Geum japonicum, commonly known as Asian herb bennet, has been used as a diuretic, astringent, anti-dizziness, and anti-headache agent in traditional medicine. Since the antidepressant-like effects of G. japonicum extract have not been well studied, we examined the antidepressant-like effects of G. japonicum extract using depressive-like behavior induced in mice through daily injection of corticosterone (CORT). ICR mice (male, 8 weeks old) were treated with CORT (40 mg/kg, i.p.) and orally administered using oral gavage needles with G. japonicum extract (30, 100, and 300 mg/kg) for 4 weeks. Behavioral experiments were performed 1 h after administration. The control mice exhibited a significant increase in the immobility times in the tail suspension and forced swim tests as well as the step-through latency time in the passive avoidance test. Further, the control group showed a significant decrease in their sucrose consumption. However, treatment with G. japonicum extract at doses of 100 and 300 mg/kg significantly improved these depression-like behaviors without altering the locomotor activity. Moreover, treatment with G. japonicum extract significantly prevented the decrease in the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus. In addition, G. japonicum extract had neuroprotective effects against CORT-induced neurotoxicity in SH-SY5Y cells. Our study indicates that G. japonicum extract exhibits antidepressant-like activity in CORT-induced depressive mice, which might be as a result of increased BDNF expression.

Hydrolyzed proteins have an advantage over intact proteins in terms of their rate of digestion and absorption. The high-pressure enzymatic extraction (HPE) method has been shown to improve the quality characteristics of hydrolysates from Protaetia brevitarsis seulensis (Kolbe) larvae (PBSL). This study investigated the effects of the HPE treatment period, a key candidate factor, on the quality characteristics of PBSL HPE hydrolysates. The hydrolysates were prepared by HPE for 0, 12, 18, 24, 30, and 36 h under optimized conditions—solid:solvent ratio (1:14 [w/v]), using complex proteases (Alcalase:Flavorzyme:Bromelain = 1:1:1, 4%), treatment temperature (50°C), and pressure level (100 MPa). All quality characteristics tended to be superior with longer HPE treatment periods, most of which had the highest values at 30 h, with no significant difference or a slight decrease after that. The quality characteristics of the PBSL HPE hydrolysates were improved by 1.3-1.7 times under conditions of optimal HPE treatment period.