Chaga

Natural History

(Ecology, Where and How it Grows)

I. obliquus is in the family Hymenochaetaceae, which contains more than fifty genera [16] and 487 species. [18] Chaga is commonly found growing as sclerotia, or a sterile conk on various birch tree species. [37]

Ethnomycology

(The Cultural and Sociological Impact of this Species)

The healers from the Cree tribe of northwestern Canada use Inonotus obliquus as an incense due to its sweet smell when burnt, and as a tinder to start fires. They also use it to keep tobacco and other herbs burning in smoking pipes. In the legend of the Cree, Chaga earned its Cree name from Wiskakecak, a mythological being who threw a scab against a birch tree after trying to consume it. The scab became a part of the tree, where it remains until the present, for the good of humanity. The native Dene of Saskatchewan used Chaga in a divination ritual. After arranging the crumbled inner part of the fungi in two long lines that represented two different events, the ends would be placed together, then ignited from their opposite sides. Whichever pile burned first, signified the event that would happen first. They call this ritual “etsen dek,” or “it smells when it’s burning.” [37]

QUICK FACTS

Cancer

Cancer is one of the leading causes of death globally. In 2012, it was responsible for an estimated 8.2 million deaths. The expected number of new cancer cases are projected to grow substantially to a total of 23.6 million by 2030, thus underscoring the importance of access to organisms which contain compounds that may help to decrease the disease’s prevalence or severity. [33]

Extracts of Inonotus obliquus have demonstrated an inhibitory effect on tumor growth and cell cycle. An extract of I. obliquus has demonstrated dose-dependent cytotoxic effects on HepG2 and Hep3B hepatoma cell cultures. After 48 hours of exposure to 1000 μg/ml, the viabilities of HepG2 and Hep3B were 36% and 67% respectively, using the MTT assay. The MTT assay is used to measure cellular metabolic activity in cell culture studies to determine cytotoxicity, viability, and proliferation. The extract’s method of action was shown to involve arresting the cancer cell lines at the G0/G1 phase by reducing the expression levels of p53, cyclins D1, Cdk2, Cdk4, and Cdk6, inducing apoptosis. More research using the rigorous standards of modern medicine needs to be conducted to support preliminary studies’ findings on Chaga’s efficacy in the prevention and treatment of cancer. [12]

I. obliquus has demonstrated an ability to “reduce the absorption of carbohydrates by inhibiting the activity of intestinal α-amylase and α-glucose, effectively reducing postprandial blood glucose levels, repairing islet damage, and improving complications.” [26]

In 2017, a study of the anti-diabetic effects of polysaccharides from I. obliquus was conducted on Streptozotocin-Induced (STZ) type 2 diabetic mice. Streptozotocin is an antibiotic extract from Streptomyces achromogenes. It is diabetogenic, meaning it produces an elevated concentration of blood-glucose. [39] Male Kunming mice were induced with type 2 diabetes via a high-fat diet for 4 weeks and 2 intraperitoneal Streptozotocin injections in a citrate buffer within a seventy-two-hour period. Mice with blood glucose levels above 11.1 mmol/L were considered diabetic. [46] 

From there, the STZ-induced type 2 diabetic mice were randomly assigned to 5 groups. A diabetic control group: diabetic mice treated with saline in a matched volume. A Rosiglitazone group: diabetic mice administered with the common anti-diabetic medication rosiglitazone at 2 mg/kg per day. Three different I. obliquus polysaccharides (IOPS) groups were formed and received 300, 600, or 900 mg/kg of IOPS per day. A sixth “normal control” group comprised of mice without the induction of STZ was treated with saline in a matched volume. [46]

During the 4-week period the mice in the normal control group received a normal chow diet, while the diabetic mice groups received a high-fat diet. Once a week, fasting blood glucose (FBG) levels were measured in blood taken via glucometer. [46]

Weight loss due to diabetes is a common occurrence. Administration of IOPS to the 600 mg/kg and 900 mg/kg diabetic mice showed body weight increases of 5.12% and 5.43%, respectively. IOPS at the 900 mg/kg dose showed significant antihyperglycemic effects on diabetic mice. The rosiglitazone-treated group had a 26.90% reduction of FBG compared to the diabetic control, while mice in the IOPS 900 mg/kg group showed a reduction rate of 49.9%. Researchers concluded that their findings demonstrated the ability to control the glucose and insulin levels in type 2 diabetics as well as those with hyperglycemia and hyperinsulinemia. [46]

To investigate the effects of IOPS on the insulin resistance in T2DM mice, the serum insulin level was determined after 4 weeks’ treatment. As shown in Fig. 1B, the diabetic mice administered with IOPS (900 mg/kg) exhibited a remarkable decrease of insulin level compared with diabetic control with the reduction rates of 22.82%. 

