Abstract
Cannabis sativa is an annual, dioecious plant belonging to the family Cannabaceae, with origins traced to equatorial and subtropical regions, particularly Central Asia. In Nepal, cannabis has long held cultural and medicinal significance within Ayurvedic and traditional healing systems, where it is associated with restoring balance between the body, mind and spirit. This review aims to provide a comprehensive overview of medicinal cannabis, with a particular focus on the current Nepalese legislative framework, its botanical and geographical characteristics, pharmacological properties, chemical composition, formulations and future perspectives.A systematic literature search was conducted using PubMed, MEDLINE, Europe PMC and Google Scholar. Relevant studies were identified using thematically aligned keyword combinations, refined iteratively and linked using Boolean operators to ensure broad and inclusive coverage of available evidence. After years of prohibition, Nepal is set to legalize the cultivation and consumption of Cannabis for medicinal purposes. It contains a variety of phytochemicals, including alkaloids, flavonoids, terpenoids and cannabinoids, which are its main bioactive compounds. Cannabinoids are classified into phytocannabinoids, endocannabinoids and synthetic cannabinomimetics, primarily interacting with CB1 and CB2 receptors. Traditionally, cannabis has been used to address digestive issues, pain relief, rheumatism and gout. In contemporary medicine, it treats conditions such as HIV/AIDS, cancer, PTSD, glaucoma and chronic pain. Medicinal cannabis presents significant therapeutic potential supported by traditional knowledge and emerging scientific evidence. A clear and robust regulatory framework, combined with further pharmacological and clinical research, is essential to ensure its safe, effective and ethical integration into Nepal’s healthcare system.
Keywords
Introduction
Global Resurgence of Medicinal Cannabis
Cannabis, a member of the family Cannabaceae, is one of the earliest cultivated plants and has been traditionally used for fiber, grain and a variety of recreational, medicinal and ritualistic purposes. 1 Historical records spanning millennia document its therapeutic application in the treatment of numerous medical conditions.2,3 It has been used to manage conditions such as childhood epilepsy, chemotherapy-induced nausea and vomiting, chronic pain and spasticity associated with multiple sclerosis. Beyond these established uses, emerging evidence suggests that medicinal cannabis may also help reduce stress, improve sleep quality and decrease reliance on certain high-risk medications.4-6
Global Cannabis Legalization Status
Medicinal Cannabis: Nepalese History and Legislation
Nepal is renowned for its incredible mega-biodiversity and is home to a wide variety of medicinal plants. 16 Since ancient times, plant-based remedies have been integral to various healing systems such as ayurveda, homeopathy, allopathy and traditional medicine. 17 Among these plants, cannabis holds a special place due to its deep connection with Lord Shiva, as mentioned in the oldest Vedic scriptures. 18 It is referred to as ganja while the squeezed forms used for consumption, either edible or smoked, are known as “charas” and “bhang” in the Nepali and Sanskrit languages. 19 Cannabis has long been a part of Nepal’s Ayurvedic healing traditions, playing a role in practices that seek to balance the body, mind and spirit. Its use is often linked to the Maha Shivratri festival, a significant celebration for Nepalese, as well as other festivals honoring Lord Shiva. However, ancient Vedic texts informed that Shiva used bhang for self-purification and mastery, but other people should pay cautions for its use. 20
During the 19th century British colonial officials documented the extensive use of cannabis products in India and Nepal. 21 Nepalese cannabis farmers harvest three distinct products from a single crop of cannabis: seed, psychoactive resin, and fiber. H. B. Hodgson initially wrote about the practice of gathering food, fiber and medicines from the same field in Nepal in 1855 AD; other regions have not yet been known to harvest all three classes of items from a single crop. The most important by product of cannabis growing is seeds since seeds are needed to plant a crop.6,10In 1975 AD, James Fisher noted that cannabis was historically cultivated across various altitudes and terrains throughout Nepal. 20 Before 1973, Kathmandu was known as a ‘hippie paradise,’ with cannabis readily available across the country. Licensed dealers even operated in the well-known ‘Freak Street’ in Kathmandu, selling hashish openly. During this time, many hippies from the West move to Nepal to indulge in the good-quality cannabis, while local farmers freely produced hashish. As a result, Nepalese youth began adopting the hippie lifestyle, leading to a rapid increase in recreational cannabis use. 18
In response to continued pressure from the United States and the United Nations, Nepal enacted the Narcotic Drugs (Control) Act of 1976, which prohibited the licensing of cannabis sellers and producers and effectively banned its production. 19 The Narcotic Drugs (Control) Act of 1976, later amended in 1998, formally prohibited the use of cannabis in the country. 18 This comprehensive legislation establishes the legal framework for regulating the cultivation, production, distribution, possession, and consumption of narcotic drugs. Section 3(a) of the Narcotic Drugs (Control) Act defines narcotic drugs to include cannabis, medicinal cannabis, opium, processed opium, coca plants and leaves, substances derived from opium, coca extracts, and their mixtures or salts, as well as any natural or synthetic narcotic drugs and psychotropic substances listed in the Nepal Gazette. Violations of this law can result in severe penalties, including life imprisonment and fines. While the use of narcotic drugs without a doctor’s prescription is a criminal offense, the Act also incorporates provisions for the prevention and treatment of drug users. 22 Nevertheless, illicit cultivation and use of cannabis continue, and advocates remain committed to pushing for its legalization. Given Nepal’s agrarian economy, legalizing cannabis could offer significant economic opportunities for farmers and agricultural entrepreneurs, as it has the potential to become a highly profitable cash crop. 23
