| Title: | Supercritical extraction of blue-green algae: process optimization and biological evaluation of formulations : process optimization and biological evaluation of formulations |
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| Authors: | ID Toplak, Sanja (Author)
ID Knez Marevci, Maša (Mentor) More about this mentor... 
ID Dias Pacheco, Rita Isabel (Comentor) |
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| Files: |  MAG_Toplak_Sanja_2026.pdf (12,05 MB, This file will be accessible after 17.03.2029)
MD5: 3137924445E2942AD20FD855827FE8FE
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| Language: | English |
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| Work type: | Master's thesis/paper |
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| Typology: | 2.09 - Master's Thesis |
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| Organization: | FKKT - Faculty of Chemistry and Chemical Engineering
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| Abstract: | The extraction of bioactive compounds from spirulina (Arthrospira platensis), produced in Slovenia and obtained from a commercial producer, was investigated in this study. The aim was to evaluate the impact of extraction technique and solvent polarity on chemical composition, biological activity, and formulation potential. Supercritical CO₂ extraction (SFE) under varying pressure and temperature conditions was compared with conventional aqueous extraction methods (WEX). In this study, biological activity was assessed through antioxidant capacity, total phenolic content, enzyme inhibition assays, and cell-based viability assays (MTT) performed on human fibroblasts. Total phenolic content (TPC) and antioxidant activity (AA) were assessed using the Folin–Ciocalteu and DPPH assays, respectively, while acetylcholinesterase enzyme inhibition was evaluated by the Ellman Assay. Cellular metabolic activity and extract safety were assessed using an MTT assay in human dermal fibroblasts.
Chemical profiling by HPLC-DAD was employed to evaluate extraction-dependent differences in the chromatographic profiles of the obtained extracts. Selected SFE extracts were further characterized using high-resolution UHPLC–ESI–QTOF–MS/MS to enable tentative annotation and identification of bioactive constituents. Based on their chemical and biological performance, selected extracts were incorporated into organogel and hydrogel systems as a preliminary formulation approach.
The SFE extract obtained at 300 bar and 40 °C exhibited the highest TPC (419.23 ± 3.95 mg TP/g dry extract), while the WEX extract prepared at 40 °C by hot maceration showed slightly lower but comparable values (337.71 ± 34.74 mg TP/g dry extract). The strongest AA was observed for SFE extract 3, with the lowest DPPH IC₅₀ value of 0.34 ± 0.029 µg/mL. Among WEX extracts, extract 12 demonstrated the highest AA (IC₅₀ = 0.51 ± 0.015 µg/mL). Acetylcholinesterase inhibition was most pronounced for SFE extract no. 6 (26% inhibition at 0.1 mg/mL) and WEX extract 12, which achieved 80% inhibition at 1 mg/mL. Dose–response analysis of extract 12 yielded an IC50 value of 0.66 mg/mL, confirming concentration-dependent inhibition. High-resolution UHPLC–ESI–QTOF–MS/MS analysis revealed extraction-dependent chemical profiles and enabled tentative identification of 6-gingerol, linoleate-derived oxylipins, and 13-hydroxy-octadecatrienoic acid. Overall, the results confirm that extraction conditions critically determine the bioactive profile and functional properties of spirulina extracts. |
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| Keywords: | spirulina (Arthrospira platensis), supercritical fluid extraction, conventional extractions, antioxidant activity, acetylcholinesterase inhibition, high-resolution mass spectrometry, organogel and hydrogel systems |
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| Place of publishing: | Maribor |
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| Place of performance: | Maribor |
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| Publisher: | [S. Toplak] |
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| Year of publishing: | 2026 |
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| Number of pages: | 1 spletni vir (1 datoteka PDF (XI, 75 str.)) |
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| PID: | 20.500.12556/DKUM-96970 |
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| UDC: | 66.061.3:54-139(043.2) |
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| COBISS.SI-ID: | 276330243 |
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| Publication date in DKUM: | 03.04.2026 |
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| Views: | 173 |
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| Downloads: | 0 |
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| Metadata: |    |
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| Categories: | KTFMB - FKKT
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