Interleukin 10 (IL10) promoter region polymorphism is associated with IL10 serum concentrations and processing speed in healthy community-dwelling older adults.

Inflammation is repressed by interleukin 10 (IL10), a potent anti-inflammatory cytokine, and unchecked inflammation can have detrimental effects on cognition. In healthy older adults enrolled in the Australian Research Council Longevity Intervention (ARCLI) cohort we explored whether a known functional single nucleotide polymorphism (SNP) in the promoter region of IL10, -1082 G/A (rs1800896), was associated with reaction times on computerized cognitive testing that included elements of processing speed (i.e., reaction time). Participants were aged 60-75 years (240 females, 158 males), free of dementia and psychiatric disorders, and provide a blood sample. Processing speed was measured using the Swinburne University Computerized Cognitive Assessment Battery (SUCCAB), which includes measures of reaction time (in milliseconds, ms) on six tasks. Blood-derived DNA was genotyped for the IL10 rs1800896 SNP and presence of the APOE E4 allele. General linear models for each SUCCAB subtest were fitted, with age, sex, education (years), APOE E4 carrier status, and IL10 genotype as independent variables. Carriers of the IL10 AA genotype had significantly slower reaction times on multiple tests compared to carriers of the minor allele (AG, GG) and lower IL10 serum levels. Although IL10 SNPs have not been detected in Alzheimer's disease genome-wide associated studies, these results support further exploration of IL10 mechanisms as a possible resilience factor.

Neuroimaging Insights: Kava's (Piper methysticum) Effect on Dorsal Anterior Cingulate Cortex GABA in Generalized Anxiety Disorder.

Generalised Anxiety Disorder (GAD) is a prevalent, chronic mental health disorder. The measurement of regional brain gamma-aminobutyric acid (GABA) offers insight into its role in anxiety and is a potential biomarker for treatment response. Research literature suggests Piper methysticum (Kava) is efficacious as an anxiety treatment, but no study has assessed its effects on central GABA levels. This study investigated dorsal anterior cingulate (dACC) GABA levels in 37 adult participants with GAD. GABA was measured using proton magnetic resonance spectroscopy (1H-MRS) at baseline and following an eight-week administration of Kava (standardised to 120 mg kavalactones twice daily) (n = 20) or placebo (n = 17). This study was part of the Kava for the Treatment of GAD (KGAD; ClinicalTrials.gov: NCT02219880), a 16-week intervention study. Compared with the placebo group, the Kava group had a significant reduction in dACC GABA (p = 0.049) at eight weeks. Baseline anxiety scores on the HAM-A were positively correlated with GABA levels but were not significantly related to treatment. Central GABA reductions following Kava treatment may signal an inhibitory effect, which, if considered efficacious, suggests that GABA levels are modulated by Kava, independent of reported anxiety symptoms. dACC GABA patterns suggest a functional role of higher levels in clinical anxiety but warrants further research for symptom benefit. Findings suggest that dACC GABA levels previously un-examined in GAD could serve as a biomarker for diagnosis and treatment response.

Effect of kava (Piper methysticum) on peripheral gene expression among individuals with generalized anxiety disorder: A post hoc analysis of a randomized controlled trial.

Kava is a South Pacific plant-based medicine with anxiolytic properties, but little is known about the impact kava has on gene expression or whether gene expression can serve as a marker of kava response. This study aimed to determine whether kava treatment alters the expression of genes with physiological relevance to anxiety pathophysiology and whether the baseline expression of these physiologically relevant genes modifies the efficacy of kava treatment. In this post hoc analysis, we examined the expression of 48 genes relevant to the pathophysiology of anxiety collected from a double-blind randomized controlled trial that assessed the efficacy of kava treatment in generalized anxiety disorder. Peripheral blood gene expression was measured in 71 (34 kava, 37 placebo) adults at baseline and in 40 (19 kava, 21 placebo) after 8 weeks of treatment by reverse transcription polymerase chain reaction (PCR). Results revealed that kava decreased the expression of a subunit of the GABAA -rho receptor gene (GABRR2) and catechol-O-methyltransferase (COMT), a gene related to catecholamine metabolism. Kava efficacy was not found to be modified by baseline (pretreatment) expression of relevant genes. Although these results did not withstand statistical correction for multiple comparisons and require external validation, they support the notion that kava's mechanism of action includes interaction with GABAergic and catecholaminergic systems.