Cannabis remains the most commonly seized narcotic in Nepal, according to statistics from the Narcotics Control Bureau. In 2018, authorities seized 4,181 kg of cannabis and 1,546 kg of hashish, reflecting a slight increase from the previous fiscal year. 24 Nevertheless, thousands of kilograms of cannabis are seized annually, indicating that the Nepal’s narcotic law has not been implemented effectively. Recently, there has been a growing movement in Nepal advocating for the commercial cultivation of cannabis, highlighting its potential as a cash crop and a source of employment. On March 2, 2020, a private bill titled “Marijuana Growing Regulation and Management in Nepal” was submitted to the House of Representatives’ parliamentary secretariat, urging the government to legalize marijuana farming. 25 Advocates for legalizing cannabis in Nepal have been attempting to convince people and government that it could be the great source of income for country. 24 They also mentioned that the cannabis should be legalized for the medicinal uses and for research purpose only and should be monitored strongly. However, the legalization of drug is very sensitive issue due to its addiction and abuse potential and spillover effects leading to increased recreational use and potential black market diversion. Researchers and critics have called attention to the rising cannabis use among young people in Nepal as well as the negative health and social effects of this behavior. 18 Its legalization to boost the economy of the nation or its restriction to manage any potential negative impacts are still hotly contested issues in Nepal. 26
After years of prohibition, Nepal is set to legalize the cultivation and consumption of marijuana for medicinal purposes. On May 28, 2024, during the presentation of the government’s budget estimates for the 2024-25 fiscal year, the then Finance Minister announced this significant policy shift. Addressing a joint session of Parliament, the minister stated that the necessary laws would be established to facilitate the commercial production of marijuana in the country. Legalizing marijuana cultivation in Nepal would require not only amending the Narcotic Drugs (Control) Act of 1976 but also submitting a formal application to the Narcotic Convention for approval from the International Narcotics Control Board. As a signatory to the United Nations Single Convention on Narcotic Drugs of 1961, which categorizes marijuana alongside hard drugs like heroin, Nepal faces significant international regulatory hurdles. 27 Nepal should also draw lessons from countries that have legalized or decriminalized cannabis, as their varied experiences and challenges highlight the need for a carefully designed regulatory framework, effective supply chain management, strong public safety measures, and sustained investment in public education.
Within this global context, Nepal’s forthcoming legal reforms underscore the urgent need for a comprehensive assessment of the country’s current legislative framework, chemical composition, pharmacological properties and potential clinical applications of cannabis. This review aims to provide an integrated overview of Nepalese legislation, the chemistry and pharmacology of cannabis, and its medicinal prospects, thereby informing policymakers, clinicians, and researchers about evidence-based approaches for safe and regulated medicinal cannabis use in Nepal.
Method
A systematic literature search was conducted using PubMed, MEDLINE, Europe PMC and Google Scholar. These databases were searched using the following search terms: “Cannabis” OR “Cannabis Sativa” AND “Pharmacology” AND “Cannabinoids receptor” OR “Phytocannabinoids” OR “Endocannabinoids” OR “Synthetic Cannabinomimetics” AND “Extraction of cannabinoids” AND “Cannabinoids Formulation” AND “Phytochemicals” OR “Legislation Nepal”. These key terms were used in multiple combinations to create strings to search study records’ titles and abstracts.
Botanical Aspects and Geographical Distribution of Cannabis
Botanical Aspects
C. sativa belongs to the Cannabaceae family, which comprises 12 genera and 102 species, including some of economic significance such as Humulus lupulus L. and Pteroceltis tatarinowii. 1 The genus Cannabis consists of a single species, sativa, which includes several subspecies or varieties, namely Cannabis sativa ssp. sativa, Cannabis sativa ssp. indica, Cannabis sativa ssp. ruderalis, and Cannabis sativa ssp. Afghanica, of which sativa, indica, and ruderalis are present in Nepal. 28 Currently, Cannabis is known by numerous local and vernacular names, as well as various synonyms, including hashish, marijuana, weed, Acapulco gold, ace, bat, bhang, log, hemp, Indian hemp, Colombian, doobie, dope (Cannabis), ganja, hydro, Jamaican, jive (sticks), joint, Maui wowie, Mexican, Panama gold, Panama red, pot, firecracker, ragweed, reefer, sativa, sinsemilla of California, spliff, Thai stick and others. These names and designations vary depending on the region, country and cultural context. 1
C. sativa is generally a dioecious, and occasionally monoecious, annual flowering plant. 29 Known for its rapid growth, it features fluted stems that typically reach 1–4 meters in height and 1–3 centimeters in diameter, with variations depending on the subspecies, environment, soil, and climatic conditions. 30 The female flowers, along with the leaves of both male and female plants to a lesser extent, are densely coated with resin, a highly valuable product due to its psychoactive and medicinal properties.31,32 This resin is rich in glandular trichomes, which produce secondary metabolites such as phytocannabinoids—the principal psychoactive and medicinal compounds in cannabis—as well as volatile terpenes that give the plant its characteristic aroma. Female flowers, which lack petals, possess two elongated stigmas that may be white, yellow, or pink. The calyx, measuring 3–6 mm, surrounds the ovary, which contains a single ovule. These flowers develop in pairs at the axils of small leaves called bracts, which are densely covered with glandular trichomes where cannabinoids, including THC, accumulate. In contrast, male flowers have five sepals approximately 5 mm long and are typically yellow, white, or green. Male plants produce pollen sacs that fertilize the resinous, hairy stigmas of female flowers.1,33
The seeds are smooth, grayish and either ovoid or spherical in shape, typically measuring 2.5 to 3.5 mm in length and 2.5 to 3 mm in diameter. Each seed contains two cotyledons that are rich in nutrients, particularly protein and oil, while the albumen is relatively small compared to that of other plant species. 34 The leaves of C. sativa are stipulate and typically arranged in opposite pairs, featuring palmate, elongated segments with spiny, toothed edges. Toward the upper part of the plant, the leaves are alternately arranged along the stem, spaced 10–30 cm apart. The plant bears three types of hairs: cystolithic, tectorial and resin-secreting. The resin-secreting hairs have a broad base topped with a cluster of cells responsible for resin production.35,36 It has a taproot system, with the main root extending up to 30 cm deep, while lateral roots can spread between 20 to 100 cm. In peaty soils, the lateral roots are more pronounced and the primary root usually penetrates to a depth of 10 to 20 cm. The root system develops more slowly during the plant’s early growth stages, while the above-ground parts grow rapidly and intensively. 37
