Cannabis sativa Linn.: A Medicinal Plant with Promising Muscle Relaxant-related Constituents

Medicinal plants have served as a source of medicine since human existence. Cannabis sativa , also known as cannabis, or hemp, is one of the most widely known medicinal plants used for the management of ailments, including muscular and/or joint pains, and their associated injuries. Cannabis contains valuable secondary metabolites, terpenes (α-pinene, β-caryophyllene, limonene, and myrcene), terpenoids (camphor, linalool, and terpineol), phenolics (stilbene, spiroindan, and cannflavin), and phytocannabinoids [cannabidiol (CBD), delta-9-tetrahydrocannabinol (Δ ⁹ -THC), cannabinol (CBN), cannabigerol (CBG), and their acidic forms]. These classes of compounds are known to contribute to the analgesic, anti-inflammatory, anti-arthritis, and other muscle relaxant-related properties of cannabis. Structurally, phytocannabinoids with an extended side chain at position C3 can activate cannabinoid receptors, promoting inhibition of signaling pathways MAPK and cAMP associated with pain and inflammation. This review discusses C. sativa phytocompounds with muscle relaxant-related properties (inflammation, pain, and arthritis) and their structure-activity relationship, with a view to identifying natural muscle relaxants as possible drug candidates.