Effects of short-term environmental stresses on the onset of cannabinoid production in young immature flowers of industrial hemp (Cannabis sativa L.)

Effect of Hormonal Treatments on Cannabinoid Content Levels in Female Hemp (Cannabis sativa L.) Inflorescences

The diverse hormonal treatments applied to hemp (Cannabis sativa L.) carry significant implications for cultivation, and yield optimization across a range of applications, including fiber, seed, oil production, and the enhancement of medicinal compounds. However, there is no evidence concerning the long-term consequences of hormonal treatment. To determine the connection between the effects of hormonal treatment and cannabinoid accumulation, hemp plants were treated with γ-aminobutyric acid (GABA), abscisic acid (ABA), and salicylic acid (SA) to investigate their effects on gene expression and cannabinoid content levels in female inflorescences at 3 days and 4 weeks after treatment. The treatments influenced the transcript levels of five key cannabinoid biosynthesis genes, with 1.0 mM GABA significantly increasing OAC, THCAS, and CBCAS transcripts within 48 to 72 h. Additionally, 1.0 mM GABA led to a significant increase in tetrahydrocannabinol content by day three and significant increases in total cannabidiol and cannabinoid by week four. In addition, both ABA and SA induced transient, dose-dependent increases or decreases in gene expressions, but cannabinoid accumulation at 4 weeks showed no significant changes compared to the control. These results provide valuable insights for hormonal application in cultivation and the development of traits that enhance cannabinoid production in cannabis cultivation, which could significantly contribute to optimizing industrial applications.

Effects of Water and Wind Stress on Phytochemical Diversity, Cannabinoid Composition, and Arthropod Diversity in Hemp

Phytochemical diversity is increasingly appreciated as an important attribute of plants that affects their interactions with other organisms and can have substantial effects on arthropod communities, but this axis of diversity is less studied for agricultural plants. For both managed and natural systems, understanding how extreme weather events, such as droughts, floods, and extreme wind, affect phytochemical diversity is an important part of predicting responses of plant-arthropod interactions to climate change. In an outdoor field experiment with two distinct varieties of hemp (Cannabis sativa L., Cannabaceae), we investigated the effects of simulated water stress from reduced water availability and flooding, along with an unplanned extreme wind event on phytochemical diversity and cannabinoid profiles. We also examined how changes in chemistry affected the diversity of the associated arthropods. Our results indicate that both genetic variety and environmental stress have substantial effects on variation in hemp phytochemical diversity and cannabinoid composition, and these effects cascaded to alter the arthropod communities on flowers. The largest differences in chemistry were found between different varieties, which accounted for over 10% of the variation in phytochemical diversity. Stress from wind and floods reduced the phytochemical diversity of flowers, wind had negative effects on cannabidiol (CBD) concentrations, and both water deficit and flooding caused subtle shifts in cannabinoid composition. The subsequent cascading effects of chemistry depended on how it was characterized, with increases in CBD causing higher arthropod richness, while increased phytochemical diversity reduced arthropod diversity. These results provide insights into the potential effects of extreme weather on hemp chemistry, as well as the consequences of hemp phytochemical diversity on colonizing arthropods.

Derived cannabinoid product availability among online vape shops

Objectives

To determine the proportion of online vape shops that offer derived cannabinoid products in a large metropolitan area (San Diego, California), measure their compliance with state hemp regulations, and estimate whether these shops receive more website traffic compared to those that offered nicotine or tobacco.

Methods

We obtained vape shops (n = 109) using browser-based (i.e., Google Search) and map-based (i.e., Google Maps and Yelp) searches in San Diego from March to August 2023 and conducted a content analysis of their websites to identify derived cannabinoid products offered for mail-order purchasing. Using website traffic data, we examined the association between derived cannabinoid product availability and monthly website visits.

Results

Among the 109 online vape shops in the study sample, 35.8 % offered derived cannabinoid products for mail-order purchase and 26.6 % sold flavored (excluding terpenes) and inhalable cannabinoid products. Compared to vape shops that did not offer derived cannabinoid products (Mean: 23,619; 95 % CI: 23,605-23,634), those offering flavored and inhalable cannabinoid products received 2.5 times more monthly website visits (Mean: 57,950; 95 % CI: 57,913-57,986) and those offering any derived cannabinoid products received 5.5 times more monthly website visits (Mean: 130,694; 95 % CI: 130,607-130,782).

