Less SO2 residue may not indicate higher quality, better efficacy and weaker toxicity of sulfur-fumigated herbs: Ginseng, a pilot study

Abstract Sulfur dioxide (SO 2 ) is a hazardous residue in sulfur-fumigated herbs. Standards limiting SO 2 content have been adopted worldwide for quality control of sulfur-fumigated herbs, and herbs with less SO 2 are believed to be better. However, the standards are based only on the safe dose of SO 2 and may not characterize changes in herbal quality, thereby the efficacy and toxicity, resulting from sulfur fumigation. To confirm this, here the correlation of residual SO 2 content with the quality/efficacy/toxicity of sulfur-fumigated herb was investigated, and ginseng was selected as a pilot study object. Four sulfur-fumigated ginseng samples with different SO 2 contents were systemically compared regarding their quality, anti-inflammatory, anti-shock and anti-stress efficacies, as well as acute and chronic toxicities. The results demonstrated that the SO 2 content did not correlate with the quality, efficacy and toxicity changes of ginseng; more specifically, less SO 2 residue did not indicate higher quality, better efficacy nor weaker toxicity. This fact suggests that SO 2 content cannot characterize the variations in quality, efficacy and toxicity of sulfur-fumigated herbs. Therefore, the standard limiting SO 2 content alone may be inadequate for quality control of sulfur-fumigated herbs, and new standards including other indicators that can exactly reflect herbal efficacy and safety are necessary.