Plant Chemistry

David Pirie a lecturer from Napier university had come in as a guest lecturer to RBGE, for the first class of the new semester and the New Year, to discuss with us the long, complex and sometimes rather questionable chemistry of plants.

We didn't look at the extreme levels of chemistry involved as they are far too complex and each small segment would require hours of explanation before the next link in the chain could be added and examined.

What is the chemistry of plants? According to scientists, the chemistry of plants is the be all and end all of what a plant is and will be. There is no more. Is this true? What goes beyond the boundaries of science?
In indigenous tribes, the scientific chemistry of plants is not known, the spiritual healer treats a patient through an identification of a mis-match in their vibrational energy, and in turn finds the correct vibrational energy in a botanical to put their body back in tune. Knowledge of which herbal medicine to use, how to use it, what its for - is all passed down through ancient knowledge and tradition. This process is older than the indepth examination of the active components of plants, and therefore should be taken into consideration. However, there is no scientific evaluation of exactly what's going on within the body, how each component within the plant is acting, and therefore there is no table of results - each patient is different, and because of that there is a value of doubt as to whether the herbal medicine will work or not, or whether there will be any adverse effects.

So what does the knowledge of the chemistry of plants do? It helps us identify what plants to use and what not to use. How the plant interacts within the body and how it involves itself withint the cells, how the plant breaks down within the body, how it subsequently moves through the system and its resulting half life - this in turn gives us the information we need to apply the correct dosage.

William Withering, a 19th century, English physician, used alcoholic tinctures of Digitalis, the foxglove, to help cure a failing heart. Without the scientific proof that Digitalis could work, or that it is now classified as poisonous, Withering used the drug. Using the whole leaf he made an alcoholic tincture, which he gave his patients in small controlled doses - he would give the tincture daily, slowly increasing the dose until the patient would be physically sick or on the verge of. This is the first symptom displayed by the body showing that the dose has become too high and has therefore become toxic to the body. Once this point has been reached that is the dose that is specific for that particular patient.
The sub-emetic dose, the dose that causes nausea, will reduce as the patient gets better - the body proves it needs less of the herbal remedy as the situation improves.

In Herbal Medicine many lifestyle details are required as lifestyle can vary the remedy and therefore vary the dose of herbal medicine needed.

St John's Wort

St John's Wort is a good example for why knowing the chemistry of plants is useful in Herbal Medicine, as mixing pharmaceutical medicine with herbal medicines can be dangerous.

Serotonin, known as the "Happiness Hormone", is one of the body's natural mood levelers. During periods of depression, patients may be prescribed anti-depressants, these are normally a form of serotonin booster e.g. SSRI's (selective serotonin reactive inhibitors) - however a herbal variety of a serotonin booster is St John's Wort. If over the counter St John's Wort supplements (which are usually 50% stronger) are mixed with anti-depressants, this can cause what is generally referred to as "Serotonin Symptom" - an overdose of serotonin essentially, which causes too much stimulation, the patient becomes manic - with heart palpitations, dilated pupils etc, this can eventually lead to a heart-attack.

Robbie Williams was known to have said that his "brain swims in serotonin" - when he was younger he used to consume ecstasy, which causes momentary serotonin "highs", however, the high is so extreme that a huge depression follows (similar to bi-polar disorder).

One note with St John's Wort is to not consume supplements with the contraceptive pill. St John's Wort has the ability to speed up the chemical pathway in the liver - which is involved in the breakdown of drugs - making the drug(s) taken less effective. It would also mean that drugs of a narrow theurapeutic range - ones that are very dose specific - have an increased secretion rate from the body, reducing their overall effect. However evidence has proven that this side-effect is only caused when specific elements of St John's Wort are taken seperately from each other, hypericin is the most abundant chemical in St John's Wort - it effects the serotonin levels in the brain and increases liver function, however hyperforin, the next most abundant chemical in St John's Wort - effects other neurotransmitters and enzymatic pathways in the liver, decreasing the speed of the overall process. Proving that the consumption of the whole plant has a neutral effect on the liver - and has been routinely prescribed in Germany, and there has been no record of pregnancy when consumed with the contraceptive pill.

