2022 Study: Anti-Cancer Effects of 25 Cannabis Samples
Updated: 11 hours ago
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A September 2022 research study entitled "Analysis of Anti-Cancer & Anti-Inflammatory Properties of 25 THC-rich Cannabis Samples" that was published in the journal Molecules analyzed 25 loose-leaf cannabis samples "containing high levels of delta-9-tetrahydrocannabinol (THC)."
The study's authors observed that cannabis is a plant "with a long history of consumption as food and medicine," but that most of the information regarding its medicinal properties is, from a scientific perspective, problematic because it is "either anecdotal or reported at the pre-clinical level" (not involving human trial subjects).
The researchers noted that cannabis samples "contain many ingredients, including major cannabinoids such as delta-9-tetrahydrocannabinol (THC), cannabidiol (CBD), cannabigerol (CBG), and cannabinol (CBN)" and that this collection of compounds also features "many minor cannabinoids, terpenes and terpenoids, flavonoids, phenols, fatty acids, and more."
THC "has many properties, including anti-cancer, anti-inflammatory, analgetic [pain reducing], and others."
The study reported that THC "has many properties, including anti-cancer, anti-inflammatory, analgesic [pain reducing], and others," but noted that "not all cannabis extracts that are high in THC appear to be equally effective." It reported that it and other scientific labs found "drastic differences in the anti-inflammatory properties of various cannabis extracts and demonstrated modulating effects of various minor cannabinoids and terpenes."
The scientists reported that they analyzed the cannabis samples for "anti-cancer and anti-inflammatory properties." As part of this investigation, the study "profiled cannabinoid and terpene concentrations and performed correlation analysis with anti-cancer and anti-inflammatory activities." It reported that it identified both "positive and negative modulating effects."
The study reported that it demonstrated "various degrees of efficacy of the tested [cannabis samples], from 66 to 92 percent of growth inhibition of squamous cell cancer cells." It also revealed that a combination of multiple terpenes decreased inflammation "with efficiency similar or greater than that of single cannabinoids."
Varying Efficacy of Cannabis Extracts
Analysis of six THC-rich examples of the extracts made from the 25 cannabis samples revealed different effects on inflammation, "with four being effective, one being neutral, and one increasing the expression of pro-inflammatory cytokines," reported the study.
THC levels in the samples were relatively weak compared to commercially available examples of the herb. The samples analyzed by the study exhibited THC levels that ranged from about seven percent to 15 percent.
Analysis of six THC-rich samples revealed different effects on inflammation, "with four being effective, one being neutral, and one actually increasing inflammation."
The 25 cannabis samples had CBD levels that varied from 0.13 percent to 1.3 percent, while cannabigerolic acid (CBGA; the acidic precursor to CBG) was present in volumes of 0.18 percent to 1.3 percent.
Terpenes Regulate Cannabinoids
The study's analysis of the terpene content of the 25 samples revealed limonene to be the most abundant terpene, followed by beta-caryophyllene (also called BCP or β-caryophyllene). In addition, the terpenes ocimene and eucalyptol were found, but in significantly lower quantities than limonene and BCP.
Interestingly, the study revealed a "very weak positive correlation between the total level of cannabinoids and total level of terpenes." The scientists hypothesized that other elements of the THC-rich cannabis samples possess "modulating effects on THC" and that these molecules include CBD and a variety of minor cannabinoids and terpenes. It noted that terpenes "were shown to regulate the activity of major cannabinoids."
The scientists "performed association analysis between the presence of individual terpenes and cannabinoids" and found "significant associations" for the following pairs:
isopulegol and CBGA
p-cymene and CBGA
terpinolene and CBGA
They also found that the terpenes terpinene, eucalyptol, and fenchone "likely have an anti-breast cancer effect" when they are either "acting alone or in combination with THC." Terpinene's ability to fight breast cancer cells "was associated with the induction of apoptosis," a genetically pre-programmed mechanism by which cancer cells kill themselves in response to an outside stimulus.
However, the scientists noted that the exact mechanism by which terpenes "potentiate the anti-cancer effects of cannabinoids remains unclear."
The study found that all cannabis samples could "inhibit the growth of cancer cells in a dose-dependent manner." It identified "a weak correlation between the concentration of CBGA and anti-cancer activity," but found no anti-inflammatory efficacy from CBGA.
"To our surprise, the correlation analysis showed none between the anti-cancer effect and THC [content] or total cannabinoid content," reported the scientists. However, they demonstrated that extracts made from the loose-leaf cannabis flower samples, which had the effect of concentrating the volumes of cannabinoids and terpenes, on average inhibited cancer growth by about 80 percent.
"Since we found no correlation between the THC levels in the extract, it appears that THC alone is not responsible for the inhibition of the growth of cancer cells," stated the study's authors.
THC may be effective in the inhibition of the growth of breast cancer cells. Other cannabinoids, including "CBD and CBG, as well as terpenes" may combat cancer.
The study concluded that not only may THC "be effective in the inhibition of the growth of breast cancer cells," but that other cannabinoids, including "CBD and CBG, as well as terpenes" demonstrate positive efficacy against cancer.
"It appears that even 25 extracts are not sufficient to clearly delineate the active ingredient(s) in cannabis or the modulating effects of the other minor components," reported the study. The scientists interpreted this to mean that perhaps all of the cannabinoids and terpenes "are active" and may result in positive efficacy for cancer patients.
The study also suggested that "other untested ingredients" of the cannabis samples, including cannflavins, may have "a strong effect on cancer and inflammation." It noted that "we have to also identify flavonoids and test their activity" and that their effects are likely cancer-specific (displaying positive outcomes for some types of cancer, but not others).