CBCA, cannabichromenic acid, is the third major product of the CBGA branch point, alongside THCA and CBDA. A dedicated oxidocyclase, CBCA synthase, converts CBGA to CBCA. In most plants this enzyme loses the competition for CBGA, so CBCA stays at low levels in mature flower. Heat or time decarboxylates it to CBC.
In practice
On a full COA, CBCA is typically a fraction of a percent of flower weight. Breeders interested in unusual chemotypes look for it, but there are few CBCA-dominant lines. Because THCA synthase can itself produce small amounts of CBCA as a side product, some CBCA appears in THC-type plants even without a highly active CBCA synthase.
Units and formula
Total CBC ≈ CBC + 0.877 × CBCA (CBCA and THCA are isomers, so the factor is the same).
Don't confuse with
- CBC: the neutral form.
- CBGA: the precursor.
- CBDA: an isomer made by a different synthase.
CBGA (cannabigerolic acid) is the precursor cannabinoid that the plant converts into THCA, CBDA or CBCA, formed by joining olivetolic acid to geranyl pyrophosphate.THCA (tetrahydrocannabinolic acid) is the acid cannabinoid that drug-type cannabis makes in its trichomes; heat or time decarboxylates it into THC, losing about 12% of its mass.CBDA (cannabidiolic acid) is the acid cannabinoid made by CBDA synthase from CBGA; it dominates hemp-type and CBD-type cannabis and decarboxylates to CBD.Decarboxylation is the loss of a carboxyl group as CO2 that turns acid cannabinoids such as THCA and CBDA into neutral THC and CBD, quickly with heat, slowly with time.CBC (cannabichromene) is a minor neutral cannabinoid formed when CBCA decarboxylates; it is usually present at well under 1% w/w in mature drug-type flower.A COA (certificate of analysis) is a lab's signed report of what it measured in a specific sample, such as cannabinoids, terpenes, moisture and contaminants, with methods and limits.THCA synthase is the trichome enzyme that converts CBGA into THCA; which alleles of its gene a plant carries largely decides whether it is THC-dominant.Total THC is a calculated figure, Δ9-THC plus 0.877 × THCA, estimating the maximum THC a sample could yield after full decarboxylation.CBDA synthase is the trichome enzyme that converts CBGA into CBDA; it competes with THCA synthase, and its alleles largely decide whether a plant is CBD-dominant.Acid cannabinoids (THCA, CBDA, CBGA) are the carboxylated forms the plant makes; neutral cannabinoids (THC, CBD, CBG) form when heat or time removes the carboxyl group.