Liver and inflammatory biomarker relationships to depression symptoms in healthy older adults.

INTRODUCTION: Early identification and management of physical and mental illness is vital to maintain quality of life as we age. Markers of peripheral inflammation and liver function show elevations with aging, and are also associated with depression symptoms, suggesting a similar pattern in both aging and clinical groups. METHODS: The current study examined the relationship between such markers and measures of depression/negative mood in 284 healthy older adults using data from the Australian Research Council Longevity Intervention (ARCLI). Baseline data in adults aged 60-75 included mood symptoms via Profile of Mood States and Beck Depression Inventory II, and peripheral inflammatory (TNF-α, IL-6, hs-CRP) and liver markers (GGT, ALT, AST, AST:ALT ratio) derived from blood samples. RESULTS: The inflammation and liver enzyme relationship significantly predicted mood symptoms scores. Results showed that a significant relationship between C-reactive protein (CRP) and negative mood scores on Total Mood Disturbance and four of the six subscales (all p < .01) was dependent upon higher levels of gamma-glutamyl transferase (GGT). DISCUSSION: Higher levels of normal-range liver metabolic and peripheral inflammatory markers are observed with negative mood in a healthy older sample experiencing the biological impact of aging, but in the absence of clinical depression symptoms, suggesting a possible role of oxidative stress or other biological mechanisms occurring with aging in depression etiology. Lifestyle interventions are discussed.

Peripheral inflammation marker relationships to cognition in healthy older adults - A systematic review.

Several cognitive domains show decline with increasing age, which is associated with poorer work performance and reduced quality of life. As many nations show a rise in the number of citizens aged over 60 years, the study of the mechanisms underlying age-related cognitive functional reductions, such as inflammation, is important. Inflammaging has been implicated in progressive minor decline through to dementia typologies, with peripheral cytokine patterns investigated for their potential role in cognitive function. Assessing the relationship between these markers and cognitive performance could elucidate mechanisms with aging beyond neuropathologies. The research literature suggests peripheral cytokines/chemokines such as interleukin-6 and c-reactive protein are associated with cognitive processing. In this systematic review, we examine the evidence for a relationship between a range of peripheral inflammatory markers and domains of cognitive function in healthy older adults. To do this, a literature search was conducted using the following databases: SCOPUS, PubMed, Web of Science, and PsycINFO. Risk of bias was assessed using the Cochrane Risk of Bias Tool. Twenty-nine studies met our inclusion criteria. Although a wide range of systemic inflammatory biomarkers were examined, IL-6 and CRP were the most studied. The evidence suggests an inverse inflammatory biomarker-cognitive function relationship whereby elevations in most cytokines were associated with poorer performance across cognitive domains. The findings contribute to our understanding of peripheral inflammation and domains of cognitive function, offering insight into inflammaging processes.

The Relationship between F2-Isoprostanes Plasma Levels and Depression Symptoms in Healthy Older Adults.

The increasing proportion of older citizens in our society reflects a need to better understand age-related biological underpinnings of mood, as depression in older age may be under-diagnosed. Pre-clinical and human studies evidence a relationship between oxidative stress (OS) biomarkers in depression symptoms, and an influence of biological factors such as Body Mass Index (BMI), but focus has been clinical or younger samples, and less is known about patterns in healthy older adults. We investigated these associations with data derived from the Australian Research Council Longevity Study (ARCLI; ANZCTR12611000487910), in 568 healthy adults aged 60-75 years using F2-Isoprostanes plasma levels, and controlling for demographic factors, in assessing mood via the Beck Depression Inventory-II, Chalder Fatigue Scale, and General Health Questionnaire 12. Elevated F2-Isoprostanes contributed to depressed mood on the BDI-II and reduced general health on the GHQ-12. BMI was positively associated with Chalder Fatigue scores, yet better ratings on the GHQ-12. Females had significantly higher F2-Isoprostanes than males. The results suggest that in otherwise healthy older adults, mood and mental health are reduced with increases in oxidative stress markers, exhibiting similar patterns observed in clinical groups. Sex as a factor should be considered when assessing OS levels in systemic pathologies. BMI as a modifiable risk factor for maintenance of mental health, and OS modification through nutrient supplementation, are discussed. The findings contribute to understanding oxidative stress marker patterns in healthy older adults and their potential role in mood symptoms and mental health.

Higher habitual dietary flavonoid intake associates with lower central blood pressure and arterial stiffness in healthy older adults.

