Diabetes mellitus is one of the most common chronic diseases and a major contributor to the development of cardiovascular diseases. It is due to a deficiency or a failure of normal action of insulin, which is responsible of the use of the sugar from the diet. The number of cases of non-insulin dependent diabetes mellitus has increased dramatically due to the changes in lifestyle, increasing prevalence of obesity, and ageing of populations. 1) In the year 2000, the number of diabetic patients was 151 million and is estimated to rise to 300 million by 2025. 2,3)The uses of natural drugs, such as plants and herbal remedies to treat diseases is very common in Asia and developing countries, where the population is linked with the use of traditional medicines, due to their efficiency or due the costs of the synthetic drugs and/or pharmaceuticals. One of the aims of phytochemists is to find the application of ethnomedicine in drug discovery. Moreover, WHO study groups emphasize strongly the optimal, rational uses of traditional and natural indigenous medicines (http://www.who.int/mediacentre/factsheets/fs134/en/). The leprosy gourd (bitter gourd, ayurveda name: karela), Momordica charantia L., a well known plant for its antidiabetic properties in Asia and some African countries, is among the candidates. Bitter and non-bitter cucurbitane triterpene aglycones and/or glycosides have been isolated from the plant. [4][5][6][7][8][9][10][11] The bitter principles so far reported have been characterized as momordicosides K and L, and momordicines I and II. 5,8) Interestingly, the four compounds have C-9 formyl, 7-OH or O-b-D-glucopyranosyl groups and are unsaturated at C-5, C-6. These features might be the structural requirement for the bitter taste and undoubtedly, the high content of saponins in the plant can be related to its taste.The constituents responsible for the glucose lowering activity are not yet well known even though over hundred scientific articles have described the phytochemical and pharmacological properties of the plant. 12,13) In the course of our phytochemical screening of medicinal plants aimed at finding the active principles for antidiabetic activities, eleven compounds (1-11) were isolated from the Indian bitter gourd sample. The structural elucidation of compounds 1-3 is reported and the major compounds (4 and 5) have been tested against the antidiabetic strain of male ddY mice. The objective of the present study is to find the relationship between Momordica charantia constituents and the antidiabetic properties of the plant. Results and DiscussionEffect of the Extracts on Diabetes Induced Mice The ether and ethyl acetate fractions of the water suspension of the bitter gourds methanol extract were tested for antidiabetic assay in mice. Oral administration of each fraction at 500 mg/kg (Figs. 3, 4, respectively) resulted marked hypoglycaemic effects comparable to glibenclamide (at 200 mg/kg).Isolation and Characterization of Constituents from the Active Extracts A combination of size exclusion and sil...

Two new dimeric sesquiterpenoids and a new trimeric drimane sesquiterpenoid named cinnafragrins A-C (1-3), together with cinnamodial (4), D-mannitol, capsicodendrin (5), and a vitamin E analogue, delta-tocotrienol, were isolated from Cinnamosma fragrans, a Malagasy medicinal plant. The structures of the new compounds were determined on the basis of physical, chemical, and spectroscopic evidence. Capsicodendrin, previously isolated from Capsicodendron dinisii and tentatively suggested to be a tetramer of cinnamodial, was revised structurally as a mixture of C-12'-epimers of 12'-hydroxycinnafragrin B by extensive 2D NMR analysis and X-ray crystallography of the lactone derivative, cinnafragrolide (6). The chemosystematics of the family Canellaceae are discussed.

No abstract

No abstract

No abstract