Conclusion

The prevalence of flavored and inhalable derived cannabinoid products, despite being prohibited under California's hemp regulations, highlights the need for additional enforcement measures to ensure retailer compliance. The higher website traffic observed among vape shops offering cannabinoid products may be indicative of greater popularity of retailers selling derived cannabinoid products compared to those selling nicotine or tobacco products alone.

The interaction effect of water deficit stress and nanosilicon on phytochemical and physiological characteristics of hemp (Cannabis sativa L.)

Different practical approaches have been employed to attenuate the destructive impacts of water deficit stress on plants, such as utilization of humic acid, salicylic acid, algae extract, mulching, and microorganisms, as well as silicon application. Nanosilicon significantly moderates the ruinous effects of abiotic and biotic stress in plants through some physiological processes. In this study, the interaction effect of drought stress and nanosilicon on phytochemical and physiological characteristics of hemp (Cannabis sativa L.) was investigated, wherein the four-week-old seedlings were subjected to irrigation treatments at four levels, including 100% (control), 80% (mild stress), 60% (moderate stress), and 40% (severe stress) of field capacity and nanosilicon at three concentrations (0, 0.5, and 1.5 mM) was foliar applied every 10 days in a factorial completely randomized design experiment with three replications for 30 days. Phytochemical and physiological analyses such as photosynthetic pigments, total phenolic and flavonoid content, and antioxidant enzyme activities were conducted. The results indicated that the highest content of Cannabidiol and Tetrahydrocannabinol was achieved using 1.5 mM (1.89%) and 0.5 mM (0.63%) nanosilicon treatments, respectively, under moderate stress. The plants subjected to severe drought stress without nanosilicon application displayed the lowest values of chlorophyll a (0.50 mg/g FW) and b (0.20 mg/g FW). The use of nanosilicon excited the activation of antioxidant enzymes, wherein the plants treated with nanosilicon and drought stress exhibited significantly higher SOD, POD, and APX activities compared to the control. Under all drought stress levels, foliar application of nanosilicon at the highest concentration decreased proline content. The results proposed that the application of 1.5 mM nanosilicon, as a more efficient concentration, improved drought tolerance in hemp plants.

Cannabis-Based Phytocannabinoids: Overview, Mechanism of Action, Therapeutic Application, Production, and Affecting Environmental Factors

This review provides an overview of cannabis-based phytocannabinoids, focusing on their mechanisms of action, therapeutic applications, and production processes, along with the environmental factors that affect their quality and efficacy. Phytocannabinoids such as THC (∆9-tetrahydrocannabinol), CBD (cannabidiol), CBG (cannabigerol), CBN (cannabinol), and CBC (cannabichromene) exhibit significant therapeutic potential in treating various physical and mental health conditions, including chronic pain, epilepsy, neurodegenerative diseases, skin disorders, and anxiety. The cultivation of cannabis plays a crucial role in determining cannabinoid profiles, with indoor cultivation offering more control and consistency than outdoor methods. Environmental factors such as light, water, temperature, humidity, nutrient management, CO2, and the drying method used are key to optimizing cannabinoid content in inflorescences. This review outlines the need for broader data transfer between the health industry and technological production, especially in terms of what concentration and cannabinoid ratios are effective in treatment. Such data transfer would provide cultivators with information on what environmental parameters should be manipulated to obtain the required final product.

