Interaction of the natural anxiolytic Galphimine-B with serotonergic drugs on dorsal hippocampus in rats

Natural product-based pharmacological studies for neurological disorders

Central nervous system (CNS) disorders and diseases are expected to rise sharply in the coming years, partly because of the world's aging population. Medicines for the treatment of the CNS have not been successfully made. Inadequate knowledge about the brain, pharmacokinetic and dynamic errors in preclinical studies, challenges with clinical trial design, complexity and variety of human brain illnesses, and variations in species are some potential scenarios. Neurodegenerative diseases (NDDs) are multifaceted and lack identifiable etiological components, and the drugs developed to treat them did not meet the requirements of those who anticipated treatments. Therefore, there is a great demand for safe and effective natural therapeutic adjuvants. For the treatment of NDDs and other memory-related problems, many herbal and natural items have been used in the Ayurvedic medical system. Anxiety, depression, Parkinson's, and Alzheimer's diseases (AD), as well as a plethora of other neuropsychiatric disorders, may benefit from the use of plant and food-derived chemicals that have antidepressant or antiepileptic properties. We have summarized the present level of knowledge about natural products based on topological evidence, bioinformatics analysis, and translational research in this review. We have also highlighted some clinical research or investigation that will help us select natural products for the treatment of neurological conditions. In the present review, we have explored the potential efficacy of phytoconstituents against neurological diseases. Various evidence-based studies and extensive recent investigations have been included, which will help pharmacologists reduce the progression of neuronal disease.

Medicinal Plants for Insomnia Related to Anxiety: An Updated Review

Sleep disorders are common among the general population and can generate health problems such as insomnia and anxiety. In addition to standard drugs and psychological interventions, there are different complementary plant-based therapies used to treat insomnia and anxiety. This review aimed to find and examine the most recent research on the use of herbal medicines for treating anxiety and insomnia as compiled from clinical trials, as well as to assess the safety and efficacy of these medicines and to elucidate their possible mechanisms of action. The process entailed a search of PubMed, Scopus, and the Cochrane Library databases from 2010 to 2020. The search terms included "sleep disorder", "insomnia", "sedative", "hypnotic", "anxiety", "anxiolytic", and "clinical trial", combined with the search terms "herbs" and "medicinal plants", in addition to individual herbal medicines by both their common and scientific names. This updated review, which focuses mainly on clinical trials, includes research on 23 medicinal plants and their combinations. Essential oils and their associations have also been reviewed. The efficacy of medicinal plants depends on treatment duration, types of study subjects, administration route, and treatment method. More clinical trials with an adequate, standardized design are necessary, as are more preclinical studies to continue studying the mechanisms of action. As a result of our work, we can conclude that the 3 plants with the most potential are valerian, passionflower, and ashwagandha, with the combination of valerian with hops and passionflower giving the best results in the clinical tests.

International Union of Basic and Clinical Pharmacology. CX. Classification of Receptors for 5-hydroxytryptamine; Pharmacology and Function

5-HT receptors expressed throughout the human body are targets for established therapeutics and various drugs in development. Their diversity of structure and function reflects the important role 5-HT receptors play in physiologic and pathophysiological processes. The present review offers a framework for the official receptor nomenclature and a detailed understanding of each of the 14 5-HT receptor subtypes, their roles in the systems of the body, and, where appropriate, the (potential) utility of therapeutics targeting these receptors. SIGNIFICANCE STATEMENT: This review provides a comprehensive account of the classification and function of 5-hydroxytryptamine receptors, including how they are targeted for therapeutic benefit.

Glaucacetalin E and galphimidin B from Galphimia glauca and their anxiolytic activity

ETHNOPHARMACOLOGICAL RELEVANCE

Galphimia glauca is a Mexican medicinal plant used to treat anxiety, fear, phobia and stress as it possesses sedative properties which produce a calming effect. Although some chemical and pharmacological studies have already been carried out on G. glauca, there are still new chemical entities from this plant whose anxiolytic activity should be established.

