Trigonelline, Stachydrine and Betonine, Betonicine and Choline are all alkaloids found within Betony. They are all called 'Betaines', a type of Zwitterion where a nitrogen or phosphorus atom has a positive charge. The negative counterpart is seldom shown - it could be any negative ion, usually the chloride ion since common salt, NaCl, is a ubiquitous source.
Choline Chloride is an example of a betaine with chlorine as the negative ion.
Trigonelline (N-methylnicotinic Acid, or Nicotinic acid betaine), is found not only in Betony, but also in
Oats, Coffee and Potatos amongst a few other plants. Trigonelline in coffee is said to impart coffee with some anti-oxidative properties and contribute to its aroma and slightly bitter taste. Trigonelline is also produced within the human body as a result of the metabolism of niacin (Vitamin B3 or
Nicotinic Acid), after which it is excreted in urine.
Stachydrine is also present also in Yarrow,
Chrysanthemum and Citrus plants. It is the betaine of L-Proline, and is also known as Proline Betaine. It is an osmoprotectant capable of helping organisms to survive extreme osmotic stress, such as the bacterium E. coli when it finds itself in harsh environments such as in the urine of mammals. The bacterium uptakes the stachydrine from the environment it is in with the help of various internal transport mechanisms. Your Author can find no evidence that Stachydrine is present in plants of the genus Stachys, such as Hedge Woundwort (Stachys sylvatica) to which Betony once belonged.
Structurally, Betonine is almost identical to Stachydrine, but with an additional hydroxyl group attached to the ring.
Betaine itself is a non-proteinogenic amino acid (NPAA) which can masquerade as an amino acid in the human body and become wrongly incorporated into proteins, which then might not function correctly. But because of great confusion between betaine and 'a betaine' the Betaine shown above is now generally referred to as
N,N,N-TrimethylGlycine, and is the betaine originally found in
Beet (Beta vulgaris) from which it derives its name.
Choline is just the cation (the part of the ion with positive charge). It can be paired up with any negative ion, but usually this is the chloride ion, making Choline Chloride.
Acetyl Choline is another important molecule with the Choline backbone, and is usually found as the chloride, Acetylcholine Chloride. Choline is an essential nutrient for mammals and is usually grouped as belonging to the B-complex vitamins.