Carbohydrates - Mucilages

Question 1

What are mucilages?

Answer 1

Mucilages are large structures of many different sugar and uronic acid units.
Tinctures are not appropriate (too viscous) with the exception of use as reflex demulcents.
* Topical emollient for the skin.
* Internal demulcent for the mucous membranes.

They are:
* Hydrophilic
* Soothing, healing, emollient for skin and mucous membranes
* Some have immunomodulating polysaccharides e.g. arabinogalactans from ribwort plantain which gives it interesting actions.
* Beta linkage not broken down, partly decomposed by flora into short chain fatty acids (SCFA)

Question 2

What are the digestive effects of mucilages?

Answer 2

• They are often called bulk laxatives as they increase stool weight e.g. psyllium husks or seeds (Plantago psyllium or P. ovata), slippery elm, flaxseed and fenugreek (Trigonella foenum-graecum).
• They are also often used as weight loss agents as they can give a feeling of fullness - they can lead to an obstruction if not taken with plenty of water
• Prebiotic
• Lower blood cholesterol, LDL and insulin after eating (retain glucose in the gut)
• Plantago major leaves against aspirin-induced gastric ulcer (in vivo).

Question 3

What are some mucilaginous plants?

Answer 3

Other mucilaginous plants
* Other mucilaginous plants include slippery elm, marshmallow, comfrey, flaxseeds
* Slippery elm: swells to many times its original volume. Partially digested, prebiotic = great for dysbiosis. Nutritive (SCFAs from bowel flora breakdown of soluble fibre)
* Heteropolysaccharides can also be classified as gums, pectins, arabinogalactans, arabinoxylans, and glucomannans.

Question 4

What are the relflex actions of mucilages (coughs etc)?

Answer 4

Reflex action of mucilages
* Mucilages are too large to be absorbed - but they are helpful for coughs
* Effect is thought to be via the sympathetic soothing action on the vagus nerve.
* Similar effect on urinary tract.
* Antitussive activity of marshmallow root in vivo: serotonergic receptors involved.

Question 5

What are carbohydrate derivatives?

Answer 5

Carbohydrate derivatives: organic acids
* Citric acid, ascorbic acid, formic acid, oxalic acid are derived from monosaccharides
* Ascorbic acid (with flavonoids): antioxidants, involved in collagen synthesis, supports capillary integrity, essential for the synthesis of CNS neuromodulators and hormones

Question 6

What is Oxalic acid?

Answer 6

Oxalic acid
* Binds mineral ions, especially calcium, magnesium and iron, reducing their bioavailability in foods.
* Calcium oxalate forms kidney stones.
* High amounts of oxalic acid are toxic, e.g. yellow dock leaves (root is low in oxalate).
* Thorough boiling breaks it down.
* A diet low in oxalate and/or a calcium intake normal to high (800-1200 mg/day) reduces urinary excretion of oxalate.

Question 7

How are Stinging nettles useful re acids?

Answer 7

Stinging nettles
* Contain organic acids, neurotransmitters/inflammatory modulators (histamine, serotonin, acetylcholine)
* Formic acid, histamine combination in hairs causes inflammatory reaction in stings
* In vitro: inhibit mast cell degranulation, prostaglandin formation and other inflammatory processes
* * Anti-inflammatory compounds, include flavonoids and phenolic acids.

Question 8

What are glycosides and how are they classified?

Answer 8

Glycosides
Glycosides
1. Sugar moiety = glycone
2. Non-sugar moiety = aglycone/ active portion.
Mostly soluble in water, though
aglycones are less soluble.

Classification of glycosides
* Cyanogenic glycosides (Rosaceae)
* Cardiac glycosides (Scrophulariaceae)
* Phenylpropanoid glycosides (Scrophulariaceae, Asteraceae)
* Anthroquinone glycosides
* Flavonoids (free or as glycosides) (Asteraceae)
* Glucosinolates (Brassicaceae)
* Iridoid glycosides (bitters)
* Anthocyanins (Malvaceae)