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179 results on '"Arnason, John Thor"'

15. Phytochemistry in the Ethnopharmacology of North and Central America

Author

Arnason, John Thor, Harris, Cory S., and Guerrero-Analco, José A.

Subjects
Pharmacology, Pharmacology (medical)
Abstract

Traditionally the role of phytochemistry in the ethnopharmacology of North and Central America has been to characterize plant materials so that they can be produced reproducibly for commercial use or to identify active principles in unstudied traditional medicines for drug discovery. With new decolonial objectives coming from Indigenous communities, emphasis has shifted to evaluating the safety and efficacy of traditional medicines and preparations for community use. With new techniques and technologies available, scientific focus has shifted from individual bioactives to more rapid and comprehensive chemical characterizations and polypharmacy of traditional medicines. Untargeted metabolomics and associated statistical treatments have greatly expanded identification of components, improved species and cultivar identification and provided means for identifying multiple activity biomarkers, via chemometric and biochemometric analysis. New integrated techniques are available for identifying multiple active principles and synergists. The recent explosion of information is not without problems that need to be addressed including many unconfirmed tentative identifications of phytochemicals, lack of quantitative testing, superficial chemical activity testing and continuing need for dereplication.

Published
2021

16. Environmental trends in the variation of biologically active phenolic compounds in Labrador tea, Rhododendron groenlandicum, from northern Quebec, Canada

Author

Rapinski, Michel, Liu, Rui, Saleem, Ammar, Arnason, John Thor, and Cuerrier, Alain

Subjects
Tea (Plant) -- Physiological aspects -- Environmental aspects, Phenols -- Health aspects, Biological sciences
Abstract

The impact of several environmental factors on the production of phenolic compounds in a North American medicinal plant, Labrador tea (Rhododendron groenlandicum (Oeder) Kron & Judd), was studied. Leaves were harvested in 2006 and 2010 over a latitudinal gradient in northern Quebec, and known phenolic markers were quantified by HPLC-DAD. The concentration of selected compounds varied geographically where they were higher between the 51st and 53rd parallel of northern Quebec and lower in the peripheral northern and southern region. Major variations were observed in the following marker compounds: (+)-catechin, (-)-epicatechin, quercetin-3-galactoside, and an undetermined quercetin-glycoside. The variation in phenolic compounds was best explained by short-term changes in annual temperature range and long-term estimates of insolation parameters such as solar radiation and photoperiod in the month of June. Key words: phenolic compounds, traditional medicine, insolation, Cree Nation of Eeyou Istchee, spatial trends, environmental trends. Resume: L'impact de plusieurs facteurs environnementaux sur la production de composes phenoliques a ete evalue chez le the du Labrador (Rhododendron groenlandicum (Oeder) Kron & Judd), une plante medicinale de l'Amerique de Nord. Les feuilles ont ete recoltees en 2006 et 2010 sur un gradient latitudinal dans le Nord-du-Quebec et des marqueurs phenoliques connus ont ete quantifies par HPLC-DAD. Les concentrations des composantes selectionnees variaient geographiquement ou elles etaient plus elevees entre le [51.sup.e] et [53.sup.e] parallele du Nord-du-Quebec et plus basses en region peripherique, au nord et au sud du gradient. Des variations majeures ont ete observees pour les composes phenoliques suivant : (+)-catechine, (-)-epicatechine, quercetine-3galactoside et un glycoside de quercetine non identifie. La variation dans les concentrations des composes phenoliques etait mieux expliquee par des changements dans la portee annuelle de la temperature a court terme et a long terme par des parametres d'insolation telles la radiation solaire et la photoperiode au mois de juin. Mots-cles: composes phenoliques, medecine traditionnelle, insolation, Nation crie d'Eeyou Istchee, tendances spatiales, tendances environnementales., Introduction Labrador tea (Rhododendron groenlandicum (Oeder) Kron & Judd, formerly Ledum groenlandicum Oeder), from the Ericaceae, is a common semi-evergreen plant growing in Canada's boreal forests with a long history [...]

Published
2014
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20. Community Stewardship and Biodiversity Enhancement of Public Greenspaces.

Author

Buckles, Daniel, Shearer, Catherine, Phillips, Kris, Bradley, Adrian, Chieu-Anh Ta, Hall, Braydon, and Arnason, John Thor

Subjects
COMMUNITIES, PLANT diversity, URBAN biodiversity, BIODIVERSITY, HERBACEOUS plants
Abstract

Plant biodiversity in urban woodlands near the Ottawa River was assessed and found to have low native biodiversity. Community volunteers responded by planting native trees using various techniques (Hügelkultur mounds, Miyawaki or "Tiny Forest" plantations, terracing) and establishing several native pollinator gardens. Biodiversity enhancement included both native Great Lakes and St. Lawrence forest species and Carolinian species, with attention to ethnobotanical and forest food species as well as herbaceous plants supporting native pollinators. The experience suggests that community stewardship of public greenspaces offers an efficient and effective means to achieve meaningful conservation and public education outcomes. [ABSTRACT FROM AUTHOR]

Published
2023

22. A review of Ethnobotany and Ethnopharmacology of traditional medicines used by Q’eqchi' Maya healers of Xna'ajeb' aj Ralch'o'och', Belize.

