrethrins and allethrin. 6,7-Dihydroxy 4-methylcoumarin has been offered as an antioxidant for phenoHcs and polymers, and as an anthelmintic. 2,4,5-Trihydroxybutyrophenone has been available as an antioxidant and light stabilizer for polyolefins, waxes, and foods. Isoflavones, eg (31), have been patented as components of antioxidant compositions for foods and cosmetics (qv) (97). 

Vigfusson, N.V., E.R. Vyse, C.A. Pemsteiner, and RJ. Dawson. 1983. In vivo induction of sister-chromatid exchange in Umbra limi by the insecticides endrin, chlordane, diazinon and guthion. Mutat. Res. 118 61-68. Wahla, M.A., G. Gibbs, and J.B. Ford. 1976. Diazinon poisoning in large white butterfly larvae and the influence of sesamex and piperonyl butoxide. Pestic. Sci. 7 367-371. 

Chemicals. Insecticides, at least 95% pure, were prepared as acetone solutions p-p DDT, lindane, parathion, paraoxon, malathion, malaoxon, propoxur, carbaryl, LandrinR, aminocarb, mexacarbate, allethrin (90%), piperonyl butoxide (PBO) and sesamex. Aldrin was 98.5% and dieldrin was 99+% pure. 

Support for this is found in the substantially greater octopa-minomimetic activity of DCDM compared to chlordimeform (20) and the observation that mixed function oxidase inhibitors, e.g. piperonyl butoxide and sesamex, strongly antagonized the toxicity of chlordimeform to the southern cattle tick larvae and synergized the toxicity of DCDM (21). Therefore, chlordimeform may be considered to be a propesticide of DCDM. 

In the molecule SBD, the reduction in toxicity effected by replacement of the syn-chlorine of dieldrin to give SD appears to be offset by an increase (compare BD) effected by further replacement of the vinylic chlorines, so that SBD is similar to dieldrin in toxicity In contrast, AD and ABD, which retain the syn chlorine, are poor toxicants In this series there was no appreciable synergism with the MFO inhibitor sesamex, indicating that when increased LD50s were seen, these were not the result of enhanced MFO attack consequent upon the progressive replacement of chlorine ... 

The first example has already been mentioned. Piperonyl butoxide, sesamex, and related compounds increase the toxicity of certain insecticides by inhibiting the insect monooxygenase system. They are of commercial importance in household aerosol formulations containing pyrethrum. This inhibition, which appears to be the same in mammals and insects, involves the formation of a metabolite-inhibitory complex with CYP. The complex probably results from the formation of a carbene (Figure 10.14), which then reacts with the heme iron in a reaction involving n-bonding, as well as the dative o-bond formed by the free pair of electrons, to form a complex that blocks CO (and presumably 02) binding and inhibits the metabolism of xenobiotics. 

Examples of these include sesamin and sesamolin, both active principles of sesame oil, and piperonyl butoxide (PBO) and sesamex, both synthetic products. Although initially developed for use with pyrethrins, they have since been observed to synergize some, but not all, carbamates, organophosphates, pyrethroids, and organochlorines. In addition to the MDP compounds, another type of synergist called MGK 264 was developed to synergize the toxicity of pyrethroids and rotenone. The structure of piperonyl butoxide and MGK 264 are as follows ... 

Table 9.14 Synergism and antagonism of some phosphorothioates by sesamex against houseflies...

Sun, Y.P., Johnson, E.R., and Ward, L.F., Jr., Evaluation of synergistic mixtures containing sesamex and organophosphorus or chlorinated insecticides tested against house flies, /. Econ. Entomol., 60,828,1967. 

Sawicki, R.M. and Famham. A.W, (1968). Examination of the isolated autosomes of the SKA Strain of houseflies < Mttsca domestiea L.) for resistance to several insecticides with and without pre-treatment with Sesamex and TBTP. Bull. Fntomol. Res. 59. 409-421. 

Methylenedioxyphenyl derivatives, primarily sesamex, can strongly synergise the action of aldrin, presumably by the inhibition of microsomal enzymes responsible for biodegradation (Brooks and Harrison, 1964 Brooks, 1966 1968 Sun et al., 1967 Casida, 1970 Khan et al., 1970). From the viewpoint of environmental hygiene this may become important, because the application of synergists may enable the use of analogues acting in the same way as compounds used at present, but which are more rapidly decomposed (Hennessy, 1969). 

Following the discovery of the synergistic active substances of sesame oil, several synthetic analogues have been developed. Some of these contain a polyethylene-oxide side-chain as, for example, piperonylbutoxide (3), sesamex (4), tropital... 

Sesamex (4) is generally prepared by the addition of sesamol (10) to vinylethyidiethyleneglycol ether ... 

The above compounds have been used as synergists of pyrethrum and synthetic pyrethroids, such as allethrin, cyclethrin and others. Later investigations showed that these compounds can also synergise other insecticides, primarily carbamates and DDT. Piperonylbutoxide and sesamex proved to be the most efficient in this respect however, the latter is unsuitable for practical use because of its sensitivity to light and humidity. 

Bowers and co-workers (Bowers, 1968 1971) investigated whether piperonyl butoxide (13), known as an insecticidal synergist, could also synergise JH and found that, when it was investigated for control purposes only, it also exhibited a juvenile hormone activity. In subsequent systematic investigations of other known insecticide synergists sesamex (14) proved to be the most efficient. 

Alterations of the aliphatic moiety of the DDT molecule to introduce degradophores (easily degraded moieties) have produced compounds such as l l bis-( -ethoxyphenyl)-3,3-dimethyloxetane (16). (I sca 26) which is synergized 50-fold by sesamex to the housefly and is readily degradable. 

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