Gums And Mucilages
Mucilage is a dense, sticky substance that is made by almost all plants and also by a number of microorganisms. Basically, mucilage is a polar glycoprotein as well as an exopolysaccharide. In plants, mucilage has an important role in storing water as well as food, germination of seeds and also the congealing the membranes. Flax seeds as well as cacti (including other succulents) are exceptional mucilage sources.
In fact, exopolysaccharides happen to the factor that stabilizes most, especially in the case of micro aggregates. Exopolysaccharides are extensively disseminated in soils. Hence, as far as the world’s soil ecology is concerned, ‘soil algae‘ that produces exopolysaccharides have a very important function. This substance actually overlays the external part of, for instance, filamentous or unicellular green algae as well as cyanobacteria. Among different types of green algae, the group known as Volvocales is particularly known to make exopolysaccharides during specific phase in their entire life cycle. In fact, this happens nearly in all plants, but generally in very less proportions. Often, production of exopolysaccharides is related to substances such as alkaloids and tannins.
In a number of carnivorous plants, mucilage is produced for a particular purpose. For instance, plant genera Pinguicula, Drosera (Sundews) and some others produce leaves that are packed with glands that discharge mucilage and these plants also possess ‘flypaper traps’ which they use to ensnare insects that come close to them.
Mucilage is safe for consumption and is also used in medications, because it possesses demulcent (soothing) attributes. Customarily, people made marshmallows using the extracts of marshmallow plant’s (botanical name Althaea officinalis) roots, which are mucilaginous. As the extract of these roots possess demulcent properties, they are used in the form of a cough suppressant. Since long people have been using the internal bark of the slippery elm plant (botanical name Ulmus rubra), a species native to North America, in the form of a demulcent. Even now, the bark of this tree is used commercially to make the demulcent for suppressing cough and other medicinal uses.
Often mucilage is blended with water to prepare glues, particularly those that are used to bind paper items like postage stamps, labels and also envelope flaps. There are a variety of mucilages that have different strengths and they can be used to prepare different types of adhesives for dissimilar applications, such as using as adhesive for wood to china, labels to metal cans and even leather to pasteboard.
When natto soybeans are fermented, the bacterium Bacillus natto produces extracellular enzymes that react with the sugars in the soybean to make mucilage. The quantity as well as the glueyness of the mucilage is vital attributes of natto and they contribute to the exceptional aroma and flavour of natto soybeans.
Mucilage produced by two different insectivorous plants – butterwort (Pinguicula) and sundew (Drosera) is employed for producing the traditional Swedish dairy product known as filmjölk, which has some resemblance with yoghurt.
In addition, mucilage may also be used for treating gastrointestinal inflammatory processes, especially those caused by external irritation agents. Mucilages work by covering the mucous membranes, thereby protecting the nerve endings from any type of irritation.
It has been found that several plants produce and contain comparatively larger concentrations of mucilage than what is found in majority of the plants. Some of the plants that contain higher levels of mucilage include:
- aloe vera
- Malabar spinach ((botanical name Basella alba)
- Irish moss (botanical name Chondrus crispus)
- Drosera (sundews)
- Dioscorea opposita (Chinese yam nagaimo)
- Drosophyllum lusitanicum
- flax seeds
- licorice root
- husks of psyllium seeds
- pinguicula (also known as butterwort)
- bark of Ulmus rubra (also known as slippery elm)
- seeds of salvia hispanica (also called chia)
Natural gums are basically naturally occurring polysaccharides that possess the aptitude to greatly increase the viscosity even when very small amounts of them are added to solutions. These gums are employed by the food industry in the form of congealing agents, emulsifying agents, gelling agents and even as stabilizers. They also have use in other industries, where they are used in the form of binding agents, adhesives, clarifying agents, crystan inhibitors, flocculating agents, encapsulating agents, foam stabilizers, swelling agents and so on. Very often they are present in the wooded parts of some plants and also in the seed coatings of a number of plants.
Disintegration of the internal tissues of a plant results in the formation of genuine gums. In most cases, these gums are formed due to the breakdown of the cellulose during a process known as gummosis. These true gums enclose elevated levels of sugar and have a very intimate relation with the pectins. These gums are basically colloidal (mixtures) and also dissolve in water – either they are completely soluble in water or they swell up when added to water. However, the genuine gums do not dissolve in ether or alcohol. They naturally exude from the stems or when the plant is injured. The commercial variety of the gums is available in the market as dehydrated exudations. In fact, gums occur more often in plants growing in arid regions. Mostly, these gums are used in the form of adhesives and sometimes they are also employed in printing as well as finishing textiles. In addition, sometimes these gums are used in the form of sizing for paper, in candy manufacturing units, paint industry and also in the form of drugs. There are three main types of gums from plants and they are known as gum Arabic, karaya gum and gum tragacanth. These three types of plant gums are described briefly below.
Gum Arabic: It is a dehydrated gummy resin or secretion that is got from the plant Acacia Senegal as well as other related species. These small trees are indigenous to the northern region of Africa and people in Sudan cultivate them extensively. Generally, the gum of these trees is extracted during the period between February and May after the fruits have matured. The incisions are made in a slanting way using a small axe, tearing off the slender stripes of the barks. As a result of this, the gum slowly seeps out of the places where incisions have been made in the form of a sticky liquid and is collected in small pots where it solidifies. Normally, the gum, also known as ‘tears’, is collected for about three to eight weeks after making the incisions on the trees. While the sunlight helps to bleach the gum, all dirt is eliminated prior to marketing it.
