Auricularia Polysaccharides and Glucose Metabolism

Auricularia and Blood Sugar

26 years of research

From a 1998 study in genetically diabetic mice to 2024 metabolomics analysis, Auricularia auricula polysaccharides have demonstrated consistent blood glucose-lowering effects across nine animal studies, with zero human clinical trials completed.

Yuan et al., Bioscience, Biotechnology, and Biochemistry, 1998

9 studies

all in rodent models (1998-2024)

PI3K/Akt

primary insulin signaling pathway affected

0 human trials

all evidence is preclinical

Yuan et al., Bioscience, Biotechnology, and Biochemistry, 1998

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A water-soluble polysaccharide extracted from Auricularia auricula-judae lowered plasma glucose in genetically diabetic KK-Ay mice by 22.4% over 7 weeks in the first published study on this topic in 1998.^[1] That finding launched a research line that now includes nine animal studies mapping the molecular pathways through which wood ear mushroom polysaccharides interact with glucose regulation. For the broader picture of how Auricularia affects blood sugar, see wood ear and blood sugar: hypoglycemic research. For the enzymatic angle, see Auricularia and alpha-glucosidase inhibition.

Every study described here used rodent models (mice or rats) with chemically or genetically induced diabetes. No human clinical trial has tested Auricularia polysaccharides for blood glucose management. The translation from diabetic rodent to human metabolic disease remains the field's central open question.

The foundational study: KK-Ay mice, 1998

Yuan et al. published the first controlled study of Auricularia polysaccharides on blood glucose in 1998, using genetically obese and diabetic KK-Ay mice. This mouse strain spontaneously develops hyperglycemia and insulin resistance, modeling type 2 diabetes without chemical induction.^[1]

Mice received water-soluble polysaccharide extracted from Auricularia auricula-judae fruiting bodies in their diet for 7 weeks. The treated group showed reduced plasma glucose, insulin levels, and urinary glucose excretion compared to controls. Food intake also decreased in the polysaccharide-fed group.^[1]

This study established the basic premise but left the mechanism entirely unexplored. It took nearly two decades before researchers began mapping the molecular pathways involved.

PI3K/Akt insulin signaling pathway

The PI3K/Akt pathway is the primary intracellular route through which insulin signals cells to absorb glucose from the bloodstream. When insulin binds its receptor, it activates insulin receptor substrate (IRS), which triggers phosphoinositide 3-kinase (PI3K), which activates protein kinase B (Akt/PKB), which ultimately moves glucose transporter 4 (GLUT-4) to the cell surface. Disruption at any step produces insulin resistance.

Shi et al. (2024) provided the most detailed pathway analysis to date. They prepared a low-molecular-weight polysaccharide acid hydrolysate (RLMP) from Auricularia auricula-judae and tested it in streptozotocin (STZ)-induced diabetic mice under conditions of oxidative stress. RLMP treatment activated PI3K, increased Akt phosphorylation, and upregulated GLUT-4 expression in liver and muscle tissue. Fasting blood glucose decreased, and oral glucose tolerance improved in treated mice.^[2]

Xu et al. (2021) confirmed PI3K/Akt involvement using a high-fat diet plus STZ model. Their polysaccharide preparation activated the AKT/AMPK signaling pathway in liver tissue, with increased phosphorylation of both AKT and AMPK measured by Western blot. The dual AKT/AMPK activation suggests Auricularia polysaccharides may affect both insulin-dependent and insulin-independent glucose uptake pathways.^[3]

These findings place Auricularia polysaccharides mechanistically at the same pathway targeted by the diabetes drug metformin (via AMPK) and the thiazolidinedione drug class (via insulin sensitization), though at a much earlier stage of evidence.

Metabolomics: mapping systemic metabolic changes

Liu et al. (2021) took a broader view, using untargeted metabolomics to identify global metabolic changes in high-fat diet/STZ diabetic mice treated with Auricularia polysaccharides at 200 mg/kg/day. Beyond confirming fasting blood glucose reduction and improved glucose tolerance, the metabolomics analysis identified shifts in amino acid metabolism, lipid metabolism, and purine metabolism that differed between treated and untreated diabetic mice.^[4]

The treated group showed improved lipid profiles with reduced total cholesterol, triglycerides, and LDL-cholesterol. Serum insulin levels also improved. The metabolomics approach revealed that polysaccharide treatment partially restored the metabolic fingerprint of diabetic mice toward that of healthy controls, though not completely.^[4]

This type of systems-level analysis is valuable because it reveals off-target effects (positive or negative) that pathway-specific studies miss. The limitation is that metabolomics identifies correlations between treatment and metabolic states without proving causation for any individual metabolite change.

