Factors affecting microbial metabolism in a human fecal fermentation model to evaluate prebiotics

In vitro fermentations using human fecal bacteria are an often used high through put strategy to evaluate the prebiotic potential of food ingredients. We investigated the influence of the substrate presented to fecal microbiota by monitoring the microbial short chain fatty acid production. We also examined the impact of cryopreserved glycerol stocks of feces on the performance of multiple batches of fermentations to examine the feasibility of using standardized inocula for multiple batches. Both composition and concentrations of bioactives (dietary fibre, polyphenols) were found to influence the metabolic capacity of human fecal microbiota. We also found that feces preserved at −80 °C provided a consistent and stable inoculum for performing batch fermentations for a duration of up to 3 years. Keywords: In vitro gastrointestinal model, Human fecal fermentation, Short chain fatty acids, Inulin, Rutin, Querceti

Timed consumption of a New Zealand blackcurrant juice support positive affective responses during a self-motivated moderate walking exercise in healthy sedentary adults

Background Affective responses experienced during exercise are a significant determinant on exercise adherence. We have previously demonstrated that consumption of New Zealand (NZ) blackcurrants preserves cognition by attenuating the feeling of fatigue. This positive affective response correlated with the ability of blackcurrant polyphenols to support monoamine neurotransmission via inhibition of monoamine oxidase-B (MAO-B) activity. Here we explore how the consumption of a NZ blackcurrant juice (BJ) influenced affective responses and potential ergogenic action on the motivation to adhere to a low impact walking exercise. Methods In a parallel randomized controlled study (Trial registration #: ACTRN12617000319370p, registered 28th February 2017, http://www.anzctr.org.au/), 40 healthy sedentary male and female participants drank a BJ or matched placebo (PLA) (n = 20 per group), 1 h prior to a self-motivated treadmill walk, where heart rate and affective responses (exertion [ES] or feeling / mood [FS]) scores) were recorded at 3 or 5 min intervals. Blood glucose, lactate, malondialdehyde (MDA) and platelet MAO-B activity were measured pre- and post-exercise and comparisons were conducted using with Student’s t-tests. Subjective data were analysed using 2-way ANOVA with appropriate post hoc tests. Results Consuming a BJ 1 h prior to exercise caused a 90% decline in platelet MAO-B activity. The exercise had no significant (p > 0.05) effect on blood lactate, glucose or plasma MDA levels. Assessment of affective responses over the first 60 mins (adjusting for participant drop-out) revealed a time-dependent ES increase in both groups, with ES reported by participants in the BJ group consistently lower than those in the PLA group (p  10 km compared to only 10% for the PLA group (p = 0.28), statistical significance was not achieved. Conclusion Our findings demonstrate that drinking a polyphenolic-rich NZ blackcurrant juice 1 h prior to exercise supports positive affective responses during a self-motivated exercise

JAK2 and AMP-kinase inhibition in vitro by food extracts, fractions and purified phytochemicals

We have identified a range of food phytochemicals that inhibit Janus Kinase 2 (JAK2) and Adenosine Monophosphate Kinase (AMPK). A mutated and dysregulated form of JAK2, a tyrosine kinase, is associated with several diseases including Crohn's disease. Using an in vitro, time-resolved fluorescence (TR-FRET) assay, we tested 49 different types of food extracts, plus 10 concentrated fractions of increasing hydrophobicity from each extract, to find foods containing JAK2 inhibitors. The food extracts tested included grains, meat, fish, shellfish, dairy products, herbs, mushrooms, hops, fruits and vegetables. Several fruits were potent inhibitors of JAK2: blackberry, boysenberry, feijoa, pomegranate, rosehip and strawberry, which all contain ellagitannins, known inhibitors of kinases. These fruits are in the Rosales and Myrtales plant orders. No other foods gave >1% of the maximal JAK2 inhibitory activities of these fruits. AMPK, a sensor and regulator of energy metabolism in cells, is a serine-threonine kinase which is reported to be activated by various flavonoid phytochemicals. Using a TR-FRET assay, we tested various fruit extracts for AMPK activation and inhibition. Ellagitannin containing foods scored highly as AMPK inhibitors. Despite several reports of AMPK activation in whole cells by phytochemicals, no extracts or pure compounds activated AMPK in our assay