The chemical diversity and distribution of glucosinolates and isothiocyanates among plants

Parasitoids and predators of herbivores have evolved and function within a multitrophic context. Consequently, their physiology and behavior are in­ fluenced by elements from other trophic levels such as their herbivore victim (second trophic level) and its plant food (first trophic level) (126) . Natural enemies base their foraging decisions on information from these different trophic levels, and chemical information plays an important role. This review is restricted to the ecology of chemical information from the first and second trophic levels. The importance of so-called infochemicals, a subcategory of semiochemicals, in foraging by parasitoids and predators has been well documented (e.g. reviewed in 31, 78, Il l , 183, 185) , and we do not intend to repeat the details. But because of a lack of testable hypotheses, all this research is conducted rather haphazardly: the total puzzle of infochemical use has not been solved for any natural enemy species. Here we approach the use of infochemicals by natural enemies from an evolutionary and ecological standpoint. Our basic concept is that information from the first and second trophic levels differs in availability and in reliability, a difference that shapes the way infochemicals are used by a species. We generate hypotheses on (a)

/pdf/ecology-of-infochemical-use-by-natural-enemies-in-a-klyl2klq7j.pdf

Ecology of infochemical use by natural enemies in a tritrophic context.

Bitter taste, phytonutrients, and the consumer: a review

The epidemiologic literature on the relationship between vegetable and fruit consumption and human cancer at a variety of sites is reviewed systematically. A total of 13 ecologic studies, nine cohort studies, and 115 case-control studies are included. Cancer of all sites, cancers of lung, breast, colon, rectum, esophagus, larynx, oral cavity and pharynx, stomach, pancreas, prostate, bladder, ovary, endometrium, cervix, and thyroid, as well as mesothelioma and gestational trophoblastic disease, are considered. Relevant data from clinical trials, animal, and in vitro studies are included. It is concluded that consumption of higher levels of vegetables and fruit is associated consistently, although not universally, with a reduced risk of cancer at most sites. The association is most marked for epithelial cancers--particularly those of the alimentary and respiratory tracts--and, currently, is weak to nonexistent for hormone-related cancers. The association exists for a wide variety of vegetables and fruit with some suggestion that raw forms are associated most consistently with lower risk. Possible mechanisms by which vegetable and fruit intake might alter risk of cancer and possible adverse effects of vegetable and fruit consumption will be considered in Part II of this review.

Vegetables, fruit, and cancer. I. Epidemiology.

Variation of glucosinolate accumulation among different organs and developmental stages of Arabidopsis thaliana.

This review surveys the occurrence, analysis, and properties of glucosinolates and derived compounds in plants and products intended for humans and animal consumption. The paper, which includes references published in 1981, is also intended to compliment existing reviews on the chemistry of these sulfur‐containing natural products. Particular emphasis is placed upon members of the Brassica family because of their importance as vegetables, condiments, oilseeds, and animal feedingstuffs. Since much of the work considered here relates to glucosinolate decomposition products, biochemical information concerning the nature, occurrence, and properties of the glucosinolate‐degrading enzyme, myrosinase, is considered in Section III. The methods available for the chemical analysis of glucosinolates and their various breakdown products are discussed critically. Factors affecting the glucosinolate content of plants and plant products arc outlined in Section VII. Particular emphasis is placed upon the effect of proces...

R K Heaney

Papers

Glucosinolates and their breakdown products in food and food plants