Molecular weight matters: degraded vs. intact polysaccharides

A recurring finding across studies is that lower-molecular-weight polysaccharide fractions show greater biological activity than intact, high-molecular-weight forms. This makes biological sense: smaller molecules are more likely to cross intestinal membranes and reach target tissues.

Shen et al. (2019) systematically compared degraded polysaccharides from Auricularia auricula-judae against intact forms. The degraded fraction showed alpha-glucosidase inhibitory activity with an IC50 of 1.39 mg/mL, while intact polysaccharides had weaker inhibition. In STZ-diabetic mice, the degraded polysaccharides also showed hypoglycemic activity, measured by fasting blood glucose reduction over the treatment period.^[5]

Lu et al. (2018) reached a similar conclusion with polysaccharide hydrolysates prepared through simulated gastrointestinal digestion. The hydrolyzed preparation reduced fasting blood glucose, improved glucose tolerance, increased hepatic glycogen and pancreatic insulin levels, and decreased serum triglycerides and LDL-cholesterol in STZ-diabetic rats over 7 weeks. The preparation consisted primarily of mannose, xylose, glucose, and galactose subunits.^[6]

Shi et al. (2024) reinforced this pattern: their acid-hydrolyzed low-molecular-weight fraction (RLMP) showed stronger PI3K/Akt pathway activation than crude polysaccharide extracts.^[2] The consistent finding across three independent groups suggests that polysaccharide processing strongly influences biological activity, which has direct implications for any future supplement or therapeutic development.

Oxidative stress and antioxidant enzyme activation

Chronic hyperglycemia generates excessive reactive oxygen species (ROS), which damage pancreatic beta cells, impair insulin signaling, and accelerate diabetic complications. Several studies in this field have measured antioxidant enzyme responses alongside glucose outcomes.

Shi et al. (2024) documented that their polysaccharide acid hydrolysate increased the activities of total superoxide dismutase (T-SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in diabetic mouse liver tissue, while reducing malondialdehyde (MDA), a marker of lipid peroxidation damage. The reduction in oxidative stress markers correlated with improved glucose tolerance and PI3K/Akt activation, suggesting that ROS reduction may be upstream of the insulin signaling improvements.^[2]

Liu et al. (2021) found similar antioxidant enzyme activation in their metabolomics study, with treated diabetic mice showing higher SOD and GSH-Px activities than untreated diabetic controls. The metabolomics data additionally revealed shifts in glutathione metabolism and taurine metabolism, both pathways linked to cellular redox balance.^[4]

Hu et al. (2017) measured antioxidant markers specifically in kidney tissue of diabetic rats, finding that polysaccharide treatment restored SOD activity and reduced MDA accumulation in renal tissue alongside the anti-nephropathy effects.^[8]

The consistent antioxidant findings across multiple groups suggest this is a genuine effect of Auricularia polysaccharides rather than an artifact of any single preparation. Whether the antioxidant activity is a direct chemical property of the polysaccharides (scavenging free radicals) or an indirect result of enzyme induction remains unclear. The distinction matters: a direct scavenger would need to be present continuously, while an enzyme inducer could have lasting effects after a single dose.

Gut microbiota and the diabetes connection

Two studies have examined how Auricularia polysaccharides interact with gut bacteria in diabetic models, connecting to a growing body of evidence that the gut microbiome influences glucose metabolism. For more on Auricularia's effects on intestinal bacteria, see Auricularia and gut microbiome modulation.

Liu et al. (2022) profiled gut microbiota composition in type 2 diabetic mice receiving Auricularia auricula polysaccharides. The treatment altered the ratio of Firmicutes to Bacteroidetes (a marker frequently disrupted in diabetes and obesity) and increased the abundance of several bacterial genera associated with short-chain fatty acid production.^[7]

Xu et al. (2021) documented similar microbiome restoration alongside their AKT/AMPK pathway findings. Diabetic mice treated with Auricularia polysaccharides showed increased microbial diversity and shifts in specific bacterial populations toward the profile seen in healthy controls.^[3]

Whether the polysaccharides improve glucose metabolism by feeding beneficial gut bacteria (a prebiotic effect), or whether the gut changes are a downstream consequence of improved metabolic status, remains unresolved. The answer likely involves bidirectional effects, but the studies were not designed to distinguish cause from consequence.

