Evaluation of plasma H2S levels and H2S synthesis in streptozotocin induced Type-2 diabetes-an experimental study based on Swietenia macrophylla seeds

Objective: To evaluate the plasma H2S levels and H2S synthesis activity in streptozotocin induced type 2 diabetes rats compared to the healthy controls and also to observe the effect of the aqueous extract of Swietenia macrophylla (S. macrophylla) seeds on the experimental groups. Methods: Seeds of S. macrophylla were separated, washed, shed-dried and finally extract was prepared. Thirty two wistar rats were selected for the experimental study. Streptozotocin was used for the induction of diabetes. H2S concentration in plasma was measured. H2S synthesizing activity in plasma was measured. Statistical analysis have done using Microsoft excel, Office 2003. Values were expressed by mean±SD. P<0.05 were considered statistically significant.Results:rats. The glucose levels are significantly lowered in the rats treated with metformin (5.48±0.03) mmol/L as well as with aqueous extract of S. macrophylla seeds (3.72±0.04) mmol/L. The HbA1c percentages in different groups of study subjects also indicate similar trends. Our study shows both the plasma H2S levels (22.07±0.73) mmol/L and plasma H2S synthesis activity (0.411±0.005 mmol/100 g) are significantly reduced in the streptozotocin induced diabetic rats.Conclusions:Although considering a small sample size, it can conclude that the fasting blood Fasting blood glucose level (7.74±0.02) mmol/L was significantly increased in diabetic glucose levels are inversely related to plasma H2S levels as well as H2S synthesis activity in plasma and the extract of S. macrophylla is associated with increased plasma H2S levels with effective lowering of blood glucose in streptozotocin induced diabetic rats.

Development of biosensor based on immobilized L-glutamate oxidase for determination of monosodium glutamate in food.

A monosodium glutamate (MSG) biosensor with immobilized L-glutamate oxidase (L-GLOD) has been developed and studied for analysis of MSG in sauces, soup etc. The immobilized enzymatic membrane was attached with oxygen electrode with a push cap system. The detection limit of the sensor was 1 mg/dl and the standard curve was found to be linear upto 20 mg/dl. Response time of the sensor was 2 min. Cross-linking with glutaraldehyde in presence of Bovine Serum Albumin (BSA) as a spacer molecule has been used for immobilization. Optimization of the sensor was done with an increase in L-GLOD concentration (6.3-31.5 IU) and also with increase in loading volume of enzyme solution (5-20 microl). Optimization of pH and temperature was also studied. The permeability of O2 through different membrane was studied with and without immobilized L-GLOD. The enzymatic membrane was used for over 20 measurements and stability of the membrane was observed.

Development of an amperometric hypoxanthine biosensor for determination of hypoxanthine in fish and meat tissue.

A hypoxanthine (Hx) biosensor based on immobilized xanthine oxidase (XO) as the bio-component was developed and studied for the rapid analysis of fish (sweet water and marine) and goat meat samples. The biosensor was standardized for the determination of Hx in the range of 0.05 to 2 mM. Crosslinking with glutaraldehyde in presence of BSA as a spacer molecule was used for the method of immobilization. One layer of gelatin (10%) was applied over the immobilized enzyme layer to reduce the leaching out of enzyme from the membrane (cellulose acetate) matrix. The optimum pH of the immobilized system was determined to be 8.5 at 25 degrees C instead 7.0-7.2 for free enzyme system. Km and Vmax values were determined for the immobilized system. The developed sensor was applied to determine the amount of Hx present in fish and meat over a period of time. The stability of the enzyme immobilized membrane was also tested over a period of 30 days.