AIM OF THE STUDY

To validate the use of G. glauca growing in Cuernavaca, Morelos, as an anti-stress agent, through the purification and structural identification of its extracts' chemical constituents; the analysis of the biogenetic relationship of its chemical compounds, and its biological evaluation to demonstrate its traditional use as anxiolytic agents.

MATERIALS AND METHODS

The structures of all isolated compounds were established based on their spectroscopic and spectrometric data. The structure of compound 2 was corroborated through X-Ray. The anxiolytic and sedative-like activities were assessed by the open-field, hole-board and exploration cylinder test.

RESULTS

The nor-triterpenes glaucacetalin E (1) and galphimidin B (2) were isolated for the first time along with seven other known compounds, one of them galphimidin (3), from the CHCl₃ fraction of the aerial parts of Galphimia glauca. The biogenesis of the natural nor-triterpenes isolated from Galphimia glauca is delineated for the first time starting from the taraxasteryl cation. Oral administration of CHCl₃ fraction and 1-3 compounds produced significant attenuation in the anxiety-response in cylinder activity, decrease in the ambulatory activity and in head dipping when compared to the vehicle. However, only the extract enhanced the pentobarbital-induced hypnosis. Diazepam was used as a positive control.

CONCLUSION

Our results suggest that G. glauca growing in Cuernavaca, Morelos, exerts anxiolytic-like activity due to the presence of the nor-triterpenes 1-3. These results reinforce the potential use of this species in the treatment of anxiety.

Novel pharmacological targets in drug development for the treatment of anxiety and anxiety-related disorders

Current medication for anxiety disorders is suboptimal in terms of efficiency and tolerability, highlighting the need for improved drug treatments. In this review an overview of drugs being studied in different phases of clinical trials for their potential in the treatment of fear-, anxiety- and trauma-related disorders is presented. One strategy followed in drug development is refining and improving compounds interacting with existing anxiolytic drug targets, such as serotonergic and prototypical GABAergic benzodiazepines. A more innovative approach involves the search for compounds with novel mechanisms of anxiolytic action using the growing knowledge base concerning the relevant neurocircuitries and neurobiological mechanisms underlying pathological fear and anxiety. The target systems evaluated in clinical trials include glutamate, endocannabinoid and neuropeptide systems, as well as ion channels and targets derived from phytochemicals. Examples of promising novel candidates currently in clinical development for generalised anxiety disorder, social anxiety disorder, panic disorder, obsessive compulsive disorder or post-traumatic stress disorder include ketamine, riluzole, xenon with one common pharmacological action of modulation of glutamatergic neurotransmission, as well as the neurosteroid aloradine. Finally, compounds such as D-cycloserine, MDMA, L-DOPA and cannabinoids have shown efficacy in enhancing fear-extinction learning in humans. They are thus investigated in clinical trials as an augmentative strategy for speeding up and enhancing the long-term effectiveness of exposure-based psychotherapy, which could render chronic anxiolytic drug treatment dispensable for many patients. These efforts are indicative of a rekindled interest and renewed optimism in the anxiety drug discovery field, after decades of relative stagnation.

Galphimine-B Standardized Extract versus Alprazolam in Patients with Generalized Anxiety Disorder: A Ten-Week, Double-Blind, Randomized Clinical Trial

Galphimine-B (G-B), a compound isolated from Galphimia glauca, has been shown to possess important anxiolytic activity. In this study, we evaluated the effectiveness and tolerability of a G-B standardized extract (experimental treatment) that was administered daily for 10 weeks in patients with moderate or severe Generalized Anxiety Disorder (GAD). Alprazolam was used as control treatment and administered under the same conditions. A total of 167 patients were included. At the start of the study, the severe anxiety condition prevailed, with an average on the Hamilton Anxiety Scale of 35.1 ± 8.8 and 35.8 ± 8.1 points in the control and experimental groups, respectively. After the 10 weeks of administration, the average was reduced in the control group to 4.6 ± 6.5 points and in the experimental group to 3.5 ± 5.5 points. Therapeutic success in the control group was 85.7% and in the experimental group, 92.0%. A high proportion of patients (22.2%) treated with Alprazolam manifested daytime sleepiness, while in the group treated with the G-B standardized extract, daytime sleepiness was found in 4.7%. In conclusion, a G-B standardized extract demonstrated therapeutic effectiveness in patients with GAD, without exhibiting significant difference with Alprazolam, but showing fewer cases of daytime sleepiness. The trial was registered at http://clinicaltrials.gov by identifier: NCT03702803.