The whole plant is greater than the sum of its parts.

Proven in the case of diuretics, which force the kidneys to expel more water, which causes a potassium loss, which is needed throughout the body. Dandelion and Nettle are strong diuretics, however, they are high in potassium so as to equalise their effect.

A knowledge of chemistry also helps to decide how to take a Herbal Medicine and in what form. Certain chemicals have an affinity for specific substances - water, oil, alcohol - how should we make our medicines? What base should be used?

Callendula resins are extracted poorly in water, however, well in alcohol (90%).

Comfrey leaf (which is high in carbohydrate) is extracted poorly in high alcohol, so using a 25% alcohol to 75% water base works best.

The 19th century medics drew on Greek knowledge, Culpepper, North American influences, and the scientific knowledge of the day to make their herbal remedies - one said (Thurston): "use 45% alcohol all the time as it is the optimum for the whole plant".

The problem with scientific analysis of herbal plants, botanicals can get banned from use because the most abundant chemical within the plant is seen as dangerous - this is a limited view, as in herbal medicine the whole plant is used, not the chemical constituents. The root "cara cara" has been banned from use (as have others), the most abundant chemical constituent was purified and tested on rats, there was a high percentage of deaths, which means no human testing was done - the reason for the deaths was linked to liver failure. The whole plant was then labelled toxic not the individual chemical constituent, which stops its usage within herbal medicines - when extracted in water and added to coconut milk (as its lipophylic), the root has a mild, physical calming effect, and more importantly, its non-toxic.

Primary Metabolites are essential for plant life.

Secondary Metabolites are extra chemicals that the plant creates for its own use, and in turn for ours, however they are not essential.

In basic photosynthesis, hundreds of chemicals are used and made, not all of which are necessary for the plants survival.

Primary Metabolites are necessary for basic survival and propagation - anabolic and catabolic pathways, assimilation, respiration, transportation, differentiation. They are common to all plants - phytosterols, acyl lipids, nucleotides, amino acids, organic acids etc.

Secondary Metabolites are less essential by products of the primary metabolites. Energy usage is critical to a plant, excessive usage can be detrimental, so why does the plant produce non-essential chemicals? The secondary metabolites are diverse within the plant kingdom (concept from Kossel 1891), they are what gives the plant colour, flavour and smell. We use them as phytomedicines, drugs, insecticides, dyes, flavourings and fragrances.

Plants used secondary metabolites as a defence against pathogens and predators - bacteriocidal, repellent, poisonous, colourful, warning etc, as an attraction to encourage fertilisation and dissemination, signalling function through plant hormones, protection against the environment e.g. free radicals, UV light etc.

Nettles produce a secondary metabolite called formic acid, which they use as a protective substance in their sting (stinging ants alos produce this substance) - dead nettles pretend to be stinging nettles for protection.

The oak gall is a form of protection for the oak, resin based it is anti-bacteriral and used to stop infection if the tree sustains a wound.

The passion flower produces secondary metabolites that produce its attractive colouring, the plant also produces alkaloids that in a herbal medicine have an effect on the nervous system, helping to calm it and it aids sleep.

Other botanicals have been known to create fake "caterpillars", and speckle their leaves with white spots so that it appears that to other butterflies that this plant is already full of developing larvae.

Secondary metabolites: acids, carbohydrates, glycosides, isoprenoids and terpenes, phenols, amines and rubber polymers.

Acids are found widely in the plant kingdom, usually very weak chemical structure, they have a particularly sour taste and become alkaline after ingestion; they are generally cleansing to toxic states, anti-septic, however they can irritate. Examples are: formic acid, acetic, citric and oxalic, found in rhubarb. Essential fatty acids are also another form of acid, the reason they're called "essential" is because our bodies cannot manufacture the fatty acids. Acids can also correct mis-balances of oils in the body, displayed through inflammation.

