Katja Schoss

Ms. Katja Schoss

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
4 December 2024 in Plants
Verified
Journal Article
Open access
PDF file
KSKatja Schoss
Katja Schoss
NGNina Kočevar Glavač
Nina Kočevar Glavač
Supercritical fluid extraction using carbon dioxide (SFE-CO2) brings a convincing advance in the production of plant oils used in cosmetics, in fortified foods and dietary supplements, and in pharmaceuticals and medicine. The SFE-CO2-extracted, hexane-extracted, and cold-pressed plant oils of pumpkin (Cucurbita pepo L.), flax (Linum usitatissimum L.), linden (Tilia sp.), poppy (Papaver somniferum L.), apricot (Prunus armeniaca L.), and marigold (Calendula officinalis L.) seeds were investigated in terms of oil yield, fatty acid composition, unsaponifiable matter yield and composition, and the antioxidant activity of unsaponifiable matter. SFE-CO2 proved to be the preferred extraction method for four out of six plant materials, especially for seeds with lower oil content. However, for seeds with higher oil content, such as apricots, cold pressing is a viable alternative. A comparison of fatty acid composition did not reveal significant differences between extraction techniques. SFE-CO2 extraction improved the total phytosterol content of oils, especially pumpkin seed oil. A high variability in the antioxidant potential of the unsaponifiable matter studied was determined, with pumpkin seed oil showing the highest antioxidant activity. A correlation analysis was performed between unsaponifiable composition and antioxidant activity, and showed statistically significant correlations with squalene, cycloartenol, and an unidentified compound. This is the first comparison of the phytosterol compositions of linseed, apricot, linden, and marigold. Through continued optimization, SFE-CO2 has the potential to revolutionize the production of plant oils and provide a sustainable and efficient alternative.

8 February 2022 in Molecules
Verified
Journal Article
Open access
PDF file
KSKatja Schoss
Katja Schoss
NGNina Kočevar Glavač
Nina Kočevar Glavač
JKJasna Dolenc Koce
Jasna Dolenc Koce
SASabina Anžlovar
Sabina Anžlovar
Fungal infections of cultivated food crops result in extensive losses of crops at the global level, while resistance to antifungal agents continues to grow. Supercritical fluid extraction using CO2 (SFE-CO2) has gained attention as an environmentally well-accepted extraction method, as CO2 is a non-toxic, inert and available solvent, and the extracts obtained are, chemically, of greater or different complexities compared to those of conventional extracts. The SFE-CO2 extracts of Achillea millefolium, Calendula officinalis, Chamomilla recutita, Helichrysum arenarium, Humulus lupulus, Taraxacum officinale, Juniperus communis, Hypericum perforatum, Nepeta cataria, Crataegus sp. and Sambucus nigra were studied in terms of their compositions and antifungal activities against the wheat- and buckwheat-borne fungi Alternaria alternata, Epicoccum nigrum, Botrytis cinerea, Fusarium oxysporum and Fusarium poae. The C. recutita and H. arenarium extracts were the most efficacious, and these inhibited the growth of most of the fungi by 80% to 100%. Among the fungal species, B. cinerea was the most susceptible to the treatments with the SFE-CO2 extracts, while Fusarium spp. were the least. This study shows that some of these SFE-CO2 extracts have promising potential for use as antifungal agents for selected crop-borne fungi.

26 January 2022 in Plants
Verified
Journal Article
Open access
PDF file
KSKatja Schoss
Katja Schoss
RBRebeka Benedetič
Rebeka Benedetič
SKSamo Kreft
Samo Kreft
Silver fir (Abies alba Mill.) is one of the most common and valuable conifer tree species in Central Europe, with well-established usage in the construction and furniture industries, as well as the food, health products, pharmaceuticals and cosmetics industries. Silver fir branch extract, a mixture of antioxidative phenols, is produced industrially as a food supplement with a wide range of therapeutic properties. This study investigates optimization of the production of silver fir branch extract by researching its antioxidant activity (ABTS and DPPH assay), phenol content (Folin-Ciocalteu assay), lignan content (HPLC) and extractable content at various distances from the trunk (0–80 cm). The antioxidative activity, phenol content and extractable content decreased from the proximal to the distal part of the branch. The decrease in ABTS assay activity was 51%, and that of the DPPH assay was 52%; the decrease in total phenol content was 35–40%; and the decrease in lignan content was 91%. The extractable matter content was reduced by 40%. Data gained in the study herein justifies the importance of researching existing and industrially produced plant extracts for further optimization of the final product. Results shows that industry can also produce extracts with elevated content of lignans with the use of short proximal parts of the branches.

