Understanding the structure of Ru(V)-oxo species is crucial for designing novel catalysts for sustainable energy applications, such as water splitting for green hydrogen production. This study reports the EPR detection of a Ru(V)-oxo intermediate stabilized by terpyridine and phenanthroline carboxylate ligands. The interaction between the carboxylate group and the ruthenium center, along with PCET-dependent hemilability under oxidative conditions, plays a critical role in achieving the high-valent state. Subtle changes in the coordination environment around the central metal also proved to be essential. Low-temperature NMR, high-resolution mass spectrometry, UV–Vis spectroscopy, and density functional theory calculations support these findings.

Exposure to oxalate crystals causes cellular injury and dysfunction in the renal tubular epithelium. Sulfated galactan with increased sulfation (SGS) from the red seaweed Gracilaria fisheri exhibits anti‑urolithiasis effects by inhibiting oxalate crystal formation and preventing sodium oxalate (NaOX)‑induced death of renal tubular (HK‑2) cells. However, the effects of SGS on wound healing and adhesion molecule expression in NaOX‑induced HK‑2 cell injury remain unexplored. The present study investigated the effects of SGS on wound healing and the regulation of adhesion molecule expression in NaOX‑induced HK‑2 cell damage. The findings showed that SGS promoted wound healing in HK‑2 cells following a scratch injury under NaOX‑induced conditions. NaOX exposure increased the expression of CD44 and vimentin while decreasing the expression of EpCAM, E‑cadherin, occludin and ZO‑1, as demonstrated by reverse transcription‑quantitative PCR, western blotting and immunofluorescence analysis. Treatment with SGS restored these adhesion molecule expression levels to near normal. Scanning electron microscopy revealed that SGS also reversed NaOX‑induced morphological changes in HK‑2 cells. Additionally, SGS reduced the expression of Akt and p38 while upregulating PI3K and Erk1/2 in NaOX‑treated HK‑2 cells. These results suggested that SGS enhances wound healing and regulates the expression of adhesion molecules, possibly through the PI3K/Akt and MAPK (p38 and Erk1/2) signaling pathways, highlighting the potential of SGS as a promising therapeutic compound for preventing and treating NaOX‑induced renal damage.