Author

Arnason, John Thor, primary, Cal, Victor, additional, Pesek, Todd, additional, Awad, Rosalie, additional, Bourbonnais-Spear, Natalie, additional, Collins, Sean, additional, Otárola-Rojas, Marco, additional, Walshe-Roussel, Brendan, additional, Audet, Patrick, additional, Ta, Chieu Anh, additional, Balick, Michael J, additional, and Ferrier, Jonathan, additional

Published
2021
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35. Culturally important plants from Southern Belize: Domestication by Q'eqchi' Maya healers and conservation

Author

Bourbonnais-Spear, Natalie, Poissant, Jocelyn, Cal, Victor, and Arnason, John Thor

Subjects
Belize -- Environmental aspects, Medicinal plants -- Protection and preservation, Plants, Protection of, Environmental issues
Abstract

The experience of managing and maintaining a culturally important medicinal plant garden by a group of traditional Q'eqchi' Maya healers in Southern Belize is reported. Some of the challenges and benefits associated with the establishment of local medicinal plant gardens are explored and a general evaluation of the sustainability of their harvesting practices, resulting in conservation of cultural and biological diversity, is provided.

Published
2006

36. Advances in the Research and Development of Natural Health Products as Main Stream Cancer Therapeutics

Author

Ovadje, Pamela, Roma, Alessia, Steckle, Matthew, Nicoletti, Leah, Arnason, John Thor, and Pandey, Siyaram

Subjects
Article Subject
Abstract

Natural health products (NHPs) are defined as natural extracts containing polychemical mixtures; they play a leading role in the discovery and development of drugs, for disease treatment. More than 50% of current cancer therapeutics are derived from natural sources. However, the efficacy of natural extracts in treating cancer has not been explored extensively. Scientific research into the validity and mechanism of action of these products is needed to develop NHPs as main stream cancer therapy. The preclinical and clinical validation of NHPs would be essential for this development. This review summarizes some of the recent advancements in the area of NHPs with anticancer effects. This review also focuses on various NHPs that have been studied to scientifically validate their claims as anticancer agents. Furthermore, this review emphasizes the efficacy of these NHPs in targeting the multiple vulnerabilities of cancer cells for a more selective efficacious treatment. The studies reviewed here have paved the way for the introduction of more NHPs from traditional medicine to the forefront of modern medicine, in order to provide alternative, safer, and cheaper complementary treatments for cancer therapy and possibly improve the quality of life of cancer patients.

Published
2015
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38. Ethnobotanical study of medicinal plants by population of Valley of Juruena Region, Legal Amazon, Mato Grosso, Brazil

Author

Bieski, Isanete Geraldini Costa, primary, Leonti, Marco, additional, Arnason, John Thor, additional, Ferrier, Jonathan, additional, Rapinski, Michel, additional, Violante, Ivana Maria Povoa, additional, Balogun, Sikiru Olaitan, additional, Pereira, João Filipe Costa Alves, additional, Figueiredo, Rita de Cassia Feguri, additional, Lopes, Célia Regina Araújo Soares, additional, da Silva, Dennis Rodrigues, additional, Pacini, Aloir, additional, Albuquerque, Ulysses Paulino, additional, and Martins, Domingos Tabajara de Oliveira, additional

Published
2015
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43. Mini Review of Phytochemicals and Plant Taxa with Activity as Microbial Biofilm and Quorum Sensing Inhibitors.

Author

Chieu Anh Kim Ta and Arnason, John Thor

Subjects
*PHYTOCHEMICALS, *BIOFILMS, *TERPENES, *ORGANOSULFUR compounds, *MICROORGANISMS
Abstract

Microbial biofilms readily form on many surfaces in nature including plant surfaces. In order to coordinate the formation of these biofilms, microorganisms use a cell-to-cell communication system called quorum sensing (QS). As formation of biofilms on vascular plants may not be advantageous to the hosts, plants have developed inhibitors to interfere with these processes. In this mini review, research papers published on plant-derived molecules that have microbial biofilm or quorum sensing inhibition are reviewed with the objectives of determining the biosynthetic classes of active compounds, their biological activity in assays, and their families of occurrence and range. The main findings are the identification of plant phenolics, including benzoates, phenyl propanoids, stilbenes, flavonoids, gallotannins, proanthocyanidins and coumarins as important inhibitors with both activities. Some terpenes including monoterpenes, sesquiterpenes, diterpenes and triterpenes also have anti-QS and anti-biofilm activities. Relatively few alkaloids were reported. Quinones and organosulfur compounds, especially from garlic, were also active. A common feature is the polar nature of these compounds. Phytochemicals with these activities are widespread in Angiosperms in temperate and tropical regions, but gymnosperms, bryophytes and pteridophytes were not represented. [ABSTRACT FROM AUTHOR]

Published
2016
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