Effect of High-Tunnel and Open-Field Production on the Yield, Cannabinoids, and Volatile Profiles in Industrial Hemp (Cannabis sativa L.) Inflorescence

This study discovered the impact of high-tunnel (i.e., unheated greenhouse) and open-field production on two industrial hemp cultivars (SB1 and CJ2) over their yield parameters, cannabinoid development, and volatile profiles. Development of neutral cannabinoids (CBD, THC, and CBC), acidic cannabinoids (CBDA, THCA, and CBCA), and total cannabinoids during floral maturation were investigated. The volatile profiles of hemp flowers were holistically compared via HS-SPME-GC/MS. Findings indicated a high tunnel as an efficient practice for achieving greater total weight, stem number, and caliper, especially in the SB1 cultivar. Harvesting high-tunnel-grown SB1 cultivars during early flower maturation could obtain a high CBD yield while complying with THC regulations. Considering the volatile profiles, hemp flowers mainly consisted of mono- and sesquiterpenoids, as well as oxygenated mono- and sesquiterpenoids. Volatile analysis revealed the substantial impact of cultivars on the volatile profile compared to the production systems.

Raman-based diagnostics of drought, heat and light-induced stresses in three different varieties of hemp

MAIN CONCLUSION

Hand-held Raman spectroscopy can be used for highly accurate differentiation between drought, heat and light-triggered stresses in hemp. The differentiation is based on the changes in the biochemistry of plants caused by such stresses. Hemp farming is a rapidly growing industry. This dioecious plant is primarily cultivated for its fibers, seeds, and cannabinoid-rich oils. The yield of these materials can be drastically lowered by many abiotic stresses, such as drought, heat and light. It becomes critically important to develop robust and reliable approaches that can be used to diagnose such abiotic stresses in hemp. In this study, we investigate the accuracy of Raman spectroscopy, an emerging tool within crop monitoring, in the confirmatory identification of drought, heat, and light-induced stresses in three varieties of hemp. Our results showed that mono, double and triple stresses uniquely alter plant biochemistry that results in small spectroscopic changes detected in the Raman spectra acquired from the hemp leaves. These changes could be used for the 80-100% accurate identification of individual abiotic stresses and their combinations in plants. These results demonstrate that a hand-held Raman spectrometer can be used for highly accurate, non-invasive, non-destructive, and label-free diagnostics of hemp stresses directly in the greenhouse or in the field.

The Development, Validation, and Application of a UHPLC-HESI-MS Method for the Determination of 17 Cannabinoids in Cannabis sativa L. var. sativa Plant Material

Cannabinoids are an important group of secondary metabolites found in the plant Cannabis sativa L. The growing interest in the use of hemp in food production (e.g., hemp teas, hemp cookies) makes it necessary to develop a method for determining these compounds in the plant, both fresh and dried. The selection of a suitable extraction liquid for the extraction of cannabinoids and the development of a method for the determination of 17 cannabinoids is a prelude to the development of an effective method for the extraction of these compounds. In the present study, a novel, simple, and efficient method was developed and validated for the determination of up to 17 cannabinoids in fresh plant parts (inflorescences and leaves) of Cannabis sativa L. and in dried material, including hemp teas. Analyses were performed using ultra-high-performance liquid chromatography-Q-Exactive Orbitrap mass spectrometry setup operating with a heated electrospray interface (UHPLC-HESI-MS). Based on the comparison, methanol was selected as the best for the extraction of cannabinoids from fresh and dried material. The efficiency and validity of the method were assessed using certified reference material (dried Cannabis) and confirmed by z-score from participation in an international proficiency test conducted by ASTM International for dried hemp.

Assessing the adaptive role of cannabidiol (CBD) in Cannabis sativa defense against cannabis aphids

Cannabis sativa is known for having unique specialized or secondary metabolites, cannabinoids that are derived from an extension of the terpene pathway in the Cannabis lineage and includes more than 100 other similar metabolites. Despite the assumption that cannabinoids evolved as novel herbivory defense adaptations, there is limited research addressing the role of cannabinoids in C. sativa responses to insect herbivores. Here we investigated the role of cannabidiol (CBD), the predominant cannabinoid in hemp, in plant defense against cannabis aphid (Phorodon cannabis), one of the most damaging pests of hemp. We hypothesize that insect feeding may induce changes in cannabinoids as an adaptive strategy for defense. We found that mean fecundity, net reproductive rate (R0) and adult longevity of cannabis aphids was reduced on the high cannabinoid cultivar compared to the low- cannabinoid cultivar in whole plant assays. In contrast, supplementation of CBD in artificial feeding assays increased aphid fecundity from day 1 to day 3. Additionally, aphid feeding did not impact cannabinoid levels in leaf tissues with the exception of Δ9-tetrahydrocannabinol (THC). This suggests that other cannabinoids and/or metabolites such as terpenes are causing the observed decrease in aphid performance in the whole plant assays. In addition to cannabinoids, C. sativa also possesses a range of defense mechanisms via phytohormone signaling pathways that are well described in other plant species. Indeed, cannabis aphid feeding significantly increased levels of the major phytohormones, salicylic acid, jasmonic acid, and abscisic acid, which are known to be involved in plant defense responses against aphid species. These results highlight the interplay between cannabinoid synthesis and phytohormone pathways and necessitate further investigation into this complex interaction.

