Preparation, Characterization, and Pharmacological Activity of Cymbopogon winterianus Jowitt ex Bor (Poaceae) Leaf Essential Oil of β-Cyclodextrin Inclusion Complexes

Nitrogen-Containing Heterocyclic Compounds Obtained from Monoterpenes or Their Derivatives: Synthesis and Properties

Directed transformation of available natural compounds with native biological activity is a promising area of research in organic and medicinal chemistry aimed at finding effective drug substances. The number of scientific publications devoted to the transformation of natural compounds and investigations of their pharmacological properties, in particular, monoterpenes and their nearest derivatives, increases every year. At the same time, the chemistry of nitrogen-containing heterocyclic compounds has been actively developed since the 1950s after the news that the benzimidazole core is an integral part of the structure of vitamin B₁₂. At the time of writing this review, the data on chemical modifications of monoterpenes and their nearest derivatives leading to formation of compounds with a nitrogen-containing heterocycle core have not been summarized and systematized in terms of chemical transformations. In this review, we tried to summarize the literature data on the preparation and properties of nitrogen-containing heterocyclic compounds synthesized from monoterpenes/monoterpenoids and their nearest derivatives for the period from 2000 to 2021.

Medicinal Properties of Cannabinoids, Terpenes, and Flavonoids in Cannabis, and Benefits in Migraine, Headache, and Pain: An Update on Current Evidence and Cannabis Science

BACKGROUND

Comprehensive literature reviews of historical perspectives and evidence supporting cannabis/cannabinoids in the treatment of pain, including migraine and headache, with associated neurobiological mechanisms of pain modulation have been well described. Most of the existing literature reports on the cannabinoids Δ⁹ -tetrahydrocannabinol (THC) and cannabidiol (CBD), or cannabis in general. There are many cannabis strains that vary widely in the composition of cannabinoids, terpenes, flavonoids, and other compounds. These components work synergistically to produce wide variations in benefits, side effects, and strain characteristics. Knowledge of the individual medicinal properties of the cannabinoids, terpenes, and flavonoids is necessary to cross-breed strains to obtain optimal standardized synergistic compositions. This will enable targeting individual symptoms and/or diseases, including migraine, headache, and pain.

OBJECTIVE

Review the medical literature for the use of cannabis/cannabinoids in the treatment of migraine, headache, facial pain, and other chronic pain syndromes, and for supporting evidence of a potential role in combatting the opioid epidemic. Review the medical literature involving major and minor cannabinoids, primary and secondary terpenes, and flavonoids that underlie the synergistic entourage effects of cannabis. Summarize the individual medicinal benefits of these substances, including analgesic and anti-inflammatory properties.

CONCLUSION

There is accumulating evidence for various therapeutic benefits of cannabis/cannabinoids, especially in the treatment of pain, which may also apply to the treatment of migraine and headache. There is also supporting evidence that cannabis may assist in opioid detoxification and weaning, thus making it a potential weapon in battling the opioid epidemic. Cannabis science is a rapidly evolving medical sector and industry with increasingly regulated production standards. Further research is anticipated to optimize breeding of strain-specific synergistic ratios of cannabinoids, terpenes, and other phytochemicals for predictable user effects, characteristics, and improved symptom and disease-targeted therapies.

Cyclodextrin⁻Drug Inclusion Complexes: In Vivo and In Vitro Approaches

This review aims to provide a critical review of the biological performance of natural and synthetic substances complexed with cyclodextrins, highlighting: (i) inclusion complexes with cyclodextrins and their biological studies in vitro and in vivo; (ii) Evaluation and comparison of the bioactive efficacy of complexed and non-complexed substances; (iii) Chemical and biological performance tests of inclusion complexes, aimed at the development of new pharmaceutical products. Based on the evidence presented in the review, it is clear that cyclodextrins play a vital role in the development of inclusion complexes which promote improvements in the chemical and biological properties of the complexed active principles, as well as providing improved solubility and aqueous stability. Although the literature shows the importance of their ability to help produce innovative biotechnological substances, we still need more studies to develop and expand their therapeutic properties. It is, therefore, very important to gather together evidence of the effectiveness of inclusion complexes with cyclodextrins in order to facilitate a better understanding of research on this topic and encourage further studies.