Geographical Distribution
Cannabis is remarkably adaptable and can flourish in various climates. It prefers calcareous, nitrogen-rich soils with a neutral or slightly acidic pH. Believed to have originated in equatorial and subtropical regions, particularly in central Asia, the plant is thought to have two main points of origin: the foothills of the Himalayas 38 and the Pamir Plateau extending across eastern Tajikistan, Afghanistan, China and Kyrgyzstan. 3 Today, cannabis is extensively cultivated worldwide, thriving in regions including Canada, the United States, Europe, Africa and South Asia.39,40 Although cannabis is an ancient species, its importance has surged significantly over the past century, transforming global views and industries. It is believed to be one of the first plants domesticated by humans, with evidence of cultivation dating back thousands of years. The earliest known instance of cannabis use is from 26,900 B.C., when a hemp rope was found in the Czech Republic. In China, cannabis was utilized as early as 10,000 B.C. for producing clothing, rope, and paper. Additional evidence of hemp use has been discovered on Chinese ceramics from the Neolithic period which featured decorations made from braided hemp fibers. Between 8000 and 300 B.C., cannabis was also grown in Japan for making cloth and paper. 41
The earliest recorded mention of cannabis’s psychotropic effects dates back to 2700 B.C., found in the Chinese pharmacopeia attributed to Emperor Shen Nong, who recommended it as a sedative and a remedy for insanity. In 1550 B.C., the Ebers Papyrus from ancient Egypt referenced cannabis as a treatment for vaginal inflammation. The plant was also noted in Greek medicine, where Dioscorides highlighted its psychoactive properties, while Galen cautioned that excessive use could damage the brain. 42 In the United States, cannabis was an important crop until 1937 AD, when the Marihuana Tax Act caused a downturn in the American hemp industry. However, during World War II, its use revived for producing military supplies such as uniforms, canvas and rope. In recent years, the most significant change in cannabis production has been the growth of indoor cultivation, particularly in Europe, Australia and North America. This method has led to a highly lucrative trade, often linked to organized crime in certain areas.34,43
Phytochemistry of Medicinal Cannabis
Cannabinoid Receptors and Chemistry
Many studies have emphasized the importance of cannabis’s secondary metabolites and their various functions. The plant is a rich source of bioactive compounds with potential uses in the pharmaceutical, nutraceutical and cosmetic sectors. Chemical analyses of different parts of the C. sativa plant have shown that terpenes, polyphenols and cannabinoids are the main secondary metabolites. 44 More than 100 terpenes have been identified in the flowers, roots and leaves of the plant, with the secretory glandular hairs serving as the primary site of their production.45,46 In addition, over 20 polyphenols have been identified, primarily consisting of flavonoids from the flavone and flavonol subclasses.
Cannabinoid receptors are distributed across various body systems, including the urinary, reproductive, and gastrointestinal tracts, endocrine glands, spleen, leukocytes, heart, arteries, and several peripheral tissues. They primarily interact with CB1 cannabinoid receptor, which is widely present throughout the body and to a lesser extent with the CB2 cannabinoid receptor.47,48 They also interact with transient receptor potential (TRP) channels, serotonin 1A receptors, opioid receptors, several ligand-gated ion channels, and peroxisome proliferator-activated receptors (PPARs).
Cannabinoid receptor shows its physiological action through G-protein modulated coupled receptors. The CB1 receptors are mostly present in brain which mediates most of the psychoactive effects of cannabinoids 49 and is responsible for the release of neurotransmitter 50 while CB2 receptors are responsible to control cytokine production and immune cell movement. Also, the cannabinoids interacts with different neurotransmitters through colocalization of cannabinoid receptors with other types of receptors. 51 Initially, it was believed that cannabinoids, due to their lipophilic properties, exerted various biological effects by nonspecifically disrupting cell membranes. However, after the discovery of THC and the emergence of several chemically synthesized cannabinoids, researchers successfully mapped and pharmacologically characterized cannabinoid binding sites in the brain. This revealed the existence of a putative cannabinoid receptor (CBR) resembling the nature of G protein-coupled receptors (GPCRs), which has since been identified as the orphan GPCR now known as CB1R.51,52
The three primary categories of cannabinoids are: phytocannabinoids, which are naturally occurring in plants; endocannabinoids, which are produced by animals and can modulate the effects of some phytocannabinoids; and synthetic cannabinomimetics, which are artificially created substances that may or may not resemble phytocannabinoids structurally but still exert agonistic effects on cannabinoid receptors. 53
Phytocannabinoids
In 1964, Gaoni and Mechoulam described the chemical composition of D9 -tetrahydrocannabinol, also known as D9 -THC, the most well-known phytocannabinoid. 52 THC shows euphoric effects brought on by cannabis of the marijuana variety. The cannabis cultivars yield dried buds that contain up to 30 % D9-THC. There are more than 100 phytocannabinoids isolated till date. The common biosynthetic precursor of phytocannabinoids is cannabigerolic acid (CBGA). It is formed by joining: olivetolic acid, and the geranyl part of geranylpyrophosphate. The enzyme geranylpyrophosphate:olivetolic acid geranyltransferase catalyzes the synthesis of CBGA. 54 Additional plant enzymes like cannabichromenic acid (CBCA), cannabidiolic acid (CBDA) and D9-tetrahydrocannabinolic acid (D9 -THCA) worked as catalyzed in production of others types of CBGA through cyclization. 55 The other phytocannabinoids are byproducts of the acids’ exposure to light, heat and oxidants. Thermally induced decarboxylation of the four cannabinoid acids can convert them into their corresponding “neutral” forms, which are cannabigerol (CBG), cannabichromene (CBC), D9-THC and CBD. When the dried grain is burned or heated, the release of carbon dioxide occurs more quickly at high temperatures. The neutral cannabinoids cause the majority of the biological effects brought on by cannabis administration, while D9-THC is frequently supplied through smoking for recreational purpose. Moreover, D9 -THC can go through a number of chemical processes. The two most significant ones are isomerization to D8 -Tetrahydrocannabinol (D8 -THC) by moving the D9 -double bond and oxidation to the completely aromatic cannabinol (CBN).
