Production of GABA-enriched Powder by Flammulina velutipes and Its Antihypertensive Effects in Spontaneously Hypertensive Rats

摘要

Gamma-aminobutyric acid (GABA) is a kind of amino acid widely distributed in nature, and the major inhibitory neurotransmitter in the central nervous system. GABA has been reported to have several physiological functions, such as antihypertensive, relaxation and improvement of memory effects. We investigated the production of GABA from glutamic acid using mushroom fruiting bodies and the effects of a single administration of GABA-enriched mushroom powder on blood pressure in spontaneously hypertensive rats (SHR) and rats with normal blood pressure (WIST). Freeze-dried powder of mushroom fruiting bodies was incubated in glutamic acid solution. It was found that Flammulina velutipes ( Enokitake) had the highest GABA production ability among 11 mushroom varieties. The GABA content of brown Enokitake was 6%-7% (dry powder) after reaction for 6 to 8 hours at 20℃. After a single administration of GABA-enriched Enokitake powder, a significant lowering of blood pressure was observed in SHR, but no effects were observed in WIST. Ingestion of GABA-enriched powder (0.9 mg-GABA/kg) resulted in a reduction in systolic blood pressure (SBP) by about 30 mmHg①. These results show that it' s possible to increase GABA content of Enokitake 60 to 70 times and GABA-enriched powder has reductive effect on SBP.