Objective: Extract from cultured Lentinula edodes mycelia (L.E.M.) is a food ingredient possessing various pharmacologic actions such as immunomodulatory properties, antitumor and hepatoprotective effects. In Japan, it has been used as a health food for 30 years or more.
In the present study to evaluate the safety of L.E.M., a genotoxicity study and acute toxicity study were conducted. In addition, the inhibitory effect of drug-metabolizing enzyme by L.E.M. was tested in vitro, to gain insight on the interaction with medicines.
Methods: The genotoxicity study was performed using a bacterial reverse mutation assay and a in vivo mammalian bone marrow cell chromosomal mutation assay. The acute toxicity study was performed using a single-dose oral toxicity test in rats. Inhibitory activity of cytochrome P-450 3A4 (CYP3A4), one of the most important drug-metabolizing enzymes, by L.E.M. was tested using a baculovirus-expressed system.
Results: In the genotoxicity study, mutagenicity was negative for both bacterial reverse mutation assay and in vivo mammalian bone marrow cell chromosomal mutation assay. In the acute toxicity study, no toxic symptoms were observed by single dose oral administration of L.E.M. at a dose of 10,000 mg/kg BW in rats. This implies LD₅₀>10,000 mg/kg BW. No inhibitory activity of CYP3A4 by L.E.M. was observed at in the in vitro screening system to investigate drug-L.E.M. interaction.
Conclusion: It is believed L.E.M. is a safety ingredient for foods used in complementary and alternative medicine, since it was toxicologically safe and showed no inhibitory activity of CYP3A4 in the studies conducted.

In this study, we examined the effects of Lentinula edodes mycelia (LEM) on fatigue and immune function in healthy subjects. 22 people were randomly assigned in a 1:1 ratio to the LEM ingestion group and the placebo group. Daily oral ingestion of LEM for 4 weeks (600 mg/day) significantly improved the VAS fatigue score compared with before treatment (p<0.01). Additionally, NK cell activity was increased by ingestion of LEM (p<0.01) and was higher level compared to the placebo group (p<0.05). These results indicate that oral ingestion of LEM may improve the feeling of fatigue and immune function.

The patient, a 71-year-old man, was admitted to our department with fever from unknown causes. Ultrasonic examination of the abdominal regions revealed abnormal multiple low-density echo legions (that could be) associated with splenomegaly. For diagnostic purposes, splenic puncture was performed with the aid of an ultra-sound imaging device. Pale yellow-green pus was obtained from the lesions. Based on this finding, we made a diagnosis on the case as multiple abscess of the splean. The patient underwent intensive chemotherapy. However, he dontinued to have a high fever. On the ninth day from hospitalization, splenectomy was performed. Since then, his fever has subsided. Abscess of the spleen is a rare disease. It is generally classified into two types: one is a multiple type, and the other, a solitary type. Multiple splenic abscess mostly occurs as one of the abnormal conditions during the course of a primary disease, which is often severe. Our case, however, did not exhibit any sign of a primary disease.

Objective: The purpose of this study was to confirm the effect of feeding Okara fermented by Bacillus coagulans on cecum microflora in rat. Method: Three groups of SD rat of 8 weeks old were used in the experiment. The experimental animals were fed control diet, 2% okara diet, 2% fermented okara diet in each group for two weeks. The experimental diet and water were provided ad libitum. Food intake was measured every day. After 24 hours fast, we performed drawing blood with heparin after the experimental period. After drawing blood, several organs were removed for measuring their weight. In addition, we removed cecum after drawing blood about each three groups and studied their microflora. We also measured about plasma albumin, ALT, AST, ALP, LDH, total cholesterol, triacylglycerol, glucose, and cytokine level. Result: Bifidobacteria of cecum and blood IFN-g levels significantly increased in the fermented okara group. The total cholesterol level in blood significantly decreased. Conclusion: Okara fermented by Bacillus coagulans had an influence on not only intestinal microflora but also the immune system in rat, suggesting that the fermented okara can expect development as functional materials.

Lentinula edodes mycelia extract has been reported to maintain and improve immune function and QOL in cancer patients. In this study, the effects of Lentinula edodes mycelia extract on immune function were investigated in 10 healthy volunteers. Ten subjects were administrated Lentinula edodes mycelia extract orally for 20 weeks on average (846 mg / day ), and the immunological function (IFNγ production amount, IL-10 production amount, lymphocyte subset)was evaluated before and after ingestion at Fukuoka Tenjin Southern Clinic. Immune function following ingestion of Lentinula edodes mycelia extract showed a tendency of IFNγ production to increase, IL - 10 to decrease, and IFNγ / IL - 10 production ratio to be improved remarkably. No significant change was observed in lymphocyte subsets such as regulatory T cells before and after ingestion. Adverse events during the intake period were not observed. It was suggested that oral intake of Lentinula edodes mycelia extract has an action to improve the immune function of healthy adults.