A NIR and ratiometric fluorescent probe for quantitative detection of SO2 derivatives in Chinese medicinal materials and bioimaging in vivo

Sulfur dioxide (SO 2 ) and its derivatives have been recognized as harmful environmental pollutants. However, they are often produced during the processing of traditional Chinese medicines, potentially compromising the quality of these medicinal materials and contributing to various health issues. Due to a lack of effective monitoring and imaging tools, the physiological effects of excessive SO 2 residues in traditional Chinese medicine remain unclear. Therefore, developing a rapid and effective tool for detecting SO 2 is crucial for understanding its metabolic pathways and effects in vivo . In this study, we developed a near infrared (NIR) and ratiometric fluorescent probe, NIR-RS , which exhibits high sensitivity, selectivity, and rapid response for SO 2 detection. Notably, NIR-RS accurately quantifies SO 2 contents in Pinelliae rhizoma ( P. rhizoma ) samples, with recovery rates from 98.46 % to 102.40 %, and relative standard deviations (RSDs) < 5.0 %. For bioimaging applications, NIR-RS has low cytotoxicity and good mitochondrial-targeting ability, making it suitable for imaging exogenous and endogenous SO 2 in mitochondria. Additionally, NIR-RS was successfully applied to image SO 2 content of P. rhizoma samples within cells, revealing that high SO 2 residue elevated mitochondria adenosine triphosphate (ATP) content, these findings reveal that P. rhizoma with excessive SO 2 can affect the organism's growth mechanisms through alterations in ATP pathways. In vivo , SO 2 was found to predominantly accumulate in the liver following gavage with P. rhizoma solution, with accumulation levels increasing in proportion to SO 2 residue concentration. High SO 2 concentrations in P. rhizoma can cause pulmonary fibrosis and gastric mucosal damage. This work provides a valuable tool for regulating SO 2 content in P. rhizoma and may help researcher better understand the metabolism of SO 2 derivatives and explore their physiological roles in biological systems. By using the NIR and ratiometric fluorescent probe, NIR-RS , we found that traditional Chinese medicine with excessive SO 2 can affect the growth mechanisms by altering ATP pathways. SO 2 from these medicines mainly accumulates in the liver, and high concentrations can lead to pulmonary fibrosis and gastric mucosal damage.