Flavonoids have shown anti-hypertensive and anti-atherosclerotic properties: the impact of habitual flavonoid intake on vascular function, central haemodynamics and arterial stiffness may be important. We investigated the relationship between habitual flavonoid consumption and measures of central blood pressure and arterial stiffness. We performed cross-sectional analysis of 381 non-smoking healthy older adults (mean age 66·0 (sd 4·1) years; BMI, 26·4 (sd 4·41) kg/m2; 41 % male) recruited as part of the Australian Research Council Longevity Intervention study. Flavonoid intake (i.e. flavonols, flavones, flavanones, anthocyanins, isoflavones, flavan-3-ol monomers, proanthocyanidins, theaflavins/thearubigins and total consumption) was estimated from FFQ using the US Department of Agriculture food composition databases. Measures of central haemodynamics and arterial stiffness included systolic blood pressure (cSBP), diastolic blood pressure (cDBP), mean arterial pressure (cMAP) and augmentation index (cAIx). After adjusting for demographic and lifestyle confounders, each sd/d higher intake of anthocyanins ((sd 44·3) mg/d) was associated with significantly lower cDBP (-1·56 mmHg, 95 % CI -2·65, -0·48) and cMAP (-1·62 mmHg, 95 % CI -2·82, -0·41). Similarly, each sd/d higher intake of flavanones ((sd 19·5) mg/d) was associated with ~1 % lower cAIx (-0·93 %, 95 % CI -1·77, -0·09). These associations remained significant after additional adjustment for (1) a dietary quality score and (2) other major nutrients that may affect blood pressure or arterial stiffness (i.e. Na, K, Ca, Mg, n-3, total protein and fibre). This study suggests a possible benefit of dietary anthocyanin and flavanone intake on central haemodynamics and arterial stiffness; these findings require corroboration in further research.

The Relationship between Oxidative Stress and Anxiety in a Healthy Older Population.

Background/study context: F2-Isoprostanes are putative markers of oxidative stress, one of the processes associated with biological senescence. Evidence exists for elevated F2-Isoprostanes in chronic conditions including psychiatric disorders. Few studies have examined the relationship between oxidative stress and mood in older healthy samples, to establish the influence on mental health. Given current aging demographics in many nations, management of brain and mental health is crucial for longevity, chronic disease management, and quality of life.Method: We investigated the relationship between F2-Isoprostanes, a marker for oxidative stress, and anxiety and mood in 262 healthy adults aged 60-75 years, using baseline data from the Australian Research Council Longevity Intervention (ARCLI; ANZCTR12611000487910), a 12-month nutraceutical intervention study.Results: Higher F2 levels significantly predicted increased Depression-dejection and Anger-hostility subscale scores from the Profile of Mood States (POMS). Fatigue-inertia subscale was predicted by increased Body Mass Index. Spielberger State-Trait Inventory (STAI) scores were significantly higher in females.Conclusion: While the primary outcome data did not find a definitive relationship between F2 and total mood or general anxiety levels, the sub-scale data adds weight toward growing literature that biological processes such as oxidative stress are in part related to mood. This is a modifiable risk factor contributing to physical and mental wellbeing that are crucial to healthy aging.

The Relationship between Gut Microbiome and Cognition in Older Australians.

Ageing is associated with changes in biological processes, including reductions in cognitive functions and gut microbiome diversity. However, not much is known about the relationship between cognition and the microbiome with increasing age. Therefore, we examined the relationship between the gut microbiome and cognition in 69 healthy participants aged 60-75 years. The gut microbiome was analysed with the 16S rRNA sequencing method. The cognitive assessment included the Cognitive Drug Research computerised assessment battery, which produced five cognitive factors corresponding to 'Quality of Episodic Secondary Memory', 'Quality of Working Memory', 'Continuity of Attention, 'Speed of Memory' and 'Power of Concentration'. Multiple linear regression showed that the bacterial family Carnobacteriaceae explained 9% of the variance in predicting Quality of Episodic Secondary Memory. Alcaligenaceae and Clostridiaceae explained 15% of the variance in predicting Quality of Working Memory; Bacteroidaceae, Barnesiellaceae, Rikenellaceae and Gemellaceae explained 11% of the variance in Power of Concentration. The present study provides specific evidence of a relationship between specific families of bacteria and different domains of cognition.

Is poor self-rated sleep quality associated with elevated systemic inflammation in healthy older adults?

