Browsing by Person "McDougall, Gordon J."

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Bioavailability and Urinary Excretion of Phenolic-Derived Metabolites after Acute Consumption of Purple Majesty Potato in Humans
(E-Cronicon, 2015-03-18) Tsang, Catherine; Smail, Nacer F.; McDougall, Gordon J.; Almoosawi, Suzana; Al-Dujaili, Emad A. S.
A novel purple potato variety, Purple Majesty (PM) contains an abundance of phenolic compounds, especially anthocyanins. The aim of this study was to assess the bioavailability of phenolic compounds in plasma measured as total polyphenols and urinary excretion of phenolic-derived metabolites after acute consumption of cooked PM. Five healthy male subjects (27-60 years; mean BMI: 26.7 ± 4.1) participated in a bioavailability study. Blood and urine were sampled at baseline and following consumption of 400 g cooked PM at 1h, 2h, 4h and 24h. A peak plasma antioxidant capacity was reached 1-2 hours post-consumption (from 1044 ± 281 µmol/L Fe(II) at baseline and increased to 1257 ± 180 after 1 hour (p = 0.045) and 1112 ± 251 µmol/L Fe(II) after 2 hours (borderline significance of p = 0.06). Total phenols level in plasma was reached after 2 hours (from 342.4 ± 28.3 at baseline to 368.4 ± 25 mg/L GAE). Liquid chromatography mass spectrometric (LC-MS) analysis was used to track the levels of anthocyanin-like derivatives and metabolites in the urine of volunteers after intake of the cooked Purple Majesty potatoes. No anthocyanin derivatives were detected in urine by liquid chromatography mass spectrometry indicating levels were < 2 nM. The majority of peaks that increased after intake were putatively identified as sulphated phenolic metabolites. Phenolic glucuronides were identified but other peaks remain unidentified. Hippuric acid was identified as a major phenolic derivative. Hydroxy benzoic derivatives, characteristic of intake of anthocyanins, were not detected in urine, however metabolites expected from the B-ring of petunidin (i.e. methyl gallic acid) may have been obscured by other peaks. Some metabolites could have arisen through metabolism of chlorogenic acid, which is present at ~ equivalent amounts to anthocyanins in cooked PM. In conclusion, acute consumption of PM resulted in an increase in excretion of urinary phenolic-derived metabolites. Identifying these unknown phenolic derivatives warrants further investigation.
Compositional analysis of Scottish honeys with antimicrobial activity against antibiotic-resistant bacteria reveals novel antimicrobial components
(Elsevier, 2017-01-09) Fyfe, Lorna; Okoro, Paulina; Paterson, Euan; Coyle, Shirley; McDougall, Gordon J.
Antibiotic-resistant bacteria are a major health concern and honey may provide an alternative to antibiotic use under certain conditions. The antimicrobial action of six Scottish honeys and Manuka Medihoney was compared against antibiotic-resistant Acinetobacter calcoaceticus, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. Certain Scottish honeys, such as Highland and Portobello honey 2011, were comparable in effectiveness to the established antimicrobial Medihoney, inhibiting growth to <1 compared to 10 log10 CFU/ ml in the control. Heather honey was the next most active while Blossom honeys were less active. Bacteria were inhibited by a sugar-matched control, but to a lesser extent, indicating that antimicrobial activity was associated with non-sugar components, such as polyphenols. However, total phenol content or antioxidant capacity did not correlate with antimicrobial activity. Liquid chromatography-mass spectrometric analysis revealed that the composition of polyphenol and non-polyphenol components differed between honeys. In addition, candidate components that could be associated with antimicrobial activity were noted including novel fatty diacid glycoside derivatives not previously identified in honeys.
Effect of pomegranate extract on blood pressure and anthropometry in adults: a double-blind placebo-controlled randomised clinical trial
(CUP, 2017-08-09) Stockton, Angela; Farhat, Grace; McDougall, Gordon J.; Al-Dujaili, E. A. S.
Pomegranate (Punica granatum), a polyphenol-rich fruit, has been suggested to reduce cardiovascular risk due to its antioxidant properties. Hypertension and obesity are the most preventable cardiovascular risk factors. Few studies on blood pressure and/or body-weight status have been conducted in human subjects. Previous investigations have tended to focus on pomegranate juice. The aim of the present study was to investigate the effect of pomegranate extract (PE) on blood pressure and anthropometric measures in adults with no symptomatic disease. A total of fifty-five participants enrolled in a randomised double-blinded placebo-controlled clinical trial where they were assigned to either PE capsules or placebo capsules for 8 weeks. Blood pressure, body weight, waist circumference, waist:hip ratio (WHR) and body composition (lean body mass, body fat) were measured at baseline, week 4 and week 8. Results showed a significant decrease in diastolic blood pressure after 8 weeks (by 279 (sd 532) mmHg; P < 005), while the decrease in systolic blood pressure did not reach statistical significance (257 (sd 74) mmHg; P > 005). Body fat percentage, lean body mass, waist circumference and WHR did not significantly differ between groups at the end of the intervention. Results suggest that PE may reduce blood pressure and possibly prevent hypertension in the normotensive population. Further large trials are required to elucidate this effect.