The study also looked at insulin resistance. After 4 weeks of treatment, diabetic mice in the IOPS 900 mg/kg group showed a reduction of insulin levels of 22.82% compared to the diabetic control group, indicating that I. obliquus polysaccharides are “beneficial for the amelioration of hyperglycemia... and insulin resistance” and “might be a good candidate for the treatment of diabetes mellitus.” [46]

Glycogen is a branched polymer of glucose stored mainly in the liver and the skeletal muscle that supplies glucose to the bloodstream during fasting periods, and to the muscle cells during muscle contraction. [1] As the “primary intracellular storage form of glucose in [the] liver and muscle,” its levels are considered relevant as a component of the insulin resistance commonly observed in type 2 diabetics. [46]

All three IOPS groups showed dramatic restoration of hepatic glycogen levels. The 300 mg/kg group exhibited an increase rate of 99.15%. The 600 mg/kg group showed 121.80% increase, and the 900 mg/kg demonstrated a glycogen level increase of 196.60%. 

Thus, these results suggested that the antihyperglycemic activity of IOPS was partially attributed to the synthesis of glycogen, which might be the representation of insulin-sensitizing in hepatic tissues.

To look into the homeostasis of blood glucose in diabetic mice, all experimental mice groups were administered glucose. The normal control group’s glucose levels peaked at thirty minutes, then returned to basal rate after 120 minutes, whereas the glucose levels of diabetic mice remained elevated.  Administration of rosiglitazone and IOPS (900 mg/kg) resulted in a “significant suppression on the blood glucose level... compared with diabetic control” indicating “that the IOPS could improve the impaired glucose tolerance” and prevent further deterioration due to diabetes. [46]

Studies by Diao [11] and Duru [12] found that Streptozotocin-induced diabetic Wistar rats administered with I. obliquus polysaccharides at doses of 10, 20, and 30 mg/kg for 6 weeks showed significantly lower LDL cholesterol levels with treatment doses of 20 mg/kg and 30 mg/kg, with the higher dose bringing the levels on par with those seen in healthy rats. This suggests that I. obliquus polysaccharides may lower the risk of heart disease. In addition, rats administered with 30 mg IOPS had lower levels of TNF-𝛼 (a proinflammatory cytokine) and a decrease in IL-1beta, suggesting a beneficial effect on beta-cell function. To summarize the findings in this study, it was concluded that 30 mg/kg of IOPS reduced blood glucose levels and restored or protected beta-cells against damage from diabetes through antioxidant, anti-inflammatory, and hypolipidemic activities.

Lower Cholesterol

In a study published in 2021, the lipid-lowering effects of I. obliquus polysaccharide (IOP) were investigated, both in vitro and in vivo (in body) experiments. [48]

Prevention of Lipid Accumulation

In the aforementioned study, a number of in vitro experiments were performed. A cell culture medium containing HepG2 cells and an oleic acid (OA) concentration of 0.2 mm was used to induce a lipid accumulation cell model, after which various concentrations of I. obliquus polysaccharide (IOP) could be tested.   

Various groups were tested according to various concentrations of IOP, as follows: Low IOP 20 mg/L (LIOP), medium 40 mg/L IOP (MIOP) and high 60 mg/L (HIOP).

Cells induced with “serious... lipid accumulation” that was observable as “large red lipid droplets” showed that “lipid accumulation was significantly reduced” in all the cell groups treated with I. obliquus polysaccharide. A positive correlation was noted. As “IOP concentration increased in HepG2 cells, the red lipid droplets became smaller and lighter.” Researchers deduced the HIOP group “exhibited significantly decreased lipid droplets, suggesting that IOP prevented HepG2 cells from excessive lipid accumulation in vitro.” [48]

Effects on Total Cholesterol, Total Triglycerides, HDL-C, and LDL-C

In the same study, all IOP cell groups at the low, medium, and high levels of IOP concentrations (LIOP, MIOP, and HIOP) “significantly” showed a decrease in total cholesterol (TC) and total triglycerides (TG). Furthermore, the HIOP group, which received 60 mg/L of IOP, showed a significant reduction of LDL-C (bad cholesterol) and an increase of HDL-C (good cholesterol). [48]

Reduction of Weight Gained by High-Fat Diet

The in vivo portion of the study supported the in vitro findings. Inonotus obliquus polysaccharide demonstrated an ability to reduce body weight in mice receiving a high-fat diet. Unsurprisingly, mice in all of the high-fat diet groups showed body weight gain that outpaced weight gain in the NC group. [48]

Forty mice, aged four-weeks old, were randomly divided into five groups. The normal control group (NC) was fed a normal diet. The four remaining groups received a high-fat diet; those groups are as follows: high-fat diet model group (HFD), low-dose I. obliquus polysaccharide group (LIOP), medium-dose group (MIOP), and high-dose group (HIOP).

