BackgroundSouth America is one of the most diverse continent in terms of culture heritage and flora, primarily because of its location and geography. Its floristic diversity is increased by its high mountains, especially the Andes Mountains, which extend from the north to south along the western part of the continent for much of its length. South America has diverse biomes such as tropical rain forests, tropical savannas, extremely dry deserts, temperate forests, and alpine tundra. The largest of these biomes are deserts, savanna, and tropical forest. With the rapid rate of deforestation in places like the Amazon basin and others zones, some plants may become extinct before being cataloged, let alone studied.
In Western modern medicine, around 25% of all drugs are derived from rainforest plants. That’s an impressive statistic, especially considering that, for example, less than 5% of Amazon plant species have been studied for their potential medicinal benefits. Below are some of the most famous examples of modern medicine derived from South American plants (e.i. Cat’s claw (Uncaria tomentosa), Cinchona (Cinchona officinalis), Curare (Strychnos toxifera and Strychnos mitscherlichii), Sangre de grado (Croton lechleri), and Boldo (Peumus bodus)), as well as some whose huge potential has been noted but remains — for now — clinically unproven, including many indigenous South American treatments. Native people of South America have a vast heritage in the knowledge and use of medicinal plants that continues to surprise the scientific community.
In this Research Topic, we plan to appraise plants used locally / traditionally in different countries of South America emphasizing the phenolic compounds reported for these plant species. Due to their importance in the pharmaceutical, nutraceutical and biotechnological fields, this Research Topic aims at gathering the most recent contributions in relation to their chemistry, extraction, and analytical techniques, as well as their biological activities of phenolic compound from South American flora.
This Research Topic includes both Review and Original Research And we encourage submissions focusing on the medicinal and edible plants from South American countries (i.e. Argentina, Bolivia, Brasil, Chile, Colombia, Ecuador, Guyana, Paraguay, Perú, Suriname, Uruguay, and Venezuela). Studies dealing with plants or plant constituents outside of these regions will not be considered. In addition, a particular focus on new achievements in the field will be appreciated. Subjects covered include, but are not limited to:
1. Studies investigating the phytochemical constituents and bioactive properties of plant extracts.
2. Isolation and phytochemical characterization of bioactive phenolic compounds from South American plant species.
3. Biodiversity, chemodiversity and chemotaxonomical studies of South American plants with relevant traditional uses.
4. Biosynthesis of the phenolic compounds and biotransformation using microorganisms and/or plants cultures if such studies are based on plants used locally / traditionally.
5. Studies focusing endemic and rare plants rich in phenolic compounds and their uses are particularly encouraged.
6. Medicinal chemistry of phenolic compounds for certain biological activity, i.e., structure modification of natural products for the evaluation of biological activities, aiming to improve pharmacological activities.
7. The specific mechanism of action of phenolic compounds (or derivatives) toward interesting drug targets.
8. Clinical studies of well characterized herbal preparations containing phenolic compounds, excluding primary clinical trials.
9. Prospective and future trends on research on phenolic compounds.
The correct botanical identification and taxonomical attribution of the studied herbal material is essential, and authors are encouraged to include their own pictures of the studied plants.
This Research Topic is in honor of the celebration of 25 Years of the Faculty of Chemistry and Biology of the University of Santiago of Chile.
Articles on the uses of such plants and metabolites in/emerging from traditional medicine will be considered for peer review in
Frontiers in Pharmacology - Ethnopharmacology, in the context of the Four Pillars of Best Practice in Ethnopharmacology described below.
1) Pharmacological Requirements:a)
Traditional context - The traditional context must be described in the introduction.
b)
Credible experimental models - methods must be state of the art, or a credible alternative. The following have specific requirements:
Antioxidant:
- FRAP, ABTS, DPPH, and Trolox equivalent antioxidant capacity assays are not accepted.
-
in silico studies are not accepted as a main method.
Antimicrobial:
- Disc diffusion experiments must be followed by
in vitro or
in vivo experiments.
- Specificity must be assessed to rule out general toxic effects, e.g. by including parallel cytotoxicity testing (
cf. Cos et al. 2006)
- The mechanism of action must be assessed in sufficient detail (for crude extracts, the effects of contaminants should also be addressed).
Inflammation:
- Experiments on the rat hind paw oedema model are not acceptable unless they are part of a larger pharmacological – phytochemical study.
Docking studies:
- These will not be accepted unless followed by benchwork confirming affinity.
- A proposed mechanism of action is required.
in silico network pharmacology studies
-Network pharmacology studies must critically assess the evidence to evaluate the potential pharmacological effects of a preparation / herbal (medical) product.
