Receptor screening technologies in the evaluation of Amazonian ethnomedicines with potential applications to cognitive deficits

Genus Triplaris (Polygonaceae): A review on traditional medicinal use, phytochemistry and biological activities

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Triplaris (Polygonaceae) comprises approximately 25 species distributed throughout South and Central America. Some species have been used in folk medicine, mainly, to treat malaria, leishmaniasis, diarrheia, dysenteria, pain and inflammation.

AIM OF THE STUDY

The purpose of this review is to provide information on the traditional uses, phytochemistry and known biological activities of Triplaris, an important genus for South America research groups on medicinal plants, in order to explore its therapeutic potential to direct future research in the search for new bioactive molecules.

MATERIALS AND METHODS

The available information on the genus Triplaris was gathered from scientific databases (LILACS, Pubmed, SciELO, Science Direct, Scopus, CAPES Periodicals Portal and Theses and Dissertations Catalog) before March 2020 using the keyword "Triplaris". Works related to traditional uses, phytochemistry and biological activities of plants were included in this review.

RESULTS

Most of the studies involving Triplaris were conducted by research groups located in Brazil, Peru e Bolivia. Probably, because the genus has been used in folk medicine only by these countries. Regarding the annual evolution of the publications, a larger number of articles published in 2010 were observed. Flavonols represent the main classe of secondary metabolites from Triplaris. In terms of the pharmacological investigations, T. americana and T. gardneriana are considered the most studied species, with extensive promising biological activities. The pharmacological activities can be attributed to bioactive phytochemicals.

CONCLUSIONS

All findings indicate that Triplaris is an important genus of the Polygonaceae family. However, considering its chemical and pharmacological importance, the studies developed with Triplaris species are still limited, representing an opportunity to investigate new bioactive molecules and extracts. The review shows that little pre-clinical or in vivo research is available to prove the ethnopharmacological records in the genre. Therefore, this review encourages further studies on Triplaris in the search for a wide range of therapeutic products.

Interaction of Plant Extracts with Central Nervous System Receptors

Background: Plant extracts have been used in traditional medicine for the treatment of various maladies including neurological diseases. Several central nervous system receptors have been demonstrated to interact with plant extracts and components affecting the pharmacology and thereby potentially playing a role in human disease and treatment. For instance, extracts from Hypericum perforatum (St. John’s wort) targeted several CNS receptors. Similarly, extracts from Piper nigrum, Stephania cambodica, and Styphnolobium japonicum exerted inhibition of agonist-induced activity of the human neurokinin-1 receptor. Methods: Different methods have been established for receptor binding and functional assays based on radioactive and fluorescence-labeled ligands in cell lines and primary cell cultures. Behavioral studies of the effect of plant extracts have been conducted in rodents. Plant extracts have further been subjected to mood and cognition studies in humans. Results: Mechanisms of action at molecular and cellular levels have been elucidated for medicinal plants in support of standardization of herbal products and identification of active extract compounds. In several studies, plant extracts demonstrated affinity to a number of CNS receptors in parallel indicating the complexity of this interaction. In vivo studies showed modifications of CNS receptor affinity and behavioral responses in animal models after treatment with medicinal herbs. Certain plant extracts demonstrated neuroprotection and enhanced cognitive performance, respectively, when evaluated in humans. Noteworthy, the penetration of plant extracts and their protective effect on the blood-brain-barrier are discussed. Conclusion: The affinity of plant extracts and their isolated compounds for CNS receptors indicates an important role for medicinal plants in the treatment of neurological disorders. Moreover, studies in animal and human models have confirmed a scientific basis for the application of medicinal herbs. However, additional investigations related to plant extracts and their isolated compounds, as well as their application in animal models and the conducting of clinical trials, are required.

