Plant Constituents and Herbal Actions, Fall Primer 2022

Let’s combine the science of herbs with herbal traditions and lots of  heart.

Sounds like a pretty good recipe, right?

Here’s some of the science ingredients! I encourage you to take in what you can for now and leave whatever you need to for later.

Plants contain complex arrays of phytochemicals, also known as secondary metabolites, or constituents.

The composition and concentration of these phytochemicals can aid the plant in attracting pollinators, defending itself from predators and disease, and to communicate (yes, even with us!). The composition and concentration of phytochemicals fluctuate according to climatic and environmental conditions, season, stage of growth, and other factors.

It is helpful to know what some of the phytochemicals are to understand the function they serve and the effects they have in our bodies. However, we want to avoid reductionist thinking! The uniquely combinations of constituents in each plant are synergistic, working together to create something more powerful than any one constituent can on its own. Therefore,  herbalism does not just seek to isolate specific phytochemicals because we see the plant as a whole, not the sum of it’s parts. 

Unfortunately, if you look at the majority of research on herbal medicine, it is typically limited to studying individual constituents, often in amounts or preparations that are contrary to their use in herbalism. In “standardizing” herbs, effectively turning them into “drugs”, research fails to consider the way the constituents complement and amplify each others effects. It also fails to consider how our bodies respond to whole herbs much differently than a single constituent. It’s like trying to make a great tasting chickens soup from just chicken breast and water. It’s the vegetables, herbs, salt and fats and broth that make it taste good and provide optimal nutrition. Just like some vitamins need to be consumed with a bit of oil to be fully utilized in our body.

Don’t worry if the constituent part is unclear at first-it will come into focus as we learn. AND it’s just one part of what we will be learning about when it comes to plant medicine.


Again, these are just a few examples of constituents that contribute to the herbal actions we just covered.

I don’t want you going cross-eyed but I do want you to start putting the pieces together.
Why? Because when we know about the constituents and how well they dissolve, or IF they dissolve  in things like oils, alcohol or water, we can use that knowledge to make EFFECTIVE plant remedies!


Alkaloids have extremely diverse and specific actions. Alkaloids can be used to reduce pain, relax muscles, and as sedatives or nervous system tranquilizers, and are often antimicrobial. They can be very powerful constituents, and some can be poisonous or fatal in high doses. They almost always end in “ine”…You may be familiar with these alkaloids: nicotine, caffeine, cocaine, morphine. You might want to get to know these: berberine, hydrastine, quinine, gamine, avenine, stachydrine. Especially the berberines…they are an important part of the medicine in Oregon grape root (Mahonia nervosa). Good to know, right?

You are going to learn to make the best medicine with the following information:

Most alkaloids are soluble in ethanol and much less so in water- the pH of the solution influences the solubility of alkaloids. Berberine is quite soluble in water though.

Alkaloids become more water soluble in acidic solutions. They are highly crystalline and the introduction of an acid will convert alkaloids to alkaloidal salts which are easier to dissolve and they become more bioavailable in solution. Conversely, in general, alkaloids are more oil soluble in high pH (alkaline) solutions. Which just goes to show you that plants definitely have a sense of humor. Oh plant medicine, you are so silly!

A good ratio for most tincturing of alkaloids is 55 alcohol/35 water/10 vinegar. In folk medicine this means just use 100 proof alcohol with a splash of apple cider vinegar!


Phenols are very large class whose actions vary widely.  Phenols are often inflammatory modulating and antiseptic, they can also have anti-viral or anti-microbial properties. Phenols vary in structure and range. Wintergreen and willow contain salicylates which our body converts to salicylic acid (a precursor to aspirin).  Some classes of phenols are: Polyphenols, Flavonoids, Anthocyanins, and Coumarins. Phenols are primarily soluble in water. Also soluble in vinegar, honey, oils and alcohol (to a lesser extent).


These are a type of carbohydrate. Long chain sugar molecules are so large that they san not be absorbed into the bloodstream, therefore they have low bioavailability. However they can have powerful effects throughout the body by way of the digestive system. Polysaccharides such as inulin are prebiotic and support a health gut microbiome. Many polysaccharides are immunomodulating. They are primarily water soluble (some require a lengthy simmer to extract) and are not alcohol soluble.


is a polysaccharide that has a slippery, demulcent feeling that is soothing to tissues and protects the mucosa that lines our gut, respiratory, urinary and reproductive organs and is a vital part of our innate immune response.Mucilage can take up water up to 200 times of its weight in water and form a gel. Plant examples include plantain, oats, comfrey, marshmallow, mullein, cinnamon, and peach leaf. Mucilage is primarily extracted with cool water over time. Tannins and alcohol can bind up mucilage and render it ineffective. 


Herbal Actions

“Actions”  are the effects that herbs can have on a person’s body,  the way the body responds to the herb, and how they alter or support physiological or psycho-spiritual processes.  Herbal actions are not a “use” for herbs or what an herb is “good for”. Actions are also technically not “anti-anything” although it can be hard to avoid using that word.

Learning the language of herbalism can seem daunting at first. Lots of new vocabulary and ways of thinking about plants and health! Be patient with yourself, the understanding will come! For those of you who have broken in your boots on the herbal path, hopefully this will be a useful refresher or a new way of thinking about these terms! If you have struggled with understanding herbal actions  in the past, I have tried to make the explanations a little more concrete with examples, including a type of constituent (plant chemical)  that helps to bring about that action.

