Browsing by Author "Percival, B."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    ItemOpen Access
    Detection and Determination of Methanol and Further Potential Toxins in Human Saliva Collected from Cigarette Smokers: A 1H NMR Investigation
    (2018-01-02) Percival, B.; Wann, A.; Masania, J.; Sinclair, J.; Sullo, N.; Grootveld, Martin
    Introduction/Objectives: The deleterious health effects of tobacco smoking are now widely recognized and documented. High-resolution 1 H NMR analysis of human saliva provides a high level of valuable molecular information regarding the nature and levels of a wide range of both endogenous and exogenous agents therein. This investigation focused on the detection of molecular modifications to the salivary 1H NMR profiles of cigarette smokers following smoking of a single cigarette product. Methods: Cigarette-smoking human participants (6 female, 7 male) provided saliva samples both prior and subsequent to smoking a single cigarette (the former following a 12 hr. overnight fasting/smoking-abstention period). A group of n = 7 non-smoking controls also provided saliva samples before and after a 4.0 min. ‘smoking mimic’ time period.1 H NMR analysis of supernatants derived therefrom was conducted at an operating frequency of 400 MHz. Results: 1H NMR analysis revealed that single cigarette smoking episodes gave rise to substantial increases in the salivary concentrations of methanol (p<10-6) and propane-1,2-diol (p = 2.0 x 10-4), i.e. ca. 40- and 3.2-fold escalations in their mean levels respectively; the identity of methanol was confirmed by GC-MS analysis. As expected, there were no modifications to these tobacco smoking marker levels in control group participants following a corresponding 4.0 min. non-smoking period. Conclusions: 1H NMR analysis of human saliva provided much valuable information on the infiltration of toxins and further agents from cigarette smoke into this biofluid. The marked elevations in salivary methanol levels observed are of much concern in view of its documented toxicological properties and adverse health effects.
  • No Thumbnail Available
    ItemMetadata only
    Molecular Composition of and Potential Health Benefits Offered by Natural East African Virgin Sunflower Oil Products: A 400 MHz 1H NMR Analysis Study
    (Open Access Publications, 2019-03-18) Percival, B.; Savel, Etienne; Ampem, G.; Gibson, M.; Edgar, Mark; Jafari, F.; Frederick, Kianna; Woodason, Katy; Wilson, Philippe B.; Grootveld, Martin
    Objectives: Sunflower oil (SFO) is regularly employed for cosmetic, emollient and food frying purposes, the latter representing its foremost use globally. Therefore, full investigations of the molecular composition and quality of sunflower oil products are a major requirement. In this study, high-field 1H NMR analysis was employed to explore the molecular composition and authenticities of East African virgin (EAV) SFO products, particularly their acylglycerol fatty acid contents, together with those of selected minor constituents. Results acquired were statistically compared to those acquired on commercially-available, EU-approved refined SFO products via NMR-linked multivariate chemometrics strategies. Methodology: High-field 1H NMR spectra of EAV and refined SFOs (n = 55 and 4 respectively) were acquired at an operating frequency of 400 MHz. Their triacylglycerol fatty acid, triacylglycerol hydrolysis product, and sterol and stanol contents were determined via intelligent frequency bucketing and electronic integration of selected resonances. Univariate analysis-of-variance, and multivariate ROC curve evaluations were conducted to determine the magnitude and statistical significance of analyte concentration differences between these two sample classifications. Further multivariate NMR-linked chemometrics analyses such as principal component, random forest and support vector machine classification analyses were also utilised for this purpose. Key Results: Multicomponent 1H NMR analysis demonstrated that EAV SFOs had significantly higher and lower contents of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs), respectively, than those of refined SFOs. Furthermore, significantly higher concentrations of ‘health-friendly’, cholesterol-blocking sterols and stanols were also found in these virgin products. Major Conclusions: 1H NMR analysis provides much valuable molecular information regarding the composition and virginal status of SFOs. The high [MUFA]:[PUFA] content ratio of unrefined EAV SFO products renders them more suitable and safer for commercial or domestic deep-frying episodes than refined SFOs (MUFAs are much more resistant to thermally-induced peroxidation than PUFAs). These products also potentially offer valuable health benefits in view of their high natural sterol and stanol contents.