madman
Super Moderator
Abstract
Introduction
Hemp (Cannabis sativa subsp. sativa), commonly used for industrial purposes, is now being consumed by the public for various health-promoting effects. As the popularity of hemp research and claims of beneficial effects rises, a systematic collection of current scientific evidence on hemp’s health effects and pharmacological properties is needed to guide future research, clinical, and policy decision making.
Objective
To provide an overview and identify the present landscape of hemp research topics, trends, and gaps.
Methods
A systematic search and analysis strategy according to the preferred reporting items for systematic review and meta-analysis-ScR (PRISMA-ScR) checklist on electronic databases including MEDLINE, OVID (OVFT, APC Journal Club, EBM Reviews), Cochrane Library Central, and Clinicaltrials.gov was conducted to include and analyze hemp research articles from 2009 to 2019.
Results
65 primary articles (18 clinical, 47 pre-clinical) were reviewed. Several randomised controlled trials showed hempseed pills (in Traditional Chinese Medicine formulation MaZiRenWan) improving spontaneous bowel movement in functional constipation. There was also evidence suggesting benefits in cannabis dependence, epilepsy, and anxiety disorders. Pre-clinically, hemp derivatives showed potential anti-oxidative, anti-hypertensive, anti-inflammatory, anti-diabetic, anti-neuroinflammatory, anti-arthritic, anti-acne, and anti-microbial activities. Renal protective effects and estrogenic properties were also exhibited in vitro.
Conclusion
Current evidence on hemp-specific interventions is still preliminary, with limited high-quality clinical evidence for any specific therapeutic indication. This is mainly due to the wide variation in test item formulation, as the multiple variants of this plant differ in their phytochemical and bioactive compounds. Future empirical research should focus on standardizing the hemp plant for pharmaceutical use, and uniformity in experimental designs to strengthen the premise of using hemp in medicine.
Introduction
Hemp and marijuana belong to the same Cannabis sativa plant species, differing botanically at a subspecies level as C. sativa subsp. sativa (hemp) and C. sativa subsp. indica (marijuana) [1]. While marijuana has long gained popularity for medical uses [2], the rise of hemp research is relatively recent, as it is traditionally used for industrial purposes [3–7]. Legally, hemp is distinguished from marijuana according to the allowable upper limit of the psychoactive delta9-Tetrahydrocannabidiol (THC). The European Union caps the levels of delta-9-THC in hemp at 0.2% [8] while the U.S Agricultural Marketing Act 1946 restricts delta-9-THC to less than 0.3% on a dry weight basis [9]. Current U.S Food and Drug Administration approved cannabis-based drugs for therapeutic use are either synthetic or derived from medical marijuana, not hemp, indicating that evidence supporting the use of hemp for therapeutic purposes may still be insufficient [10–12].
Due to its non-psychoactive nature, nutrient-rich content, and easy accessibility in several countries, hemp has increasingly garnered public attention and is being commercialized and consumed by the general public as health-promoting and benefiting products, with or without cannabidiol (***), another major cannabinoid found in the Cannabis plant [13–15]. Recently, there is emerging evidence of non-cannabinoid active compounds contributing to the pharmacological effects of hemp [16, 17]. This evidence is different from current published systematic reviews of Cannabis, which have focused mainly on cannabinoids [18, 19]. A narrative review by Crescente et al., 2018 highlighted the historical use, phytochemicals, and some potential nutraceutical properties of hemp. However, there was a lack of systematic research, compilation, and analysis of all related studies and therefore this review does not provide an objective overview of current hemp research [14].
Despite hemp’s growing popularity, a systematic collection of available scientific evidence detailing the beneficial health effects in humans and pharmacological properties specific to hemp is limited. Since hemp-related biomedical research is a relatively new field of study, such evidence syntheses are valuable in guiding future research, clinical recommendations, and policy decisions making [20]. Hence, this paper aims to delineate the current landscape of hemp research, through recent scientific findings specific to the pharmacological properties of the hemp plant and its derived compounds, at both pre-clinical and clinical levels. Here, we present an overview of the research characteristics, patterns, and trends, identify gaps, and suggest a focus point for future research for the hemp plant. To our knowledge, this is the first scoping review on hemp’s overall pharmacological properties and health effects.
Hemp research scientific evidence: Topics, trends, and gaps
*Multiple sclerosis
*Epilepsy
*Anxiolytic effects
*Promotion of skin health
*Promotion of brain health
-Anti-neuroinflammation.
-Acetylcholinesterase (AChE) inhibition and Alzheimer’s disease
-Antidepressant effects
-Traumatic brain injury
*Anti-inflammatory effects
*Pain
*Cancer
*Constipation
Conclusions
There is a growing number of studies conducted on hemp and hemp-derived compounds, representing an increasing interest in this field of research. Most hemp-specific evidence is preliminary with insufficient high-quality clinical evidence for any specific therapeutic indications. In addition to cannabinoids, a few non-cannabinoid bioactive compounds including protein hydrolysates and propionamides demonstrated some pharmacological potential that can be further explored. There is limited quantitative data and uniformity in the contents of hemp extracts and formulations investigated. As hemp is highly varied in both cannabinoid and non-cannabinoid contents, there is a need for a more focused selection on hemp as test items for biomedical research purposes. Improved methodological design is an important factor in strengthening and focusing on future hemp research.