Available records show that people in Egypt used gum Arabic way back in 2,000 B.C. In Sudan, people traded the gum as early as 100 A.D. Various types of gum Arabic are available in the markets across the world. While the variety known as Hashab or Kordofan gum was exported from the Port Sudan and Cairo, the gum variety known as Senegal gum has its origin in a place located in the northern part of the Senegal River. Gum Arabic dissolves very slowly, but totally in cold water. The viscosity and adhesiveness of this gum is of very high degree. This gum is mainly used by the textile industry, the confectionery industry, in the form of mucilage, in pastes, polishes and also in the form of a shiny finish in painting. Gum Arabic also has medicinal use and is employed in the form of an emulsifying agent as well as in the form of a demulcent (a soothing substance).
Gum Tragacanth: This gum forms when the pith plus medullary ray cells convert into a mucilaginous (a glue like) substance that secretes naturally or when the bark of the tree has been cut or damaged in some way. This gum is obtained from the tree called Astragalus gummifer and other species belonging to the same genus. Prior to collecting it, the gum is left to dehydrate on the bark of the tree itself. It is available in the market in the form of ‘tears’ that are actually dehydrated natural resins or exudates; vermiform gum that comprise slender twisted strings or coils; and ‘flakes’ that are small pieces similar to ribbons. Majority of the marketable supply of this gum comes from Turkey and Iran. Generally, this variety of true gum is employed in calico painting as well as for other different industrial uses. In fact, gum tragacanth is among the oldest medicines and people have known its existence and used it for medical purposes as early as 300 B.C. In contemporary medicine, gum tragacanth is being used in the form of a glue for pills as well as troches. In addition, it is also used for suspension of powders that are not soluble.
Karaya Gum: This true gum has been employed in the form of an alternative for gum tragacanth. In fact, by the mid-1900s, many million pounds of this gum was imported from India every year. Karaya gum has a number of uses and is employed in the textile, cigar, cosmetic, ice cream and paste industries. This variety of true gum is got from a large tree called Sterculia urens, which is native to central India. In order to obtain the gum, small cuts are made in the heartwood and, as a result, the gum seeps out and collects in the form of big asymmetrical knobs. Subsequently, the gum is gathered, sorted out and arranged depending on its quality. Then the gum is taken to the market for trade.
Several other plants also produce gums that have commercial value. For instance, gum ghatti, which is got from a big tree indigenous to India as well as Sri Lanka and called Anogeissus latifolia. This gum is often used as an alternative to gum Arabic. The leaves of this tree are also useful and employed for tanning. Similarly, trees such as Cochlospermum religiosum and Feronia limonia that are native to India, Java and Burma also produce gums, which are also used as alternatives to gum Arabic. Cycas gum is obtained from the plant known as the Asiatic Cycas ciccinalis. Similarly, Ceratonia siliqua, or the carob (a tree found in the Mediterranean region), also yields mucilaginous semi-cellulose that is found in pods and known as tragasol. In North America, people obtain mesquite gum from the plants P. glandulosa, Posopis juliflora as well as other different species of the genus. Different species belonging to the Prunus genus yield a gum called the cherry gum.
The gums and mucilages are better known for their physical properties and though the first group can be referred to as being tacky and the second group slimy, there is no specific difference between the 2 groups. These are best considered when they are together and they are found to be together and in unison in plants.
The after effects of these constituents is not much chemical and it can be referred to as being physical. The gums and mucilages are made of
sugar derivatives and uronic acid and have no great pharmacological effect even if they are broken down in the process of digestion. The molecules only survive in the bowel. Plants containing them such as Symphytum officinale or comfrey, Plantago major or plantain, Ulmus fulva or slippery elm bark, Tussilago farfara or coltsfoot, Althaea officinalis or root of marshmallow all have effects of some sort on the urinary, respiratory and digestive system. Of course the effects on the last two namely, the urinary and respiratory system is quite far fetched.
When mucilages come in contact with a surface, they are covered with a coating that soothes the surface that is exposed. The mucilaginous plants work on remedies for wounds, to soothe itching, irritation and pain and also for drying and binding a tissue that is damaged. The action is referred to as being emollient or demulcent.
The demulcent action is continued in the lining of the digestive tract and this explains the remedies that mucilage bring for ulcers, lesions, inflammations in the gastrointestinal tract and for reducing the excessive acid secretions. The slippery elm powder, which is a very well known remedy for relieving dyspepsia due to acidity and also in the case of ingestion of food that is hard to digest.
The digestive tract is a neuromuscular organ that is vast and it is responsive and it is supposed to be the most complex organ in the human body with its own nervous system and a hormonal system and autonomy. Every minute response is passed on to the wall tract receptors and there is feedback from the actions that take place.
When there is an irritation in the small intestine, or in the stomach, following a diarrhea, there are the nerve endings in the lining and this leads to inflammation too. The symptoms of this irritation would mean dysphagia, a problem in swallowing, diarrhea, vomiting, regurgitation, flatulence, spastic bowel, colic, dyspepsia and also abdominal pain which is present mainly in children. The mucilages cause the irritation to get soothed and die down that the symptoms may be reduced. This is not a remedy but it helps to manage the trauma.
The mucilaginous remedies are also used in the urinary and the respiratory system. The mucilages do not reach these parts or organs of the body. There is some association between the urinary tract, the bronchial and the digestive tract as these are supposed to have a common origin and they have a common relationship with the respective supply of the nerves.
The mucilaginous remedies have properties that are soothing for the urinary tracts, the bronchial tissues, and acts as a comfort where there is vigorous coughing syndrome and they increase the bronchial secretions if they go dry and also in an asthmatic condition they help to reduce the spasms. Thus in asthmatic situation, there are symptoms of breathlessness and nervous coughing, this provides great help. In bladder infections or in urinary infections, they help to reduce colic pain due to stones. So it is looking into management rather than providing a remedy but these conditions bring in many cases where the approach may be very much useful.