The Cannabis sativa plant (marijuana and hemp) has a long history of use in medical therapy. There are records of the use of this plant dating back almost 5,000 years ago in China to treat gout, malaria, constipation, rheumatism, and other conditions . Extracts of C. sativa contain a large number of phytochemicals such as terpenes and flavonoids, as well as a unique class of molecules known as cannabinoids. There are over 100 different known cannabinoids, with the 2 most abundant being delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). Unlike THC, CBD does not produce euphoria but has been shown to modulate the activity of THC and have anti-inflammatory and analgesic activities [2-4].
Our results – showing that there does not appear to be an entourage effect when comparing pure CBD to high CBD content hemp oils – are in contrast to a recent study in breast cancer cells that showed botanical drug preparations were more efficacious than pure THC at reducing cell viability . We also conducted an experiment in which CRCs were treated with equal amounts of CBD and THC in media containing serum and did not see any further enhancement of the toxic effect of CBD alone (data not shown). However, there are several differences between our study and the study of Blasco-Benito and colleagues . First, our study did not serum-starve cells, and this likely accounts for the difference in findings. Cannabinoids have been found to be greater than 90% bound to protein in blood samples from human pharmacokinetic experiments and so, in the absence of plasma proteins, the effective concentration of free drug will be much higher. In the present study, we chose to avoid serum starvation because it less accurately reflects the human system and renders the cells more fragile and sensitive to drug treatment [33-36]. Second, the 2 studies examined different principal cannabinoids; here, we examined the effect around CBD oil and attendant additional phytochemicals, and the former study focused on THC. Interestingly, their plant extract did not contain any CBD . We have not observed an ability of pure THC to reduce viability in CRC cells , nor melanoma or GBM cells (data not shown). Several studies have reported that THC can reduce cancer cell viability; however, these studies were all performed in low or no serum conditions [10, 19, 21, 22]. In agreement with these studies, we did find that THC can reduce cell viability in CRCs to levels similar to CBD under no serum conditions (data not shown) and so, our findings are not in conflict. However, in the presence of serum, we do not see an effect of THC, and this is in agreement with a study that showed that cell viability of cancer cells in serum was not impacted by THC at concentrations less than 63.5 μM.
Efforts were made to select high-quality oils for this study. Oils were selected based upon the following criteria: (1) unflavored oils to avoid added chemicals; (2) the company provided third party analysis of composition; (3) the company tracked lot numbers; and (4) the company was highly reviewed by independent online sources. Three oils that met these criteria were selected for study, hereafter referred to as Oil A, Oil B, and Oil C.
To compare the efficacy of pure CBD compared to the most potent CBD oil preparation (Oil A), we performed dose effect experiments for each preparation based upon the CBD content. As shown, in Figure 3 and Table 3, the efficacy of CBD was generally better than that observed for Oil A; however, this difference only achieved statistical significance between pure CBD and Oil A in the CRC cell line SW480.
Cells were treated as described above at varying concentrations of CBD or CBD Oil A (the most potent of the 3 oils based on viability analyses (Fig. 2)): 100, 56, 33, 18, 10, 3.3, 1.0, 0.33, and 0.1 μM. Viability was measured as described above and GraphPad Prism software (GraphPad Software; San Diego, CA, USA) was used to calculate IC50 values and to prepare semi-logarithmic dose-effect curves.
What, if anything, can CBD oil do to alleviate the symptoms of cancer or the side effects of cancer treatment?
Quality, cleanliness and regulation are the biggest concerns.
CBD oil (cannabidiol) is everywhere these days. Once available only at novelty or vitamin shops, it’s now also at your local grocery store, pharmacy or even yoga studio.
Third, the plant itself may have higher levels of THC than expected. This could be due to its environment, prolonged flowering periods or cross-contamination and pollination between male and female plants, resulting in offspring with higher THC content. This especially affects hemp plants, which should have less than 0.3% THC levels.
Other sorts of substances have been found in CBD products, too, such as dextromethorphan, which is an ingredient in cough medicines. Heavy metals like lead and arsenic, pesticides and mold have also been found in CBD products.