From ice to neurons: investigating the neuroprotective effects of Antarctic microalgae Chlorella variabilis and Chlorella pyrenoidosa extracts.

Abstract

In this study, it was aimed to examine the neuroprotective effects of ethanolic extracts of Chlorella variabilis YTU.ANTARCTIC.001and Chlorella pyrenoidosa OZCIMEN.001microalgae that were isolated from Antarctica in a H2O2-induced oxidative stress model using SH-SY5Y cell line. In this context, first, Antarctic microalgae were cultivated and characterized. It was determined that C. pyrenoidosa and C. variabilis had specific growth rates of 0.093 and 0.097day-1, respectively, and doubled their cell concentration in 7days. With the antioxidant and phenolic content analysis, it was found that 1mg/mL C. pyrenoidosa and C. variabilis ethanolic extracts had 33-37% radical scavenging activity and 102-107mg GAE/mg extract phenolic content, respectively. Then, the cytotoxic effects of the microalgae extracts on SH-SY5Y cells were assessed across a concentration range of 6.25-125µg/mL. The results indicated a concentration-dependent effect on cell viability, with no observed cytotoxicity within the tested range. Notably, the highest neuroprotective activity was recorded with C. variabilisextract at a concentration of 75µg/mL, which maintained cell viability at 73.7% ± 0.3. These findings showed the significant neuroprotective potential of C. pyrenoidosaandC. variabilisethanolic extracts, attributed to their substantial antioxidant properties and non-cytotoxic nature at effective concentrations. The promising neuroprotective efficacy of these extracts highlights their potential for therapeutic applications in neurodegenerative disease prevention and treatment.