Kato A et al. (2008) Protective effects of dietary chamomile tea on diabetic complications. J Agric Food Chem 56: 8206–8211

The active components of Matricaria chamomilla—which is used to make chamomile tea—have shown some evidence of protective effects against chronic health disorders. Kato et al. have investigated whether chamomile hot water extract, and several individual active components of chamomile, have any beneficial effect on hyperglycemia and other features of diabetes mellitus.

In vitro, chamomile hot water extract and the active components esculetin and quercetin inhibited the activity of α-glucosidases. These enzymes are involved in breaking down carbohydrates and might, therefore, contribute to hyperglycemia. The efficacy of these compounds in vivo was examined in a sucrose-loading test in mice; all three components lowered the raised blood glucose levels in this model to some degree, although esculetin had the greatest effect.

Chamomile hot water extract, quercetin and luteolin suppressed the activity of enzymes involved in liver glucose production, which could potentially reduce hepatic glucose output and so lower blood glucose levels. The authors then performed a 21-day feed test in rats with streptozotocin-induced diabetes. Administration of chamomile hot water extract or quercetin significantly increased liver glycogen levels and decreased blood glucose levels. A final in vitro study demonstrated that several active components inhibited the accumulation of sorbitol in erythrocytes, which is associated with diabetic complications such as cataracts and neuropathy.

The authors suggest that daily consumption of chamomile tea with meals could help to prevent the development or worsening of hyperglycemia and diabetic complications.