Projects / Programmes source: ARIS

Development of biologically active and chemically stable xanthophylls based on a sustainable esterification of xanthophylls from renewable natural resources

Research activity

Code Science Field Subfield
4.03.00  Biotechnical sciences  Plant production   

Code Science Field
4.01  Agricultural and Veterinary Sciences  Agriculture, Forestry and Fisheries 
natural renewable resources, invasive alien plant species, natural bioactive compounds, xanthophylls, xanthophyll esters, synthesis, stability, antioxidant activity, bioaccessibility, structure-property relationship, green chemistry, sustainable development, food supplements
Evaluation (rules)
source: COBISS
Data for the last 5 years (citations for the last 10 years) on May 28, 2024; A3 for period 2018-2022
Data for ARIS tenders ( 04.04.2019 – Programme tender, archive )
Database Linked records Citations Pure citations Average pure citations
WoS  320  6,593  5,607  17.52 
Scopus  325  7,482  6,405  19.71 
Researchers (15)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  29488  PhD Alen Albreht  Chemistry  Head  2021 - 2024  128 
2.  32694  PhD Katarina Bolko Seljak  Pharmacy  Researcher  2022 - 2024  55 
3.  18325  PhD Simon Caserman  Biochemistry and molecular biology  Researcher  2021 - 2024  108 
4.  28446  PhD Ilija German Ilić  Pharmacy  Researcher  2021 - 2024  143 
5.  28562  PhD Vesna Glavnik  Plant production  Researcher  2021 - 2024  174 
6.  51457  Blaž Grilc  Pharmacy  Researcher  2021 - 2024  39 
7.  39711  Maja Jamnik    Technical associate  2021 - 2024  21 
8.  39114  PhD Urška Jug  Chemistry  Researcher  2021 - 2022  53 
9.  24445  PhD Mitja Križman  Chemistry  Researcher  2021 - 2024  152 
10.  34548  PhD Katerina Naumoska  Chemistry  Researcher  2021 - 2024  73 
11.  53730  Tinka Palkovič    Technical associate  2022 - 2023 
12.  34927  Vladimira Petrovič Šenk  Forestry, wood and paper technology  Technical associate  2022 - 2024  12 
13.  17266  Mateja Puklavec    Technical associate  2021 - 2024  22 
14.  11395  PhD Irena Vovk  Chemistry  Researcher  2021 - 2024  565 
15.  15991  PhD Marjan Vračko - Grobelšek  Chemistry  Researcher  2021 - 2024  271 
Organisations (2)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0104  National Institute of Chemistry  Ljubljana  5051592000  21,316 
2.  0787  University of Ljubljana, Faculty of Pharmacy  Ljubljana  1626973  17,264 
Age-related macular degeneration (AMD) is the most common form of visual impairment in the world, affecting more than 67 million people in the EU alone. Early stages are often asymptomatic and there is no cure or treatment to reverse the course of the disease. Supplementation with two natural xanthophylls, lutein and zeaxanthin, is currently the only effective measure to prevent AMD. As powerful antioxidants, these two compounds not only protect our vision during our lifetime, but they also help combat metabolic disorders, cardiovascular diseases, cancer, and they also have positive effects on cognitive performance. Lutein and zeaxanthin can be found in green leafy vegetables, however, their bioavailability from such biological tissues is generally very low. Therefore, extraction of these pigments prior to consumption is preferred, but once extracted xanthophylls become extremely unstable, which reduces the shelf-life and efficacy of xanthophyll-based formulations. This project addresses the stability and bioavailability of xanthophylls and is divided into two interconnected parts. The first part is dedicated to the search for new renewable sources of xanthophylls and the development of a first green synthetic platform for a sustainable preparation of xanthophyll esters. Different waste materials, such as waste stemming from invasive alien plant species or inedible parts of fruits and vegetables, will be extracted, screened, and ranked according to the content of free xanthophylls to identify the most promising source. An optimised synthetic procedure following the 12 basic principles of green chemistry will be developed to convert xanthophylls into esters since no sustainable methods currently exist. Renewable, GRAS, and recyclable materials will be prioritised such as bio-based solvents (or solvent-free reactions) and polymer-supported catalysts. Energy efficient reactions at ambient temperatures and pressures will be preferred. The second part of the project aims to solve the problems of xanthophyll stability and bioaccessibility by converting them into esters with different carboxylic acids: aliphatic, aromatic, hydrophilic (charged), (un)saturated, linear, branched, short- and long-chained and others. In-depth characterization of the resulting compounds will identify key structural motifs and chemical mechanisms which determine the chemical stability, bioavailability, antioxidant activity, and potential toxicity of a particular synthesized xanthophyll ester. The chemical stability of the conjugated xanthophyll backbone will be determined independently under various stress conditions: elevated temperatures, acidic environments, oxidizing agents, UV irradiation, and in the presence of metal ions. Potential changes in antioxidant activity caused by esterification (enhancement or reduction) will be determined by radical scavenging assays. Potential toxic effects of esterified pigments will be evaluated using in silico methods. Bioaccessibility, i.e. the ability of a particular xanthophyll ester to reach a target human tissue, will be estimated by a coupled in vitro assay combining a standardized static digestion protocol and an intestinal mucosal model based on the Caco-2 cell line. Chromatography and mass spectrometry will be the main analytical tools used for the qualitative and quantitative determination of xanthophylls and xenobiotics. The comprehensive characterization results will be systematically compiled to form a xanthophyll ester database containing key structure-property relationships related to xanthophyll esters. Finally, the identified lead xanthophyll esters will be incorporated into a suitable model formulation that will demonstrate that rational design of new and bioactive xanthophylls with improved properties is possible, based on the scientific knowledge uncovered in this project.
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