Multidisciplinary Investigations on Galphimia glauca: A Mexican Medicinal Plant with Pharmacological Potential

Galphimia glauca (Cav.) Kuntze is an important endemic plant species, which possesses many medicinal properties and has been used in the Mexican traditional medicine for its sedative, anxiolytic, anticonvulsant, antiasthmatic and antiallergic properties. The therapeutic properties of this plant are mainly due to the presence of diverse bioactive compounds such as flavonoids, triterpenoids, and phenolics. Several triterpenoids and flavonoids compounds have been isolated and identified. Modern studies have demonstrated many biological activities such as anti-inflammatory, antidiarrheal, gastroenteritis, antimalarial and cytotoxic activities. Nevertheless, many studies are restricted to the crude extract, and many bioactive compounds are yet to be identified and validated according to its traditional use. However, its commercial exploitation and use are highly limited due to the non-availability of enough plant material and lack of knowledge about its agronomical practices. Moreover, the misinterpretation and mislabeling of closely related species of the genus Galphimia Cav. as G. glauca or G. gracilis is a common problem for its rigorous scientific study and commercial exploitation. The present review provides comprehensive knowledge based on the available scientific literature. To the best of our knowledge, this is the first review on G. glauca. This comprehensive information will certainly provide a guide for the better understanding and utilization of G. glauca for its scientific and industrial exploitation.

Mexican medicinal plants with anxiolytic or antidepressant activity: Focus on preclinical research

ETHNOPHARMACOLOGICAL RELEVANCE

Anxiety and depression are considered the most prevalent psychiatric disorders worldwide. In Mexico, the use of medicinal plants to alleviate the symptoms associated with these psychiatric disorders is increasing. However, there is little scientific evidence that validates the efficacy of these plants. This evidence needs to be critically revised, and further studied to provided scientific support for their use.

AIM OF THE STUDY

To identify the plants that are used in Mexico for the treatment of disorders related to anxiety and depression, and to review the current preclinical and when available, clinical information of these plants.

METHODS

We searched in scientific databases (Pubmed, Web of Science, Scopus and other web sources such as "Biblioteca digital de la medicina tradicional Mexicana" ) for Mexican plants used for the treatment of anxiety and depression that have been analyzed in preclinical studies. Additional information was obtained from published books. For this review, we also consider those plants used in Mexican traditional medicine for the treatment of "nervios," "susto" or "espanto;" common terms that describe symptoms related to anxiety and depression disorders.

RESULTS

The bibliographic search identified 49 plants used in Mexican traditional medicine for the treatment of disorders related to anxiety and depression. From all these plants, 59% were analyzed in preclinical research, and only 8% were tested in clinical studies; only a few of these studies tried to elucidate their mechanism of action. In general, it is proposed that the plant extracts interact with the GABAergic system. However, only part of these studies attempted to analyze other neurotransmitter systems. Finally, in some cases, drug-herbal interactions were reported.

CONCLUSIONS

There is a large number of Mexican medicinal plants used as a treatment for anxiety and depression disorders. Although some of these plants have been studied in preclinical research, in most cases these studies are preliminary, and the understanding of the mechanism of action is inconclusive. The need for systematic studies in preclinical and clinical research is evident, and efforts should be done to fulfill these research. Finally, it is important also to study possible drug-herbal interactions to establish specific recommendations for people that use these plants as anxiolytic or antidepressant treatments either alone or in combination with another type of medicine.

