“Cannabis sativa L. (cannabis) is an annual diecious member of the Cannabaceae family. Since ancient times cannabis has been used by humans for its fiber, seed, as well as its psychoactive and medicinal resin. Despite a long history of use, the legal status of cannabis in modern times often depends on its intended use. Cannabis grown for its fiber or seed, commonly known as hemp, is legally cultivated in many nations. Cannabis used for its psychoactive properties, in North American commonly known as “marijuana,” has been illegal in most nations worldwide since the 1961 United Nations Single Convention on Narcotic Drugs. Recently however, laws concerning the legal status of cannabis are changing around the world. In the United States of America, many states have legalized cannabis for medical use, whereas some have even legalized cannabis for adult consumption. Uruguay recently legalized cannabis and laws in various countries within the European Union (EU) are also changing regarding cannabis. Due to its many and controversial uses, the taxonomic classification of cannabis has been the subject of both legal and scientific debate.
From a morphological perspective, three main types of cannabis have been described sativa, indica, and ruderalis. Generally sativa plants are described as taller and loosely branched, whereas indica is typically shorter, more densely branched, and conical in shape. Ruderalis is described as short (≤2 feet) at maturity and sparsely if at all branched.7Whether the genus Cannabis is monotypic and composed of just a single species (C. sativa) or polytypic and composed of multiple species is an old taxonomic debate. A more recent taxonomic classification dividing cannabis into seven putative taxa based on morphological, geographical, and genetic traits has been proposed.
Cannabinoids are a group of terpenophenolic compounds found in cannabis. Today over 100 cannabinoids from cannabis have been characterized. (−)-Trans-Δ9-tetrahydrocannabinol (THC) is considered the primary active ingredient responsible for the intoxicating and medical effects attributed to cannabis. THC has antiemetic, neuroprotectant, and anti-inflammatory properties as well as the ability to reduce certain forms of neuropathic and chronic pain. Another important cannabinoid, cannabidiol (CBD), has neuroprotective, anti-inflammatory, antipsychotic, and antiseizure properties without the intoxicating effects of THC. Other minor cannabinoids, such as cannabigerol (CBG), cannabichromene (CBC), and tetrahydrocannabivarin (THCV), also exhibit interesting pharmacological properties.
Since cannabinoids are the major active ingredients found in cannabis, it makes sense to classify cannabis from a chemotaxonomic perspective according to cannabinoid levels for both medical and legal purposes. Early studies noted that cannabis used for fiber tended to have higher levels of CBD, whereas cannabis used for drug purposes had higher levels of THC
Terpenoids represent another interesting group of biologically active compounds found in cannabis. Due to their volatile nature, the mono- and sesquiterpenoids found in cannabis contribute to the plants’ aroma and flavor. About 100 terpenoids have been identified in cannabis, many of which are found in other plants. Both cannabinoids and terpenoids are produced in the trichomes of cannabis, which are found at highest density on female flower buds.Terpenoids are usually present in cannabis flower buds in the 0.5–3.5% range and are found at significant levels in cannabis smoke and vapor. As biologically active compounds, terpenoids may play a role in the overall effects of herbal cannabis.
The popularly understood distinctions between indica and sativa may have more to do with aroma and subjective effects than plant morphology. Recent studies have shown that terpenoids are useful in distinguishing cannabis cultivars that have similar cannabinoid content. A study of cannabinoid and terpenoid profiles among medical cannabis samples analyzed by a cannabis testing laboratory in California found a continuum of terpenoid profiles among the wide variety of sample names.Another study found that cannabis samples described as indica contained more myrcene and hydroxylated terpenoids, whereas those described as sativa tended to contain more terpinolene, 3-carene, and a few specified sesquiterpenes.” http://online.liebertpub.com/doi/full/10.1089/can.2016.0040
“Due to its astonishing efficacy, nowadays cannabis is prescribed by physicians for the treatment of neurological, psychiatric, immunological, cardiovascular, gastrointestinal, and oncological conditions. The active principles inside plants have been exploited by humans for centuries, with Cannabis sativa being one of the oldest ever used for medicinal purposes. Surprisingly, contrary to whole plant extracts, medicinal products containing exclusively THC have been found to lack efficacy and lead to unbearable side effects. These results arise from the fact that these products lack other important co-factors typically found in the Phyto-complex, such as terpenoids and other cannabinoids that contribute to the synergistic effects seen with whole plant extracts.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5482328/
“In silico discovery of terpenoid metabolism in Cannabis sativa. Due to their efficacy, cannabis based therapies are currently being prescribed for the treatment of many different medical conditions. Interestingly, treatments based on the use of cannabis flowers or their derivatives have been shown to be very effective, while therapies based on drugs containing THC alone lack therapeutic value and lead to increased side effects, likely resulting from the absence of other pivotal entourage compounds found in the Phyto-complex. Among these compounds are terpenoids,” https://www.ncbi.nlm.nih.gov/pubmed/28690830
“Terpenoids as anti-colon cancer agents – A comprehensive review on its mechanistic perspectives.” https://www.ncbi.nlm.nih.gov/pubmed/27940056
“Let’s get medicinal, says Olivia Newton-John, who has spoken out about the use of medicinal cannabis on a recent visit to Australia. “I will do what I can to encourage it. It’s an important part of treatment and it should be available,” the singer, who announced a second battle with breast cancer in May, told News Corp Australia. The Australian entertainer said the drug – which is legal in her home state of California – had helped her during her second fight against cancer.” 
