Sleep-enhancing activity of fermented pea protein hydrolysate with enhanced GABA content by Lactobacillus brevis SYLB 0016 fermentation.

Abstract

Background: Sleep is essential for overall health and wellbeing. This study investigated the sleep-promoting effects of fermented pea protein hydrolysate (PPF) with increased gamma-aminobutyric acid (GABA) content produced by Lactobacillus brevis SYLB 0016. The effects of PPF on sleep duration and structure were assessed in pentobarbital-induced ICR mice and Sprague Dawley (SD) rats using electroencephalogram (EEG) analysis.

Results: Hydrolysis of pea protein with Alcalase, Protana Prime, and Protana UBoost increased the amino nitrogen content, degree of hydrolysis and glutamate content to 160.51 mmol L^-1. Fermentation by Lactobacillus brevis SYLB 0016 increased the GABA content from 3.16 to 90.35 mmol L^-1. PPF significantly increased sleep duration (56.3 min) compared to the normal control (30.6 min) in pentobarbital-induced sleep tests. Non-rapid eye movement (NREM) sleep time increased with a significant rise in δ-waves activity following administration of 150 mg kg^-1 of PPF. In caffeine-induced insomnia, both low- and high-dose PPF significantly increased sleep duration. Three weeks of oral PPF administration elevated GABA_A and GABA_B receptor expression, with GABA_A receptor protein levels showing a significant change. Co-administration of flumazenil with PPF reduced sleep time, indicating the involvement of the GABA_A receptor benzodiazepine site in PPF's sleep-enhancing effects.

Conclusion: In conclusion, PPF with enhanced GABA content improves NREM sleep by increasing δ waves activity. As a hypoallergenic compound, PPF holds potential as a supplement to ameliorate sleep disorders. © 2025 Society of Chemical Industry.