OBJECTIVE: Examine subjective sleep quality and inflammation among healthy older adults participating in the Australian Research Council Longevity Intervention (ARCLI). METHODS: Data was taken from a sub-set of 232 participants aged between 60-70 years (M = 65.88 ± SD 4.08 years) who participated in the baseline assessment phase of the Australian Research Council Longevity Intervention (ARCLI) study. Subjective sleep was assessed via the Leeds Sleep Evaluation Questionnaire (LSEQ). Inflammatory markers (TNF-α, IL-1ß, IL-6, IL-10, IL-2, IFN-γ, IL-4, hs-CRP) were derived from whole blood. Correlation and multiple regression analyses were used to examine associations between each of the four sleep outcome variables and inflammatory outcomes, examined as a group and following gender stratification. RESULTS: Difficulties getting to sleep were independently associated with higher IL-2 [F(1,156) = 4.62, adjusted R2 = 0.02, p = 0.03] and IL-1ß [F(1,141) = 8.52, adjusted R2 = 0.05, p = 0.004] (whole group). Difficulties getting to sleep were associated with greater IL-1ß [males: F(1,58) = 7.36, adjusted R2 = 0.097 p = 0.009; females: F (1,81) = 4.25, R2 = 0.038, p = 0.04], and negatively associated with hs-CRP (women) [F (1,129) = 4.71, R2 = 0.028, p = 0.032]. DISCUSSION: Subjective sleep-onset difficulties are associated with systemic inflammation.

Effects of Panax quinquefolius (American ginseng) on the steady state visually evoked potential during cognitive performance.

OBJECTIVE: To investigate the effects of acute Panax quinquefolius (American ginseng) administration on steady state visually evoked potentials (SSVEPs) during completion of working memory and continuous performance tasks. METHODS: A randomised, double-blind, placebo controlled, balanced, cross-over trial was conducted in middle-aged volunteers aged between 40 and 60 years. Participants were administered 200 mg P. quinquefolius and placebo on two separate testing sessions. Six-h post-dose participants completed spatial working memory (SWM) and continuous performance (CP) tasks while SSVEP from a diffuse task-irrelevant 13 Hz flicker was recorded. RESULTS: During SWM retrieval, P. quinquefolius was associated with significantly reduced prefrontal SSVEP latency. There were no significant treatment effects on CP nor behavioural performance of either task. CONCLUSIONS: These findings provide preliminary evidence of increased recruitment of prefrontal brain regions during working memory processing following a single acute dose of P. quinquefolius.

S-Adenosylmethionine (SAMe) monotherapy for depression: an 8-week double-blind, randomised, controlled trial.

RATIONALE: Dysregulation of the one carbon cycle is documented in depression. Thereby, S-adenosylmethionine (SAMe), a one-carbon cycle nutraceutical compound with a favourable side effect profile, has a theoretical rationale for efficacy. However, further controlled studies are required to confirm SAMe's efficacy. OBJECTIVES: To test the efficacy of SAMe versus placebo in unmedicated DSM-5 diagnosed (major depressive disorder) (MDD) patients with mild-to-moderate levels of depressive symptoms. METHODS: We conducted an 8-week, double-blind, randomised controlled trial testing 800 mg/day of SAMe monotherapy versus placebo in 49 patients with MDD (Montgomery-Åsberg Depression Rating Scale [MADRS] score 14-25) who were not currently taking antidepressants. One-carbon cycle biomarkers, brain-derived neurotropic factor (BDNF), and relevant single nucleotide polymorphisms (SNPs) were analysed as potential treatment moderators. RESULTS: A clinically relevant differential reduction from baseline to week 8 of 3.76 points occurred on the primary outcome (MADRS) in favour of SAMe. This however was not significant (p = 0.13) on an adjusted linear mixed model, notwithstanding a medium to large effect size of 0.72. A high placebo response rate of 53% occurred (> 50% reduction on MADRS). Exploratory analyses showed that SAMe was however effective in reducing depression amongst participants with milder depression severity (MADRS ≤ 22, p = 0.045). Response was not moderated by BDNF, SNPs, or one-carbon cycle biomarkers, although increased folate concentrations were correlated with improved symptoms in the SAMe group (r = - 0.57, p = 0.026). The treatment was safe and well tolerated. CONCLUSIONS: Although a differential reduction in depression symptoms between groups was observed in favour of SAMe, the results of this pilot study were not statistically significant. TRIAL REGISTRATION: ANZCTR-Australian New Zealand Clinical Trials Registry; No.: ACTRN12613001299796; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=364900.