Biology and management of hemp russet mite (Acari: Eriophyidae)

Hemp is rapidly becoming a crop of global agricultural importance, and one of the more serious pests of this crop is hemp russet mite (HRM) Aculops cannabicola (Acari: Eriophyidae). Significant knowledge gaps presently exist regarding critical aspects of pest biology, quantification of crop damage, and efficacy of pesticides. Here we assessed the role of cannabidiol (CBD) on HRM performance, efficacy of sulfur treatments in field trials, and effect of hot water immersion with and without surfactants in reducing HRM counts on hemp cuttings. We found that HRM fecundity was reduced on a high-CBD cultivar compared with a low-CBD cultivar in detached leaf assays. In contrast, HRM fecundity and survival were not impacted when reared on high-CBD diet in artificial feeding assays. This suggests that cannabinoids other than CBD may aid in reduction of mite populations on the high-CBD cultivar. Sulfur sprays reduced HRM populations by up to 98% with the greatest effects seen in plants receiving dual applications, one during the vegetative period in July and the second at the initiation of flowering in August. Yields of plants treated with sulfur increased by up to 33%, and there was a further increase in cannabinoid production by up to 45% relative to untreated plants. Hot water immersion treatments with and without surfactant solution reduced HRM on infested hemp cuttings, and no phytotoxicity was observed. This study provides novel approaches to mitigating HRM at multiple stages in hemp production.

Drought and heat stress mediated activation of lipid signaling in plants: a critical review

Lipids are a principal component of plasma membrane, acting as a protective barrier between the cell and its surroundings. Abiotic stresses such as drought and temperature induce various lipid-dependent signaling responses, and the membrane lipids respond differently to environmental challenges. Recent studies have revealed that lipids serve as signal mediators forreducing stress responses in plant cells and activating defense systems. Signaling lipids, such as phosphatidic acid, phosphoinositides, sphingolipids, lysophospholipids, oxylipins, and N-acylethanolamines, are generated in response to stress. Membrane lipids are essential for maintaining the lamellar stack of chloroplasts and stabilizing chloroplast membranes under stress. However, the effects of lipid signaling targets in plants are not fully understood. This review focuses on the synthesis of various signaling lipids and their roles in abiotic stress tolerance responses, providing an essential perspective for further investigation into the interactions between plant lipids and abiotic stress.

Therapeutic targeting of the tumor microenvironments with cannabinoids and their analogs: Update on clinical trials

Cancer is a major global public health concern that affects both industrialized and developing nations. Current cancer chemotherapeutic options are limited by side effects, but plant-derived alternatives and their derivatives offer the possibilities of enhanced treatment response and reduced side effects. A plethora of recently published articles have focused on treatments based on cannabinoids and cannabinoid analogs and reported that they positively affect healthy cell growth and reverse cancer-related abnormalities by targeting aberrant tumor microenvironments (TMEs), lowering tumorigenesis, preventing metastasis, and/or boosting the effectiveness of chemotherapy and radiotherapy. Furthermore, TME modulating systems are receiving much interest in the cancer immunotherapy field because it has been shown that TMEs have significant impacts on tumor progression, angiogenesis, invasion, migration, epithelial to mesenchymal transition, metastasis and development of drug resistance. Here, we have reviewed the effective role of cannabinoids, their analogs and cannabinoid nano formulations on the cellular components of TME (endothelial cells, pericytes, fibroblast and immune cells) and how efficiently it retards the progression of carcinogenesis is discussed. The article summarizes the existing research on the molecular mechanisms of cannabinoids regulation of the TME and finally highlights the human studies on cannabinoids' active interventional clinical trials. The conclusion outlines the need for future research involving clinical trials of cannabinoids to demonstrate their efficacy and activity as a treatment/prevention for various types of human malignancies.

