Oct 01 2010
alacia is a genus of plants in the family Celastraceae. One species in particular, Salacia oblonga, used for thousands of years in Ayurvedic medicine, is increasingly becoming the subject of considerable medical interest because of its potential as an anti-diabetic agent. The herb is a native of India and Sri Lanka and has been used in traditional Indian medicine and Ayurveda successfully for years. The active constituents, salacinol and kotalanol, inhibit alpha-glucosidase and aldose reductase. The inhibition of these substances decreases the breakdown of carbohydrates into absorbable monosaccharides and therefore decreases postprandial (after meal) blood glucose levels. (1)
Alpha-glucosidase inhibitors are used to establish greater glycemic control over hyperglycemia in diabetes mellitus type 2, particularly with regard to the postprandial hyperglycemia. They may be used in conjunction with an appropriate diabetic diet and exercise, or they may be used in conjunction with other anti-diabetic drugs. Inhibition of these enzyme systems reduces the rate of digestion of complex carbohydrates. Less glucose is absorbed because the carbohydrates are not broken down into the simpler, rapidly assimilable glucose molecules. In diabetic patients, the short-term effect of these drug therapies is to decrease current blood glucose levels: the long term effect is a modest reduction in hemoglobin A1c level.
In a randomized, double-blinded crossover study of sixty-six patients with diabetes were studied to evaluate the effect of an herbal extract of Salacia oblonga on postprandial glycemia and insulinemia in patients with type 2 diabetes after ingestion of a high-carbohydrate meal. The study was divided into three groups: a control meal with a high dose (480mg) of Salacia extract, a control with a lower dose (240mg) of Salacia extract, and a control group given just the meal.Both doses of the Salacia extract significantly lowered the postprandial positive area under the glucose curve (14% for the 240 mg extract and 22% for the 480 mg extract) and the adjusted peak glucose response (19% for the lower dose and 27% for the higher dose of extract) compared to the control meal. In addition, both doses of the herbal extract significantly decreased the postprandial insulin response, lowering both the positive area under the insulin curve and the adjusted peak insulin response (14% and 9%, respectively, for the 240 mg extract; 19% and 12%, respectively, for the 480 mg extract) in comparison with the control meal. (2)
Salacia oblonga extract functions as a PPARα activator, providing a potential mechanism for improvement of postprandial hyperlipidemia and hepatic steatosis in diabetes and obesity. (3)
The PPARs (peroxisome proliferator-activated receptors) receptor family is comprised of three closely related isotypes (PPARα, β/δ and γ, which have been identified in various species and are structurally homologous. PPARα and PPARγ are found predominantly in liver and adipose tissue, respectively, and PPARβ/δ is ubiquitously expressed. PPARs can be activated by fatty acids, fatty acid derivatives, and synthetic compounds, heterodimerize with retinoid x receptors (RXRs), and bind to peroxisome proliferator response elements (PPREs) located in the promoter region of their target genes. Each member of the PPAR family plays a distinct role in lipid metabolism. PPARα enhances fatty acid combustion in liver by inducing genes that encode enzymes involved in β-oxidation. PPARα, the first PPAR identified, is activated by natural lipophilic ligands, like fatty acids and their derivatives, certain leukotriene products, and synthetic ligands, such as fibrates. PPARα regulates lipid metabolism and transport, fatty acid oxidation, and glucose homeostasis. In addition, PPARα exerts anti-inflammatory effects. (4)
Like most alpha-glucosidase inhibitors, Salacia extract can cause a temporary increase in breath hydrogen excretion. (5) There is often a bout of flatulence that occurs during the early stages of treatment. (6)
Salacia extracts were determined not to be genotoxic under the conditions of the reverse mutation assay and mouse micronucleus assay, and weakly positive for the chromosomal aberrations assay. However even these mild genotoxic changes were deemed insignificant due to the enormous amount of plant material needed to produce the genetic changes. (7) Salacia extract, in a medical food consumed for 2 weeks in amounts estimated at 10-fold greater than proposed for human intake, did not result in clinical chemistry or histopathologic indications of toxic effects in male Sprague-Dawley rats. (8)
- Benalla W, Bellahcen S, Bnouham M. Antidiabetic medicinal plants as a source of alpha glucosidase inhibitors. Curr Diabetes Rev. 2010 Jul 1;6(4):247-54.
- Williams JA, Choe YS, Noss MJ, Baumgartner CJ, Mustad VA. Extract of Salacia oblonga lowers acute glycemia in patients with type 2 diabetes. Am J Clin Nutr. 2007 Jul;86(1):124-30. [full text]
- Huang TH, Yang Q, Harada M, Uberai J, Radford J, Li GQ, Yamahara J, Roufogalis BD, Li Y. Salacia oblonga root improves cardiac lipid metabolism in Zucker diabetic fatty rats: modulation of cardiac PPAR-alpha-mediated transcription of fatty acid metabolic genes.Toxicol Appl Pharmacol. 2006 Jan 1;210(1-2):78-85
- D’Adamo PJ. ‘Network Medicine’ in: Fundamentals of Generative Medicine, Volume I. 2010. Drum Hill Books, Wilton CT USA
- Collene AL, Hertzler SR, Williams JA, Wolf BW.Effects of a nutritional supplement containing Salacia oblonga extract and insulinogenic amino acids on postprandial glycemia, insulinemia, and breath hydrogen responses in healthy adults.Nutrition. 2005 Jul-Aug;21(7-8):848-54.
- Collene AL, Hertzler SR, Williams JA, Wolf BW. Effects of a nutritional supplement containing Salacia oblonga extract and insulinogenic amino acids on postprandial glycemia, insulinemia, and breath hydrogen responses in healthy adults.Nutrition. 2005 Jul-Aug;21(7-8):848-54.
- Flammang AM, Erexson GL, Mecchi MS, Murli H. Genotoxicity testing of a Salacia oblonga extract.Food Chem Toxicol. 2006 Nov;44(11):1868-74.
- Wolf BW, Weisbrode SE. Safety evaluation of an extract from Salacia oblonga. Food Chem Toxicol. 2003 Jun;41(6):867-74.