Actions of the traditional anti-diabetic plant, Agrimony eupatoria (agrimony): effects on hyperglycaemia, cellular glucose metabolism and insulin secretion

Agrimony eupatoria (agrimony) has been documented as a traditional treatment of diabetes. Here, the effects of dietary administration of agrimony on streptozotocin (STZ)-diabetic mice and on in vitro glucose uptake and glucose metabolism, and on insulin secretion by BRIN-BD11 cells were investigated. Agrimony incorporated into the diet (62.5 g/kg) and drinking water (2.5 g/l) countered the weight loss, polydipsia, hyperphagia and hyperglycaemia of STZ-diabetic mice. Aqueous extract of agrimony (1 mg/ml) stimulated 2-deoxy-glucose transport (1.4-fold), glucose oxidation (1.4-fold) and incorporation of glucose into glycogen (2.0-fold) in mouse abdominal muscle comparable with 0.1 microM-insulin. In acute 20 min tests, 0.25-1 mg/ml aqueous extract of agrimony evoked a stepwise 1.9-3.8-fold stimulation of insulin secretion from the BRIN-BD11 pancreatic B-cell line. This effect was abolished by 0.5 mM-diazoxide and previous exposure to extract did not adversely affect subsequent stimulation of insulin secretion by 10 mM-L-alanine, thereby indicating that there was no detrimental effect of the extract on cell viability. The effect of extract was glucose-independent and was not evident in BRIN-BD11 cells exposed to a depolarizing concentration of KCl. The ability of agrimony extract to enhance insulin secretion was dependent on use of heat during extract preparation. These results demonstrate the presence of antihyperglycaemic, insulin-releasing and insulin-like activity in Agrimony eupatoria.

Traditional plant treatments for diabetes. Studies in normal and streptozotocin diabetic mice

The effects on glucose homeostasis of eleven plants used as traditional treatments for diabetes mellitus were evaluated in normal and streptozotocin diabetic mice. Dried leaves of agrimony (Agrimonia eupatoria), alfalfa (Medicago sativa), blackberry (Rubus fructicosus), celandine (Chelidonium majus), eucalyptus (Eucalyptus globulus), lady's mantle (Alchemilla vulgaris), and lily of the valley (Convallaria majalis); seeds of coriander (Coriandrum sativum); dried berries of juniper (Juniperus communis); bulbs of garlic (Allium sativum) and roots of liquorice (Glycyrhizza glabra) were studied. Each plant material was supplied in the diet (6.25% by weight) and some plants were additionally supplied as decoctions or infusions (1 g/400 ml) in place of drinking water to coincide with the traditional method of preparation. Food and fluid intake, body weight gain, plasma glucose and insulin concentrations in normal mice were not altered by 12 days of treatment with any of the plants. After administration of streptozotocin (200 mg/kg i.p.) on day 12 the development of hyperphagia, polydipsia, body weight loss, hyperglycaemia and hypoinsulinaemia were not affected by blackberry, celandine, lady's mantle or lily of the valley. Garlic and liquorice reduced the hyperphagia and polydipsia but did not significantly alter the hyperglycaemia or hypoinsulinaemia. Treatment with agrimony, alfalfa, coriander, eucalyptus and juniper reduced the level of hyperglycaemia during the development of streptozotocin diabetes. This was associated with reduced polydipsia (except coriander) and a reduced rate of body weight loss (except agrimony). Alfalfa initially countered the hypoinsulinaemic effect of streptozotocin, but the other treatments did not affect the fall in plasma insulin. The results suggest that certain traditional plant treatments for diabetes, namely agrimony, alfalfa, coriander, eucalyptus and juniper, can retard the development of streptozotocin diabetes in mice.