Kava for generalised anxiety disorder: A 16-week double-blind, randomised, placebo-controlled study.

OBJECTIVE: Previous randomised, double-blind, placebo-controlled studies have shown that Kava (a South Pacific medicinal plant) reduced anxiety during short-term administration. The objective of this randomised, double-blind, placebo-controlled study was to perform a larger, longer-term trial assessing the efficacy and safety of Kava in the treatment of generalised anxiety disorder and to determine whether gamma-aminobutyric acid transporter (SLC6A1) single-nucleotide polymorphisms were moderators of response. METHODS: The trial was a phase III, multi-site, two-arm, 16-week, randomised, double-blind, placebo-controlled study investigating an aqueous extract of dried Kava root administered twice per day in tablet form (standardised to 120 mg of kavalactones twice/day) in 171 currently non-medicated anxious participants with diagnosed generalised anxiety disorder. The trial took place in Australia. RESULTS: An analysis of 171 participants revealed a non-significant difference in anxiety reduction between the Kava and placebo groups (a relative reduction favouring placebo of 1.37 points; p = 0.25). At the conclusion of the controlled phase, 17.4% of the Kava group were classified as remitted (Hamilton Anxiety Rating Scale score < 7) compared to 23.8% of the placebo group (p = 0.46). No SLC6A1 polymorphisms were associated with treatment response, while carriers of the rs2601126 T allele preferentially respond to placebo (p = 0.006). Kava was well tolerated aside from poorer memory (Kava = 36 vs placebo = 23; p = 0.044) and tremor/shakiness (Kava = 36 vs placebo = 23; p = 0.024) occurring more frequently in the Kava group. Liver function test abnormalities were significantly more frequent in the Kava group, although no participant met criteria for herb-induced hepatic injury. CONCLUSION: While research has generally supported Kava in non-clinical populations (potentially for more 'situational' anxiety as a short-term anxiolytic), this particular extract was not effective for diagnosed generalised anxiety disorder.

Higher plasma levels of F2-isoprostanes are associated with slower psychomotor speed in healthy older adults.

Oxidative stress has been identified as a process which is detrimental to brain health, and associated with age-related cognitive declines. Few studies to-date have examined the relationship between in vivo oxidative stress biomarkers and cognitive performance within healthy elderly populations. The current study investigated the relationship between reaction time and oxidative stress, as measured by blood plasma concentrations of F2-isoprostanes using a sample of 251 healthy, non-demented, elderly volunteers (Male; 111: Female 140) aged 60-75 years from the Australian Research Council Longevity Intervention (ARCLI) study cohort. A Jensen Box was used in conjunction with the Hick paradigm in order to differentiate simple from choice reaction time (two, four and eight-choice conditions) as well as movement (MT) and decision times (DT). MT, but not DT, was found to be significantly slower for participants in the high F2-isoprostane group compared to the low F2-isoprostane group, across all stimulus choices. F2-isoprostanes, age and Wechsler Abbreviated Scale of Intelligence (WASI) full scale intelligence quotient (IQ) were found to be significant predictors of average MT in the sample as a whole. These findings provide preliminary evidence to suggest that higher levels of oxidative stress may be associated with impaired psychomotor speed in the healthy elderly population.

Nutraceuticals for major depressive disorder- more is not merrier: An 8-week double-blind, randomised, controlled trial.

BACKGROUND: One of the most pressing questions in "Nutritional Psychiatry" is whether using combinations of different nutraceuticals with putative antidepressant activity may provide an enhanced synergistic antidepressant effect. METHODS: A phase II/III, Australian multi-site, 8-week, double-blind, RCT involving 158 outpatients with a DSM-5 diagnosis of MDD. The intervention consisted of a nutraceutical combination: S-adenosyl methionine; Folinic acid; Omega-3 fatty acids; 5-HTP, Zinc picolinate, and relevant co-factors versus placebo. The primary outcome was change in MADRS score. Hypothesis-driven analyses of potential moderators of response involving key SNPs, and BDNF were also conducted. RESULTS: Placebo was superior to the nutraceutical combination in reducing MADRS score (differential reduction -1.75 points), however a mixed linear model revealed a non-significant Group X Time interaction (p = 0.33). Response rates were 40% for the active intervention and 51% for the placebo; remission rates were 34% and 43% for active and placebo groups, respectively. No significant differences were found between groups on any other secondary depression, anxiety, psychosocial, or sleep outcome measures. Key SNPs and BDNF did not significantly moderate response. No significant differences occurred between groups for total adverse effects, aside from more nausea in the active group. LIMITATIONS: Very high placebo response rates suggest a placebo run-in design may have been valuable. INTERPRETATION: The adoption of a nutraceutical 'shotgun' approach to treating MDD was not supported, and appeared to be less effective than adding placebo to treatment as usual.

