# New Methods for the Comprehensive Analysis of Bioactive Compounds in _Camabis sativa_ L. (hemp)
## 1 Introduction  
In recent years, _Camabis sativa_ L. has been the focus of the attention of the scientific community all over the world, definitely becoming one of the most studied plants [1]. It is one of the two representatives of the _Camnabaceae_ family and nowadays it is widely distributed all over the world. _C. sativa_ has been cultivated for a long time for medicinal, food, and abuse purposes, together with its use as a source of textile fibre [1, 2]. The taxonomy of the plant has always represented a critical issue, due to the huge variability within the same genus [1, 2, 3]. Recently, a monotypic classification has been preferred, in which one species (_C. sativa_) is recognised and it is divided into different chemotypes on the basis of the specific cannabinoid profile [3]. Nonetheless, in the pharmaceutical field, only two phenotypes are considered, on the basis of the content in the psychoactive principle \(\Delta^{9}\)-tetrahydrocannabinol (\(\Delta^{9}\)-THC) [4]. In detail, the first one is drug-type _Cannabis_, which is rich in psychoactive \(\Delta^{9}\)-THC, and is used for medicinal or recreational purposes [4]; the second one is fibre-type _Cannabis_ (commonlyknown as hemp or industrial hemp), used for both textile or food purposes, which has content of \(\Delta^{9}\)-THC below the legal limit of 0.2-0.3% [2; 5] and is rich in non-psychoactive cannabinoids. Currently, 69 hemp varieties have been approved for commercial use by the European Community [6]. The pharmaceutical interest in this plant has been mainly addressed to drug-type _Cannabis_, thanks to its new therapeutic applications [7], while hemp is at the moment under-employed in this ambit. However, the number of studies focused on the characterisation of fibre-type hemp varieties and on the evaluation of the biological potential of non-psychoactive compounds has increased lately [2; 3; 8; 9; 10; 11; 12; 13; 14; 15; 16]. The chemistry of _C. sativa_ is known to be very complex; indeed, several chemical classes have been identified in the plant, encompassing terpen, carbohydrates, fatty acids and their esters, amides, amines, phytosteros, phenolic compounds, and cannabinoids [17]. From a chemical point of view, the latter are meroterpenoids and they are specific of this plant [2; 17]. Usually, the most abundant cannabinoids present in fibre-type plants are cannabinoic acids, such as cannabidiolic acid (CBDA) and cannabigerolic acid (CBGA), followed by their decarboxylated forms, namely cannabidiol (CBD) and cannabigerol (CBG) (Figure 1) [9]. In plant tissues, cannabinoids are biosynthesized in the acid form; environmental factors, such as heat and light, generally induce a spontaneous decarboxylation process to form decarboxylated cannabinoids [2; 4; 9; 16; 18; 19]. Among non-psychoactive cannabinoids, CBD represents the most promising one from the pharmaceutical point of view, due to its high anti-oxidant and anti-inflammatory activity, in addition to its anticonvulsant, anxiolytic, neuroprotective, and antibiotic properties [2; 4; 20; 21; 22; 23]. CBDA has antimicrobial and anti-nausea properties [2; 20; 22], while CBG has anti-inflammatory, antimicrobial and analgesic activities [2; 20; 22; 24]. Concerning other phenolic compounds, several flavonoids have been identified in _C. sativa_, belonging mainly to flavones and flavonoids [25]. In particular, cannflavin A and B represent hemp-specific methylated isoprenoid flavones (Figure 2) [25]. Several biological effects have been ascribed to hemp flavonoids, including anti-inflammatory, anti-microbial, neuroprotective, and anti-proliferative activities [17]. In particular, cannflavin A and B are known to possess an anti-inflammatory action [17] and microsomal prostaglandin E\({}_{2}\) synthase (mPGES-1) and 5-lipoxygenase (5-LO) have been identified as their molecular targets [26]. In addition to flavonoids, dihydrotislbenoids represent another class of polyphenic substances isolated from hemp, of which canniprene is the main representative (Figure 2) [25].