Phytosterol-rich compressed fluids extracts from Phormidium autumnale cyanobacteria with neuroprotective potential

Phormidium autumnale (P. autumnale) is a cyanobacteria with an unknown metabolic system, since only few studies have been reported. Among the produced metabolites, sterols profile is important considering the ability to this cyanobacterium in producing such compounds and their important benefits for human health. In this study, compressed fluid technologies were evaluated to obtain phytosterol-rich extracts from P. autumnale cyanobacteria for investigating their potential neuroprotective properties. A preliminary study was performed by comparing gas-expanded liquid extraction and supercritical fluid extraction using ethanol as a co-solvent. The following steps were optimized using a two-level factorial design and considering solvent composition and pressure as experimental factors. The bioactive potential of the optimized compressed fluid extract was tested using in vitro bioactivity assays, including acetylcholinesterase, lipoxygenase inhibition, and antioxidant capacity. The supercritical fluid multi-optimization response presented optimum phytosterol enrichment conditions at 266.3 bar of pressure and 7% of ethanol. Moreover, the optimized extract had higher in-vitro neuroprotective activity than the non-enriched extract, presenting the biochemical half maximal inhibitory concentration (IC50) values of 65.80 ?g mL-1 for acetylcholinesterase, 58.20 ?g mL-1 for lipoxygenase inhibition, and 7.40 ?g mL-1 for antioxidant activity. In-silico molecular docking analyses showed the specificity of sterol interaction with acetylcholinesterase active sites. These results provide evidence for further exploring P. autumnale as a source of bioactive phytosterols, demonstrating that compressed fluid technologies are powerful tools to obtain phytosterol-rich extracts.

Automated summary

This study evaluated compressed fluid technologies to extract phytosterol-rich extracts from P. autumnale cyanobacteria, showing that the optimized extract had higher in-vitro neuroprotective activity compared to non-enriched extract. The study highlights the potential of P. autumnale as a source of bioactive phytosterols and demonstrates the power of compressed fluid technologies in obtaining such extracts.