A new study found that cannabidiol (CBD)-rich and cannabigerol (CBG)-rich cannabis extracts demonstrated antioxidant and antimicrobial activity in laboratory testing, while CBG proved substantially more stable than CBD when incorporated into a topical formulation.
The study, published this week in the Journal of Cannabis Research, was conducted by researchers at the University of Campinas in Brazil. Researchers developed simple oil-in-water topical emulsions containing CBD-rich or CBG-rich extracts and examined their biological activity and stability.
Both extracts demonstrated antioxidant activity, although their performance varied depending on the testing method. In one assay measuring free-radical scavenging, the CBD-rich extract produced a value of 38.3% at a concentration of 0.5 milligrams per milliliter, compared with 31.7% for the CBG-rich extract.
In a separate antioxidant test, however, the CBG-rich extract showed roughly twice the activity of CBD, with researchers reporting values of 50 milligrams of gallic acid equivalents per gram of extract for CBG and 25 milligrams for CBD. The CBG extract also contained higher levels of phenolic and flavonoid compounds.
The extracts produced identical results in antimicrobial testing and were most effective against Gram-positive bacteria. Researchers found that microbial growth was inhibited at concentrations ranging from 1 to 2 micrograms of extract per milliliter.
Researchers then incorporated the cannabinoid-rich extracts into topical oil-in-water emulsions and subjected them to accelerated stability testing for six months.
Both formulations maintained a homogeneous appearance, relatively stable pH and high consistency throughout the testing period. Chemical stability differed sharply, however.
CBD content declined by approximately 65%, while CBG content fell by just 16% over the same period. Researchers said the substantially greater stability of CBG suggests the cannabinoid could be a more robust candidate for future topical formulations.
The findings add to growing research examining CBD, CBG and other nonintoxicating cannabinoids for topical applications, including potential dermatological and cosmetic uses.
Researchers cautioned that further work is needed to evaluate cannabinoid release from the formulations, improve chemical stability and better characterize their physical properties.
The study was laboratory-based and did not test the formulations on human patients, meaning the antimicrobial and antioxidant findings do not establish that CBD- or CBG-containing topical products can prevent or treat skin infections or other medical conditions.
“Greater stability of CBG suggests its potential as a more robust candidate for formulations,” researchers concluded.