These are some terms that will be useful for you to learn in this Fall Primer. There are more but we won’t try to learn them all at once. Let’s just focus on these  first!

Diaphoretic- dilates capillaries on surface of skin, may increase circulation and stimulate elimination through sweating. An herb that has a diaphoretic action may make us feel warm-even if it’s not changing our temperature. Many constituents can produce this action and often aromatic or pungent herbs are diaphoretic. The alkaloid adenine in yarrow contributes to this action in that plant. Ginger (Zingiber officinal)  is a common herb that you may have experienced this effect with. Capsasinoids (found in chile peppers) can also produce this effect! Just the thing when you start to feel an illness coming on. As in let’s get the party over with before it gets too out of control. Buzz kill for viruses!

Inflammation-modulating – inflammation is a natural and helpful reaction to an injury or infection, it is part of our immune system’s response. It works by bringing increased blood supply to area to begin healing. Swelling can stabilize the tissues as well as speed healing by increasing the amount of blood and fluid to the area to remove waste. It can sometimes be necessary to support the body in modulating the inflammatory response, and relieving too much swelling, especially if it is causing the body to be out of balance and creating new problems.  Many different types of constituents can contribute to this action. Resveratrol, a phenol, is an example of a constituent that  been shown to reduce inflammation. There are SO many plants that can produce this action in the body. Celery seed (Apium graveolens) is one you probably have in your kitchen!

Antimicrobial– though not a true “action”- many herbs are shown to be antimicrobial, meaning the herb may (or may not) directly kill a pathogen (bacteria, virus, fungi, or protozoa are examples of pathogens). Sometimes an herb works in this way by increasing the body’s resistance to a pathogen or causing a change that makes the body more inhospitable to pathogens. Phenols (including antioxidants), volatile oils, resins, and alkaloids are just some examples of constituents that have antimicrobial actions. Examples of herbs that are antimicrobial include thyme (Thymus vulgarus), and Oregon Grape Root (Mahonia spp.)… BUT they cannot be used indiscriminately. You need to know the type of pathogen you are dealing with and the proper way to use them. Some need to have direct contact with the tissue that is infected (antiseptic), others can enter the blood stream. One of the really wonderful things about herbal anti-microbials is that they do not typically have the side effects that drugs like conventional antibiotics do. In fact, much research is demonstrating the effectiveness of herbs on inhibiting and even destroying biofilm formation and killing multi-drug resistant bacteria such as MRSA. I know, right?!

Expectorants-help to excrete excessive mucous. Think “excrete”. They can be stimulating by irritating the bronchioles and thus producing a cough-helpful for when there is a lot of mucous that’s moist but not moving up and out. This can be due to the presence of constituents such as resins and saponins (Elecampane is a good example). Expectorants can also be relaxing, such as when mucilage soothes the membranes or volatile oils relax smooth muscle-useful for an unproductive or spasmodic cough. Mullein in a good example here. Could be combined with an anti-catarrhal herb to thin sticky mucous.

Anti-catarrhal or mucolytic- Think “too much mucous”. This one is not much used by modern herbalists, but I think it should be and so I am including it. Mucous is good! It is a primary component of our immune system. But too much of it is sometimes not a great thing, especially if the mucous is thick, stuck, or causing a great deal of inflammation.  Anti-catarrhals work to thin mucous so it can be more effectively excreted. Plant Aromatic resins, pungent herbs such as ginger or garlic are examples of this action. And anti-catarrhals can also work to reduce excessive excretion. Tannins can produce both effects. Pretty neat

Cholagogue -stimulates the flow of bile from the liver and or increases the amount of bile produces in the liver or pancreas. Hepatics are herbal remedies with a wide range of liver support. Bitters and cholagogues all act as hepatics to some degree. Examples of herbs include dandelion (Taraxicum offiinale), Oregon grape root (Mahonia spp.), and motherwort (Leonurus cardiaca).

Nervine – produces a positive effect on nervous system. Nervines can relax, stimulate or restore damaged nerves. Many nervines are aromatics, polyphenols and/or alkaloids. Some nervines can have an especially relaxing effect, such as sedative or hypnotic nervines that can make you sleepy such as hops (Humulus lupulus). Nervines can also relieve pain, such as St John’s Wort (Hypericum perforatum) or Sitka valerian (Valeriana sitchensis).

Antispasmodic or Spasmolytic-relaxes smooth muscle to reduce cramping and spasms. Some alkaloids can have this effect as well as cyanogenic glycosides like prunasin in wild cherry (Prunus serotina, et al.) or the volatile oils in fennel.

Astringent– decreases permeability of skin and mucous membranes, and reduces secretions. Tannins (the primary constituent that elicits this action) bind to and precipitate proteins, thereby tightening, toning and strengthening tissues. Although the feeling astringency produces may be one of dryness, it can have the opposite effect, actually helping the body to retain moisture. Used excessively or over long periods of time, it can cause dryness so this action should be used judiciously. Or balance out their use with demulcent herbs (see below). Examples of herbs with this action include willow (Salix spp.) and hawthorn (Crataegus spp.).