Following a series of studies conducted in Cahn’s lab in the 1930s, CBN was the first cannabinoid to be thoroughly characterized.
56
CBDA is the primary cannabinoid produced in cannabis cultivars that are more closely related to hemp than to marijuana, which were initially developed to produce large amounts of D9-THCA. Medical marijuana producers often cultivate a variety of strains, ranging from those high in CBDA to those rich in D9-THCA, as combinations of CBD and D9-THC have the potential to treat various human ailments and diseases. Additionally, cannabis contains smaller amounts of D9-THC and CBD derivatives with methyl, n-propyl, n-butyl, and n-heptyl groups, alongside the primary phytocannabinoids that feature n-pentyl side chains (Figure 1) (Table 1).
57
The “varinoids,” which include tetrahydrocannabivarinic acid (D9-THCVA), tetrahydrocannabivarin (D9-THCV), cannabidivarinic acid (CBDVA), and cannabidivarin (CBDV), are the only analogues consistently quantified in cannabis samples.
58
Structure of various isolated Phytocannabinoids
Endocannabinoids
Following the discovery of the CB1 and CB2 mammalian receptors for phytocannabinoids in the early 1990s, researchers began identifying endogenous cannabinoids. The endocannabinoid system, a widespread lipid signaling network present in all vertebrates, plays a critical regulatory role throughout the body. It consists of endogenous cannabinoids, cannabinoid receptors and the enzymes responsible for the synthesis and degradation of endocannabinoids. The two most extensively studied endocannabinoids are 2-arachidonoyl glycerol (2-AG) and arachidonoyl ethanolamide (anandamide) (Figure 2).56,59 These endocannabinoids exhibit distinct physiological and pathological effects due to their production and metabolism via different enzymatic pathways.
60
They act on a family of G-protein-coupled receptors located in brain regions involved in motor control, cognition, emotional responses, motivated behavior and homeostasis.
61
Endocannabinoids are released on demand from lipid precursors in a receptor-dependent manner, functioning as retrograde signaling messengers at GABAergic and glutamatergic synapses while modulating postsynaptic transmission. They also influence postsynaptic signaling by interacting with other neurotransmitters, including dopamine.
62
Recent pharmacological advances have led to the development of cannabinoid receptor agonists and antagonists, anandamide uptake inhibitors, and potent, selective blockers of endocannabinoid degradation.
62
Structure of various isolated Endocannabinoids
The O-acyl analogue of anandamide is virodhamine, and 2-arachidonylglycerol ether (2-AGE, 17) is a reduced version of 2-AG. Other endocannabinoids include N-acylamino acids (eg N-arachidonoylserine, 18) and N-acylated neurotransmitters, N-acylserotonins as well as the N-acyldopamine. 63 Ethanolamides are suggested congeners of anandamide likewise; 2-oleoylglycerol and 2-linoleoylglycerol are 2-AG congeners. Glycine and 2-aminoethanesulfonic acid-derived N-acylated amino acid analogues of N-arachidonoylserine are examples of participating analogues (taurine). 63
Synthetic Cannabinomimetics
The term “classical cannabinoids” refers to the earliest class of cannabinomimetics, was largely developed in Raphael Mechoulam’s lab at Hebrew University in 1972.
64
They synthesized a variety of analogs using techniques discovered during the synthesis of phytocannabinoids and evaluated their biological activity.
52
The 1,10 -dimethylheptyl (DMH) substituent became prominent and can now be found in several important cannabinomimetics including HU-210 [(6aR,10aR)-9-(hydroxymethyl)-6,6-dimethyl-3-(2-methyloctan-2-yl)-6a,7,10,10a-tetrahydrobenzo[c] chromen-1-ol)]
65
ajulemic acid
66
and nabilone.
67
Synthetic cannabinoids dronabinol is a partial agonist at the CB1 receptor and with a somewhat lesser affinity at CB2 receptors, is (−)trans-Δ9-tetrahydrocannabinol (THC).
68
Additional cannabinomimetic compounds with the DMH side chain include HU-320 (7-nor-7-carboxy-CBD-1,1-DMH)
67
which resembles a CBD metabolite and the more complex HU-308.
