Therapeutic Polysaccharides - Report Example

THERAPEUTIC POLYSACCHRAIDES Carbohydrates Carbohydrates or the saccharides are a group of organic compounds or bio molecules that basically consist of the elements carbon, hydrogen and oxygen. The ratio of hydrogen is two times that of carbon and oxygen. Diet rich in carbohydrates give high amount of energy. In simple terms, it can be said that sugars, starches, cellulose and several other compounds present in the living organisms are carbohydrates. These compounds are classified based on their chemical structure into monosaccharides, disaccharide, oligosaccharides and polysaccharides (Zamora, 2011). Apart from the fact that carbohydrates are energy bundles in the form of glucose, recent studies have identified several therapeutic benefits especially among the higher polysaccharides. This paper presents an overview of carbohydrate chemistry, chemical structures of different types of carbohydrates, benefits and some of the major functions. Therapeutic functions of polysaccharides are also a brief subject that is described in this paper. Simple sugars or the monosaccharides are the basic carbohydrates. These simple sugars combine to form disaccharides (2 simple sugars), oligosaccharides (2-10 simple sugars) and polysaccharides (more than ten simple sugars). All carbohydrates are either simple sugars or monosaccharides that join with each other to form more complex carbohydrates. Monosaccharides and Classification Monosaccharides are classified based on three categories. First classification is based of the number of carbon atoms present in the compound. Table 1: Monosaccharide classifications based on the number of carbons No. of Carbon Classification Example 3 Triose Dihydroxyacetone 4 Tetrose Erythrose 5 Pentose Ribose 6 Hexose Fructose 7 Heptose Sedoheptulose Monosaccharides are also classified based on the location of the carbonyl group and also based on the chirality of the carbohydrate (Zamora, 2011). Disaccharides These are sugars that contain two simple sugars. Some of the common disaccharides are sucrose, maltose and lactose. Sucrose Lactose Maltose The sugar that we use on a day-to-day basis is Sucrose and is made from sugarcane or sugar beets. It is also one of the main ingredients in turbinado sugar, brown sugar, and confectioners sugar. Lactose is a combination of one molecule each of galactose and glucose. It is a main ingredient in milk. The result of consuming milk and other dairy products in the absence of lactase enzyme which is necessary for the absorption and digestion of lactose is that the undigested lactose moves into the large intestine and is acted up on by bacteria leading to gas formation and further diarrhoea (The Chemistry of Carbohydrates Found in Food, n.d.). In some people due to the lack of the enzyme lactase, a condition known as lactose intolerance occur and these people are allergic to milk and milk products. Maltose consists of two α-D-glucose molecules with the alpha bond at carbon 1 of one molecule attached to the oxygen at carbon 4 of the second molecule. It is also possible that α-D-glucose molecules connected through carbon number one in a 1α→1 linkage resulting in Trehalose on the other hand Cellobiose which is a tasteless disaccharide consisting of two β-D-glucose molecules that have a 1β→4 linkage as in cellulose (Zamora, 2011). Oligosaccharides When two to the molecules of simple sugar combine, it forms oligosaccharide. Raffinose or melitose is one of the common oligosaccharide naturally found in legumes and cruciferous vegetables such as beans, peas, cabbage, brussels sprouts, and broccoli. It consists of galactose connected to sucrose via a 1α→6 glycosidic linkage. Raffinose The digestion of raffinose by human system is not possible and as a result, there can be problems such as gas trouble and bloating (Zamora, 2011). Polysaccharides Most of the vegetarian diet consist of polysaccharides and these are large group of complex carbohydrates with undetermined numbers of sugar molecules. In general most of the polysaccharides are insoluble in water but in the presence of acids or enzymes, polysaccharides can be hydrolyzed to form their constituents or monosaccharides. Some of the common examples of polysaccharides are starch, cellulose, glycogen (from animals), Dextrins, etc (Chow and Halver n.d.). The general formula of Polysaccharides is Cx(H2O)y where ‘x’ is in general a very large number between 200 and 2500. Polysaccharides are classified as Storage (e.g. Starch, Glycogen), Structural (e.g. Cellulose, Arabinoxylans, Chitin, and Pectins), Acidic and Bacterial polysaccharides (peptidoglycan, lipopolysaccharides, capsules and exopolysaccharides) (Sutherland 2002). Dietary fiber includes both polysaccharides as well as oligosaccharides. The two distinct forms of fibers are soluble and insoluble fibers. These polymers are in general difficult to be digested and absorbed