pyrazinoylguanidine may be the guanidine of choice

Doug Skrecky (
Tue, 22 Dec 1998 14:55:12 -0800 (PST)

Looks like pyrazinoylguanidine is greatly superior to aminoguanidine in the prevention of cataracts. It might be the guanidine of choice for the purpose of life extension as well.

Citations: 1-2


Follansbee MH. Beyer KH Jr. Vesell ES. Institution
Department of Pharmacology, Pennsylvania State University College of Medicine, Hershey 17033, USA.
Studies on pyrazinoylguanidine. 6. Prevention of cataracts in STZ-diabetic rats.
Pharmacology. 54(5):256-60, 1997 May. Abstract
This study was designed to determine whether pyrazinoylguanidine (PZG) can attenuate cataract development in streptozotocin (STZ)-induced diabetic rats. After a single, intraperitoneal dose of STZ (45 mg/kg in 0.05 mol/l sodium citrate buffer), Sprague-Dawley rats (250-260 g) were divided into three groups. Beginning a week later, each group of diabetic rats received twice daily for 24 weeks by gavage one of the following: vehicle (saline 10 ml/kg), PZG (35 mg/kg), or captopril (15 mg/kg). PZG treatment prevented the development of diabetic cataracts (p = 0.0009 compared to vehicle). In contrast to PZG, 38% of vehicle-treated rats exhibited cataracts after 12 weeks, increasing to 89% after 16 weeks. At week 16, 22% of captopril-treated rats exhibited cataracts, a 75% reduction from vehicle-treated rats (p = 0.4289 compared to vehicle; p = 0.0571 compared to PZG). These results indicate that captopril can attenuate cataract formation in STZ-diabetic rats, whereas PZG completely suppresses it.


Swamy-Mruthinti S. Green K. Abraham EC. Institution
Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912, USA.
Inhibition of cataracts in moderately diabetic rats by aminoguanidine.
Experimental Eye Research. 62(5):505-10, 1996 May. Abstract
The effect of aminoguanidine (AG), an inhibitor of advanced glycation, on the development of cataracts was studied in diabetic rats. Rats were made diabetic with streptozotocin, and based on the level of plasma glucose they were grouped as moderately (< 350 mg dl-1 plasma glucose) and severely (> 350 mg dl-1 plasma glucose) diabetic. One half of the animals in each group received AG (25 mg kg-1 body weight each day), intraperitoneally, starting from the day of streptozotocin injection. Progression of lens opacification was recorded using Fundus and Scheimpflug photography at regular time intervals. On the ninetieth day all the rats were killed and the levels of advanced glycation end products (AGE) was determined by measuring the non-tryptophan fluorescence of the lens soluble and insoluble fractions. Densitometric analysis of Scheimpflug images showed that in diabetic rats lens opacification progressed in a biphasic manner, an initial slow progression for the first 60 days, followed by a steep increase during next 30 days. Moderately and severely diabetic rats developed lens opacities more or less at the same time. AGE fluorescence in the lens soluble fractions increased three-fold and seven-fold in the moderately and severely diabetic rats, respectively; whereas in insoluble fractions there was a 30% and three-fold increase in the moderately and severely diabetic rats, respectively. Although AG treatment inhibited the AGE fluorescence of lens soluble and insoluble fractions by about 56% and 75% in moderately diabetic and by 19% and 52% severely diabetic rats, respectively, the development of cataracts was delayed only in the moderately diabetic rats. These results thus suggest that the effect of AG is indeed inhibition of the formation of AGEs. However, in the severely diabetic rats the beneficial effect of AG is overwhelmed by the excessive accumulation of AGEs.

(diet seems to be important too.....)


Tavani A. Negri E. La Vecchia C.
Istituto di Ricerche Farmacologiche Mario Negri, Universita di Milano, Italy. Title
Food and nutrient intake and risk of cataract. Source
Annals of Epidemiology. 6(1):41-6, 1996 Jan. Abstract
The relationship between cataract extraction and diet was considered in a case-control study conducted in northern Italy. A total of 207 patients who had cataract extraction and 706 control subjects in a hospital for acute, nonneoplastic, nonoculistic, nondigestive tract diseases were interviewed during their hospital stay. Odds ratios (ORs) and their 95% confidence intervals (CIs), according to the intake of alcohol, coffee, tea, and cola, and frequency of intake of 34 food items and 8 micronutrients were derived from multiple logistic regression equations, including terms for age, sex, education, smoking status, body mass index, diabetes, and total calorie intake. Alcohol, coffee, decaffeinated coffee, tea, and cola intakes were not associated with cataract extraction. Among food items, reduced ORs for cataract extraction (highest tertile of intake compared to the lowest), with a significant inverse trend in risk, were found for intake of meat (OR 0.6, 95% CI 0.4 to 0.9), cheese (OR 0.7, 95% CI 0.5 to 1.0), cruciferae (OR 0.5, 95% CI 0.3 to 0.8), spinach (OR 0.6, 95% CI 0.4 to 0.9), tomatoes (OR 0.5, 95% CI 0.4 to 0.8), peppers (OR 0.7, 95% CI 0.4 to 1.1), citrus fruit (OR 0.5, 95% CI 0.2 to 1.3), and melon (OR 0.5, 95% CI 0.4 to 0.8). A significant increase in risk was found for the highest intake of butter (OR 2.8, 95% CI 1.2 to 6.4), total fat (OR 1.8, 95% CI 1.2 to 2.8), and salt (OR 2.4, 95% CI 1.4 to 4.0) compared to the lowest, and for consumption of oil other than olive oil (OR 1.6, 95% CI 1.1 to 2.2). Among micronutrients, lower ORs for cataract extraction (highest quintile of intake compared to the lowest) were found for intake of calcium (OR 0.5, 95% CI 0.3 to 0.8), folic acid (OR 0.4, 95% CI 0.2 to 0.7), and vitamin E (OR 0.5, 95% CI 0.3 to 1.0), while estimated intakes of methionine, retinol, beta-carotene, and vitamins A, C, and D were not associated. Thus, this study indicates that diet plays a considerable role in the risk of cataract extraction in this Italian population, with a protective action played by some vegetables, fruit, calcium, folic acid,and vitamin E, and an increased risk associated with elevated salt and fat intake.