Increases in total cholesterol and low density lipoprotein associated with decreased cognitive performance in healthy elderly adults.

The current study examined associations between blood lipid profiles and cognitive functioning using a healthy non-demented elderly sample. The sample comprised 196 healthy volunteers (male; 86: female 110) aged 60-75 years from the Australian Research Council Longevity Intervention (ARCLI) study cohort. Serum total cholesterol (T-C), low density lipoprotein cholesterol (LDL-c), high density lipoprotein cholesterol (HDL-c) and triglycerides (TGL) were collected, and participants completed the Swinburne University Computerized Cognitive Assessment Battery (SUCCAB). In line with prediction, higher levels of T-C and LDL-c were found to be associated with impaired speeds of response in tasks assessing recognition memory, working memory and inhibitory processing. However, contrary to prediction both TGL and HDL-c were found to be unrelated to cognitive functioning in the current sample. It is suggested that frontal lobe function may be differentially sensitive to the effects of T-C and LDL-c accumulation during the aging process. Future data collection as part of the larger ARCLI intervention study will provide important follow-up data regarding the ability of the baseline blood lipid data to predict subsequent cognitive change.

Adjunctive S-adenosylmethionine (SAMe) in treating non-remittent major depressive disorder: An 8-week double-blind, randomized, controlled trial.

There has been increasing interest in nutraceutical augmentation strategies to boost the efficacy of antidepressants. This study assessed whether S-adenosylmethionine (SAMe), a methyl donor that occurs naturally in the body, may be of such benefit. We conducted an 8-week, double-blind RCT in which 107 treatment non-remittent outpatients with DSM-5 diagnosed Major Depressive Disorder (MDD) were randomized to either SAMe or placebo adjunctively to antidepressants. One-carbon cycle nutrients, pertinent single nucleotide polymorphisms (SNPs), and BDNF were also analysed as potential moderators of response. A linear mixed-effects model revealed a significant overall reduction in Montgomery-Asberg Depression Rating Scale (MADRS) score across time, however there was no significant between-group difference observed (p = 0.51). Response rates at Week 8 were 54.3% in the SAMe group and 50.0% in the placebo group, with remission rates 43.5% for SAMe and 38.3% for placebo (all results NS). No effect of SAMe was found on any secondary outcome. Differential response to SAMe was not modified by a range of key genotypes (e.g. COMT), nor reflected in a change of homocysteine, red cell folate, or BDNF. Use of SAMe elicited no significant adverse effects beyond placebo, however it was implicated in one case of serotonin syndrome-like symptoms. This study concludes that 800 mg/day of SAMe is not an effective adjunctive treatment in MDD, and no obvious biomarker reflected any differential response to treatment. Due to such a distinctly high placebo-response (despite rigorous screening), future studies should employ a placebo run-in period and other strategies to minimize placebo response.

GABA-modulating phytomedicines for anxiety: A systematic review of preclinical and clinical evidence.

Anxiety disorders are chronic and functionally disabling conditions with high psychological stress, characterised by cognitive symptoms of excessive worry and focus difficulties and physiological symptoms such as muscle tension and insomnia. Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter within the central nervous system and is a key target of pharmacotherapies in the treatment of anxiety. Although current pharmaceutical treatments are often efficacious, they may cause undesirable side effects including cognitive decrements and withdrawal symptoms. Plant-based "phytomedicines" may provide novel treatment options, to act as an adjunctive or alternative to existing anxiolytic medications. As such, we conducted a systematic review to assess the current body of literature on anxiolytic phytomedicines and/or phytoconstituents. An open-ended search to 5 July 2017 was conducted using MEDLINE (PubMed), Scopus, and Cochrane library online databases and performed in a stepped format from preclinical to clinical investigations. Eligible studies must have had (a) in vitro evidence of GABA-modulating activity, (b) animal studies using anxiety models to test an anxiolytic effect, and (c) human clinical trials. Ten phytomedicines were identified as having preclinical investigations showing interaction with the GABA system, in addition to human clinical trials: kava, valerian, pennywort, hops, chamomile, Ginkgo biloba, passionflower, ashwagandha, skullcap, and lemon balm. Collectively, the literature reveals preclinical and clinical evidence for various phytomedicines modulating GABA-pathways, with comparative anxiolytic effect to the current array of pharmaceuticals, along with good safety and tolerability profiles.