Characterization and Antiproliferative Activity of a Novel 2-Aminothiophene Derivative-β-Cyclodextrin Binary System

The novel 2-aminothiophene derivative 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile (6CN) has shown potential anti-proliferative activity in human cancer cell lines. However, the poor aqueous solubility of 6CN impairs its clinical use. This work aimed to develop binary 6CN-β-cyclodextrin (βCD) systems with the purpose of increasing 6CN solubility in water and therefore, to improve its pharmacological activity. The 6CN-βCD binary systems were prepared by physical mixing, kneading and rotary evaporation methods and further characterized by FTIR, XRD, DSC, TG and SEM. In addition, molecular modeling and phase solubility studies were performed. Finally, MTT assays were performed to investigate the cytostatic and anti-proliferative effects of 6CN-βCD binary systems. The characterization results show evident changes in the physicochemical properties of 6CN after the formation of the binary systems with βCD. In addition, 6CN was associated with βCD in aqueous solution and the solid state, which was confirmed by molecular modeling and the aforementioned characterization techniques. Phase solubility studies indicated that βCD forms stable 1:1 complexes with 6CN. The MTT assay demonstrated the cytostatic and anti-proliferative activities of 6CN-βCD binary systems and therefore, these might be considered as promising candidates for new anticancer drugs.

Chronic orofacial pain animal models - progress and challenges

INTRODUCTION

Chronic orofacial pain is one of the most common pain conditions experienced by adults. Animal models are often selected as the most useful scientific methodology to explore the pathophysiology of the disorders that cause this disabling pain to facilitate the development of new treatments. The creation of new models or the improvement of existing ones is essential for finding new ways to approach the complex neurobiology of this type of pain. Areas covered: The authors describe and discuss a variety of animal models used in chronic orofacial pain (COFP). Furthermore, they examine in detail the mechanisms of action involved in orofacial neuropathic pain and orofacial inflammatory pain. Expert opinion: The use of animal models has several advantages in chronic orofacial pain drug discovery. Choosing an animal model that most closely represents the human disease helps to increase the chances of finding effective new therapies and is key to the successful translation of preclinical research to clinical practice. Models using genetically modified animals seem promising but have not yet been fully developed for use in chronic orofacial pain research. Although animal models have provided significant advances in the pharmacological treatment of orofacial pain, several barriers still need to be overcome for better treatment options.

The Distinction of Hot Herbal Compress, Hot Compress, and Topical Diclofenac as Myofascial Pain Syndrome Treatment

This randomized controlled trial aimed to investigate the distinctness after treatment among hot herbal compress, hot compress, and topical diclofenac. The registrants were equally divided into groups and received the different treatments including hot herbal compress, hot compress, and topical diclofenac group, which served as the control group. After treatment courses, Visual Analog Scale and 36-Item Short Form Health survey were, respectively, used to establish the level of pain intensity and quality of life. In addition, cervical range of motion and pressure pain threshold were also examined to identify the motional effects. All treatments showed significantly decreased level of pain intensity and increased cervical range of motion, while the intervention groups exhibited extraordinary capability compared with the topical diclofenac group in pressure pain threshold and quality of life. In summary, hot herbal compress holds promise to be an efficacious treatment parallel to hot compress and topical diclofenac.

