Cannabis Oil : chemical evaluation of an upcoming cannabis-based medicine

Luigi L. Romano, Arno Hazekamp

Cannabinoids, 2013, 1, (1), 1-11

© International Association for Cannabinoid Medicines

 

Abstract

Concentrated cannabis extracts, also known as Cannabis oils because of their sticky and viscous appearance, are becoming increasingly popular among self-medicating patients as a claimed cure for cancer. In general, preparation methods for Cannabis oils are relatively simple and do not re-quire particular instruments. The most well-known example of such a product is called ‘Simpson oil’. The purpose of the extraction, often followed by a solvent evaporation step, is to make canna-binoids and other beneficial components such as terpenes available in a highly concentrated form. Although various preparation methods have been recommended for Cannabis oils, so far no stud-ies have reported on the chemical composition of such products.

Recognizing the need for more information on quality and safety issues regarding Cannabis oils, an analytical study was performed to compare several generally used preparation methods on the basis of content of cannabinoids, terpenes, and residual solvent components. Solvents used include ethanol, naphtha, petroleum ether, and olive oil. The obtained results are not intended to support or deny the therapeutic properties of these products, but may be useful for better understanding the experiences of self-medicating patients through chemical analysis of this popular medicine.

Keywords : cannabis oil, Rick Simpson oil, cancer, cannabinoids, terpenes

Introduction

Cannabinoids exert palliative effects in cancer patients by reducing nausea, vomiting and pain, and by stimu-lating appetite [1]. In addition, preclinical evidence has shown cannabinoids to be capable, under some condi-tions, of inhibiting the development of cancer cells by various mechanisms of action, including apoptosis, inhibition of angiogenesis, and arresting the cell cycle [2,3]. As a result of such exciting findings, a growing number of videos and reports have appeared on the internet arguing that cannabis can cure cancer. But although research is on-going around the world, there is currently no solid clinical evidence to prove that cannabinoids – whether natural or synthetic – can effec-tively treat cancer in humans. It is therefore important to be cautious when extrapolating preclinical results to patients.
Anecdotal reports on cannabis use have been historical-ly helpful to provide hints on the biological processes controlled by the endocannabinoid system, and on the potential therapeutic benefits of cannabinoids. The antiemetic [4], appetite-enhancing [5], analgesic [6], and muscle-relaxant effects [7] and the therapeutic use of cannabinoids in Tourette’s syndrome [8] were all discovered or rediscovered in this manner. But alt-hough it is possible – and even desirable – that cannabis preparations exert an antineoplastic activity in, at least some, cancer patients, the current anecdotal evidence reported on this issue is still poor, and, unfortunately, remains far from supporting that cannabinoids are efficacious anticancer drugs for large patient populations [9]. It should be noted, however, that the potential effects of terpenes on cancer, either alone or in combi-nation with cannabinoids, have not yet been addressed in laboratory studies. Indeed, the synergistic effect between cannabinoids and terpenes is often claimed to be the major difference between ‘holistic’ herbal prepa-rations of cannabis, and products based on single can-nabinoids [10]. Moreover, self-medicating patients often use extraction methods and/or administration forms that are quite different from conditions used in (pre)clinical studies, possibly resulting in different serum profiles of cannabinoids and their metabolites [11] and, consequently, in different therapeutic effects. Because of this gap between clinical research and real experiences, the curative potential of whole cannabis preparations for the treatment of different cancer types remains unclear.

In recent years an increasing number of patients have been using concentrated extracts of herbal cannabis, which, because of its sticky and viscous appearance, has become known as “Cannabis oil”. Among the self-medicating population, it is firmly believed that these products are capable of curing cancer, a claim that is backed up by numerous anecdotal patient stories. Can-nabis oil is a concentrated extract obtained by solvent extraction of the buds or leaves of the cannabis plant. Various non-polar solvents have been recommended for this purpose, including petroleumether, naphtha, alcohol and olive oil. The purpose of the extraction, often followed by a solvent evaporation step, is to make cannabinoids and other beneficial components such as terpenes available in a highly concentrated form. In general, preparation methods for Cannabis oil are relatively simple and do not require particular in-struments. For this reason, people who have access to cannabis, either home grown or obtained from licensed pharmacies, dispensaries, coffee shops or the black market, may prepare it at home by themselves.
In particular, the captivating story of a former patient called Rick Simpson, a Canadian who claims to have cured his skin cancer through repeated topical applica-tion of Cannabis oil produced according to his own recipe, has received increasing attention. His detailed story is described on his website [12] and in a docu-mentary film called “run from the cure” [13] where various cancer patients describe the therapeutic effects of ‘Simpson’ oil on their medical condition. In both the website and documentary, it is explained in detail how to prepare and administer the product. The method suggests the use of naphtha or petroleum ether as a solvent for the extraction, without specifying a particu-lar quality or source. Both solvents are a mixture of petroleum hydrocarbons (PHCs), often available in a wide range of qualities. In general, petroleum ether and naphtha refer to very similar products, even though different names may be used around the world; e.g. in some countries naphtha is equivalent to diesel or kero-sene fuel. As a result, extensive discussions on solvent choice can be found on web-forums. Following the success of Simpson oil, a number of related recipes have sprung up, emphasizing small but significant changes to the original recipe. Examples include focus-ing on extraction with safer solvents such as ethanol [14], or preventing exposure to organic solvents alto-gether, by using olive oil [15].

Since cancer is a devastating disease that affects a large proportion of the world population, it causes some patients to seek alternative treatments outside the realm of modern medicine. With a growing interest in Can-nabis oils for self-medication it is important not to overlook the importance of quality control and stand-ardization. In this regard it should be noted that none of the production methods for Cannabis oil have been validated in published literature, and no reports have been made on the chemical composition of these prod-ucts either. As a result, although many believe Canna-bis oil may cure cancer, no one seems to know what is actually in it. Instead, the positive effects of Cannabis oil are based almost exclusively on case-reports by people who have used it. This paper evaluates the ef-fects of preparation methods, and particularly the sol-vents used, on the final composition of the different Cannabis oils. The obtained results are not intended to support or deny the therapeutic properties of these products, but may be useful for better understanding the experiences of self-medicating patients through chemical analysis of this popular medicine.