69
JWH-133A (Dimethylbutyl-deoxy-Delta-8-THC) much simpler mimetic
70
which is closely related to D8 – THC. The first synthetic cannabinomimetic to be discovered in a commercial “synthetic cannabis” was the octyl analogue of (C8)-CP 47,497, commonly known as “cannabicyclohexanol,” along with a stereoisomer, CP 47,497 and 1-Pentyl-3-(1-naphthoyl) indole (JWH-018) (Figure 3).67,71 Structure of various Synthetic Cannabinomimetics
Extraction and Analysis of Cannabinoids
Cannabis extraction can be employed to concentrate specific ingredients for new product development. Key factors such as mean particle size, size distribution, temperature, agitation rate and extraction time can significantly affect the yield of the extract. Various methods related to cannabis extraction have been explored, including solvent-less, solvent-based, conventional and alternative techniques. 72
Soxhlet and dynamic maceration are two examples of conventional extraction techniques that require a lot of solvent to finish the extraction process. Newer techniques, such as those utilizing pressurized liquid extraction, supercritical fluid, microwave, and ultrasonic assistance, can be thought of as slightly more environmentally friendly alternatives to traditional techniques. These processes decrease the need for synthetic and organic solvents, shorten the processing time and result in a higher yielding, higher-quality extract however conventional methods are recognized for their reliability as systematic side by side assessment is lacking. 73
The preferred product in the cannabis industry historically been dried cannabis flowers, but as the market grows, so does the desire for other products with different qualities. Hence, while choosing a drying procedure or an extraction method to create a certain product, a number of things should be taken into account. Although there is currently a paucity of academic study and supporting data, freeze-drying is thought to be a more suitable drying technique when compared to other methods for post-harvest processing. The most practical method for lowering the prevalence of mold and bacteria during storage before extraction is still hang-drying. Due to their high yield, simple and quick processes, solvent less extraction and hydrodynamic extraction are of interest, but they lack the scholarly publications to support their use in large-scale production. Slightly polar solvents are advised for cannabis’ hydrophobic or lipophilic characteristics when determining extraction methods. However non-polar solvents are advised for terpenes with more than 15 carbons. Traditional procedures like soxhlet and dynamic maceration are utilized since they take a lot of time and solvent but are accurate enough to be compared to newer methods.74,75
In case of analysis GC-flame ionization detector (FID) and HPLC-UV are the two most popular instrumental techniques for cannabis analysis 75 ; Nonetheless, HPLC has become the technique of choice for cannabinoid investigation of the plant’s natural makeup. Although the cannabinoids are biosynthesized as carboxylic acids, the heat—applied from an ignition source or a GC injector—decarboxylate the carboxylic acids and transform them into their physiologically active forms. Decarboxylation is avoided via derivitization, however additional sample processing procedures are necessary. Additionally, it has been demonstrated that the conversion procedures in the GC injector are insufficient and extremely reliant on the instrument setup (29). All the analytes of interest are separated using HPLC methods, although the procedure took 36 minutes and used mobile phases that required buffer solutions, which are more difficult to work in everyday circumstances. Another extensively used technique is thin layer chromatography. Despite TLC’s outstanding sensitivity and selectivity, the technique cannot compete with other quantitative analysis methods because it always necessitates an additional step for quantification. TLC, on the other hand, is frequently used to find cannabis metabolites. 76
Pharmacological Uses and Adverse Effects of Cannabis
Pharmacological Activity of Cannabis sativa as Reported From Different Studies
Antioxidant Activity
The cannabis plant contains a diverse array of secondary metabolites, including cannabinoids, terpenes, and flavonoids, which are responsible for many of its pharmacological properties. 101 Research conducted by Tura et al demonstrated that CBD exhibits notable antioxidant activity in vitro. 102 In addition, another study evaluated the antioxidant potential of CBC, CBG and other hemp-derived compounds. 103
Further investigations assessed the antioxidant capacity of ethanolic cannabis root extracts using ABTS and ferric reducing antioxidant power (FRAP) assays, along with cellular antioxidant activity assays in Saccharomyces cerevisiae. The findings indicated that extracts from all examined chemovars showed moderate antioxidant effects in vitro (FRAP and ABTS assays), while cellular antioxidant activity appeared more pronounced. However, these effects were highly influenced by the specific chemovar and external factors such as harvest timing. 104
Moreover, a study by Kubiliene et al evaluated the antioxidant effects of Cannabis sativa L. extract by measuring malondialdehyde (MDA) and glutathione (GSH) levels, as well as catalase (CAT) activity, in BALB/c mice. The results revealed that cannabis extract significantly reduced GSH levels in the blood by 26.81% (p < 0.05), as well as MDA concentrations in the brain (by 82.12%) and liver (by 53.5%) compared to the AlCl3-treated group. Additionally, the extract significantly increased CAT activity in the brain (by 64.79%) and liver (by 72.37%) following AlCl3-induced oxidative stress. 80
Neurological Disorders