Inclusion Complexes of Copaiba (Copaifera multijuga Hayne) Oleoresin and Cyclodextrins: Physicochemical Characterization and Anti-Inflammatory Activity

Complexation with cyclodextrins (CDs) is a technique that has been extensively used to increase the aqueous solubility of oils and improve their stability. In addition, this technique has been used to convert oils into solid materials. This work aims to develop inclusion complexes of Copaifera multijuga oleoresin (CMO), which presents anti-inflammatory activity, with β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) by kneading (KND) and slurry (SL) methods. Physicochemical characterization was performed to verify the occurrence of interactions between CMO and the cyclodextrins. Carrageenan-induced hind paw edema in mice was carried out to evaluate the anti-inflammatory activity of CMO alone as well as complexed with CDs. Physicochemical characterization confirmed the formation of inclusion complex of CMO with both β-CD and HP-β-CD by KND and SL methods. Carrageenan-induced paw edema test showed that the anti-inflammatory activity of CMO was maintained after complexation with β-CD and HP-β-CD, where they were able to decrease the levels of nitrite and myeloperoxidase. In conclusion, this study showed that it is possible to produce inclusion complexes of CMO with CDs by KND and SL methods without any change in CMO’s anti-inflammatory activity.

Assessment of different Lippia sidoides genotypes regarding their acaricidal activity against Rhipicephalus (Boophilus) microplus

Abstract The aim of this study was to select different genotypes of Lippia sidoides with the highest activity against larvae and engorged females of the tick Rhipicephalus (Boophilus) microplus. The germplasms studied were LSID006, LSID102, LSID103 and LSID104. The LSID104 genotype, that presented carvacrol as a major constituent, was the germplasm with the worst larvicide effect (LC50 2.99 mg/mL). The LSID006 genotype was the least effective against engorged females (LC50 12.46 mg/mL), and it was chemically similar to the LSID102 genotype, which presented the highest acaricide activity (LC50 2.81 mg/mL). We conclude that chemical similarity of the germplasms was not correlated with acaricide activity against R. (B.) microplus. The essential oil of L. sidoides is a potent natural agent. However, the findings of this work provide a better understanding for product development based on this natural product, which must consider synergic effects or the action of minor compounds.

Docking, characterization and investigation of β-cyclodextrin complexed with citronellal, a monoterpene present in the essential oil of Cymbopogon species, as an anti-hyperalgesic agent in chronic muscle pain model

BACKGROUND

Citronellal (CT) is a monoterpene with antinociceptive acute effect. β-Cyclodextrin (βCD) has enhanced the analgesic effect of various substances.

HYPOTHESIS/PURPOSE

To evaluate the effect of CT both complexed in β-cyclodextrin (CT-βCD) and non-complexed, in a chronic muscle pain model (CMP) in mice.

STUDY DESIGN

The complex containing CT in βCD was obtained and characterized in the laboratory. The anti-hyperalgesic effect of CT and CT-βCD was evaluated in a pre-clinical in vivo study in a murine CMP.

METHODS

The complex was characterized through differential scanning calorimetry, derivative thermogravimetry, moisture determination, infrared spectroscopy and scanning electron microscopy. Male Swiss mice were pre-treated with CT (50mg/kg, po), CT-βCD (50mg/kg, po), vehicle (isotonic saline, po) or standard drug (tramadol4 mg/kg, ip). 60 min after the treatment and then each 1h, the mechanic hyperalgesia was evaluated to obtain the time effect. In addition, the muscle strength using grip strength meter and hyperalgesia were also performed daily, for 7 days. We assessed by immunofluorescence for Fos protein on brains and spinal cords of mice. The involvement of the CT with the glutamatergic system was studied with molecular docking.

RESULTS

All characterization methods showed the CT-βCD complexation. CT-induced anti-hyperalgesic effect lasted until 6h (p <0.001) while CT-βCD lasted until 8h (p <0.001vs vehicle and p <0.001vs CT from the 6th h). CT-βCD reduced mechanical hyperalgesia on all days of treatment (p <0.05), without changing muscle strength. Periaqueductal gray (p <0.01) and rostroventromedular area (p <0.05) showed significant increase in the Fos protein expression while in the spinal cord, there was a reduction (p <0.001). CT showed favorable energy binding (-5.6 and -6.1) to GluR2-S1S2J protein based in the docking score function.

CONCLUSION

We can suggest that βCD improved the anti-hyperalgesic effect of CT, and that effect seems to involve the descending pain-inhibitory mechanisms, with a possible interaction of the glutamate receptors, which are considered as promising molecules for the management of chronic pain such as CMP.