Planta Med 2019; 85(18): 1493
DOI: 10.1055/s-0039-3399908
Main Congress Poster
Poster Session 1
© Georg Thieme Verlag KG Stuttgart · New York

Modification of oligomeric and polymeric proanthocyanidins via oxidation in alkaline conditions

BI Imran
1  Natural Chemistry Research Group, Department of Chemistry, University of Turku,, 20014, Turku-Finland
,
M Karonen
1  Natural Chemistry Research Group, Department of Chemistry, University of Turku,, 20014, Turku-Finland
,
JP Salminen
1  Natural Chemistry Research Group, Department of Chemistry, University of Turku,, 20014, Turku-Finland
› Author Affiliations
Further Information

Publication History

Publication Date:
20 December 2019 (online)

 
 

Proanthocyanidins (PAs) are the secondary metabolites that are responsible for many positive effects related to ruminant nutrition and health. We were looking for naturally modified PAs that cannot be found in plants. To develop the production methods of such rare PAs we used a unique method where these are modified by oxidation in alkaline conditions. It included the collection of 300 plant samples from the Botanical Garden of the University of Turku, Finland. From the preliminary screening, 130 plant samples have procyanidin and prodelphinidin rich oligomers and polymers, which has polyphenol oxidase enzyme activity. The PAs in these plant samples were extracted and analyzed as such by UPLC connected to Waters XEVO TQ triple quadrupole mass spectrometer. Then the plant extracts were oxidized by an oxidation test using a pH 10 buffer. These samples were further studied by QExactive Orbitrap mass spectrometers, in order to characterize the modified PA structures. In addition, the proanthocyanidin oligomers and polymers in oxidized and non-oxidized samples were quantified by Multiple Reaction Monitoring (MRM) methods by UPLC-MS/MS. These results suggested that prodelphinidin (PD) rich oligomers have higher chances to modify the PA structure in the alkaline condition whereas procyanidin (PC) rich oligomers and polymers have less chances to modify the structure. However, the PC helps to stable the tannin structure. On the other hand, if the PD is absent in the sample then the structure is more stable, or no oxidation occurs.

Zoom Image
Fig. 1 UPLC-DAD profiles of modified proanthocyanidins.

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Zoom Image
Fig. 1 UPLC-DAD profiles of modified proanthocyanidins.