in the human small intestine but can undergo partial fermentation by different bacteria in the large intestine. Polysaccharides are of great importance in terms of nutrition, biology, or food preparation (Zamora, 2011). Both soluble as well as insoluble types of fiber are composed of intense indigestible polysaccharides that cannot be converted into glucose by human digestive enzymes. As a result these fibers make it a very healthy addition to daily diet. Besides, the insoluble fiber such as cellulose and lignin present in abundance in plants and whole grains benefits digestion by stimulating peristalsis or help the excretory process. People suffering with constipation are often advised to consume more of these insoluble fibers. Additionally, these fibers reduce the risks of colonic cancers. Soluble fiber such as pectin that is present in apples, β-Glucan present in oats help in the reduction of cholesterol levels. An increase in cholesterol levels may increase the risks of heart diseases. Hence both soluble and insoluble fibers are of great importance in the human diet as they make us feel full after a meal and help reduce the problems of overeating and obesity (How Do Carbohydrates Benefit The Body? 2006). Today, many of the weight management programs include dietary fibers as supplement. Starch Plants store carbohydrates in the form of starch. The basic unit of this polymer is α-D-Glucose and is present in a linear structure (amylose) and highly branched (amylopectin). Amylose Amylopectin Glycogen Glycogen is the polysaccharide obtained from the animal tissues. This is the result of glucose stored in the animal tissues by the process of glycolysis. Glycogen is a polymer of α-D-Glucose and has the similar branched structure of amylopectin with the only difference that the in each branch is short with about 13 units of glucose (Zamora, 2011). Cellulose These are structural polysaccharides that are present in the cell walls of plants. These are insoluble and unlike starch and glycogen these are polymers of β-D-Glucose oriented with -CH2OH groups alternating above and below the plane of the cellulose molecule thus producing long, un-branched chains (Zamora, 2011). The un-branched nature of cellulose helps in the formation of rigid structures in the cell walls. Wood has cellulose and cotton is almost pure cellulose. These cellulose are of major use in the paper and pulp industry. With the help of micro organisms, cellulose can be hydrolyzed into its constituent glucose molecules. Cellulose Chitin The exoskeleton of several anthropoids and other lower animals (e.g., insect, crab, lobsters and shrimp shells) are made up of chitin. Studies point out that chitin in also found in fungi. Chemically it is un-branched polymer of N-acetylglucosamine (C8H13O5N)n. It may be considered as a derivative of cellulose with a simple change of hydroxyl groups of the second carbon of each glucose unit in cellulose substituted with acetamido (-NH(C=O)CH3) groups. Chemical structure of Chitin Beta-Glucan β-Glucan is polysaccharide with the basic unit of β-D-Glucose. Recent studies have revealed the anti-tumor and immune stimulating property and are presently of great significance to the medical science. Additionally, β-Glucan has been considered in blood sugar and cholesterol management (Zamora, 2011). Being a soluble fiber, β-Glucan is present abundantly in the bran of grains such as Barley and oats. β-Glucan Xyloglucan Xyloglucan is a common name of linear polysaccharides consisting of 1β→4 linked D-glucan substituted with xylose (Zamora, 2011). These are structural hemicellulosic polysaccharides found in vascular plant cell wall. The primary cell wall consists of cellulose microfibrills rooted in a medium that is made from pectins and hemicelluloses. It is found in some of the seed of trees such as Tamarindus, Annona, etc. (Nishinari et al. 2007). Pectin These are polysaccharides that act as cementing material or those materials that hold together the cell walls of all plant tissues. This compound is the methylated ester of polygalacturonic acid containing chains of 300 to 1000 galacturonic acid units combined together with 1α→4 linkages. It is abundantly found in apples and the saying that an apple a day keeps the doctor away is due to this polysaccharide. In general these are used in jams, jellies and also for preservation of fruits. Recent studies also finds that pectin can be of use in therapeutic fields in the form of cholesterol reducers, prevents colon cancer and also is useful treating Diarrhoea (Apple Pectin Medicinal Uses n.d.). Pectin Glucomannan It is a dietary fiber taken from tubers of Amorphophallus konjac cultivated in Asia. The flour from these tubers is mainly used in noodles which are low in calories. It is a well known hunger suppressant and hence finds its use in the treatment of obesity. The reason behind this is that glucomannan has high water