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The young leaves of green tea become lighter in color than usual when protected from sunlight by a shading net for about two weeks while growing. These leaves are called "shaded white leaf tea" or SWLT. In the eluate of SWLT, the amount of amino acids (361 mg/L) was significantly higher than that in regular tea (53.5 mg/L). Since theanine and arginine, the first and second most abundant amino acids in SWLT, have significant antistress effects, we examined the antistress effect of SWLT on humans. SWLT or placebo green tea (3 g) was eluted with room-temperature water (500 mL). Participants consumed the tea for one week prior to pharmacy practice and continued for 10 days in the practice period. The state-trait anxiety inventory, an anxiety questionnaire, tended to be scored lower in the SWLT group than the placebo, but other stress markers showed no differences. The effect of the difference in SWLT components examined with mice showed that aspartic acid and asparagine, which are abundant in SWLT, counteracted the antistress effects of theanine and arginine. Large amounts of caffeine also interfered with SWLT's antistress effect. Thus, SWLT, which is high in caffeine and amino acids, suppressed depressant behavior in mice.

This study develops a hand-held stress assessment meter with a chemically colorimetric strip for determining salivary α-amylase activity, using a 3,5 dinitrosalicylic acid (DNS) assay to quantify the reducing sugar released from soluble starch via α-amylase hydrolysis. The colorimetric reaction is produced by heating the strip with a mini polyester heater plate at boiling temperature to form a brick red colored product, which measured at 525 nm wavelength. This investigation describes in detail the design, construction, and performance evaluation of a hand-held α-amylase activity colorimeter with a light emitted diode (LED) and photo-detector with built-in filters. The dimensions and mass of the proposed prototype are only 120 × 60 × 60 mm³ and 200 g, respectively. This prototype has an excellent correlation coefficient (>0.995), comparable with a commercial ultraviolet⁻visible spectroscope, and has a measurable α-amylase activity range of 0.1⁻1.0 U mL -1 . The hand-held device can measure the salivary α-amylase activity with only 5 μL of saliva within 12 min of testing. This sensor platform effectively demonstrates that the level of salivary α-amylase activity increases more significantly than serum cortisol, the other physiological stressor biomarker, under physiologically stressful exercise conditions. Thus, this work demonstrates that the hand-held α-amylase activity meter is an easy to use and cost-effective stress assessment tool for psychoneuroendocrinology research.

Objective: To ascertain whether stress biomarkers and psychological indices of stress may predict both conception and miscarriage rates in women undergoing in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI)., Design: Prospective observational study., Setting: A university-affiliated tertiary hospital., Population: Infertile women who were undergoing fresh or frozen IVF/ICSI cycles., Methods: Women were recruited to (1) complete validated psychological questionnaires (visual analogue scale of stress, state-trait anxiety inventory, perceived stress scale, fertility problem inventory, Beck depression inventory, and general health questionnaire), at the time of embryo transfer (ET) and pregnancy testing (PT), and (2) provide saliva samples for α-amylase (sAA) measurement before and after ET and at PT., Main Outcome Measures: Women were grouped according to subsequent reproductive outcome; scores/levels of all tests were then compared between groups at each time-point., Results: In all, 197 women completed the study, of which 92 conceived and 28 miscarried. The level of psychological stress, as measured by questionnaires, was highest at the time of PT, whereas the level of biological stress as measured by sAA level (IU/l) post-ET (1.8 × 10 5  ± 1.5 × 10 5 ) was significantly (P < 0.001) higher than pre-ET (1.2 × 10 5  ± 1.0 × 10 5 ) and at PT (1.0 × 10 5  ± 1.1 × 10 5 ). However, there was no difference in psychological scoring and in sAA levels between women who did or did not conceive and who had miscarried or had an ongoing pregnancy., Conclusions: The level of sAA is highest following ET, whereas psychological stress is highest at PT. However, neither stress level appeared to be of prognostic value in predicting conception or miscarriage., Tweetable Abstract: Stress level fluctuated at different time-points, but it did not predict conception or miscarriage., (© 2018 Royal College of Obstetricians and Gynaecologists.)

