1. MEDICINAL PLANTS WITH ANTIDIABETIC PROPERTIES AVAILABLE IN BANGLADESH 1.1 Anacardium Occidentale L. Anacardium occidentale L. is a Latin American originated herb, belonging to anacardiaceae family which is locally familiar as kaju, kajubadam or Hisjlibadam. It is a cultivated plant, which is found in a reserved scale in hill tract area (Chittagong) of Bangladesh. The bark of this herb has the hypoglycemic and antihypertensive potentiality. This plant was used as folk medicine in the various African communities for the treatment of diabetes mellitus. It has been narrated that, the leaves of this herb are opportunistic for renal impairment and as hypoglycemic based on the streptozotocin treated diabetes rats. The study also claimed that, it has a good impact on diabetes- associated kidney problems like histological and functional alteration. In diabetes animal model studies (Anacardium occidentale) has shown remarkably decrease in the collection of mucopolysaccharides in the kidneys.
1.2 Annona Squamosa L. Annona squamosa L. belongin to Annonaceae family is frequently cultivated throughout Bangladesh. In Bengali it’s known as Ata, Sharifa, Luna and in English as Custard Apple, Sweet stop. The different part of this plant has such as seeds, leaves and aerial parts has important pharmacological properties due to presence of active medicinal ingredients. A.Squamosa helps in diabetes regulation in two different ways. Firstly, acts by increasing the extra amount of insulin from pancreatic isletsmuscle. Similarly, it increase the utilization of glucose by muscle and liver glucose get interrupted to increase blood glucose level. Leaf extracts of this plant is effective in the management of blood sugar and lipid level. Aqueous root extracts of Annona squamosa has not only shown in reduction in blood glucose level after administration to STZ-initiated diabetic rats but also rise in the antioxidant properties of enzyme along with decrease the renal and liver lipid peroxidation.
1.3 Boerhaavia Diffusa L. Boerhaavia diffusa L. is a native medicinal plant of Bangladesh. This belongs to the family of Nyctaginaceae and It is small perennial pervading herb. In Bengali, this is commonly known as Punarnava and in English widely known as “Red Hogweed. It is taken as a herbal medicine for pain relief in many parts of Bangladesh. It is widely cultivated in fallow lands all over Bangladesh. Roots and whole plant have been used for the treatment of stress, dyspepsia, abdominal pain, inflammation, diabetes, jaundice, enlargement of the spleen enlargement and also microbial infections. Alloxan-induced hyperglycemic rats model exhibited tremendous antihyperglycemic activities when treated with ethanolic Boerhaavia. Overweight obesity related high serum cholesterol as well as triglyceride levels of diabetes may be improved by using extract of this plant. A study investigated the effect of an aqueous extracts of Boerhaavia diffusa leaf (200mg/kg) on alloxan induced and normal diabetic rats for investigating the blood glucose concentration along with hepatic enzymes in daily oral administration for four weeks. It not only showed remarkable decrease in blood glucose level but also significantly increase in plasma insulin level on the normal and alloxaninduced rat model. The herb of this plant has been found responsible for reducing blood glucose level and increasing insulin sensitivity.
1.4 Catharanthus Roseus L. Catharanthus roseus Linn.is a belongs to the family Apocynaceae. This plant is commonly grown in garden. In Bengali, it is known as Nayantara and as Madagascar Periwinkle in english. The plant not only has antidiabetic properties but also anticancer properties. Many tropical and subtropical regions of the world use the whole plant or the leaves of Catharanthus roseus, processed it with hot water decoction and yields are used for the antidiabetic properties. Alkaloids of the leaf extract are active and play a significant in lowering the blood glucose level. Dichloromethane-methanol extract(1:1) of the leaves and twigs was tested for antidiabetic activityand its effect on enzymes of carbohydrate metabolism was explored. In a study, both normal and diabetic rabbits exhibited the dose-dependent reduction in blood glucose level followed by administration of extracts of C. roseus, and the results were comparable with a standard hypoglycemic agent, glibenclamide. The outcome may be the result of enhanced secretion of insulin.
1.5 Cocculus Hirsutus L. Cocculus hirsutus Linn. is a member of Menispermaceae family that is grow throughout Bangladesh, especially in dry regions like Dhaka, Bagerhat, Dinajpur, Jhalakathi, Kustia etc. This is commonly known as Daikhai, Jalajmani, Heyer in Bengali. The roots are bitter in taste and its decoction acts as laxative, demulcent and antiperiodic in fever. Leaf juice mixed with water forms jelly, which has the cooling and soothing effect in case of prurigo, eczema, and gonorrhoea.[20] Badole et al. have demonstrated the antihyperglycemic activity of aqueous extract of leaves of Cocculus hirsutus (L) Diels in alloxan-induced diabetic mice. It has been found, that aqueous extract of leaves of C. hirsutus minimized the serum glucose level and improved glucose tolerance significantly in the presence of alkaloids. Moreover, the leaf extract exhibited prevention in loss of body weight in diabetic mice. The possible reason behind the antihyperglycemic activity of C. hirsutus may be the insulinogenic activity of the extract. Hence, it can be said that, C. hirsutus extract may stimulate the secretion from remnant cells and from regenerated cells.