Nephroprotective and therapeutic potential of Helichrysum orientale (L.) Gaertn. on hydrogen peroxide-injured kidney cells.

Acute kidney injury (AKI) is a severe form of kidney disease that is characterized by dysfunction. Excessive production of reactive oxygen species (ROS) is a major contributing factor in AKI pathogenesis. This study aims to investigate the cytoprotective effects of Helichrysum orientale (L.) Gaertn.'s capitulum aqueous extract against hydrogen peroxide (H₂O₂)-induced oxidative stress and apoptosis of 293 T cells (in vitro AKI model). The polyphenolic content of the extract was determined using ultra-high-performance liquid chromatography (UHPLC) revealing substantial amounts of cinnamic acid derivatives as well as notable quantities of polyphenolic compounds. Cell viability assays demonstrated that H₂O₂ induced dose-dependent cytotoxicity, whereas the extract significantly mitigated these effects and increased cell viability up to 2.43-fold. The antioxidant activities of the extract were evidenced by 5.1-fold increase in catalase (CAT) activity, 3.3-fold increase in superoxide dismutase (SOD) activity, and 2.3-fold reduction in malondialdehyde (MDA) levels. These results indicate its capacity to counteract H₂O₂-induced oxidative damage. Additionally, the extract prevented apoptotic cell death by significantly downregulating Bax expression by 16% and suppressing caspase-3 activation to control levels in damaged cells. These findings demonstrate that the aqueous extract of H. orientale's capitulum exhibits robust antioxidant and antiapoptotic properties in H₂O₂-injured kidney cells, offering preliminary pre-clinical substantiation.