Chromium in a series of Portuguese plants used in the herbal treatment of diabetes

Chromium (Cr3+) is an essential micronutrient for humans. Its main action is thought to be the regulation of blood sugar, because chromium deficiency is associated with diabetic-like symptoms, and chromium supplementation is correlated with increased glucose tolerance and insulin sensivity. Some Portuguese aromatic plants are utilized as tisanes by diabetic people as medicinal plants. Their active principle is not yet known, and the importance of their chromium content in the claimed therapeutic properties should not be discarded. Therefore, determination of chromium in some Portuguese medicinal plants was performed by flameless atomic absorption. AU the analyzed plants contain chromium at the normal level for this element, but the plants used to prepare tisanes to help diabetic conditions contain higher levels (2.2 mu g/g dry wt +/- 0.88; n = 11) than the others (0.88 mu g/g dry wt +/- 0.18; n = 17).