Recent Advances in Polyphenol Research. Группа авторов
Читать онлайн книгу.
plant resources (Schmidt and Cheng 2017), but these trust issues frequently prevent outsiders from gaining access into traditional ecological knowledge about culturally important species. In order to bridge these concerns, our collaborating laboratory teams from three US universities (www.gibex.org) joined together to produce a portfolio of mobile biodiscovery kits. The interactive experiments in the kits enable participation of both elders and youth in bioexploration and therapeutic lead discovery, focusing on indigenous local plants with a history of medicinal use in traditional ecological knowledge (Kellogg et al. 2010; Flint et al. 2011; McOliver et al. 2015). This unconventional approach provided a sustainable and equitable entrée into traditional cultures and local healing practices, and allowed us to interface with tribal groups in Africa, Asia, and the Americas to create a bridge between traditional knowledge and chemical/physical science discovery experiments.
The mobile discovery workshops have been added into high school and junior college curricula in several participating countries including the USA (Alaska and North Dakota). The mobile biodiscovery kits are simple, straightforward, rapidly deployed bioassays. Experiential learning is the key to resolving the bioactivity of the natural resources, and all of the demonstration/instruction takes place in a team‐centered environment. Initial scouting in the forest or field is led by traditional healers, identified plantings in the wild are coded with GPS coordinates, and samples of identified local medicinal species undergo botanical authentication and are vouchered as herbarium specimens. Next, small quantities of plant material (leaves, bark, roots, stems, fruits) are ground, and crude ethanolic extracts are prepared and tested in a series of screens (antifungal, antibacterial, antiprotozoal, enzyme inhibitory, etc.) (Table 3.1). Assays can be conducted using only a few grams of plant material, and allow the participants to identify bioactive properties of plants used in traditional medicines that have been underappreciated by modern pharma‐based medicine (Figure 3.2). The strategy has successfully engaged youth from junior high school to college age in science discovery that is hands on, and utilizes plants with intrinsic cultural significance (Kellogg et al. 2010, 2016). The traditional ecological knowledge of ethnic groups regarding harvest and use of polyphenol‐rich plants can be lost due to habitat destruction (wars, overharvesting, development or clearing of wild lands for agriculture), but it can also be sidelined or lost when younger generations lose interest in the traditional knowledge of their elders (Schmidt and Klaser Cheng 2017). Community elders report a loss of interest in traditions and subsistence foods among tribal youth, and with that disconnect, a shift to commodity and fast‐food diets which increases incidence of diabetes and obesity. Due to these trends, the mobile biodiscovery approach has been widely accepted and encouraged by tribal elders as a means to refocus on traditional values (Kellogg et al. 2010).
Following the leads provided by naturopathic healers in various global settings, the mobile biodiscovery approach was used to shed light on the mechanistic properties of some of the traditionally wildcrafted polyphenol‐rich plants.
3.5.1 Phlorotannins in Alaskan Seaweeds/Marine Algae
Alaska’s Unangan (Aleut) name is Alaxsxix, which means “place the sea crashes against”; as such, it is a rich harvest site for seaweeds all along its 10,690 km coastline. Seaweeds are utilized for food, livestock fodder, and traditional medicines for Pacific Rim Native American, Alaska Native, and First Nation tribal communities. As foods, they provide a limitless resource for macro‐ and micronutrients, and are prepared by drying, toasting, fermenting, and brewing in soups (Kellogg et al. 2015). Recent research has cited the utility of seaweed extracts to significantly increase insulin sensitivity and diminish hyperglycemia (Paradis et al. 2011; Nuno et al. 2013). In partnership with the Southeast Alaska Regional Consortium and Alaska Native elders, we were able to engage in a deeper analysis of the phytoactive constituents of seaweeds and their relevant bioactivities. Extracts from six species of seaweed and one tidal plant were screened for antioxidant capacity using first the mobile biodiscovery kits (described previously) to establish “first hits,” then in both chemical and in vitro bioassays, and total phenolic content was gauged. A brown seaweed (Fucus distichus) proved to have both the highest total phenolic content (557 μg/mg extract, measured in phloroglucinol equivalents) and one of the highest radical scavenging activities (Kellogg and Lila 2013). Follow‐up work established that the phlorotannin oligomers (fucophloroethol structures with DP from 3‐18 monomer units) of F. distichus (Figure 3.3) were involved in potent α‐amylase and α‐glucosidase inhibition, suggesting a mechanism for their traditionally recognized antidiabetic properties (Kellogg et al. 2014).
Table 3.1 Portfolio of mobile biodiscovery training modules used in workshops with both elders and youth in participating native communities.
| Module ID | Approximate workshop time required to conduct the bioassays/procedures | How long before results can be evaluated | Relevant‐disease targets |
|---|---|---|---|
| Field collection* | 2–3 hours | n/a | n/a |
| Plant material extraction | 1–2 hours | n/a | n/a |
| Antibacterial assay | 2–3 hours | 24–48 hours | Bacterial pathogens |
| Antioxidant assay | 1 hour | Immediate | General health |
| Glucosidase and glucosidase inhibitor assays | 2 hours | Immediate | Metabolic syndrome type 2 diabetes |
| α‐amylase inhibition | 1–2 hours | Immediate | Metabolic syndrome type 2 diabetes |
| Anthocyanin detection | 1 hour | Immediate | General health |
| Protease and protease inhibitor assay | 30 minutes–1 hour | 10 minutes | Digestive diseases Viral pathogens |
| Planaria lethality assay | 1–2 hours | 8–24 hours | Parasitic worms |
| Planaria regeneration assay | 1–2 hours | 5 days | Parasitic worms |
| Nematode lethality assay | 1 hour | 4 hours | Parasitic worms |
* Field identification of medicinal plants and sample collection are conducted in concert with local elders from the community.