# The Origin and Biomedical Relevance of Cannabigerol
## 6 Pharmacokinetics of Cannabigerol
In contrast, other studies have reported that cannabinoid was only sporadically present (in approx. 2% of the samples tested) in plasma obtained from individuals participating in several clinical trials focused on the effects of medical marijuana on various pathological conditions (e.g., Parkinson's disease, brain tumors in children, childhood epilepsy). It was observed that the samples in which CBG was detected showed a significant \(\Delta^{9}\)-THC content, indicating that medical marijuana had been consumed shortly before the study took place [76]. The above data, therefore, suggests that monitoring cannabinoid levels in the blood may constitute an effective marker to confirm the fact of recent cannabis smoking. A similar evaluation of the effect of the mode of administration of _Cannabis sativa_ L. on oral fluid levels of cannabinoid showed that when _Cannabis sativa_ L. is taken orally, the maximum mean CBG content is the lowest in both occasional users and frequent  
Figure 6: Changes in cannabinoid levels in human blood and oral fluid over time depending on the route of administration of _Cannabis sativa_ L. Abbreviation: S—smoking, V—vaporization, OA—oral administration [74; 75]. smokers (11.9 \(\upmu\)g/L and 17.0 \(\upmu\)g/L, respectively). Interestingly, in terms of the mode of administration, of the three analyzed routes, the time required to reach the maximum CBG concentration in oral fluid is the longest in the case of smoking (approximately 28 min and 25 min for occasional and frequent smokers, respectively). The highest concentration values (C\({}_{\text{max}}\)) in individuals in the study groups were again observed when \"active\" cigarettes were smoked (165 \(\upmu\)g/L and 118 \(\upmu\)g/L, for occasional and frequent smokers, respectively). In contrast, the time required to reach maximum CBG concentrations in the analyzed oral fluid samples was about 10 min for both occasional and frequent smokers. Hence, cannabinoid introduced into the body by smoking _Cannabis sativa_ L. persists in the body for much longer than in the case of other forms of cannabis use (over 10 h on average for frequent smokers and nearly 5 h for occasional smokers) and reaches significantly higher levels, especially in oral fluid, compared to blood [75]. Considering the pathway of CBG biosynthesis in a living organism, the presence of both CBG and its precursor, i.e., cannabigerolic acid (CBGA), was tested in the blood plasma of patients in addiction treatment units by analyzing the presence of phytocannabinoids at different times after _Cannabis sativa_ L. was ingested [77]. CBG was found in 22 out of 56 subjects at 24 h and in 4 out of 17 subjects at 26.4-73 h after ingestion. In contrast, CBGA was only present in 12 out of 56 subjects (after 24 h) and in 1 in 17 subjects (after 26.4-73 h). The mode of ingestion of _Cannabis sativa_ L. (smoking or oral ingestion) was not taken into account in the study, nor was it possible to check whether the ingested cannabis had undergone heat treatment [77]. Considering these observations, it can be concluded that the determination of cannabinoid levels in oral fluid makes it possible to estimate the time of ingestion of orally administered cannabis-based preparations. A simultaneous analysis of both blood and oral fluid suggests that it is possible to obtain information not only about the time elapsed since the ingestion but also on how _Cannabis sativa_ L. was introduced into the body. In addition, it has been shown that it is possible to determine urinary cannabigerol levels in _Cannabis sativa_ L. smokers. The compound is absorbed into the body during smoking, where it is metabolized and then excreted in the urine [78]. It was observed that cannabinoid was removed from the bodies of _Cannabis sativa_ L. smokers in urine in the form of a conjugate with glucuronic acid, which was not found in either the control or the CBG-enriched urine samples.