Secondary Metabolites, Part II: The Alkaloids
Last week we talked about plant secondary metabolites and how important they are both to plants (to ensure their own propagation and safety). One of the most important classes of secondary metabolites for herbalists would be the alkaloids. When it comes to medicinal and/or psychoactivity, it’s generally the alkaloids that have the most noticeable effects on humans and animals. I knew I would see places where I was unclear (I think) after I posted. That is, unfortunately, something I’m still grappling with.
Alkaloid is a chemical category that will always contain nitrogen, specifically these nitrogen containing compounds are “amines,” Monoaminergic or catecholaminergic compounds are closely related to the activity of many major neurotransmitters like Serotonin (5-HT, the happiness neurotransmitter, also involved in perception), Dopamine (joy, pleasure, focus, motivation and reward/feedback) and norepinephrine (vigilance, wakefulness, focus, and fight-or-flight fueled energy) are major monoaminergic neurotransmitters. These monoaminergic or catecholaminergic compounds are vital to our body and brain’s functioning and affect mood, energy levels and more. Currently, accepted models of depression are based around the idea of imbalance or shortage of the primary catecholaminergic/monoaminergic neurotransmitters (serotonin, dopamine, norepinephrine, epinephrine).
So what exactly IS an alkaloid and why are they so important in the study of herbalism? The dictionary tells us an alkaloid is “any of a class of nitrogenous organic compounds of plant origin that have pronounced physiological actions on humans. They include many drugs (morphine, quinine) and poisons (atropine, strychnine).” So we get that they have medical application potential and physiological action, also potential toxicity.
It’s theorized that alkaloids, like the other secondary metabolites, are meant to perform the vital function of attracting or repelling other life forms in order to maintain their continued propagation and existence. In addition, however, it is believed that they may be able to serve as a secondary nitrogen source for plants to fuel themselves. Interestingly enough, certain types of animals have been known to seek out or forage for certain herbs and plant matter when they’re sick, self-medicating as it were. The technical term for this is Zoo Pharmacognosy.
The first alkaloid discovered was morphine, a by-product of Papaver Somniferum (the opium poppy). One concern with some alkaloids is the fact that, since they were often designed as a protective mechanism for the plant, they can possibly be poisonous. “Sola dosis facit venenum,” as Paracelsus, one of the fathers of Classical medicine put it, “the dosage makes the poison.”
Caffeine is the most widely used psychoactive in the world, it too is an alkaloid. The theobromine in cacao that is responsible for it’s energizing and mood lifting quality, also an alkaloid. Alkaloids are often well soluble, especially in honey, vinegar, alcohol, water (boiled or via steam percolation) glycerine or even vinegar. Honey and/or glycerine syrups, glycerine, vinegar or (more commonly) alcohol tinctures or simple teas are one of the best ways to extract the alkaloids from the plant we’re using.