Kava for the treatment of generalised anxiety disorder (K-GAD): study protocol for a randomised controlled trial.

BACKGROUND: Generalised anxiety disorder (GAD) is a chronic and pervasive condition that generates high levels of psychological stress, and it is difficult to treat in the long term. Current pharmacotherapeutic options for GAD are in some cases only modestly effective, and may elicit undesirable side effects. Through targeted actions on the gamma-aminobutyric acid (GABA) pathway, the South Pacific medicinal plant kava (Piper methysticum) is a non-addictive, non-hypnotic anxiolytic with the potential to treat GAD. The evidence for the efficacy of kava for treating anxiety has been affirmed through clinical trials and meta-analyses. Recent research has also served to lessen safety concerns regarding the use of kava due to hepatotoxic risk, which is reflected in a recent German court overturning the previous kava ban in that country (which may in turn influence a reinstatement by the European Union). The aim of current research is to assess the efficacy of an 'aqueous noble cultivar rootstock extract' of kava in GAD in a larger longer term study. In addition, we plan to investigate the pharmacogenomic influence of GABA transporters on response, effects of kava on gene expression, and for the first time, the neurobiological correlates of treatment response via functional and metabolic imaging. METHODS/DESIGN: This clinical trial is funded by the Australian National Health and Medical Research Council (APP1063383) and co-funded by MediHerb (Integria Healthcare (Australia) Pty. Ltd). The study is a phase III, multi-site, two-arm, 18-week, randomised, double-blind, placebo-controlled study using an aqueous extract of noble kava cultivar (standardised to 240 mg of kavalactones per day) versus matching placebo in 210 currently anxious participants with diagnosed GAD who are non-medicated. The study takes place at two sites: the Centre for Human Psychopharmacology (Swinburne University of Technology), Hawthorn, Melbourne, Australia; and the Academic Discipline of Psychiatry (The University of Queensland) based at the Royal Brisbane and Women's Hospital, Herston, Brisbane, Australia. Written informed consent will be obtained from each participant prior to commencement in the study. The primary outcome is the Structured Interview Guide for the Hamilton Anxiety Rating Scale (SIGH-A). The secondary outcomes involve a range of scales that assess affective disorder symptoms and quality of life outcomes, in addition to the study of mediating biomarkers of response (assessed via genomics and neuroimaging). DISCUSSION: If this study demonstrates positive findings in support of the superiority of kava over placebo in the treatment of GAD, and also is shown to be safe, then this plant-medicine can be considered a 'first-line' therapy for GAD. Genomic and neuroimaging data may reveal clinical response patterns and provide more evidence of the neurobiological activity of the plant extract. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov: NCT02219880 Date: 13 August 2014:.

Improved working memory performance following administration of a single dose of American ginseng (Panax quinquefolius L.) to healthy middle-age adults.

OBJECTIVE: A ginsenoside-rich extract of American ginseng (Panax quinquefolius L.), Cereboost(TM), was previously shown to improve working memory and mood in healthy young individuals. The present study represented a partial replication investigating whether these effects extended to healthy middle-aged individuals. METHODS: Fifty-two healthy volunteers (40-60 years old, mean age 51.63) received 200 mg of P. quinquefolius or a matching placebo according to a double-blind, placebo-controlled, balanced, crossover design. The Cognitive Drug Research battery and the Computerised Mental Performance Assessment System were used to evaluate cognitive performance at baseline then 1, 3 and 6 h following treatment. Blood glucose and mood were co-monitored. RESULTS: Compared with placebo, P. quinquefolius improved cognitive performance on 'Working Memory' factor at 3 h. Similar effects were observed in one of the two tasks making up this factor, spatial working memory. There were no significant effects on mood or blood glucose levels. CONCLUSIONS: These data confirm that P. quinquefolius can acutely benefit working memory and extend the age range of this effect to middle-aged individuals. These changes are unlikely to be underpinned by modulation of blood glucose in this population.