Beta-cryptoxanthin (β-CRX, (3R)-β, β-caroten-3-ol) is an oxygenated carotenoid and a potent antioxidant that is abundant in Satsuma mandarin orange (Citrus unshiu MARC.), which is the most popular fruit in Japan. Since our preliminary data suggested that the ingestion of β-CRX had an anti-stress effect in female participants, the effect was evaluated in another set of female participants. The study design was a double-blind group comparison and participants (n = 23) were randomly assigned to β-CRX-rich orange juice or placebo (β-CRX was removed from orange juice) groups. β-CRX or placebo juice (125 mL, after breakfast) were consumed from 1 week prior to pharmacy practice and continued for 5 d into the practice period. Salivary α-amylase activity (sAA), a marker of sympathetic nervous system activity, was significantly higher in the evening than in the morning in the placebo-group during pharmacy practice, but not in the β-CRX-group. This result supports the anti-stress effect of β-CRX. The dose-dependency of β-CRX was observed in male mice that were loaded with stress. These results indicate that the ingestion of β-CRX is helpful to reduce stress.

Early life adversity (ELA) can lead to poor health later in life. However, there is significant variation in outcomes, with some individuals displaying resilience even in the face of adversity. Using longitudinal data collected from free-ranging rhesus macaques between birth and 3 years, we examined whether individual variation in vigilance for threat, an early emerging attentional bias, can account for variation in long-term outcomes between individuals reared in similar environments. We found that ELA and vigilance during infancy interact to predict physiological dysregulation in Sympathetic Nervous System (SNS) and Hypothalamic-Pituitary-Adrenal (HPA) stress responses during juvenility. During high stress periods, High ELA juveniles with high vigilance exhibit less asymmetry than High ELA juveniles with low vigilance. This suggests that although increased vigilance is viewed as a negative consequence of ELA, it might also be a mechanism by which vulnerable individuals proactively buffer themselves from negative outcomes in unstable or threatening environments., (© 2017 Wiley Periodicals, Inc.)

Caffeine, one of the main components in green tea, can interfere with sleep and block the effect of theanine. Since theanine, the main amino acid in tea leaves, has significant anti-stress effects in animals and humans, we examined the effects of green tea with lowered caffeine content, i.e., low-caffeine green tea (LCGT), on stress and quality of sleep of middle-aged individuals ( n = 20, mean age 51.3 ± 6.7 years) in a double-blind crossover design. Standard green tea (SGT) was used as the control. These teas (≥300 mL/day), which were eluted with room temperature water, were consumed over a period of seven days after a single washout term. The level of salivary α-amylase activity (sAA), a stress marker, was significantly lower in participants that consumed LCGT (64.7 U/mL) than in those that consumed SGT (73.9 U/mL). Sleep quality was higher in participants that consumed a larger quantity of LCGT. In addition, a self-diagnostic check for accumulated fatigue was significantly lower in those participants that consumed LCGT than SGT. These results indicate that LCGT intake can reduce stress in middle-aged individuals and improve their quality of sleep. The reduction in caffeine is suggested to be a valid reason for enhancing the anti-stress effect of green tea., Competing Interests: The authors declare no conflicts of interest.

Theanine, an amino acid in tea, has significant anti-stress effects on animals and humans. However, the effect of theanine was blocked by caffeine and gallate-type catechins, which are the main components in tea. We examined the anti-stress effect of green tea with lowered caffeine, low-caffeine green tea, on humans. The study design was a single-blind group comparison and participants (n=20) were randomly assigned to low-caffeine or placebo tea groups. These teas (≥500 mL/d), which were eluted with room temperature water, were taken from 1 week prior to pharmacy practice and continued for 10 d in the practice period. The participants ingested theanine (ca. 15 mg/d) in low-caffeine green tea. To assess the anxiety of participants, the state-trait anxiety inventory test was used before pharmacy practice. The subjective stress of students was significantly lower in the low-caffeine-group than in the placebo-group during pharmacy practice. The level of salivary α-amylase activity, a stress marker, increased significantly after daily pharmacy practice in the placebo-group but not in the low-caffeine-group. These results suggested that the ingestion of low-caffeine green tea suppressed the excessive stress response of students. This study was registered at the University Hospital Medical Information Network (ID No. UMIN14942).