Moving Away from 12:12; the Effect of Different Photoperiods on Biomass Yield and Cannabinoids in Medicinal Cannabis

The standard practice to initiate flowering in medicinal cannabis involves reducing the photoperiod from a long-day period to an equal duration cycle of 12 h light (12L)/12 h dark (12D). This method reflects the short-day flowering dependence of many cannabis varieties but may not be optimal for all. We sought to identify the effect of nine different flowering photoperiod treatments on the biomass yield and cannabinoid concentration of three medicinal cannabis varieties. The first, "Cannatonic", was a high cannabidiol (CBD)-accumulating line, whereas the other two, "Northern Lights" and "Hindu Kush", were high Δ9-tetrahydrocannabinol (THC) accumulators. The nine treatments tested, following 18 days under 18 h light/6 h dark following cloning and propagation included a standard 12L:12D period, a shortened period of 10L:14D, and a lengthened period of 14L:10D. The other six treatments started in one of the aforementioned and then 28 days later (mid-way through flowering) were switched to one of the other treatments, thus causing either an increase of 2 or 4 h, or a decrease of 2 or 4 h. Measured parameters included the timing of reproductive development; the dry weight flower yield; and the % dry weight of the main target cannabinoids, CBD and THC, from which the total g cannabinoid per plant was calculated. Flower biomass yields were highest for all lines when treatments started with 14L:10D; however, in the two THC lines, a static 14L:10D photoperiod caused a significant decline in THC concentration. Conversely, in Cannatonic, all treatments starting with 14L:10D led to a significant increase in the CBD concentration, which led to a 50-100% increase in total CBD yield. The results show that the assumption that a 12L:12D photoperiod is optimal for all lines is incorrect as, in some lines, yields can be greatly increased by a lengthened light period during flowering.

Exogenous application of stress-related signaling molecules affect growth and cannabinoid accumulation in medical cannabis (Cannabis sativa L.)

Medical cannabis (Cannabis sativa L.) is a source of bioactive phytochemicals with promising pharmacological and therapeutic applications. Enhancing the accumulation of valuable bioactive compounds is potentially a way of increasing the economic importance of this crop. Signaling molecules like salicylic acid (SA), jasmonic acid (JA), and γ-aminobutyric acid (GABA) are involved in the regulation of plant development and responses to biotic and abiotic stresses. Moreover, several phytohormones regulate plant trichome formation and elicit the synthesis of secondary metabolites in many plant species in both in vitro and in vivo systems. Therefore, exogenously delivered plant signaling molecules have the potential to modify the chemical profiles of medical cannabis. In this study, we found that the foliar application of SA, methyl jasmonate (MeJA), and GABA produces changes in the accumulation of the two major cannabinoids, cannabidiolic acid (CBDA) and Δ⁹- tetrahydrocannabinolic acid (THCA), in leaves and inflorescences of a medical cannabis variety. MeJA at 0.1 mM increased the CBDA content in inflorescences by 15.6%, while SA and MeJA at 0.1 mM increased CBDA and THCA accumulation in leaves by up to 57.3%. Treatments did not change the expression of genes participating in the final steps of the biosynthetic pathway of cannabinoids: olivetolic acid cyclase (CsOAC-1 and CsOAC-2), 2-acylphloroglucinol 4-prenyltransferase (CsPT4), cannabidiolic acid synthase (CsCBDAS), and tetrahydrocannabinolic acid synthase (CsTHCAS). Trichome density was not significantly different from the control plants in any treatment. Besides, we found strong correlations between several plant growth parameters and cannabinoid yields, showing a direct link between plant fitness and the production of cannabinoids.