Chloroplast ultra structure, photosynthesis and enzyme activities in regenerated plants of Stevia rebaudiana (Bert.) Bertoni as influenced by copper sulphate in the medium.

Stevia rebaudiana (Bert.) Bertoni is an important medicinal plant used as noncaloric commercial sweetener. Plants regenerated with higher levels of copper sulphate in the medium exhibited enhanced activity of peroxidase and polyphenoloxidase (PPO) enzymes. Transmission electron microscopy (TEM) revealed increase in size and number of electron dense inclusions in the chloroplasts of plants regenerated at optimised level of copper sulphate (0.5µM) in the medium. There was decrease in chlorogenic acid (CGA) content. Chl-a-fluorescence transient pattern (OJIP) showed that the photosynthesis process was more efficient at 0.5µM CuSO4 in the medium. 

Comparative study on the effects of steviosides and aspartame on glucose, urea and creatinine levels of normal and type 2 diabetic rats

Comparing the effects of the natural nonnutritive sweetener [steviosides] and the artificial sweetener [aspartame] on the plasma glucose, urea, and creatinie levels of normal and type 2 diabetic rats revealed that treating normal and diabetic rats with different doses of both sweeteners reduced the plasma glucose levels except in normal rats treated with low dose of aspartame and high dose of steviosides that increased glucose levels by 17.3% and in normal rats treated with the high aspartame dose [38%] but fortunately they were still within the normal glucose range. All doses of both sweeteners increased urea levels in normal rats by percentages ranging from 5.2% to 41.7% though they were within the normal urea range except the low aspartame dose and high steviosides dose, moreover medium aspartame dose reduced urea level by 11.1%. All doses of both sweeteners reduced the urea levels in diabetic rats with the highest reduction percentage in those treated with the high steviosides dose [63.8%] while the lowest [40.9%] was in those treated with the medium dose of aspartame but unfortunately, no dose succeeded to lower urea levels to their normal ranges. Treating normal rats with different doses of both sweeteners increased the plasma creatinine by percentages ranging from 33.3% in the medium steviosides dose to 33.3% in the low spartame dose although they were kept within the normal creatinine range. Treating diabetic rats with different doses of both sweeteners succeeded to lower creatinine levels to their normal ranges with reduction percentages ranging from 25.8% to 38.1%. The creatinine levels were more or less similar in diabetic rats treated with different doses of both sweeteners with no significant differences between the two sweeteners in any dose