Diabetic complications: kidney damage and AGE formation

Diabetes causes damage beyond blood glucose elevation. Two studies have examined whether Auricularia polysaccharides affect downstream complications.

Hu et al. (2017) tested polysaccharide fractions in diet-STZ diabetic rats, focusing on kidney damage. Treated rats showed reduced blood glucose alongside decreased markers of diabetic nephropathy, including improved kidney histopathology and reduced urinary protein excretion.^[8] Whether kidney protection was a direct effect of the polysaccharides or simply a consequence of lower blood glucose was not determined. For related research on diabetes-related tissue damage, see wood ear and diabetic complications.

Gong et al. (2024) investigated advanced glycation end-products (AGEs), the molecular damage products formed when sugars react with proteins under chronic hyperglycemic conditions. AGEs accumulate in tissues and contribute to diabetic retinopathy, neuropathy, and vascular disease. In vitro, Auricularia polysaccharides inhibited AGE formation in a dose-dependent manner.^[9] This finding is preliminary (in vitro only) but addresses a mechanism distinct from blood glucose lowering that could be relevant to long-term diabetic tissue damage.

What the animal data cannot answer

All nine studies use chemically induced (STZ) or genetically determined (KK-Ay) diabetes in rodents. These models share important features with human type 2 diabetes (hyperglycemia, insulin resistance, dyslipidemia) but differ in critical ways. STZ directly destroys pancreatic beta cells, producing a model closer to type 1 diabetes in its mechanism. The KK-Ay model involves a single genetic mutation, while human type 2 diabetes involves polygenic susceptibility interacting with decades of metabolic stress.

Dosing in these studies ranged from approximately 100 to 400 mg/kg/day of polysaccharide in mice. Scaling these doses to humans requires allometric conversion and assumptions about oral bioavailability of large polysaccharide molecules in the human gut, neither of which has been studied for Auricularia polysaccharides.

The structural heterogeneity of "Auricularia polysaccharides" across studies is a further complication. Different extraction methods (hot water, acid hydrolysis, enzymatic degradation) produce preparations with different molecular weights, monosaccharide compositions, and branching patterns. Comparing results across studies assumes these preparations share a common active component, which has not been established.

No study has measured whether Auricularia polysaccharides interact with common diabetes medications (metformin, sulfonylureas, insulin). Given that the polysaccharides appear to act on some of the same pathways as these drugs, the potential for additive or synergistic effects exists but remains unexplored. For considerations about mushroom-drug interactions broadly, see Auricularia and atherosclerosis prevention for related cardiovascular research context.

The Bottom Line

Nine animal studies published between 1998 and 2024 demonstrate that Auricularia auricula polysaccharides lower blood glucose in diabetic rodent models. The mechanism involves PI3K/Akt/GLUT-4 insulin signaling activation, AMPK pathway engagement, alpha-glucosidase inhibition, and gut microbiota modulation. Lower-molecular-weight polysaccharide fractions consistently outperform intact forms. No human clinical trial has tested these findings, and fundamental questions about oral bioavailability, human dosing, and drug interactions remain entirely unanswered.

Frequently Asked Questions

Do wood ear mushroom polysaccharides lower blood sugar?

In rodent studies, water-soluble polysaccharides from Auricularia auricula (wood ear mushroom) consistently reduced fasting blood glucose in diabetic mice and rats. The earliest study showed a 22.4% reduction in genetically diabetic KK-Ay mice (Yuan et al., 1998). More recent work confirmed these effects using high-fat diet/STZ models with 200 mg/kg/day dosing (Liu et al., 2021). All evidence is from animal models with no published human trials.

How do Auricularia polysaccharides affect insulin signaling?

Auricularia polysaccharides activate the PI3K/Akt/GLUT-4 insulin signaling pathway in diabetic animal models. Shi et al. (2024) showed that polysaccharide acid hydrolysate increased PI3K activity, Akt phosphorylation, and GLUT-4 expression in liver and muscle tissue. Xu et al. (2021) also demonstrated dual activation of AKT and AMPK pathways, suggesting effects on both insulin-dependent and insulin-independent glucose uptake.