- The identification of the compounds must be sound. This information may be derived from the existing literature or from benchwork. It is essential that the quantities of the compounds in the preparation or plant are stated and are high enough to be of pharmacological relevance.
- The bioavailability of the compounds must be assessed.
- Ubiquitous or very widely known compounds are highly unlikely to be ‘active’.
- Transcriptomic data need to be validated using RT-PCR, and proteomic data with Western blots.
Single dose studies:
- These are not accepted unless they focus on a species / compound not yet studied in detail, and can be justified on specific ethical grounds
c)
Dose - ranges must be therapeutically relevant:
- Implausibly high doses will not be considered.
- Both positive and negative controls are essential.
- Multiple doses are strongly recommended, as single dose studies are rarely accepted - only in some specific complex models.
2. Composition Requirements:Whether the material under investigation is a crude plant extract, a multi-herbal preparation, a single compound from a commercial source or extracted from plant, chemical and botanical composition must be explicitly stated.
a) Chemical:
- The concentrations of the dominating compounds must be listed, including dominant impurities if these compounds have been identified in previous studies. Stating the class of compounds present (such as “alkaloids”) is insufficient. We will usually ask for a HPLC or UPLC to establish the compounds present to ensure replicability, if this is not possible a credible alternative can be used.
- Referring to a previously used preparation in the literature is not acceptable, unless it has come from the same preparation or has the same batch number.
- For purchased compounds, purity (%) and the supplier name must be included.
- For extracted compounds, purity (%) and the method used to determine the purity must be stated.
- The structure of active compounds should be included as figures.
b) Botanical:
- Species names must be fully validated and should be described in their full taxonomy, using the
Kew Medicinal plant names service.
- Samples must be deposited in a recognised herbarium, and accessible if necessary. To find out if your institution is indexed, please use the
NYBG Steere Herbarium Search tool- Voucher numbers from the herbarium must be included in the Methods.
- Coordinates of plant picking should also be included, or the commercial source of a preparation, which must include a batch number and details on the preparation’s composition.
3. Basic Experimental and Ethical Requirements:a)
The study must contribute substantially to the existing literature. How it does so must be explicitly stated. The most up-to-date surrounding literature should be discussed, including related compounds, to demonstrate the contribution of the study to the field.
b)
Compliance with all international ethical standards is essential.
The Convention on Biological Diversity and the Nagoya Protocol are of particular relevance. This includes that research in the field should benefit the original users and consider their traditions.
c)
The use of animals must be justified. If a material is well-characterised, and its properties well-known, performing another in vivo study is considered an unethical use of animals. A thorough knowledge of the literature is essential to avoid this mistake. Conversely, if a material is not well characterised, initial experiments in cell-based models are necessary to justify moving onto animal experiments.
d)
The effects of traditional medicinal preparations must be testable in scientific terms. We acknowledge the importance of the understanding of medicinal preparations in their cultural context, and it may be that the treatment of symptoms as defined by traditional practices forms a basis for such investigations. However, pharmacological studies generally do not provide evidence for such uses, but rather for the established therapeutic targets of the model. Experimental outcomes should be linked to and described in these terms. For example, a series of in vitro tests will not demonstrate relevant evidence that will contribute to a physiological understanding of traditional therapeutic concepts, e.g. “dispelling wind” or “dampness” in Traditional Chinese Medicine. A justification must therefore be given for choosing a certain model to test a certain preparation.
4. Article-type Specific Requirements:a) FIELD STUDIES
- Data must be substantial and original.
- The study must be discussed in the context of previous studies carried out in the region. How the study contributes to the development of the field must be made explicit.
- Must comply to the
ConsEFS standards, including any updates.
b) REVIEWS
- The objective of the review must be clearly defined.
- They must provide a specific, critical assessment of the literature. The scientific quality of the original articles must be critically assessed. This includes the experimental design, and reliability of the studies.
- The traditional use must be linked to scientific evidence.
- Future needs and priorities must be clearly defined.
c) SYSTEMATIC REVIEWS & META ANALYSES
- To assure the quality of the studies included, we ask for the inclusion of a summary table (templates available on the
Ethnopharmacology About page).
- We ask that a chemical analysis is included, taken from one of the included studies. The chemical composition of the study material must be well defined. If the composition is poorly characterised, this must be highlighted.
- Quality control measures taken, as defined by a pharmacopoeia, must also be included.
- If the included studies do not use full botanical taxonomic names, this should be highlighted, as must any naming inconsistency between studies.