Five Major Cannabinoids: The Dates on the Record

1899, four years before flight

1899. That is the year the first cannabinoid was isolated and put on the record, in a paper on cannabinol by Wood, Spivey and Easterfield [1]. For a sense of the distance involved: the Wright brothers got a powered aircraft off the ground four years later. Nobody had flown yet. Someone had already taken a single compound out of hemp and written it up where other chemists could check the work.

The five compounds usually grouped together as the majors are cannabinol, cannabidiol, tetrahydrocannabinol, cannabigerol and cannabichromene. Five names, five dates, and the dates are not evenly spaced. The gaps between them tell you as much as the entries do.

That first status, the first cannabinoid ever isolated, is easy to underrate. We read the names now as a tidy list on a lab report. In 1899 there was no list. There was plant material with an unknown number of components in it, and a claim that one of those components could be pulled out, held, and described.

The word isolated is worth translating. A plant extract is a mixture, and a fairly crowded one. Isolating a compound means separating one component from everything else and ending up with enough of it to weigh, describe and work with. Reporting it means writing that down in a form other people can dispute. Both steps happened in 1899.

The toolkit of the day explains the achievement and its limits at the same time. Separating a mixture meant patient hand work, repeated over weeks. Thin layer and gas chromatography, the methods that later cut the same job down to hours, only came into use from the 1950s. Nuclear magnetic resonance and mass spectrometry, which read structural information straight off a small sample, arrived later still. So a chemist in 1899 could isolate a compound and name it. Settling its structure to the standard a mid-century paper would demand was a different job entirely.

Which is also why the record then goes quiet for a long stretch. The next of the five majors to be described in print does not turn up for another four decades.

One more thing about that 1899 entry. It is chemistry, not biology. That turns out to be the pattern for everything that follows: the compounds get described first, and any account of what the body does with them comes much later. The receptor at the centre of that account was not cloned until 1990. Read the timeline in that order and it stops looking odd.

There is a habit in the early chemistry worth borrowing. Isolate the claim. Cite where it came from. Mark the point where the evidence stops. Every date on this page is handled the same way: a year, a named paper, and nothing rounded up into certainty it does not carry.

A structure written down in 1940

Forty-one years pass between the cannabinol paper and the next entry on the list. In 1940, Adams, Hunt and Clark reported the structure of cannabidiol [2].

Structure is the key word, so it is worth unpacking. A structure is the arrangement: which atoms, joined in which order, in which shape. Once that is on paper, other laboratories can reproduce it, argue with it, correct it, or build something on top of it. A named compound is a starting point. A structure is a working document.

The wording of the 1940 report repays attention. It describes a structure for a compound isolated from an extract of wild hemp. Two things are being stated. The compound came out of a mixture, by extraction. And what the paper delivers is chemistry: an arrangement of atoms, not an account of what the compound does in a person.

By the 1930s, laboratory methods had already changed considerably from the ones available in 1899. The 1940 work sits on a different bench, with different equipment, and that shows in what it was able to claim. Not just this compound exists, but this is how it is put together.

Now the part that surprises people. Cannabidiol had a published structure roughly seventy-five years before it became a consumer category and a regulatory subject. The chemistry was settled long before there were labels, shelves, dosing questions or national rules to argue about. Shops came late to this story.

It also works the other way round. Current interest in the compound does not reach backwards and change anything about the 1940 chemistry. Attention does not add evidence. The paper says what it said in 1940, no more and no less, and a reader in 2026 gets exactly the same document a reader in 1941 did.

What the 1940 report does not cover is worth stating plainly, because a lot of writing on this topic blurs it. There is nothing in it about receptors, nothing about a system in the body, nothing about mechanism. None of that was answerable yet. That side of the field opens in 1990, and everything between 1940 and then is still chemistry filling in the map of what is present in the plant.

So the record at this point holds two named compounds and one settled structure. Three of the five are still missing, and they arrive together.

One decade, three of the five

1964. Gaoni and Mechoulam reported the isolation of the intoxicating constituent of hashish, determined its structure, and described a partial synthesis of it [3]. The compound is tetrahydrocannabinol. Twenty-four years had gone by since the cannabidiol structure, and for all of that time the constituent behind the intoxicating effect had not been identified.

Partial synthesis is the phrase that marks how far the work had come. It means the compound was built in the laboratory from a related starting material, rather than only pulled out of the plant. Doing that is a check on the structure. If you can make it and it matches, your arrangement of atoms is standing on firmer ground.

Those twenty-four quiet years were not idle years, and the reason the 1960s look so productive is mostly instrumentation. From the 1950s, thin layer and gas chromatography let a chemist separate a mixture in hours instead of weeks. Nuclear magnetic resonance and mass spectrometry gave structural information directly from small samples. Put those together and a plant resin stops being an obstacle and becomes a queue of compounds waiting to be described.

The consequence shows up in the dates. The same programme characterised cannabigerol [3]. Then in 1966, the same two authors reported cannabichromene, described in the language of the time as a new active principle in hashish [4].

Count it up. Three of the five major cannabinoids come from one research effort inside a single decade. That is not a coincidence of talent alone. It is what happens when the tools finally match the question, and it is the clearest example on this timeline of method setting the pace of discovery.

A note on the vocabulary of the era. Active principle was how chemists of the 1960s referred to a compound they considered responsible for the activity of a plant preparation. It is a chemistry term about a constituent, not a product claim, and it should not be read as one.

Even at the end of this decade, the whole record is still one kind of knowledge. Five compounds, four of them named and described by 1966, all of it structural. What happens when any of them meets a cell was still an open question, and the equipment needed to answer it did not exist in a routine form yet.

The receptor that arrived in 1990

1990. Matsuda and colleagues reported the structure of a cannabinoid receptor and the functional expression of its cloned cDNA [5]. The receptor is the one now known as CB1. Ninety-one years after the first isolated cannabinoid, the biological half of the field finally had something concrete to work with.

In plain terms, that 1990 result did two things. It described the receptor itself, and it showed that a copied version of the gene could be put into cells that then produced a working receptor. Working is the important part. A sequence on paper tells you what something is. A functioning receptor in a dish is something you can test, measure and compare.

Why 1966 to 1990, though? Not for lack of curiosity. Cloning a gene and getting it to express a functional protein only became routine laboratory practice in the 1980s. Before then the question was perfectly askable and simply not answerable. That is the honest explanation for the longest gap on the list, and it is a useful reminder that a quiet stretch in the literature usually means a missing method rather than a missing idea.

After 1990 the field changes shape fast. Mapping where the receptor sits. Searching for the compounds the body makes itself, along with the enzymes that build them and break them down. Pharmacology, comparing how different molecules behave at the receptor. That whole bundle is what people now call the endocannabinoid system, and the 1990 paper is the trigger for it.

So the pattern across the whole record is chemistry first, biology second. Which means the young part of this subject is not the chemistry. Cannabinol has been on the books since 1899. The biology is the recent arrival.

Where does that leave things today? The central receptor was first described in 1990, and the map around it is still filling in. That is a fair reason to be careful with confident sentences about mechanism, and a fair reason to say we do not know yet when that is the accurate answer.

Cibdol has been working with cannabinoids since 2014. On a timeline that opens in 1899, that is a recent stretch, not an origin, and we would rather say so than blur it. What we can stand behind is the same discipline the early chemists used: date the claim, name the paper, and mark where the evidence stops.