What is the best form of Auricularia polysaccharide for blood sugar?

Animal studies consistently show that lower-molecular-weight (degraded or hydrolyzed) polysaccharide fractions have greater biological activity than intact high-molecular-weight forms. Shen et al. (2019) found degraded polysaccharides had stronger alpha-glucosidase inhibition (IC50 1.39 mg/mL), and Shi et al. (2024) showed acid-hydrolyzed fractions activated PI3K/Akt more strongly. No human study has compared forms.

Can Auricularia mushroom polysaccharides help with type 2 diabetes?

Auricularia polysaccharides reduced blood glucose, improved insulin sensitivity, and restored lipid profiles in multiple type 2 diabetes rodent models. Xu et al. (2021) showed improvements in AKT/AMPK signaling and gut microbiota diversity. These findings are preclinical only. Whether Auricularia polysaccharides can achieve therapeutic concentrations in human tissue through oral consumption is unknown.

Do wood ear mushrooms affect gut bacteria related to diabetes?

Two studies found that Auricularia polysaccharides altered gut microbiota composition in diabetic mice. Liu et al. (2022) documented changes in Firmicutes/Bacteroidetes ratios and increased short-chain fatty acid-producing bacteria. Xu et al. (2021) showed restored microbial diversity alongside metabolic improvements. Whether the gut changes cause or result from improved glucose metabolism is not yet clear.

Are there human clinical trials on Auricularia and blood sugar?

As of 2026, no published randomized controlled trial has tested Auricularia auricula polysaccharides specifically for blood glucose management in humans. All nine studies in the literature used rodent models (mice or rats) with chemically or genetically induced diabetes. Basic human pharmacokinetic data for these polysaccharides has not been published.

Sources & References

1. 1RTHM-00028·Yuan, Z et al. (1998). “Hypoglycemic effect of water-soluble polysaccharide from Auricularia auricula-judae Quel. on genetically diabetic KK-Ay mice..” Bioscience.Study breakdown →PubMed →↩
2. 2RTHM-00909·Shi, Qianwen et al. (2024). “Effects of Auricularia auricula-judae (Bull.) Quél. polysaccharide acid hydrolysate on glucose metabolism in diabetic mice under oxidative stress..” Phytomedicine : international journal of phytotherapy and phytopharmacology.Study breakdown →PubMed →↩
3. 3RTHM-00728·Xu, Nuo et al. (2021). “Auricularia auricula-judae (Bull.) polysaccharides improve type 2 diabetes in HFD/STZ-induced mice by regulating the AKT/AMPK signaling pathways and the gut microbiota..” Journal of food science.Study breakdown →PubMed →↩
4. 4RTHM-00704·Liu, Nannan et al. (2021). “Hypoglycemic effects of Auricularia auricula polysaccharides on high fat diet and streptozotocin-induced diabetic mice using metabolomics analysis..” Food & function.Study breakdown →PubMed →↩
5. 5RTHM-00586·Shen, Meng et al. (2019). “Hypoglycemic Effect of the Degraded Polysaccharides from the Wood Ear Medicinal Mushroom Auricularia auricula-judae (Agaricomycetes)..” International journal of medicinal mushrooms.Study breakdown →PubMed →↩
6. 6RTHM-00522·Lu, Aoxue et al. (2018). “Preparation of the Auricularia auricular polysaccharides simulated hydrolysates and their hypoglycaemic effect..” International journal of biological macromolecules.Study breakdown →PubMed →↩
7. 7RTHM-00780·Liu, Nannan et al. (2022). “Effects of Auricularia auricula Polysaccharides on Gut Microbiota Composition in Type 2 Diabetic Mice..” Molecules (Basel.Study breakdown →PubMed →↩
8. 8RTHM-00474·Hu, Xinyu et al. (2017). “Hpyerglycemic and anti-diabetic nephritis activities of polysaccharides separated from Auricularia auricular in diet-streptozotocin-induced diabetic rats..” Experimental and therapeutic medicine.Study breakdown →PubMed →↩
9. 9RTHM-00880·Gong, Pin et al. (2024). “Potential inhibitory effect of Auricularia auricula polysaccharide on advanced glycation end-products (AGEs)..” International journal of biological macromolecules.Study breakdown →PubMed →↩