Shitake mushroom

Introduction

Shitake mushrooms are also called brown-capped mushrooms; they are used as food and supplements worldwide. Shitake mushrooms are fungi that naturally grow on decaying hardwood trees; they are tan to dark brown with a cap that is around 2-4 inches native to East Asia.

Shitake mushrooms are one of the most popular mushrooms worldwide and appreciated for their savoury, rich taste and myriad health benefits, available in fresh or dried forms and dietary supplements. The polysaccharide, lentinan present in Shitake mushrooms is known to help boost immunity, fight cancer, support a healthy heart. 

Nutritional Profile of Shitake mushrooms

Shitake mushrooms are low in calories, but there are ample Fiber, Vitamins, Minerals, and other health-promoting factors. 

For four dried shitake mushrooms, approximately 15 grams, there are 44 Calories, 11 grams of carbohydrates, 2 grams of fibre and 1 gram of proteins.

Lentinan 

It is the polysaccharide found in the mycelium/fruit body of the shitake mushrooms. Lentinan is also called 1, 3 beta-glucan. Lentinan is classified under a dietary supplement. It is observed in some studies that it does not directly affect the cancer cells but enhances the immune system, which helps in slows down the growth of tumours, it is also known to directly kill the microbes and viruses in preclinical studies. 

Shitake mushrooms (Lentinan) and Cancer

There is no direct cytotoxic effect on cancer/tumour cells observed, but it has been shown to enhance the activity of cancer drugs(cisplatin, gemcitabine, docetaxel and paclitaxel) and monoclonal antibodies. 

In a study, it is observed that for the cancer treatment, paclitaxel (cancer drug) used along with lentinan has produced ROS and activated NLRP3 inflammasome and ASK1/p38 MAPK signal pathway which has heightened the effect in the lung cancer cell lines. 

A study showed that the use of lentinan along with gemcitabine has enhanced the T24 cell apoptosis in urothelial bladder cancer cell lines.

Lentinan with the combination of cisplatin and docetaxel combined has induced apoptosis in gastric cancer cells. 

Paclitaxel-induced apoptosis and DNA damage were reduced by lentinan via inflexion of cellular antioxidant levels in the murine bone marrow cells. 

Lentinan is observed to improve the quality of life of cancer patients with different types of cancer like gastric cancer, oesophagal carcinoma. A Meta-analysis study has shown that lentinan as an adjuvant can be beneficial for advanced gastric cancer. 

1, 3 beta glucan the active polysaccharide of lentinan has been observed to enhance T-Helper cells’ function and increase the stimulation of Interleukins(IL-4), Interferons and Natural killer cells (NK-cells).

A study has shown that in cancer patients suffering from gastric cancer, lentinan along with chemotherapy has tended to decrease the frequency of the adverse events, thereby increasing the patient’s quality of life.

Other therapeutic uses of Shitake mushrooms (lentinan)

Counting to the antitumor activity shitake mushrooms also possess antiviral property, antimicrobial property, immune-regulating effects and cholesterol-lowering effects. 

They help in reducing cholesterol levels.

Few studies showed that they help in increasing the activity of particular types of immune cells(Immunostimulation).

They help in treating infections.

Side effects and risk factors

Side effects of lentinan can be as follows, mild or severe anaphylactic reactions, depression, fever, rigour, chills, back and leg pain, raised liver enzymes and granulocytopenia(drop in the count of peripheral blood granulocytes), discomfort in the stomach or intestine.

Some adverse reactions are also seen like the tightness of the chest is observed after the parenteral injection of lentinan, Shitake dermatitis(whiplash-like marks) is observed cause due to the toxic reactions of lentinan mainly by consumption of raw shiitake mushrooms, but reduced from few days to a week.