C. sativa has gained considerable attention in epilepsy management, particularly because conventional antiepileptic drugs (AEDs) fail to adequately control seizures in approximately one-third of patients with refractory epilepsy. 103 A major milestone in this area was the U.S. FDA approval of Epidiolex in 2018, marking the first cannabis-derived medication authorized for epilepsy treatment. 105 Ibeas Bih et al, reported that CBD reduces neuronal inflammation and neurotoxicity, indicating both symptomatic and neuroprotective benefits in chronic epilepsy. 106 In another study, Marsh et al, evaluated neuroprotection using the thiazolyl blue tetrazolium bromide (MTT) assay and found that tetrahydrocannabinol (THC) and tetrahydrocannabinolic acid (THCA)-dominant cannabis extracts provided the strongest protection against Aβ1–42-induced cytotoxicity in PC12 cells. 107 Similarly, Jones et al, demonstrated that CBD significantly decreased seizure frequency and severity in mice while producing minimal adverse effects, highlighting its anticonvulsant and neuroprotective properties. 104
Mechanistically, CBD is believed to enhance the activity of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter that helps regulate neuronal excitability, thereby reducing seizure susceptibility. 108 Additionally, different receptor systems appear to contribute to CBD’s broader neurological effects. Some studies suggest that the 5-HT1A receptor is involved in its anxiolytic action, while others point to the CB1 receptor as a key mediator under varying experimental conditions. 109 These inconsistencies indicate that further research is required to fully clarify the mechanisms underlying CBD’s anxiolytic and antidepressant-like effects. 104
Cannabinoids, particularly CBD and THC, are also being explored as potential treatments for anxiety disorders, supported by both preclinical and clinical findings. 110 Observational and cross-sectional studies have reported mixed outcomes regarding the relationship between cannabis use and anxiety. Some studies among university students have found that cannabis use is associated with lower reported anxiety and depressive symptoms, whereas others have observed no significant relationship with state anxiety. In contrast, a 10-year longitudinal study (N = 1,395) identified an association between cannabis use (and cannabis use disorder) and anxiety disorders, even after adjusting for confounding variables. 111
Preclinical research has further examined the anxiolytic effects of CBD using animal models. The Elevated Plus Maze (EPM), a commonly used behavioral test, assesses anxiety based on rodents’ conflict between exploratory behavior and fear of open spaces. Additional models, including the Forced Swimming Test (FST) and the Vogel Conflict Test (VCT), have also been employed to evaluate the anxiolytic potential of C. sativa. 83 Moreover, CBD has been shown to reduce the production of pro-inflammatory cytokines and reactive oxygen species (ROS), thereby protecting neurons from excitotoxic damage and contributing to its overall neuroprotective profile.
Regarding effects on the neurological disorder, there is insufficient preclinical evidence to support the efficacy of hemp across many in vivo neurological models, although some in vitro studies suggest potential benefits. 112 Given the limited therapeutic options and the high failure rates of clinical trials for neurological disorders, more robust preclinical research is essential to enable successful translation into clinical applications.
Anti-Inflammatory Activity
C. sativa is considered a promising source of anti-inflammatory compounds. The anti-inflammatory effects of cannabis extracts and individual cannabinoids have been investigated in lipopolysaccharide (LPS)-induced inflammation models using human acute monocytic leukemia (THP-1) macrophages. These studies demonstrated that pre-treatment with cannabidiol (CBD), tetrahydrocannabinol (THC), or extracts rich in these cannabinoids significantly reduced the induction of multiple pro-inflammatory cytokines. 113 In a similar investigation using mouse microglial (BV2) cells, the anti-inflammatory activity of C. sativa L. extracts was assessed by measuring nitrite production and the expression of key inflammatory mediators, including inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. The findings revealed that C. sativa extract enhanced oxygen balance, inhibited mast cell degranulation in deep cervical lymph nodes, and significantly suppressed the expression of IL-1β, IL-6, TNF-α, nitrite, iNOS, and COX-2 in BV2 microglial cells. 114
Further evidence from a study by Shebaby et al, evaluated both in vitro and in vivo anti-inflammatory effects of Lebanese C. sativa oil extracts (COE). Using carrageenan- and formalin-induced paw edema models in rats, along with LPS-stimulated rat monocytes, the study showed that COE markedly reduced TNF-α production. Western blot analysis confirmed that COE significantly inhibited LPS-induced expression of COX-2 and iNOS proteins, as well as the phosphorylation of mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 MAPK. Additionally, COE significantly decreased paw edema in both experimental rat models. 115 Another study by Wolinska investigated the effects of a high-CBD C. sativa L. extract (eCBD) in a rat model of acute dermatitis induced by repeated application of 2,4-dinitrochlorobenzene (DNCB) to the ear skin. The results indicated that the anti-edematous effect was more pronounced in rats treated with eCBD compared to those treated with 1% hydrocortisone ointment. However, while hydrocortisone showed a clear antipruritic (anti-itch) effect, eCBD did not significantly reduce DNCB-induced scratching behavior. 116
Current evidence from in vitro and in vivo studies indicates that inflammatory effects vary depending on the inflammatory environment, plant species, geographic origin, and cell lines. The mechanisms driving these differences remain unclear, and further research is necessary to translate these findings into clinically meaningful models.