A perspective on natural products research and ethnopharmacology in Mexico: the eagle and the serpent on the prickly pear cactus

Mexico's extraordinarily rich cultural and floristic diversity has fascinated explorers and researchers ever since the "New World" was discovered for and by Europeans. For many decades, natural product research has been a very active field of research in Mexico, and there also are some ongoing ethnopharmacological research efforts. This review provides an overview and critical appraisal on some key developments in these fields and examples of medicinal plants used by indigenous communities that have become of great local importance in Mexican popular medicine. In this review, the focus is on plants with effects on the CNS, diabetes, metabolic syndrome, inflammatory processes, and gastrointestinal disorders. While some of the major food plants consumed worldwide originate from southern North America, only very few medicinal plants have become of major global importance. Opuntia species are now used increasingly to manage diabetes and metabolic syndrome and represent an example of a novel medicinal product/supplement. Undoubtedly, narcotic and mind-altering drugs both have received the widest scientific interest and have attracted considerable popular attention. The history of use of the indigenous Mexican Materia Medica in the context of research on local and popular resources specifically with regard to the diverse challenges in the context of studying the world's biodiversity and the development of comparative and semiquantitative ethnobotanical research methods is discussed herein. Natural product and ethnopharmacological research in Mexico seems to have been influenced by the political and societal developments originating from the Convention on Biological Diversity (CBD) and subsequent conventions, which have not yet had the desired effect of giving value to these local resources, as they might deserve. Their equitable and sustainable implementation remains a challenge. Natural product research and ethnopharmacology will play a key role in developing an adequate evidence base for such products derived from local and traditional knowledge in Mexico.

Plant-based medicines for anxiety disorders, part 2: a review of clinical studies with supporting preclinical evidence

Research in the area of herbal psychopharmacology has revealed a variety of promising medicines that may provide benefit in the treatment of general anxiety and specific anxiety disorders. However, a comprehensive review of plant-based anxiolytics has been absent to date. Thus, our aim was to provide a comprehensive narrative review of plant-based medicines that have clinical and/or preclinical evidence of anxiolytic activity. We present the article in two parts. In part one, we reviewed herbal medicines for which only preclinical investigations for anxiolytic activity have been performed. In this current article (part two), we review herbal medicines for which there have been both preclinical and clinical investigations of anxiolytic activity. A search of MEDLINE (PubMed), CINAHL, Scopus and the Cochrane Library databases was conducted (up to 28 October 2012) for English language papers using the search terms 'anxiety' OR 'anxiety disorder' OR 'generalized anxiety disorder' OR 'social phobia' OR 'post-traumatic stress disorder' OR 'panic disorder' OR 'agoraphobia' OR 'obsessive compulsive disorder' in combination with the search terms 'Herb*' OR 'Medicinal Plants' OR 'Botanical Medicine' OR 'Chinese herb*', in addition to individual herbal medicines. This search of the literature revealed 1,525 papers, of which 53 plants were included in the review (having at least one study using the whole plant extract). Of these plants, 21 had human clinical trial evidence (reviewed here in part two), with the other 32 having solely preclinical evidence (reviewed in part one). Support for efficacy was found for chronic use (i.e. greater than one day) of the following herbs in treating a range of anxiety disorders in human clinical trials: Piper methysticum, Matricaria recutita, Ginkgo biloba, Scutellaria lateriflora, Silybum marianum, Passiflora incarnata, Withania somniferum, Galphimia glauca, Centella asiatica, Rhodiola rosea, Echinacea spp., Melissa officinalis and Echium amoenum. For several of the plants studied, conclusions need to be tempered due to methodological issues such as small sample sizes, brief intervention durations and non-replication. Current evidence does not support Hypericum perforatum or Valeriana spp. for any anxiety disorder. Acute anxiolytic activity was found for Centella asiatica, Salvia spp., Melissa officinalis, Passiflora incarnata and Citrus aurantium. Bacopa monnieri has shown anxiolytic effects in people with cognitive decline. The therapeutic application of psychotropic plant-based treatments for anxiety disorders is also discussed, specifically Psychotria viridis and Banisteriopsis caarti (ayahuasca), Psilocybe spp. and cannabidiol-enriched (low tetrahydrocannabinol (Δ(9)-THC)) Cannabis spp.