2 January 2023 in Plants
Verified
Journal Article
Open access
PDF file
KSKatja Schoss
Katja Schoss
NGNina Kočevar Glavač
Nina Kočevar Glavač
SKSamo Kreft
Samo Kreft
Norway spruce (Picea abies) is one of the most important commercial conifer species naturally distributed in Europe. In this paper, the composition and abundance of essential oil and hydrosol from the needles and branches of P. abies were investigated with an additional evaluation of changes related to different times of the year, annual shoots and branches, and differences in composition under different microenvironments. Essential oils and hydrosols obtained via hydrodistillation were analyzed using gas chromatography–mass spectrometry (GC-MS), where 246 compounds in essential oil and 53 in hydrosols were identified. The relative amounts of monoterpenes, sesquiterpenes, and diterpenes in essential oil changed significantly during the year, with the highest peak of monoterpenes observed in April (72%), the highest abundance of sesquiterpenes observed in August (21%), and the highest abundance of diterpenes observed in June (27%). The individual compound with the highest variation was manool, with variation from 1.5% (April) to 18.7% (June). Our results also indicate that the essential oil with the lowest allergenic potential (lowest quantity of limonene and linalool) was obtained in late spring or summer. Location had no significant influence on composition, while the method of collection for distillation (whole branch or annual shoots) had a minor influence on the composition. All nine main compounds identified in the hydrosol samples were oxygenated monoterpenes. The composition of P. abies hydrosol was also significantly affected by season. The method of preparing the branches for distillation did not affect the composition of P. abies hydrosol, while the location had a minor effect on composition.

20 July 2024 in Applied Sciences
Verified
Journal Article
Open access
PDF file
Sara Diogo GonçalvesSara Diogo Gonçalves
Sara Diogo Gonçalves
Francisco PeixotoFrancisco Peixoto
Francisco Peixoto
KSKatja Schoss
Katja Schoss
NGNina Kočevar Glavač
Nina Kočevar Glavač
Isabel GaivãoIsabel Gaivão
Isabel Gaivão
Elderberry (Sambucus nigra L.) hydrolate, derived from domestic steam distillation, holds promise as a multifunctional ingredient for skincare and cosmetic applications. This study investigates the chemical composition and biological activities of elderberry hydrolate obtained through steam distillation. Despite the growing interest in elderberry hydrolate, there has been a lack of comprehensive studies elucidating its chemical composition and potential bioactive constituents. To address this gap, we conducted a detailed analysis of elderberry hydrolate’s composition, antioxidant activity, and antigenotoxicity. Genotoxic evaluation and antioxidant assays (ABTS, DPPH) were conducted to assess its biological properties. We obtained elderberry hydrolate with a notable transfer of aromatic compounds through the steam distillation process, highlighting its efficacy and sustainability. The chemical characterization identified vital compounds, including phenylacetaldehyde, 2-acetyl-pyrrole, and an unidentified major component, collectively contributing to the hydrolate’s aromatic and biological properties. The genotoxic evaluation using the Comet assay demonstrated the hydrolate’s protective effects against DNA damage induced by hydrogen peroxide and streptonigrin. The optimal DNA protection was observed at 10% (w/v), attributed to the antioxidant activity of the identified compounds. The hydrolate exhibited significant antioxidant potential, demonstrating concentration-dependent responses and correlating higher concentrations with increased antioxidant activity. These findings underscore the multifaceted attributes of elderberry hydrolate, positioning it as a promising natural ingredient for skincare. This study supports elderberry hydrolate as a valuable natural and sustainable product development resource.

3 January 2026 in Pharmaceutical Biology
Verified
Journal Article
Open access
KSKatja Schoss
Katja Schoss
UFUrša Pečar Fonović
Urša Pečar Fonović
NGNina Kočevar Glavač
Nina Kočevar Glavač
Silver fir (Abies alba) contains polyphenols and lignans with antioxidant and therapeutic properties. Efficient extraction methods are essential to preserve these compounds and maximize bioactivity. To compare extraction techniques and identify the optimal method for obtaining high-quality silver fir extracts with strong antioxidant activity and minimal cytotoxicity. Extracts from bark and branches were prepared using subcritical water extraction (SWE, 70-200 °C), supercritical CO2 extraction, and high-pressure ethanol extraction. Extracts were analyzed for total polyphenol content (TPC), lignan concentration (HPLC), antioxidant activity (DPPH and ABTS assays), and volatile profile (GC-MS). Cytotoxicity and cell migration were evaluated in HaCaT and Caco-2 cell lines via MTS and gap closure assays. The SWE bark extract at 100 °C (SWE-BA-100) showed the highest TPC (73.8 mg GAE/g), lignan content (secoisolariciresinol 204.7 µg/mL), and antioxidant activity (DPPH: 24.2, ABTS: 32.0 mg GAE/g). Bark extracts had superior bioactive profiles compared to branches, though branch extractions gave higher yields. All extracts were non-cytotoxic. SWE-BA-100 inhibited cell migration, indicating a complex interaction between composition and cellular response. SWE at 100 °C is a promising green method for producing potent antioxidant extracts from A. alba. Bark extracts offer strong antioxidant potential and safety for pharmaceutical, cosmetic, and nutritional uses. However, high lignan content may influence cellular behavior. Further studies should address the role of non-phenolic antioxidants and refine extraction strategies to balance efficacy and bioactivity.