In the diet, the consumption of vegetable and sunflower oils should be decreased, while fish, hemp, flaxseed and evening primrose oil should be increased as the oils are lighter. Olive oil is a more stable oil and is better to fry foods with.

Carbohydrates are made of sugar molecules: mono, di and poly. They are mucilagenous, demulcent and emollient e.g. comfrey, slippery elm and marshmallow. They reduce inflammations, especially in ecto-based cells such as the GIT (gastro-intestinal tract), lungs and the urinary tract - all of which have very soft, absorbant linings and therefore have similar reactions. Carbohydrates are also used in modern cancer treatments in the form of immuno-stimulating echinacea, calendula and daisy. They also provide pectin and fibres to the body.

Phenols are based around phenol rings, there are thousands of these - they are a very diverse range of molecules. Phenols includes: salicylic acid (found in the inner bark of willow trees and meadowsweet), tannins, coumarins, flavonoids, anthaquinones (found in botanicals such as rhubarb and dock - causes a laxative action, similar to aloe vera), they are the base for flower and fruit pigments and found within many families. Phenols have many medicinal properties i.e. cardiovascular, antioxidants, antiseptic. The salicylic acid found in willow, birch and meadowsweet (mainly the leaf and flower) are anti-pyritic and anti-inflammatory which can help with ailments such as arthritis. Phenols are also analgesic - some of the by-properties of aspirin are that it irritates the digestive tract, whereas herbal remedies don't. On a spiritual level, it is said that if you're stiff and stuck in a rut, you should take willow as it will help move you along.

Tannins are precipitating proteins, they astringe, bind and heal inflamed tissues. They are mildly antiseptic, they can form eschar's (a new skin layer over external or internal (ulcers) wounds to allow for healing). They can be found most concentrated in bark and dead plant parts - tea, oak bark (external bark), witch hazel (do not take internally) and within the rose family (hawthorn, agrimony), however, there can be problems with absorption of foods in the GIT with overuse e.g. strong black tea causes mucus membranes in mouth to curl up and bind together, a pucker effect, this has the same effect in the GIT, however adding milk to tea reduces the effect of the tannins. Tannins are well known for binding proteins to create leather.

Anthraquinones stimulate peristalsis in the GIT, they are also used as dyes - yellow dock (mildly stimulating in the liver), aloe vera, rhubarb root, senna pods (cassia). They are usually given with carminatives (celery seed etc), they take around 10 hours to have an effect. If the faeces become "stuck" in the GIT, it can cause constipation, which is when re-absorption of water and toxins happens within the GIT as long as the faeces remains there, this can lead to a toxic overload, and if the GIT muscles are over-stimulated this can lead to them "knackering out". Consuming herbs high in anthraquinones when pregnant is not recommended, as these herbs are downward stimulating.

Volatie Oils are chemically structurally based on isoprene C5H8 group. Volatile oils are responsible for plant fragrance, they are generally responsible for affecting mood, either stimulating (rosemary) or sedating (valerian). They are antiseptic, antibacterial, antifungal (e.g. sage), can irritate internally and externally, they dissipate readily and are used extensively in aromatherapy.

Saponins are soapy when put into water, such as soapwort, they are regarded as having a subtle sweet taste, and have been used as arrow poisons in the past because of their ability to cause lysis of the red blood cells. Saponins are structurally closely related to cholesterol, steroids, hormones, vitamin D, hormonal balancers (e.g. wild yam) and hormonal contraceptives. They are also anti-inflammatory (liquorice) and are used as immune tonics (astragalus), and in traditional chinese medicine they are used within "King Remedies" (ginseng). Saponins are broken down within the GIT to make them non-toxic.

Red clover - pea family - is soapy when put in water. It has a estrogenic effect in the body, there are therefore potential problems with breast cancer (in patients it has been noted that this usually shows higher levels of estrogen). However in a herbal remedy, it has shown that it can be good in both excessive and deficiency states, as it provides a weaker estrogen which, in excessive states, will bind to estrogen receptors and stop stronger estrogen binding, whereas in deficiency states it provides general estrogen levels to the body.

