Diabetes mellitus is a debilitating and often life-threatening disorder with increasing incidence throughout the world [
1]. Diabetic complications arise partly from glycosylation damage to structural and functional proteins and reflect chronic failure to maintain blood glucose homeostasis. Other complications such as diabetic nephropathy, diabetic retinopathy, diabetic neuropathy and diabetic cardiomyopathy prevail as a result of hyperglycemia. A scientific investigation of traditional herbal remedies for diabetes may provide valuable leads for the development of alternative drugs and strategies. Alternatives are clearly needed for better management of diabetes because of high cost and poor availability of current therapies for many rural populations, particularly in developing countries. Diabetic nephropathy is one of the microvascular complications of diabetes. The pathophysiology involves an interaction between metabolic and hemodynamic factors. Metabolic factors include advanced glycation, increased formation of polyols and activation of protein kinase-C. Hemodynamic factors include systemic hypertension, intraglomerular hypertension and the role of vasoactive hormones, such as anglotensin II. Clinical course progresses from microalbuminuria to overt proteinuria and then to renal failure [
2].
The field of herbal medicines research has been gaining significant importance in the last few decades and the demand to use natural products in the treatment of diabetes is increasing worldwide. The available literature shows that there are more than 400 plant species showing antidiabetic activity [
3,
4]. Although some of these plants have great reputation in Ayurveda, the indigenous Indian system of medicine, many remain to be scientifically established [
5].
The dried ripe fruit of
Terminalia chebula Retz. (Combretaceae), is used extensively in Ayurveda and is widely distributed throughout India, Burma and Sri Lanka. It is commonly known as black myroblans in English and has traditionally been used in the treatment of asthma, sore throat, vomiting, hiccough, diarrhoea, bleeding piles, gout and heart and bladder diseases [
6]. A herbal formulation containing
T. chebula under the name 'TRIPHALA' is a very popular traditional medicine for the treatment of chronic disorders including diabetes [
7,
8]. It is reported to have antioxidant and free radical scavenging activities [
9]. It has shown effectiveness against cancer cells [
10] and helicobacter pylori [
11]. It is also useful as anticaries agent [
12] in dermal wound healing [
13], improving gastrointestinal motility [
14] and anaphylactic shock [
15]. The methanolic extract of
T. chebula has been shown to exhibit antidiabetic activity in rats [
16]. Although the fruits are known for their antidiabetic properties, the whole powder of dried ripe fruits is also being widely used for the control of diabetes. So far, little is known on the medicinal values of
T. chebula seeds. In the present study, the chloroform extract of the seeds of
T. chebula was tested for its antidiabetic activity using short term and long term study protocols after oral administration in streptozotocin-induced diabetic rats. Moreover, the extract was also tested for its renoprotective effects upon long term study in diabetic rats.