Recommended testing in diabetes research.

Diabetic disease is increasing rapidly and vast amounts of resources are spent in all countries. Thus, the screening of new compounds including plant extracts for antidiabetic effects is mandatory. In this review both simple assays [e.g., on blood glucose (after or without a glucose load), plasma insulin and extrapancreatic effects] are described as well as specific in vivo tests in diabetic animals and in vitro tests with respect to the mechanism of compounds. In total, approx. 30 selected tests are evaluated and references are given. Thus, the investigator is guided through the tests and is advised that measuring only one parameter such as glucose will not be sufficient. In the case that the financial resources are poor for the investigator, more than glucose still has to be measured. A balance is made by describing absolutely necessary investigations while concentrating on those at low cost. It has to be started with simple assays; to use one test only, however, means oversimplifying the diabetes disease; additionally antidiabetic effects may be missing. The investigator is guided through the advantages and limitations of diabetic animal models and is advised about specific in vitro tests to look at the mechanism of action. All investigators should profit from these details, not only the phytoresearchers.