In a recent review published in Nutrients, researchers reviewed existing data on the structure, extraction, health benefits, and mechanisms of Dendrobium officinale polysaccharides (DOP).
survey: Structure, health benefits, mechanisms and gut microbiota of Dendrobium officinale polysaccharides: a revieww. Image credit: bennie/Shutterstock.com
Background
DOP are active polysaccharides present in Dendrobium officinalea traditional food ingredient or herbal medicine in China.
DOPs can alter the microbial composition of the gut and the enzymatic degradation capacity of symbiotic bacterial organisms, which may affect the effectiveness of dietary treatments. Data on the relationship between DOP and gut microbes are limited.
About the research
In the present study, researchers investigated the structure, extraction, biological functions, underlying mechanisms, and associations of DOP with gut microbes.
Structure and derivation of DOP
Dendrobium officinalea Chinese herbal medicine, has approximately 20% water-soluble, non-starch active polysaccharides (DOP).
These polysaccharides are primarily heteropolysaccharides including mannose, glucose, xylose, galactose, rhamnose and arabinose. Fresh DOPs are cleaned, dried and ground into powder under low thermal conditions. Organic solvents are used to extract crude DOP by eliminating low molecular weight compounds.
Ultrasound-assisted extraction, hot water extraction (HWE), enzyme-assisted extraction, microwave-assisted extraction, mechanochemical-assisted extraction, steam-assisted extraction, and enzyme-assisted extraction using eutectic solvents are common extraction procedures. Among the methods, hot water extraction is the most commonly used because of its simplicity, ease and safety.
Higher yields were obtained with ultrasound-assisted hot water extraction and freeze-thaw cold pressing, while mechanochemical-assisted extraction increased efficiency and reduced extraction time.
Solvent-based deep eutectic extraction is attractive due to its stable performance and fewer environmental concerns, while enzyme-assisted extraction offers gentle reaction conditions and excellent efficiency.
Health benefits and underlying mechanisms
DOPs can help with metabolic problems such as obesity, type 2 diabetes, and inflammation. DOP alleviated metabolic abnormalities in C57BL/6 mice fed a high-fat diet (HFD) for 11 weeks, including glutamine metabolism, fatty acid synthesis, Kreb’s cycle, butyrate metabolism, and glutathione metabolism. These effects can be partially transmitted by transplanting fecal microbes into obese mice induced by a high-fat diet.
DOPs also ameliorate mitochondrial damage by increasing phosphorylated AMP-stimulated protein kinase (p-AMPK) levels and enhancing citric acid cycle functions.
They inhibit glucose metabolism and glycogen synthesis by activating the phosphoinositide-3-kinase-protein kinase (PI3K/Akt) signaling pathway, mediating the protein kinase A (PKA) and protein kinase/forkhead box O1 (Akt/ FoxO1) to inhibit glycogen breakdown, increase liver glycogen formation, inhibit hepatic gluconeogenesis, and regulate peroxisome proliferator-activated receptor (PPAR) levels to improve lipid metabolism.
In Wistar rats with streptozotocin-induced type 2 diabetes, a 28-day treatment with two naturally acetylated glucomannans and DOP corrected metabolic disturbances related to lipid and glucose levels.
DOP performed excellently, was safe, and had no dangerous adverse effects when treating obese mice at one gram per kg per day for 11 weeks.
DOPs restore intestinal barrier function and preserve the intestinal mucosal barrier. They enhance intestinal epithelial tight protein production, maintain mucosal barrier stability, minimize lipopolysaccharide translocation, and lower serum lipopolysaccharide (LPS) levels.
They stimulate the nuclear factor erythroid-2-related factor 2 (Nrf2)/heme oxygenase (HO-1) signaling pathway in damaged cells at inflammatory sites, reducing oxidative damage and effectively controlling inflammation.
Associations of DOPs with the gut microbiome
Gut microbes process DOPs in the colon, producing short-chain fatty acids (SCFAs) and oligosaccharides that alter gut microbial composition and improve human health. DOP has been shown to reduce harmful bacteria such as E. coli and Staphylococci while promoting useful like Bifidobacterium.
DOPs alter the composition and diversity of the gut microbiome and enhance the synthesis of SCFAs such as acetate, propionate and butyrate. This supplement can restore gut microbial balance and improve microbial diversity in obese mice and animal models, bringing the gut microbiota closer to a healthy state.
DOPs also influence changes in gut microbiota at the phylum level, with obesity being associated with a decline in Firmicutes/Bacteroidetes ratio. DOPs can degrade DOPs and create SCFAs, promoting the development of Bifidobacterium and Lactobacillus microbial populations.
Common probiotic strains can also degrade and consume DOP, creating SCFAs, preventing the growth of pathogenic bacteria and reducing Ackermansia formation.
Based on the review findings, DOPs may improve gut health as potential prebiotics, offering health benefits such as metabolic regulation, inflammation modulation, immune moderation, and cancer intervention.
They can improve the composition of the gut microbiome, offering new strategies for metabolic and inflammatory diseases. However, the relationship between DOPs and the gut microbiome is not fully understood.
Future research should focus on the growth-promoting effect of DOP on probiotics and their role in cancer processes and immune activity.
