The mankind has received a gift from mother-nature in the form of natural laboratories present within diversified plant kingdom.The plants create secondary metabolites for their own safety and many of these secondary metabolites are useful for human beings in various kinds of ailments.Diabetes is not an exception to this, there are many secondary metabolites isolated from plants which are now being utilized for treatment.The significance of isolating metabolites from plants is that they have comparatively very less side effects as compared to allopathic system of medicine (oral hypoglycaemic agents).This review takes into account, the recent updates in the treatment of diabetes mellitus using herbal products and phytochemical constituents reported so far.A total number of 150 plant species belonging to numerous families are presented in this review which is useful in the treatment of diabetes mellitus.Article also contains more than fifty medicinal compounds recently updated in literature.The most important families in present review are fabaceae and cucurbitaceae.The plants from these families are found to be of high therapeutic value to treat diabetes mellitus however families like musaceae, punicaceae and aloaceae have been found to contain least number of effective plant species.The plant parts contributing mostly active compounds are leaves, fruit & seeds.

To investigate the bioactive principles obtained from chloroform extract of Indian medicinal plant Annona squamosa. The successively extracted twigs of A. squamosa using various solvents were analyzed for their antiulcer activity and finally two new compounds are isolated and characterized based on bioassay guided fractionation and isolation. Isolated compounds (compound no. 1 & 2) were examined for Hydrogen Potassium ATPase activity. When compared to the standard drug omeprazole, both compounds are showing better activity. The results obtained justify the traditional usage of A. squamosa for their antisecretory activity.

Annona squamosa L. is a widely used Indian medicinal plant for the cure of deadly disease, diabetes. In recent decades, a great no. of chemical and pharmacological studies have been done on A. squamosa L. and still more research is required in order to search its bioactive components. Bioassay dependent fractionation & isolation technique is used & repeated column chromatography was utilized to get pure compounds. Structure elucidation for compound A & compound B has been done using Mass, NMR, IR, UV, 1D & 2D NMR techniques. In this paper we report one new compound from Indian medicinal plant A. squamosa L. which is characterized as 6,7-dimethoxy-2-methylisoquinolinium & is obtained from the twigs of the plant in its chloroform fraction. One known compound Rutin is also obtained from n -butanol fraction and is reported for the first time from this plant which is characterized as 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-3-[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-{{(2S,3R,4R,5R,6S)-3,4,5-trihydroxy-6-methyltetrahydro-2H-pyran-2-yloxy}methyl}tetrahydro-2H-pyran-2-yloxy]-4H-chromen-4-one.

Increased hepatic glucose output is one of the major causes of fasting hyperglycemia in diabetic patients. In this study, we investigated the mechanism of action of coagulanolide on hepatic glucose, regulating enzymes in type 2 diabetic C57BL/KsJ-db/db (db/db) mice. Coagulanolide is an active component of Withania coagulans fruit. Oral administration of coagulanolide for 3 weeks decreases fasting blood glucose and plasma insulin significantly, and it improves glucose tolerance in the db/db mice group. The enzyme activity and protein expression of glucokinase and pyruvate kinase was significantly enhanced in coagulanolide-treated db/db group when compared with untreated one. On the other hand, activities and protein expression of fructose-1,6-bisphosphatase, glucose 6-phosphatase, phosphoenolpyruvate carboxykinase, and glycogen phosphorylase enzymes were significantly lowered in treated group. The treatment with coagulanolide also normalizes the concentrations of plasma cholesterol, triglyceride, free fatty acid, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in the db/db mice. These findings suggested that the coagulanolide is useful in the control of fasting hyperglycemia in type 2 diabetes by regulating the production of hepatic glucose.

One new withanolide, (17S,20S,22R)-14 alpha,15 alpha,17 beta,20 beta-tetrahydroxy-1-oxowitha-2,5,24-trienolide) named coagulanolide (4) along with four known withanolides 1-3 and 5 have been isolated from Withania coagulans fruits and their structures were elucidated by spectroscopic techniques. The compounds 1-5 showed significant inhibition on postprandial rise in hyperglycemia post-sucrose load in normoglycemic rats as well as streptozotocin-induced diabetic rats. The compound 5 also showed significant fall on fasting blood glucose pro. le and improved the glucose tolerance of db/db mice. Further compound 5 showed antidyslipidemic activity in db/db mice. The median effective dose of the compound 5 was determined to be around 25 mg/kg in streptozotocin-induced diabetic rats, which is comparable to the standard antidiabetic drug metformin. Our results provide further support to explain the traditional use of W. coagulans as antihyperglycemic cum antidyslipidemic agent by the traditional medical practitioners. (C) 2008 Elsevier Ltd. All rights reserved.