Cannabis sativa L. as a Natural Drug Meeting the Criteria of a Multitarget Approach to Treatment

Anna Stasiłowicz, Anna Tomala, Irma Podolak and Judyta Cielecka-Piontek

International Journal of Molecular Sciences, 2021, 22, 778.

Doi : 10.3390/ijms22020778

Abstract :

Cannabis sativa L. turned out to be a valuable source of chemical compounds of various structures, showing pharmacological activity. The most important groups of compounds include phytocannabinoids and terpenes. The pharmacological activity of Cannabis (in epilepsy, sclerosis multiplex (SM), vomiting and nausea, pain, appetite loss, inflammatory bowel diseases (IBDs), Parkinson’s disease, Tourette’s syndrome, schizophrenia, glaucoma, and coronavirus disease 2019 (COVID-19)), which has been proven so far, results from the affinity of these compounds predominantly for the receptors of the endocannabinoid system (the cannabinoid receptor type 1 (CB1), type two (CB2), and the G protein-coupled receptor 55 (GPR55)) but, also, for peroxisome proliferatoractivated receptor (PPAR), glycine receptors, serotonin receptors (5-HT), transient receptor potential channels (TRP), and GPR, opioid receptors. The synergism of action of phytochemicals present in Cannabis sp. raw material is also expressed in their increased bioavailability and penetration through the blood–brain barrier. This review provides an overview of phytochemistry and pharmacology of compounds present in Cannabis extracts in the context of the current knowledge about their synergistic actions and the implications of clinical use in the treatment of selected diseases.

Keywords : Cannabis; phytocannabinoids (THC and CBD); terpenes; multitarget; receptors

 

1. Introduction

The history of many drugs currently used in medicine has its origins in plant raw materials. Morphine, atropine, paclitaxel, and, recently, artemisinin are the most famous examples in the drug discovery process [1]. With the development of analytical techniques and separation methods, it was possible to isolate individual compounds and, consequently, define their molecular mechanisms of action by assessing their interactions with selected receptors. Often, the therapeutic demand for compounds of plant origin is enormous, and effective synthesis pathways have to be developed, as in the case of morphine [2]. It took, however, many years from its discovery to a chemical synthesis. At the beginning of the nineteenth century, Friedrich Sertürner, for the first time in history, isolated this alkaloid from the opium poppy (Papaver somniferum) [3]. However, it was not until over 100 years later that Sir Robert Robinson first proposed the correct morphine structure in 1925, which was confirmed by the first total synthesis of morphine by Gates and Tschudi in 1952 [4–6]. Since then, many attempts have been made to develop extraction methods or reactions leading to obtaining morphine [7,8].

Drug reactions may be extracellular or cellular. The former involve noncellular constituents (physical effects, chemical reactions, physicochemical mechanisms, and modification of the composition of body fluids) [9]. In contrast, cellular mechanisms of action involve functional constituents of the cell and, more frequently, depend on specific biochemical reactions. Cellular drug reactions apply to physicochemical and biophysical mechanisms, the modification of cell membrane structure and function, and enzyme inhibition, as well as interactions with receptors. Receptors in various locations—for example, on the plasma membrane, in the cytosol, or in the nucleus—and interactions with the receptor typically activate or inhibit several sequences of biochemical events. The existence of receptors
has not always been a matter of course in the world of science. Their first exponents were John Langley with his theory of receptive substances in cells and Paul Ehrlich and his side-chain theory [10,11]. These theories evolved, and a one-drug one-receptor model was proposed, based on the assumption that a given drug interacts only with one receptor.

Hitherto, drugs with high target selectivity in the body, designed to affect a single biological entity to avoid adverse side effects, have been used and searched for [12]. It is the concept of a “single molecule, single target, and single drug” that has dominated the pharmaceutical market for the last several decades. In some disease entities, a drug’s effect on one target is insufficient to achieve the therapeutic effect. Therefore, combination therapy is also used, i.e., the simultaneous use of drugs with different body targets—for instance, in the treatment of hypertension [13]. Diseases with multifactorial pathogenesis or not fully understood pathogenesis are often treated with more than one drug, which increases the risk of adverse drug reactions. Therefore, more and more often, as in the case of Alzheimer’s disease, drugs with multiple biological targets are chosen in order to increase effectiveness, safety, and to facilitate administration—for example, galantamine, caproctamine, or memoquin [12].

Unlike the treatment with synthetic drugs, phytotherapy is based on herbal medicines, and their actions result from the combined mechanisms of compounds contained in the raw materials or their products [14]. Thus, the effect of a given herbal drug is the result of all the synergies or antagonisms between its constituents.

Cannabis sativa L. is one of the most ancient plant species used by humans for many purposes. Besides medicinal use, it also serves as a fiber; food; and is an important raw material for the production of rope, textiles, and paper. Surprisingly, the first human use of Cannabis is reported to be 10,000 years ago, at the end of the Ice Age [15]. The most ancient Chinese Pharmacopoea (written in the first century before the current era), the “Shen Nung Pen Ts’ao Ching”, is the first historical evidence of the use of Cannabis in traditional medicine. It includes all the traditional remedies used and orally bequeathed for over two thousand years when it was emperor Shen Nung’s (2700 years before the current era) reign [16]. The Cannabis plant first arrived in Europe with Scythians or proto-Scythians moving from Central Asia about 3500 years ago [17]. Modern reports on medical marijuana date back to the nineteenth century, when the Irish doctor William Brooke O’Shaughnessy performed experiments on the pharmacological and toxic properties of Cannabis [18,19]. He suggested Indian hemp as a treatment for tetanus and other convulsive diseases. In 1851, for the first time, Cannabis was included in the third edition of the United States Pharmacopoeia (USP) with the use of Cannabis flowers as an analgesic, anticonvulsant, and hypnotic [20]. In the second half of the nineteenth century, there was a significant increase in the use of Cannabis in medicine and research on its phytochemistry and pharmacology. At the beginning of the twentieth century, as the recreational use of Cannabis grew, in 1937, the “Marijuana Tax Act” was introduced, and in 1941, Cannabis was removed from the twelfth edition of the U.S. Pharmacopeia by the American Medical Association [19]. In the 1960s, the use of recreational Cannabis increased throughout the Western world. The discovery of the chemical structure of D9-tetrahydrocannabinol (D9-THC), which was identified by Gaoni and Mechoulam, boosted multidirectional research on Cannabis [21].

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