Glycosides are made up of sugar molecules and active components, such as cyanogenic glycosides, cardiac glycosides, saponins, flavones, tannins, anthraquinones etc. They are found in many families, sometimes poisonous, and have many differing medicinal properties depending on the active components. Cardiac glycosides are derived from foxgloves (no longer used), lily of the valley, limeflower and hawthorn. They are negatively chronotonic and positively contractually - making them great aids for the heart.

There have been over 3000+ Alkaloids identified, they have nitrogen groups and are often poisonous. They are found in the Solanaceae family, legumes, rubiaceae and fungi. They effect the nervous system, similar to caffeine, nicotine, cocaine, morphine, quinine and ephedrine - ephidra is not good for the heart, but is used for coughs and asthma. They stimulate the central nervous system activating a mini fight and flight mood, they also cause broncho-dilation which makes the patient feel alert, awake and providing significantly more blood to the muscles.

Tropane alkaloids occur predominantly in Solanaceae family members, in the components hyoscyamine and atropine, in such botanicals as Datura, Atropa belladonna and Hyoscyamus. Some of the post-ingestion symptoms may include: reduce salivary and sweat secretions, spasmolytic, seduce motor activity in GIT, menstrual cramps, anticholinergic, para-sympathetic depressant.

The White Poppy is the most potent.

In Traditional Chinese Medicine, there is a lot more tied in than just problem and solution.

In TCM, organ problems are related to elements, to seasons, to emotion and to taste, they're also inter-related in a family-like chain.

Hence why in family meals, there are meals related to each of the five tastes noted in TCM, this is to make sure each member of the family has a balanced meal, and therefore is in good health.

The five tastes are: sweet, salty, bitter, sour and pungent - astringent can also be seen as a sixth taste.

Sweet tastes are found in cereals, peas, cooked root vegetables and fruit. They provide carbohydrates and saponins to the body. Sweet tastes relate to the spleen, providing a cooling quality; they are also linked with the earth and so therefore provide nourishment to the body and soul, they are used to tonify and balance. They aid the heart, however in excess can damage the kidneys.

Salty tastes are found in seaweeds. Mineral tastes are also included within nettles and horsetail. They relate to the kidneys, providing a heating quality. Salty tastes moisten and soften by drawing water to them and are therefore good for swellings and tumours. They assist the kidneys, however in excess can damage the heart.

Bitter tastes are found in dandelion root and yellow dock, for example, they provide the body with alkaloids, volatile oils and phenols. In TCM bitter tastes are related to anger, they effect the heart primarily, but also have an effect on the liver, heating it up, which circles back to helping the heart and providing a cooling quality. Bitter tastes are used to sedate, dry and harden; they stimulate digestive secretion, by overall aiding the liver and digestive tract. However in excess they can damage the lungs.

Sour tastes, found, for example, in yarrow, provide the body with acids and tannins. They aid the liver, providing a heating quality. They are used for absorbing and binding, making them good for discharges, inconsistency, perspiration and loss of fluid through premature ejaculation and excessive menstruation. They help to tonify the lungs, however, in excess can damage the spleen.

Pungent tastes are found in hot spices, they help to open pores and vessels. They aid digestion, providing a heating quality. They help to dispense and liquefy (esp. hot curries), they are often used to treat colds by encouraging the production and movement of phlegm, they are also usually anti-bacterial, anti-microbial and anti-septic. They are used to aid the liver but in excess can also damage the liver.

Even from the base description of the five tastes, you can see that each interlinks, what can damage one will be aided by another.

With this, David, over-viewed the hefty topic of plant chemistry, delving briefly into the depths, and concluding on the mind-tangling traditional Chinese herbal medicine, with its own history and style.

Linking Botanicals - Latin names, Common names, Parts used and main constituent.