Fatigue is one of the most commonly reported complaints in the general population. As physical activity (PA) has been shown to have beneficial effects, we hypothesized that everyday life PA improves fatigue. Thirty-three healthy students (21 women, 22.8 ± 3.3 years, 21.7 ± 2.3 kg/m(2)) completed two ambulatory assessment periods. During five days at the beginning of the semester (control condition) and five days during final examination preparation (examination condition), participants repeatedly reported on general fatigue (awakening, 10 am, 2 pm, 6 pm and 9 pm) by means of an electronic diary, collected saliva samples for the assessment of cortisol and α-amylase immediately after providing information on fatigue and wore a triaxial accelerometer to continuously record PA. Self-perceived chronic stress was assessed as a moderator. Using hierarchical linear modeling, including PA, condition (control vs. examination), sex and chronic stress as predictors, PA level during the 15 min prior to data entry did not predict momentary fatigue level. Furthermore, there was no effect of condition. However, a significant cross-level interaction of perceived chronic stress with PA was observed. In fact, the (negative) relationship between PA and fatigue was stronger in those participants with less chronic stress. Neither cortisol nor α-amylase was significantly related to physical activity or fatigue. Our study showed an immediate short-term buffering effect of everyday life PA on general fatigue, but only when experiencing lower chronic stress. There seems to be no short-term benefit of PA in the face of higher chronic stress. These findings highlight the importance of considering chronic stress when evaluating the effectiveness of PA interventions in different target populations, in particular among chronically stressed and fatigued subjects.

Background: This study tested the hypothesis that maternal physiological and psychological variables during pregnancy discriminate between theoretically informed infant stress reactivity profiles., Methods: The sample comprised 254 women and their infants. Maternal mood, salivary cortisol, respiratory sinus arrhythmia (RSA), and salivary α-amylase (sAA) were assessed at 15 and 32 weeks gestational age. Infant salivary cortisol, RSA, and sAA reactivity were assessed in response to a structured laboratory frustration task at 6 months of age. Infant responses were used to classify them into stress reactivity profiles using three different classification schemes: hypothalamic-pituitary-adrenal (HPA)-axis, autonomic, and multi-system. Discriminant function analyses evaluated the prenatal variables that best discriminated infant reactivity profiles within each classification scheme., Results: Maternal stress biomarkers, along with self-reported psychological distress during pregnancy, discriminated between infant stress reactivity profiles., Conclusions: These results suggest that maternal psychological and physiological states during pregnancy have broad effects on the development of the infant stress response systems. © 2016 Wiley Periodicals, Inc. Dev Psychobiol 58: 578-599, 2016., (© 2016 Wiley Periodicals, Inc.)

Of the major diagnostic specimen types, saliva is one of the most easily collected. Many studies have focused on the evaluation of salivary proteins secreted by healthy people and patients with various diseases during responses to acute mental stress. In particular, such studies have focused on cortisol, α-amylase, chromogranin A (CgA), and immunoglobulin A (IgA) as salivary stress markers. Each of these salivary stress markers has its own strengths and weaknesses as well as data gaps related to many factors including collection technique. In this review, we summarize the critical knowledge of the positive and negative attributes and data gaps pertaining to each salivary stress marker., (© 2013.)

Purpose: Theanine, an amino acid in tea, has significant anti-stress effect on experimental animals under psychosocial stress. Anti-stress effect of theanine on humans was evaluated in 5th-year university students during pharmacy practice., Method: The study design was a single-blind group comparison and participants (n=20) were randomly assigned to theanine or placebo groups. Theanine or placebo (lactose) tablets (200 mg, twice a day, after breakfast and lunch) were taken from 1 week prior to the pharmacy practice and continued for 10 days in the practice period. To assess the anxiety of the participants, the state-trait anxiety inventory test was carried out before the pharmacy practice. Salivary α-amylase activity (sAA) was measured as a marker of sympathetic nervous system activity., Results: In the placebo-group, sAA in the morning (pre-practice sAA) was higher than in theanine-group during the pharmacy practice (p=0.032). Subjective stress was significantly lower in the theanine-group than in the placebo-group (p=0.020). These results suggest that theanine intake had anti-stress effect on students. Furthermore, students with higher pre-practice sAA showed significantly higher trait anxiety in both groups (p=0.015). Similarly, higher pre-practice sAA was correlated to shorter sleeping time in both groups (p=0.41×10(-3))., Conclusion: Stressful condition increased the level of sAA that was essentially affected by individual trait anxiety. The low levels of pre-practice sAA and subjective stress in the theanine-group suggest that theanine intake suppressed initial stress response of students assigned for a long-term commitment of pharmacy practice., (© 2013. Published by Elsevier Inc. All rights reserved.)