Neuroprotective effects of hydroponic ginseng fermented by Lactococcus lactis KC24 in oxidatively stressed SH‐SY5Y cells

BACKGROUND Panax ginseng Meyer, a traditional herb in Asia, contains bioactive compounds such as polyphenolic compounds, flavonoids, and ginsenosides. Furthermore, fermentation with probiotics can promote the biofunctional activities of ginseng. This study's object was to investigate the neuroprotective effect of hydroponic ginseng against hydrogen peroxide (H2O2)‐induced cytotoxicity and its effect on the fermentation time. RESULTS Nonfermented hydroponic ginseng (HNF) was fermented with Lactococcus lactis KC24 at 37 °C for 12 h (H12F) or 24 h (H24F). As fermentation progressed, the content of ginsenosides Rd and F2 increased slightly. The viability of cells pretreated with H2O2‐exposed nonfermented soil‐cultivated ginseng (SNF), HNF, H12F, and H24F gradually improved. In addition, a similar cytotoxicity trend was observed for the level of lactate dehydrogenase released. Fermentation with L. lactis KC24 also enhanced the protective effect of HNF in all assays related to the neuroprotective pathway. In other words, superoxide dismutase and catalase messenger RNA (mRNA) expression levels were upregulated in H24F‐treated cells. Similarly, H24F also upregulated the mRNA and protein expression of brain‐derived neurotrophic factor to the highest observed concentration. Moreover, the Bax/Bcl‐2 ratio was the lowest after H24F pretreatment in H2O2‐induced SH‐SY5Y cells. Attenuating the cytotoxicity in H2O2‐induced SH‐SY5Y cells, H24F markedly reduced caspase‐3 and ‑9 mRNA expression and caspase‐3 activity. CONCLUSION These results suggest that HNF exhibited higher neuroprotection than SNF, which was enhanced after fermentation. This study demonstrates that H12F and H24F can be potential ingredients for developing healthy functional foods and pharmaceutical materials. © 2023 Society of Chemical Industry.