Subclass of Alkaloids

Amines & Protoalkaloids

Simple nitrogen bases — histamine, serotonin, melatonin, and the ephedra phenethylamines.

Overview

About Amines & Protoalkaloids

Amines are the simplest nitrogen-bearing plant compounds — an amino acid with its carboxyl group removed, and little else. Because the nitrogen sits outside a ring rather than within one, they are strictly protoalkaloids or biological amines rather than true alkaloids.

Their simplicity is exactly why they matter. These are often the same molecules the body uses as neurotransmitters and hormones, or one enzymatic step away from them, so a plant amine can plug straight into human signalling.

Where Amines Occur

Scattered widely, with a few plants concentrating one to notable levels:

Ephedra

ephedrine and pseudoephedrine

Bitter orange

synephrine and octopamine

Fermented and aged foods, mistletoe, cheese

tyramine and histamine

Cacao

phenethylamine

Many plants

serotonin, melatonin, dopamine in trace amounts

Melatonin and serotonin in plants are a genuine curiosity: the same molecules that regulate human sleep and mood occur across the plant kingdom, generally at doses far too low to matter.

Pharmacological Importance

The phenethylamine amines are sympathomimetics — they release noradrenaline and stimulate adrenergic receptors directly, producing bronchodilation, raised heart rate and blood pressure, appetite suppression and thermogenesis.

Ephedrine is the archetype and remains a legitimate bronchodilator and vasopressor; pseudoephedrine is the standard oral decongestant. Synephrine took ephedra's place in weight-loss products after the ephedra ban, on a much thinner evidence base.

Toxicity & Safety

This subgroup has caused more regulatory action than any other on this site. Ephedra-containing weight-loss supplements were banned in the United States in 2004 after deaths from cardiac arrhythmia and stroke, particularly in combination with caffeine.

The tyramine problem is the other headline: monoamine oxidase normally destroys dietary tyramine before it reaches circulation, so anyone taking an MAO inhibitor — pharmaceutical or the herbal beta-carbolines — risks a hypertensive crisis from tyramine-rich foods. Sympathomimetic amines are also contraindicated in hypertension, cardiovascular disease, hyperthyroidism and glaucoma.

Constituents

All Amines & Protoalkaloids

36 total Filter amines & protoalkaloids

Open in filterable index

Source Plants

Herbs Containing Amines & Protoalkaloids

22 herbs

Plants in the materia medica documented to carry amines & protoalkaloids, with the compounds each one is listed for. The bar counts how many DISTINCT amines & protoalkaloids are on record for a plant, relative to the best-documented — it measures breadth of record, not potency, so a plant with one well-studied compound can outrank a richer source that has simply been analysed less. Where a measured concentration is on record it is quoted inline; most entries have none yet.