Comparison of Herbarium Label Data and Published Medicinal Use: Herbaria as an Underutilized Source of Ethnobotanical Information

The use of herbarium specimens as vouchers to support ethnobotanical surveys is well established. However, herbaria may be underutilized resources for ethnobotanical research that depends on the analysis of large datasets compiled across multiple sites. Here, we compare two medicinal use datasets, one sourced from published papers and the other from online herbaria to determine whether herbarium and published data are comparable and to what extent herbarium specimens add new data and fill gaps in our knowledge of geographical extent of plant use. Using Brazilian legumes as a case study, we compiled 1400 use reports from 105 publications and 15 Brazilian herbaria. Of the 319 species in 107 genera with cited medicinal uses, 165 (51%) were recorded only in the literature and 55 (17%) only on herbarium labels. Mode of application, plant part used, or therapeutic use was less often documented by herbarium specimen labels (17% with information) than publications (70%). However, medicinal use of 21 of the 128 species known from only one report in the literature was substantiated from independently collected herbarium specimens, and 58 new therapeutic applications, 25 new plant parts, and 16 new modes of application were added for species known from the literature. Thus, when literature reports are few or information-poor, herbarium data can both validate and augment these reports. Herbarium data can also provide insights into the history and geographical extent of use that are not captured in publications.

Spiritual and ceremonial plants in North America: an assessment of Moerman's ethnobotanical database comparing Residual, Binomial, Bayesian and Imprecise Dirichlet Model (IDM) analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnobotanical research and the study of plants used for rituals, ceremonies and to connect with the spirit world have led to the discovery of many novel psychoactive compounds such as nicotine, caffeine, and cocaine. In North America, spiritual and ceremonial uses of plants are well documented and can be accessed online via the University of Michigan's Native American Ethnobotany Database.

AIM OF THE STUDY

The objective of the study was to compare Residual, Bayesian, Binomial and Imprecise Dirichlet Model (IDM) analyses of ritual, ceremonial and spiritual plants in Moerman's ethnobotanical database and to identify genera that may be good candidates for the discovery of novel psychoactive compounds.

MATERIALS AND METHODS

The database was queried with the following format "Family Name AND Ceremonial OR Spiritual" for 263 North American botanical families. Spiritual and ceremonial flora consisted of 86 families with 517 species belonging to 292 genera. Spiritual taxa were then grouped further into ceremonial medicines and items categories. Residual, Bayesian, Binomial and IDM analysis were performed to identify over and under-utilized families.

RESULTS

The 4 statistical approaches were in good agreement when identifying under-utilized families but large families (>393 species) were underemphasized by Binomial, Bayesian and IDM approaches for over-utilization. Residual, Binomial, and IDM analysis identified similar families as over-utilized in the medium (92-392 species) and small (<92 species) classes. The families Apiaceae, Asteraceae, Ericacea, Pinaceae and Salicaceae were identified as significantly over-utilized as ceremonial medicines in medium and large sized families. Analysis of genera within the Apiaceae and Asteraceae suggest that the genus Ligusticum and Artemisia are good candidates for facilitating the discovery of novel psychoactive compounds.

CONCLUSIONS

The 4 statistical approaches were not consistent in the selection of over-utilization of flora. Residual analysis revealed overall trends that were supported by Binomial analysis when separated into small, medium and large families. The Bayesian, Binomial and IDM approaches identified different genera as potentially important. Species belonging to the genus Artemisia and Ligusticum were most consistently identified and may be valuable in future studies of the ethnopharmacology.

An update on the strategies in multicomponent activity monitoring within the phytopharmaceutical field

Background

To-date modern drug research has focused on the discovery and synthesis of single active substances. However, multicomponent preparations are gaining increasing importance in the phytopharmaceutical field by demonstrating beneficial properties with respect to efficacy and toxicity.

Discussion

In contrast to single drug combinations, a botanical multicomponent therapeutic possesses a complex repertoire of chemicals that belong to a variety of substance classes. This may explain the frequently observed pleiotropic bioactivity spectra of these compounds, which may also suggest that they possess novel therapeutic opportunities. Interestingly, considerable bioactivity properties are exhibited not only by remedies that contain high doses of phytochemicals with prominent pharmaceutical efficacy, but also preparations that lack a sole active principle component. Despite that each individual substance within these multicomponents has a low molar fraction, the therapeutic activity of these substances is established via a potentialization of their effects through combined and simultaneous attacks on multiple molecular targets. Although beneficial properties may emerge from such a broad range of perturbations on cellular machinery, validation and/or prediction of their activity profiles is accompanied with a variety of difficulties in generic risk-benefit assessments. Thus, it is recommended that a comprehensive strategy is implemented to cover the entirety of multicomponent-multitarget effects, so as to address the limitations of conventional approaches.

Summary

An integration of standard toxicological methods with selected pathway-focused bioassays and unbiased data acquisition strategies (such as gene expression analysis) would be advantageous in building an interaction network model to consider all of the effects, whether they were intended or adverse reactions.