Structural Elucidation of Irish Ale Bioactive Polar Lipids with Antithrombotic Properties
by
Alexandros Tsoupras 1,2,3,*
, Ronan Lordan 1,2, Eoin O'Keefe 1, Katie Shiels 4, 
Sushanta Kumar Saha 4 and 
Ioannis Zabetakis 1,2
Alexandros Tsoupras 1,2,3,*, Ronan Lordan 1,2, Eoin O'Keefe 1, Katie Shiels 4, Sushanta Kumar Saha 4 and Ioannis Zabetakis 1,2
1
Department of Biological Sciences, University of Limerick, V94 T9PX Limerick, Ireland
2
Health Research Institute, University of Limerick, V94 T9PX Limerick, Ireland
3
Bernal Institute, University of Limerick, V94 T9PX Limerick, Ireland
4
Shannon Applied Biotechnology Centre, Limerick Institute of Technology, Moylish Park, V94 E8YF Limerick, Ireland
*
Author to whom correspondence should be addressed.
Received: 28 May 2020 / Revised: 14 July 2020 / Accepted: 16 July 2020 / Published: 18 July 2020
Abstract
The structures of bioactive polar lipids (PLs) of Irish ale with potent
antithrombotic and cardioprotective properties were elucidated. Ale PL
was fractionated by preparative thin layer chromatography (TLC) into
subclasses, and their antithrombotic effect was assessed against human
platelet aggregation induced by the pro-inflammatory mediator,
platelet-activating factor (PAF). The fatty acid content and the overall
structures of ale PL were elucidated by liquid chromatography mass
spectrometry (LC-MS). Phosphatidylcholines (PC) and molecules of the
sphingomyelin (SM) family exhibited the strongest anti-PAF effects,
followed by phosphatidylethanolamines (PE). PC contained higher amounts
of omega-3 polyunsaturated fatty acids (n-3 PUFA) and thus the lowest
n-6/n-3 ratio. Bioactive diacyl and alkyl-acyl PC and PE molecules
bearing n-3 PUFA at their sn-2
position, especially docosahexaenoic acid (DHA) and α-linolenic acid
(ALA) but mostly oleic acid (OA), were identified in both PC and PE
subclasses. Eicosapentaenoic acid (EPA) was present only in bioactive PC
molecules and not in PE, explaining the lower anti-PAF effects of PE.
Bioactive sphingolipid and glycolipid molecules with reported
anti-inflammatory and anti-tumour properties, such as specific ceramides
and glucosylcerebrosides with sphingosine, phytosphingosine and
dihydrosphingosine bases but also specific monogalactodiglycerides and
SM species bearing ALA at their sn-2
position, were identified in the SM subclass, providing a rational for
its strong bioactivities against the PAF pathway. Further studies are
required on the health benefits of bioactive PL from beer and brewery
by-products.
View Full-Text
