Effect of Enzyme-Treated Asparagus Extract (ETAS) on Psychological Stress in Healthy Individuals

Abstract

The aim of this study was to examine the effectiveness of Enzyme-Treated Asparagus Extract (ETAS) on improving stress response. A randomized, double-blind, placebo-controlled cross-over trial was undertaken in healthy volunteers. ETAS (150 mg/d) or a placebo was consumed for 28 d, with a washout period. Psychological parameters were examined using a self-report scale questionnaire and psychological stress was applied using the Uchida-Kraepelin (U-K) test. During the stress load, autonomic nervous function was analyzed. After the stress load, a profile of mood states (POMS) psychological rating was performed, and serum cortisol, plasma catecholamine, salivary secretory immunoglobulin A (sIgA), and salivary cortisol were analyzed. ETAS intake improved the self-reported rating for the items "Feel tired," "Hard to get up," and "Feel heavy" in the psychological questionnaire; ameliorated the self-reported rating for the items "Depression-Dejection" and "Fatigue" in the POMS questionnaire; and increased salivary sIgA levels after the U-K test. In contrast, serum and salivary cortisol levels, and plasma catecholamine did not change. During the U-K test, ETAS significantly upregulated the sympathetic nerve activity. Furthermore, ETAS intake significantly increased the number of answers and the number of correct answers in the U-K test, suggesting that it might improve office work performance with swiftness and accuracy under stressful conditions. In conclusion, ETAS supplementation reduced feelings of dysphoria and fatigue, ameliorated quality of sleep, and enhanced stress-load performance as well as promoted stress response by increasing salivary sIgA levels. These data suggest ETAS intake may exert beneficial effects, resulting from well-controlled stress management, in healthy individuals.

ETAS®50 Attenuates Ultraviolet‐B‐Induced Interleukin‐6 Expression by Suppressing Akt Phosphorylation in Normal Human Dermal Fibroblasts

“…Ongoing analysis suggested that ETAS 50 contains proline-containing 3-alkyldiketopiperazine derivatives as its active compounds. When ETAS 50 was orally administered, it attenuated sleep deprivation-induced stress responses, promotes good sleep, and increases salivary secretory immunoglobulin A levels in mice and humans [ 13 – 15 ]. These previous findings suggest a possibility that the compounds or their metabolites are delivered to central nervous system via circulation.…”

“…ETAS 50 is a standardized extract from the Asparagus officinalis stem, produced by Amino Up Chemical Co. Ltd. (Sapporo, Japan). It is a unique eco-friendly functional food that attenuates sleep deprivation-induced stress responses, promotes good sleep, and increases salivary secretory immunoglobulin A levels in mice and humans [ 13 – 15 ]. In addition to its antistress effects, later studies demonstrated the beneficial effects of ETAS 50 on brain functions, including the ability to ameliorate cognitive impairment in senescence-accelerated mice [ 16 ], protect neuronal PC-12 cells from amyloid β -induced cytotoxicity [ 17 ], and improve learning ability in young healthy rats [ 18 ].…”

Anti‐Inflammatory Effect of ETAS®50 by Inhibiting Nuclear Factor‐κB p65 Nuclear Import in Ultraviolet‐B‐Irradiated Normal Human Dermal Fibroblasts

“…It has been found to be a novel and unique functional food that attenuates sleep deprivation-induced stress responses and promotes sleep in mice and humans [ 14 , 15 ]. A recent study also showed that ETAS 50 supplementation reduced the feelings of dysphoria and fatigue, ameliorated the quality of sleep, and enhanced stress-load performance as well as increasing salivary secretory immunoglobulin A levels in healthy adults [ 16 ]. In addition to these anti-stress effects, ETAS 50 has antiaging potencies via its ability to ameliorate cognitive impairment in senescence-accelerated mice [ 17 ], to protect neuronal PC-12 cells from amyloid β peptide-induced oxidative stress and cytotoxicity [ 18 ], and to improve learning ability in young healthy rats [ 19 ].…”

A standardized extract of Asparagus officinalis stem prevents reduction in heat shock protein 70 expression in ultraviolet-B-irradiated normal human dermal fibroblasts: an in vitro study

“…This previous finding suggests that the compounds or their metabolites directly act on the cells and induce HSP70 expression. Moreover, oral EAS intake attenuated sleep deprivation-induced stress responses, promoted good sleep, and increased salivary secretory immunoglobulin A levels in mice and humans [ 5 , 7 , 12 ]. Therefore, it is conceivable that the compounds or their metabolites are delivered to central nervous system after digestion ingestion via circulation.…”