Traditional healthy Mediterranean diet: estrogenic activity of plants used as food and flavoring agents.

The Italian-style Mediterranean diet has been defined as healthy by epidemiologists and nutritionists. Besides being low fat, the Mediterranean diet is rich in biologically active minor compounds. Among these, phytoestrogens seem to have an impact on the prevention of chronic degenerative disease. It is important to understand how this occurs. The in vitro estrogenic activity of crude extracts from typical Mediterranean foods was tested using a yeast estrogen screen (YES), containing human estrogen receptor. Species belonging to Leguminosae, Apiaceae, Graminaceae, Iridaceae, Chenopodiaceae, Cruciferae and Solanaceae showed the greatest number of positive responses. These species include some foods which are traditionally widely consumed, such as beans and other legumes, tomatoes, cabbage, carrots and some cereals. The highest activity was found in the more polar extracts (aqueous, methanol and chloroform: methanol) indicating that polar compounds are mainly responsible for the estrogenic activity. This is also supported by the traditional cooking practices. According to data from in vitro tests, the estrogenic activity is present in numerous plants which are commonly used as food in the Mediterranean diet. Vegetable foods rich in phytoestrogens, as in the Mediterranean tradition, may contribute to the maintenance of health status.

Cloning of a chub metallothionein cDNA and development of competitive RT-PCR of chub metallothionein mRNA as a potential biomarker of heavy metal exposure.

Metallothionein has been assayed in a range of aquatic animal tissues as an indicator of metal exposure. We sequenced chub (Leuciscus cephalus) metallothionein cDNA which showed over 90% homology to common carp, goldfish and stone loach and 77% homology to rainbow trout sequences for metallothionein. We then used the extended primer method to develop an accurate quantitative competitive RT-PCR assay for metallothionein mRNA. RT-PCR was used to measure metallothionein mRNA in feral chub from a range of field sites, with different levels of heavy metal pollution, in the West Midlands, UK. Measurements were complemented by analysis of liver and gill metallothionein protein by capillary electrophoresis. There was no significant difference in the metallothionein protein levels between fish of different rivers and there was no evidence of elevation of mRNA at the sites of highest metal exposure. The level of metal exposure (e.g. zinc, nickel and cadmium each ranging between 15 and 28 microg/l ) at the pH (7.5-8.5) of these rivers appears insufficient to elevate hepatic or gill metallothionein in chub. A lack of elevation of hepatic metallothionein mRNA in chub exposed to zinc, copper and manganese for 24 h and 10 days in the laboratory also suggests a non-responsiveness of this species.