Until early 1940, Cannabis sativa L. was widely cultivated in Turkey for production of hemp and hemp-derived products, mostly employed for industrial purposes. Hemp fibres were largely used in textiles, paper and ropes because of their strength and durability, but they were mostly replaced by synthetic ones over the years. Production decreased from year to year to 10 decares in 2015. One of the important reasons for this decline was the privatization of the factory which uses hemp as a raw material in 2004. The privatized factory purchases the hemp need from abroad because it is cheaper, bringing the hemp production in Turkey to the end . Cannabis was brought back to the agenda as an agricultural product at the “Symposium on Local Governments in the Presidential Government System” held on January 9, 2019. The purpose of Turkey's recent hemp policy is to produce and spread hemp production to meet domestic needs.
Cannabis (Cannabis sativa L.) is a herbaceous plant that has found commercial value in textile, food, papermaking and construction industry for centuries. Several countries, such as Australia, France and the United States, have recently permitted cultivation of low (<0.3% w/w) tetrahydrocannabinol (THC) hemp . The plants of Cannabis sativa L. produce more than 100 natural cannabinoids, known as phytocannabinoids  divided in psychotropic and non-psychotropic cannabinoids. In the fresh plant material, most of the cannabinoids are initially synthesized as non-psychotropic carboxylic acids. These precursors are converted into the neutral form after decarboxylation induced by drying, heating, combustion or aging . While there is no male and female distinction in cannabis seeds, there is a distinction between male and female in grown plants. It is known that there are less cannabinoids in male plants than in female .
Increasing evidences suggested that cannabinoids can be used in different pathological conditions, such as symptoms of muscle problems associated to multiple sclerosis, nausea and vomiting caused by chemotherapy, and anorexia in cancer or HIV patients [6, 7].
The main cannabinoids are Δ9-Tetrahydrocannabinol (THC) and its structurally analogue, although not psychoactive, cannabidiol (CBD). They are present in the plant as inactive acids (THC-A and CBD-A) and they can be converted in the corresponding non-acidic forms via thermal decarboxylation .
As the analysis of cannabis has gained new global importance, mainly for quality control within the legalized recreational and medical cannabis industry, and also for forensic differentiation between drug-type cannabis and legal products such as fibre hemp and CBD-rich and THC-poor cannabis the importance of the correct choice of an extraction method for the extraction of cannabinoids from various matrices e.g. cannabis plant extracts, hemp food products, biomass, cannabis oils, whole blood, plasma, oral fluids, hair and so on, has become paramount [9, 10]. There are a wide variety of cannabinoids in cannabis. The occurrence of these cannabinoids in different parts of the cannabis is strongly dependent on the genetic expression and growing environmental conditions. Such as, female plants gives higher quantity of cannabinoids at the stage of maturity. While, male plants are preferable for higher yields of the non-cannabinoids and flavonoids i.e. hemp form .
The choice of an extraction method relies on the nature of the source material, e.g. dried plant powder, biological materials, soil or water, as well as the target compounds, e.g. cannabinoids . Prior to deciding on a particular extraction method for naturally occurring cannabinoids, one must consider the following: purpose of extraction, quantity of extraction, purification steps to be carried out, purity level of cannabinoids, possible artefact formation, stability of target cannabinoids, physicochemical properties of target cannabinoids, and obviously the cost and environmental impacts. In addition to traditional methods like maceration, distillation or boiling, several other modern extraction methods and techniques can be applied for the extraction of naturally occurring cannabinoids, and those methods include, soxhlet, accelerated solvent extraction, pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), ultrasound assisted extraction (UAE), supercritical fluid extraction (SFE), solid phase extraction (SPE) and micro solid-phase extraction (MSPE) [12, 13]. The choice of solvent for extraction is equally important to have maximum extraction yield. For the extraction of naturally occurring cannabinoids, most often, organic solvents are preferred, because of the lipophilic nature of most of the naturally occurring cannabinoids.
Traditional methods, like maceration, percolation, and soxhlet, are known to have some limits such as time and solvent consumption, and decomposition of heat sensitivity bioactive compounds . However, soxhlet technique is still common in laboratories and industries being involved in a wide variety of official methods .
According to the scanning results of the literature, generally hemp seed, seed oil yield, essential oil composition or mostly non-psychoactive ingredient CBD and sometimes only THC have been researched. And also there are a few researches by ultrasonic and microwave extractions. Apart from extraction methods, various analytical methods (such as GC-MS and HPLC) have been reported for the analysis of cannabinoids in cannabis plant. There was no publication in the literature that cultivated several strains at the same time, developed a soxhlet extraction procedure, and analyzed CBD and THC at the same time.
Searching “cannabidiol” in literature scanning web-sites and filtering results just for the last 20 years, it is amazing to realize that most of the work, about 60%, are interested on pharmacological activity of the compound, 30% are still researching and progressive analytical methods able to separate the presence of other cannabinoids. Finally, only 6% of the published researches is interested in the extraction protocols.
Therefore in this context, the aim of the present study was to develop and a soxhlet extraction procedure to get CBD and THC extracts from the different four strains which planted from different four regions of Konya, Turkey. It is the first study to show the different climatic conditions effect on the yield of CBD and THC.