Analgesic Activity
The analgesic effects of THC, crude marijuana extract (CME), CBN, CBD, morphine sulfate, and aspirin have been comparatively evaluated in animal models following oral administration. Pain responses were assessed in mice using acetic acid-induced writhing and hot plate tests, and in rats using the Randall–Selitto paw pressure test. The findings indicated that THC and morphine exhibited comparable potency across most tests, although morphine was significantly more effective in increasing the pain threshold in the uninflamed rat hind paw. When standardized for THC content, CME demonstrated similar potency in the hot plate and Randall–Selitto tests, but showed approximately threefold greater effectiveness in the acetic acid-induced writhing assay. In contrast, CBN, similar to aspirin, was only effective in reducing writhing frequency in mice. 84
In another investigation, Tavhare et al examined the analgesic and sedative properties of water-washed Cannabis sativa leaves using experimental animal models. The study utilized Wistar albino rats (200 ± 20 g) and Swiss albino mice (25–35 g) of both sexes. Analgesic activity was evaluated using the formalin test and tail flick method, while neuromuscular coordination was assessed through the rotarod test. The results confirmed significant analgesic effects along with observable sedative properties. 88
Additionally, Vargas et al (2023) explored the analgesic efficacy of a CBD-rich cannabis extract formulated within polymeric micelles (CBD/PMs) using mouse models of thermal, chemical, and mechanical pain. The pharmacological assessments revealed that orally administered CBD/PMs were safe and produced greater analgesic effects compared to non-encapsulated CBD or cannabis extract. In the chemical pain model, the micellar formulation achieved up to 42% analgesia. The study further demonstrated successful encapsulation of the cannabis extract within the nanocarrier system, which enhanced its stability and improved the efficiency of CBD release. Overall, the micelle-based formulation exhibited superior analgesic activity relative to the free extract, highlighting its potential as an effective drug delivery strategy. 94
Anticancer Activity
One of the most extensively explored therapeutic potentials of C. sativa lies in its possible role as an anticancer agent. Evidence suggests that cannabinoids may exert antitumor effects through multiple mechanisms, such as inducing apoptosis in malignant cells, inhibiting angiogenesis and limiting metastasis. 117 Recent investigations across different cancer models have shown that the phytocannabinoids tetrahydrocannabinol and cannabidiol display anticancer activity in both in vitro and in vivo settings, although their use may also enhance the adverse effects of certain chemotherapeutic drugs. These compounds act through diverse biological and signaling pathways, involving both receptor-mediated and receptor-independent mechanisms. THC, in particular, has been reported to promote apoptosis in various cancer cell types, suppress tumor growth and inhibit angiogenesis. 118
Through activation of cannabinoid receptors CB1 and CB2, THC reduces cancer cell survival and proliferation while enhancing apoptotic processes in glioblastoma multiforme (GBM) cells in vitro. Additionally, it has demonstrated the ability to inhibit tumor growth in GBM xenograft models in vivo. 119 In contrast, CBD generally shows low affinity for CB1 and CB2 receptors, making its primary molecular targets in anticancer activity less clearly defined. Cannabichromene (CBC), however, has been found to exhibit significant activity against breast and prostate cancer cells and to act synergistically with THC in bladder cancer models.120,121 THC has also been shown to suppress estradiol-induced proliferation in MCF-7 breast cancer cells by inhibiting estrogen receptor α activation and counteracting 17β-estradiol-driven cell growth, despite not directly binding to estrogen or androgen receptors. Conversely, findings by Takeda et al suggest that THC may upregulate human epidermal growth factor receptor 2 (HER2) expression, which could potentially enhance cancer cell proliferation in the same cell line.122,123
In leukemia models, both THC and CBD have demonstrated inhibitory effects, with IC50 values of 13 µM and 8 µM, respectively. Notably, when combined in a 1:1 ratio, the IC50 decreased to 4 µM, indicating enhanced potency. Furthermore, combining THC and CBD with conventional anticancer agents has, in some cases, produced synergistic effects, achieving comparable therapeutic outcomes at lower concentrations than when the compounds were used individually at higher doses. 124 Given the current understanding that different hemp cultivars contain a diverse range of compounds—many of which remain unidentified and vary in concentration thus further research is essential.
Adverse Effects Associated With Use of C Sativa
In addition to the medical benefits of marijuana already mentioned, both short- and long-term marijuana uses have been linked to a number of detrimental effects. In terms of somatic side effects, anxiety and panic attacks, as well as an elevated heart rate and alterations in blood pressure, are the most significant acute adverse effects brought on by overdose. 125 Long-term marijuana use is linked to addiction 126 also there is a debate regarding the potential long-term negative effects of cannabis on the immune system, fertility, and pregnancy, including the severity of these effects74,127 In addition, heavy marijuana users showed symptoms of bronchitis, poor IQ, and sluggish brain development. 128 There is still much to learn about the connection between marijuana use and cancer; studies on head and neck tumors have yielded inconsistent results, whilst research on lung cancer has found no association. However, some research has been able to prove a link between marijuana usage and testicular cancer. 128
As parents seek alternatives to traditional allopathic medications, there has been a recent rise in the number of adolescents who are prescribed medical marijuana. Early research on cannabis’ potential to cure a range of pediatric illnesses, including as cancer, autism, and attention deficit hyperactivity disorder, has yielded some encouraging results. Sadly, these have only been fairly brief investigations with very small sample sizes, not reliable and thoroughly planned controlled trials. Studies that used randomized controlled trials failed to demonstrate any conclusive benefits. Few studies have been conducted, making it challenging to predict the long-term effects of medical marijuana on the developing brain. 129
Cannabinoid Formulations
An increasing amount of research suggests that cannabinoids are helpful for a number of clinical problems, including anorexia, schizophrenia, multiple sclerosis symptoms, pain, inflammation, epilepsy, and sleep disturbances. Hence, the conversion of cannabis from herbal remedies into strictly controlled prescription pharmaceuticals is developing quickly. Well-controlled clinical trials must be conducted prior to the creation of such drugs in order to objectively assess therapeutic efficacy, dose ranges, and safety. Due to the low oral bioavailability of cannabis, practical delivery routes as transdermal, intranasal, and transmucosal adsorption have been proposed. Cannabinoids are thought to be good candidates for cutting-edge nanosized drug delivery systems because of their extremely lipophilic character, which can be used in a variety of ways. Nanotechnology-based drug delivery methods have proliferated in a number of therapeutic fields in recent years, and numerous drugs have entered the market. 130
