Table 1.

Classification of phytocannabinoids. Adapted from [9], MDPI, 2021.

Class of Compounds	The Number of Compounds in Each Class	The First Representative Compound of the Class	Chemical Structure of the Representative Compound
Δ9-trans-tetrahydrocannabinol	25	Δ9-THC—isolated in 1964 by Goani and Mecholum using chromatography techniques [10]
Δ8-trans-tetrahydrocannabinol	5	Δ8-THC—isolated in Maryland in 1966 [11]
cannabidiol	10	CBD-C5—isolated in 1940 from native Minnesota hemp [12]
cannabigerol	16	CBG—isolated in 1964 using florisil chromatography [13]
cannabichromene	9	CBC—isolated in 1966 by Gaoni Y. [14]
cannabinol	11	CBN synthesized by Adams et al. in the US and by Todd’s group in the UK in 1940 [15,16]
cannabinodiol	2	CBND-C3—isolated in 1973 [17] CBND-C5—isolated in 1977 [18]
cannabicyclol	3	CBL—compound was isolated by Korte and Sieper in 1964, and the structure was elucidated by Crombie et al. in 1968 [19,20]
cannabielsoin	5	CBE-C5—isolated in 1973 from Lebanese hashish [21]
cannabitriol	9	CBT-C5—isolated in 1966 from Japanese hemp, but the complete chemical structure was established 10 years later [21,22]
other unclassified types of cannabinoids	30	The first ones isolated in 1975 (examples: dehydrocannabifuran DCBF-C5, cannabifuran CBF-C5) [23]