holding capacity and it produces a feeling of fullness. Glucomannan forms highly viscous solutions when dissolved in water (Canga et al. 2004). The structure consists of glucose (G) and mannose (M) in a proportion of 5:8 joined by 1β→4 linkages (Zamora, 2011). One Unit of Glucomannan Therapeutic Properties of Polysaccharides The complexity of polysaccharides has provided the scientific community with unbound potentials in its application especially in the field of medicine. For instance, botanical or plant based polysaccharides demonstrate innumerable therapeutic properties, and this is basically because of high or natural immunity and macrophage function. The plant based polysaccharides come from various species of flora including some algae, mushrooms and lichens. There are several researchers who have explored the primary effect of botanical polysaccharides in the field of immunology. These higher polysaccharides are known is to enhance and/or activate macrophage immune responses, important to immuno-modulation, anti-tumor activity, wound-healing and other therapeutic effects. Thus, the assessment of polysaccharides particularly from the plants provides an exceptional prospect for the innovation of new therapeutic agents and adjuvant that exhibit valuable immuno-modulatory properties (Schepetkin and Quinn 2006). Plant based polysaccharides have also been preferred over the synthetic compounds due to their broad spectrum application as well as low toxicity levels and no side effects (Tzianabos 2000; Wasser 2002). While there is still a lot more to be explored in terms of the immunological properties of polysaccharides, there are evidences of its anti-tumor, bactericidal, wound-healing action and other therapeutic effects (Wang et al. 1997). Further, there are also experimental and clinical studies that has established that polysaccharides from plants and mushrooms show evidence of innumerable beneficial therapeutic properties, including immuno-stimulatory (Tzianabos 2000), anti-tumor, wound-healing (Wang et al. 1997), hematopoietic, radioprotective, anti-ulceric and anti-atherosclerotic properties. Of late researchers have demonstrated that plant polysaccharides are also used in clinical oncology to boost the efficacy of chemotherapeutic measures and decrease their side effects (Schepetkin and Quinn 2006). It is a well known fact that vegetables such as Butternut Squash, are good source of nutrition and can help in the weight management programs. These contain essential vitamins and minerals along with complex carbohydrates and dietary fiber. As a result a regular intake of butternut Squash can be good for health, digestive process and in controlling blood glucose levels. In conclusion, it can be said that plant based polysaccharides have not only helped in the food industry but are currently entering the field of medicine. Though there are several therapeutic applications already in practice, potential clinical usefulness of these substances needs further research. It is clear that polysaccharides derived from higher plants, mushrooms and algae are a reliable and significant source for therapeutic medicine and represent a rich resource for potential innovation and improvement of new compounds of medical value. Bibliography ‘Apple Pectin Medicinal Uses’, n.d., viewed 16 July 2011, Canga, GA, Martínez, FN, Sahagún, AM, Vieitez, GJJ, Liébana, DMJ, Pardo, CAP, Robles, CLJ & Vega SM. 2004, ‘Glucomannan: properties and therapeutic applications’, Nutr Hosp. Jan-Feb;19(1): pp45-50. Chow, K.W. & Halver, J.E. n.d., ‘Chapter 5. Carbohydrates’ viewed 16 July 2011, How Do Carbohydrates Benefit The Body? 2006, viewed 16 July 2011, Nishinari, K., Takemasa, M., Zhang, H. and Takahashi, R 2007, ‘2.19 Storage Plant Polysaccharides: Xyloglucans, Galactomannans, Glucomannans’ Elsevier Ltd. pp 615. viewed 16 July 2011, Schepetkin, IA and Quinn, MT, 2006, ‘Botanical polysaccharides: Macrophage immunomodulation and therapeutic potential’ International Immunopharmacology 6, Elsevier ltd. pp317– 333. Sutherland, I. W. 2002, Vandamme, E. J., (Ed..) ‘Polysaccharides from Microorganisms, Plants and Animals’, In: Biopolymers, Vol. 5, Polysaccharides I: Polysaccharides from Prokaryotes. Weiheim Wiley pp. 1–19. ISBN 978-3-527-30226-0. ‘The Chemistry of Carbohydrates Found in Food’, n.d, viewed 18 July 2011, Tzianabos AO. 2000, ‘Polysaccharide immunomodulators as therapeutic agents: structural aspects and biological function’. Clin Microbiol Rev; 13:pp 523– 533. Wang SY, Hsu ML, Hsu HC, Tzeng CH, Lee SS, Shiao MS, et al. 1997, ‘The anti-tumor effect of Ganoderma lucidum is mediated by cytokines released from activated macrophages and T lymphocytes’. Int J Cancer;70: pp 699– 705. Wasser SP. 2002, ‘Medicinal mushrooms as a source of anti-tumor and immunomodulating polysaccharides’. Appl Microbiol Biotechnol;60: pp258–74. Zamora, A. 2011, ‘Carbohydrates’ viewed 18 July 2011, . Read More