After receiving IOP for 10 weeks, the body weight of mice in the all IOP-receiving groups (LIOP, MIOP, HIOP), was significantly lower than the model HFD group (p < 0.05). Researchers deduced that “IOP can effectively reduce the body weight gain of mice induced by a high-fat diet.”

Furthermore, the lipid-reducing, total cholesterol and total triglyceride-lowering effects were also demonstrated in in vivo experiments. As expected, the serum TC, TG, and LDL-C concentrations of mice in the HFD groups were significantly higher than those in the NC group (p < 0.05). Mice in all IOP groups (LIOP, MIOP, HIOP) showed a significant decrease in serum TC, TG, and LDL-C concentrations, demonstrating IOP’s “obvious lipid-lowering effect.” In the HIOP group receiving 60 mg/L, total cholesterol (TG) decreased dramatically—by 40%, total triglycerides fell by 24.8%, and LDL-C fell by 30.1%. Compared to mice in the HFD group, the serum HDL-C concentrations of mice in all three IOP-receiving groups (LIOP, MIOP, HIOP) showed significant increases of 22.2%, 30.3%, and 49.2%, respectively, which led researchers to deduce that “IOP can increase the level of serum HDL-C'' at varying dose levels, as demonstrated. [48]

gut health

Gut disorders are a global problem. A large-scale multinational study conducted in 2021 found that, worldwide, 40% of human beings have functional gastrointestinal disorders (FGIDs). [41] Our microbiomes need both prebiotics and probiotics for optimum health. A gut with an array of beneficial bacterial enzymes has the ability to function well, properly digest foods and nutrients, and fight off harmful pathogens.  

Inonotus obliquus contains powerful gut-loving prebiotics. As The Mayo Clinic explains, unlike probiotics, prebiotics are not living organisms, such as bifidobacterium, lactobacillus acidophilus, saccharomyces, enterococcus, escherichia, and bacillus. Prebiotics can be thought of as “fertilizers that help stimulate the growth of healthy bacteria” and provide necessary foundational support to the colonies of probiotics which populate the gut. [28]  

 The prebiotics found in I. obliquus depress the activity of disease-causing endogenous (i.e., in body) pathogens found in the gastrointestinal tract, as well as increase the immune system’s ability to fight exogenous (external) pathogens which enter the body through environmental exposure. The oligosaccharides found in the mushroom also “exert a combined effect on both the pH environment of the gut and the metabolism of [the] bacterial community” thus promoting the growth of the gut’s micro flora. [5] If the pH levels fall above or below optimal ranges, the absorption of minerals, proteins, and vitamins can be adversely impacted. [17]

Unfavorable gut microbiota can lead to the onset of “metabolic dysregulations, leading to inflammation in the intestine, liver, and brain” and also negatively impact the body’s energy metabolism. A 2017 study revealed that I. obliquus induces changes in the gut microbiota and “increases the Bacteroidetes at the phylum level,” thus commencing “changes towards a healthy bacterial profile.” [15]

Immunity

All immune system cells are created within bone marrow. As the Children’s Hospital of Philadelphia’s website explains, “If the immune system is a police force, the bone marrow is the police academy because this is where the different types of immune system cells are created.” [8] It is at this locus that Inonotus obliquus appears to work as a powerful immunomodulator.

An in vivo study conducted on mice which were chemically immunosuppressed and treated with a water-based I. obliquus extract “increased levels of chemically protective cytokines including IL-6 and TNF-α ”… were observed, which are “known to stimulate stem cell recovery and hematopoietic regeneration after bone marrow damage.”  [18]

Chaga mushroom extract also demonstrated an ability to increase the amount of granulocyte-macrophage progenitor (CFU-GM), a multipotent cell, produced within bone marrow [38], that can differentiate to osteoclasts (OCLs), macrophages, or granulocytes. [29]

In mice with chemically-induced bone marrow damage, I. obliquus boosted the amount of CFU-GM, and thus enabled them to overcome the immunosuppressive state that arose from that damage. Erythroid burst-forming units (BFU-E), a progenitor of red cells, were also increased “almost to the normal levels.” Administration of the extract was also followed by a high increase in cells “committed to splenocyte” The splenocytes are believed to seed the production of bone marrow in the body. Scientists observing I. obliquus’ ability to increase protective cytokines as well as GFU-CM, the immune system cell progenitor, and red-cell-progenitor BFU-E, surmised that the “data suggests the potential of the Chaga mushroom extract as an effective BRM” (biologic response modifier aka immunomodulator) and “… immune enhancer in immunocompromised and immunosuppressed individuals.” [18]

Medicinal Compounds

(Beta-Glucans, Phenols, etcetera)

Chaga has over 200 different compounds that include:

Medicinal Compounds sourced from R.D Rogers. “The Fungal Pharmacy: The Complete Guide to medicinal mushrooms and lichens of North America.” North Atlantic Books. 2011.

SOURCES AND FURTHER READING: