Author: Janvi Mistry
Mistry, Janvi, 2024 Plasma Assisted Extraction of Biological Substances from Spirulina maxima to apply for biomedical applications, Flinders University, College of Medicine and Public Health
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In recent years, emphasis has been made on the investigation of natural compounds for incorporation as active components or nutraceuticals with medicinal uses. Currently the demand for naturally occurring bioactive compounds is growing rapidly in pharmaceutical and biological industries. This has led to the development of extraction techniques that embrace green chemistry which provide higher efficacy and sustainability. Spirulina spp., and other microalgae, are good sources of bioactive nutrients such as antioxidants, anti-inflammatory, antibacterial, and immunomodulatory compounds. Traditional extraction techniques, solvents extraction in particular, can be limited by extraction yield, adverse effects on the environment and degradation of biomolecules during the process. The restrictions make it challenging to develop the scientific approach to the conservation of bioactivity of natural compounds along with advanced, eco-friendly technologies for subsequent extraction for pharmaceutical and other industrial uses. Thus, atmospheric plasma treatments can be considered as a promising solution for improving the extraction yield without employing toxic solvents.
This work aims to evaluate the use of atmospheric plasma in different gas environments: Nitrogen, Argon and Compressed Air and treatment periods on the bioactive compounds of Spirulina spp. for possible use in medicine. These results suggest that the different plasma treatments in terms of the used gas types did not show any influence to the C-phycocyanin, protein concentration, and protein purity profiles; hence, the type of gas does not have an impact on the efficiency of the extraction process. Extraction process was affected by plasma treatment duration. An optimal concentration and purity of C-PC were achieved within a 5-minute treatment, even though its protein content was still high, which points to the fact that plasma-assisted extraction is best done within a five-minute time period. The results also showed that both short and long treatment durations negatively affected yields of bioactive compounds, emphasizing the importance of accurately controlling plasma exposure time.
The plasma exposure did not influence the antioxidant capacity of Spirulina, as evaluated using antioxidant activity, which remained unaffected in terms of Trolox equivalents. The cytotoxicity of tested compounds on THP-1 macrophages and HaCaT keratinocytes was evaluated by MTT assays concerned with cell viability. Compared to the control, the relative cell viability of THP-1 macrophage cells was lower, revealing cytotoxicity of samples at higher concentration of plasma treated Spirulina extract. On the other hand the viability of HaCaT cells was not significantly affected and it was observed that Spirulina extracts are not toxic to human keratinocyte cells. Thus, these findings suggest that the role of drug dosage and administration must be viewed within a biomedical framework. The tests on antimicrobial activity against Staphylococcus aureus revealed no substantial levels of bacterial inhibition after plasma treatment, which confirmed the need for additions to improve the antimicrobial functions.
In conclusion, the findings of this study suggest that atmospheric plasma might be considered an environmentally sustainable extraction method for acquiring bioactive compounds from Spirulina spp. The parameters of plasma treatment, especially the time, are critical to the efficacy of extraction. The current study aims at developing a new strategy of extraction of bioactive molecules for the use in biological and pharmaceutical industries whereby it demonstrates that the Atmospheric Plasma treatment is a more sustainable approach to addressing the above constraints. Future work should be directed towards optimizing plasma parameters in order to increase biocompatibility and antibacterial efficacy.
Keywords: Spirulina maxima, Therapeutic activities, conventional extraction techniques, Plasma assisted extraction, Atmospheric plasma technique
Subject: Medical Biotechnology thesis
Thesis type: Masters
Completed: 2024
School: College of Medicine and Public Health
Supervisor: Prof. Krasimir Vasilev