Introduction
Hemp (Cannabis sativa subsp. sativa), commonly used for industrial purposes, is now being consumed by the public for various health-promoting effects. As the popularity of hemp research and claims of beneficial effects rises, a systematic collection of current scientific evidence on hemp’s health effects and pharmacological properties is needed to guide future research, clinical, and policy decision making.
Objective
To provide an overview and identify the present landscape of hemp research topics, trends, and gaps.
Methods
A systematic search and analysis strategy according to the preferred reporting items for systematic review and meta-analysis-ScR (PRISMA-ScR) checklist on electronic databases including MEDLINE, OVID (OVFT, APC Journal Club, EBM Reviews), Cochrane Library Central, and Clinicaltrials.gov was conducted to include and analyze hemp research articles from 2009 to 2019.
Results
65 primary articles (18 clinical, 47 pre-clinical) were reviewed. Several randomised controlled trials showed hempseed pills (in Traditional Chinese Medicine formulation MaZiRenWan) improving spontaneous bowel movement in functional constipation. There was also evidence suggesting benefits in cannabis dependence, epilepsy, and anxiety disorders. Pre-clinically, hemp derivatives showed potential anti-oxidative, anti-hypertensive, anti-inflammatory, anti-diabetic, anti-neuroinflammatory, anti-arthritic, anti-acne, and anti-microbial activities. Renal protective effects and estrogenic properties were also exhibited in vitro.
Conclusion
Current evidence on hemp-specific interventions is still preliminary, with limited high-quality clinical evidence for any specific therapeutic indication. This is mainly due to the wide variation in test item formulation, as the multiple variants of this plant differ in their phytochemical and bioactive compounds. Future empirical research should focus on standardizing the hemp plant for pharmaceutical use, and uniformity in experimental designs to strengthen the premise of using hemp in medicine.
Introduction
Hemp and marijuana belong to the same Cannabis sativa plant species, differing botanically at a subspecies level as C. sativa subsp. sativa (hemp) and C. sativa subsp. indica (marijuana) [1]. While marijuana has long gained popularity for medical uses [2], the rise of hemp research is relatively recent, as it is traditionally used for industrial purposes [3–7]. Legally, hemp is distinguished from marijuana according to the allowable upper limit of the psychoactive delta9-Tetrahydrocannabidiol (THC). The European Union caps the levels of delta-9-THC in hemp at 0.2% [8] while the U.S Agricultural Marketing Act 1946 restricts delta-9-THC to less than 0.3% on a dry weight basis [9]. Current U.S Food and Drug Administration approved cannabis-based drugs for therapeutic use are either synthetic or derived from medical marijuana, not hemp, indicating that evidence supporting the use of hemp for therapeutic purposes may still be insufficient [10–12].
Due to its non-psychoactive nature, nutrient-rich content, and easy accessibility in several countries, hemp has increasingly garnered public attention and is being commercialized and consumed by the general public as health-promoting and benefiting products, with or without cannabidiol (***), another major cannabinoid found in the Cannabis plant [13–15]. Recently, there is emerging evidence of non-cannabinoid active compounds contributing to the pharmacological effects of hemp [16, 17]. This evidence is different from current published systematic reviews of Cannabis, which have focused mainly on cannabinoids [18, 19]. A narrative review by Crescente et al., 2018 highlighted the historical use, phytochemicals, and some potential nutraceutical properties of hemp. However, there was a lack of systematic research, compilation, and analysis of all related studies and therefore this review does not provide an objective overview of current hemp research [14].
Despite hemp’s growing popularity, a systematic collection of available scientific evidence detailing the beneficial health effects in humans and pharmacological properties specific to hemp is limited. Since hemp-related biomedical research is a relatively new field of study, such evidence syntheses are valuable in guiding future research, clinical recommendations, and policy decisions making [20]. Hence, this paper aims to delineate the current landscape of hemp research, through recent scientific findings specific to the pharmacological properties of the hemp plant and its derived compounds, at both pre-clinical and clinical levels. Here, we present an overview of the research characteristics, patterns, and trends, identify gaps, and suggest a focus point for future research for the hemp plant. To our knowledge, this is the first scoping review on hemp’s overall pharmacological properties and health effects.
Hemp research scientific evidence: Topics, trends, and gaps
*Multiple sclerosis
*Epilepsy
*Anxiolytic effects
*Promotion of skin health
*Promotion of brain health
-Anti-neuroinflammation.
-Acetylcholinesterase (AChE) inhibition and Alzheimer’s disease
-Antidepressant effects
-Traumatic brain injury
*Anti-inflammatory effects
*Pain
*Cancer
*Constipation
Conclusions
There is a growing number of studies conducted on hemp and hemp-derived compounds, representing an increasing interest in this field of research. Most hemp-specific evidence is preliminary with insufficient high-quality clinical evidence for any specific therapeutic indications. In addition to cannabinoids, a few non-cannabinoid bioactive compounds including protein hydrolysates and propionamides demonstrated some pharmacological potential that can be further explored. There is limited quantitative data and uniformity in the contents of hemp extracts and formulations investigated. As hemp is highly varied in both cannabinoid and non-cannabinoid contents, there is a need for a more focused selection on hemp as test items for biomedical research purposes. Improved methodological design is an important factor in strengthening and focusing on future hemp research.