Cannabinoids are extremely lipophilic compounds (log P 6-7) with very poor water solubility (2-10 g/mL) that are prone to deterioration, especially in solution, by the effects of light, temperature, and auto-oxidation. Hence, formulation has a significant impact on the medications’ physicochemical stability and solubility. Salt formation and cosolvency are common techniques in commercial products, as are micellization (e.g., polysorbate 80, cremophor ELP, etc.), (nano)-(micro)-emulsification, complexation (e.g., cyclodextrins), and encapsulation in lipid-based formulation.125,130,131
The two most frequent ways to consume cannabis products are orally or through smoking or vaporization. Minor but intriguing administration methods include oromucosal, topical-transdermal, and rectal. With absorption displaying the highest variation among the main pharmacokinetic phases, the pharmacokinetics and dynamics of cannabis vary depending on the route of administration. Inherent organ tissue variations and product lipophilicity both have an impact on absorption (i.e., alveolar, dermal vs. gastric). For oral delivery, cannabinoid absorption ranges from 20–30% while for inhalation; it can reach 10–60%. Various factors, such as recent meals (for oral delivery), the depth of inhalation, the length of breaths sustained, and vaporizer temperature might affect cannabinoid absorption. 132
The semi-synthetic THC derivative dronabinol, available as both a solution and a pill, has been approved by the FDA for treating chemotherapy-induced nausea in AIDS patients. Oh et al conducted a pharmacokinetic study comparing the oral solution and capsule forms of dronabinol in both fasting and fed conditions. When choosing the most suitable dronabinol product for a patient, it may be particularly important to consider the solution’s lower variability in absorption between individuals compared to the capsule form. While dronabinol’s analgesic effect on central pain in multiple sclerosis patients was minimal, it was still clinically significant.133,134 A polyvinylpyrrolidone capsule containing nabilone is available which have antiemetic properties for chemotherapy induced vomiting. 135
Conclusion and Future Perspective
Cannabis has been used for centuries for a wide range of medicinal and therapeutic purposes, and its social acceptance has gradually increased worldwide. In recent years, many countries have begun to reconsider their regulatory policies on cannabis in response to emerging scientific evidence supporting the potential therapeutic value of cannabinoids such as CBD and THC. For instance, in the United States, cannabis is legally permitted for certain medical uses in most states, and several states have also legalized it for adult recreational use. Despite these developments, regulatory challenges remain. Agencies such as the U.S. Food and Drug Administration maintain that CBD and THC cannot currently be marketed legally as ingredients in foods or dietary supplements under the Federal Food, Drug, and Cosmetic Act. Nevertheless, regulatory authorities are actively exploring the possibility of establishing a lawful pathway for the development and commercialization of cannabis-derived products. 136 These regulatory complexities illustrate the broader challenges involved in translating cannabis-derived compounds into standardized and approved prescription medications.
In the context of Nepal, cannabis holds a distinctive historical, cultural, and socio-economic significance. Although cannabis has traditionally been used in certain cultural and medicinal contexts, the current legal framework strictly prohibits its cultivation, distribution, and use. As discussions surrounding potential legalization or decriminalization gain attention, it becomes increasingly important to generate a strong evidence base to guide policy decisions. 137 However, the implementation of large-scale epidemiological or interventional research in Nepal is often hindered by limited research funding, infrastructure, and institutional support. Consequently, further well-designed and high-quality studies are necessary to better understand the therapeutic potential, safety profile, and long-term risks associated with cannabinoids such as CBD and THC.
From a policy perspective, if Nepal considers the legalization or regulated medicinal use of cannabis, the government must prioritize the development of a comprehensive regulatory framework. Such a framework should address critical issues including cultivation control, product quality assurance, adulteration, illegal trade, smuggling, and unauthorized export. These considerations are particularly important given Nepal’s open border with India, which could present additional regulatory and enforcement challenges. Therefore, policymakers should carefully examine the experiences and regulatory models of countries that have already implemented cannabis legalization or medical cannabis programs. Such comparative evaluations would help in developing evidence-based policies that balance potential therapeutic benefits with effective public health safeguards.
Future research should also focus on elucidating the biological mechanisms underlying cannabinoid activity, particularly their interactions with the endocannabinoid system and their role in modulating various pharmacological responses. Advanced experimental models, including cannabinoid receptor–knockout animals and receptor-specific ligands, may provide valuable insights into the roles of endocannabinoids, cannabinoid-like terpenes, and cannabinoid receptors in disease modulation. In addition, further investigation into the molecular signaling pathways activated by cannabinoid receptors is warranted. Studies exploring the influence of cannabinoids on immune-related processes such as adhesion molecule expression, co-stimulation, and chemotaxis in immune cells could significantly enhance our understanding of cannabinoid-mediated immunomodulation. 138 Such research may clarify the complex interactions between cannabinoids and the immune system during pathogenic insults and immune-related disorders. Overall, accumulating evidence suggests that cannabinoids may offer promising therapeutic potential as relatively safe and effective anti-inflammatory agents, particularly through the selective targeting of cannabinoid receptor pathways.
In conclusion, although cannabinoids demonstrate considerable pharmacological potential and promising therapeutic applications, the current body of scientific evidence remains insufficient to support their widespread clinical use for many medical conditions. Clear clinical guidance and robust evidence-based recommendations are therefore essential to ensure their safe and responsible application in medical practice. Moving forward, interdisciplinary collaboration among researchers, clinicians, policymakers, and regulatory authorities will be critical for advancing cannabis research and establishing effective governance frameworks. Through rigorous scientific investigation, culturally informed policymaking, and well-regulated supply and monitoring systems, Nepal may be able to responsibly explore the potential benefits of medicinal cannabis while minimizing possible risks to public health and society.
Footnotes
Ethical Considerations
Ethical Approval is not applicable for this article.
Consent to Participate
There are no human subjects in this article and informed consent is not applicable.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.