Comparison of the toxicities, activities and chemical profiles of raw and processed Xanthii Fructus

Abstract

Background: Although toxic, the Chinese medicinal herb Xanthii Fructus (XF) is commonly used to treat traditional Chinese medicine (TCM) symptoms that resemble cold, sinusitis and arthritis. According to TCM theory, stir-baking (a processing method) can reduce the toxicity and enhance the efficacy of XF.

Methods: Cytotoxicities of raw XF and processed XF (stir-baked XF, SBXF) were determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay in normal liver derived MIHA cells. Nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) mRNA expression were measured by the Griess reagent and quantitative real-time PCR, respectively. The chemical profiles of XF and SBXF were compared using an established ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-TOF-MS) method.

Results: SBXF was less toxic than XF in MIHA cells. Both XF and SBXF had anti-inflammatory effects as demonstrated by their abilities to reduce nitric oxide production as well as inducible nitric oxide synthase mRNA expression in lipopolysaccharide-stimulated RAW 264.7 macrophages. Interestingly, the anti-inflammatory effects of SBXF were more potent than that of XF. By comparing the chemical profiles, we found that seven peaks were lower, while nine other peaks were higher in SBXF than in XF. Eleven compounds including carboxyatractyloside, atractyloside and chlorogenic acid corresponding to eleven individual changed peaks were tentatively identified by matching with empirical molecular formulae and mass fragments, as well as literature data.

Conclusion: Our study showed that stir-baking significantly reduced the cytotoxicity and enhanced the anti-inflammatory effects of XF; moreover, with a developed ultra-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry method we differentiated XF and SBXF by their chemical profiles. Further studies are warranted to establish the relationship between the alteration of chemical profiles and the changes of medicinal properties caused by stir-baking.

Fig. 1

Cytotoxicities of XF and SBXF fractions in cultured MIHA cells. MIHA cells were treated with various concentrations of XF and SBXF fractions as indicated for 48 h, cell viability was determined by the MTT assay. All data were presented as mean ± SD. PE: petroleum; EA: ethyl acetate; n-Bu: n-butanol. *p<0.05, **p<0.01

Fig. 2

Effects of XF and SBXF on NO production (a), iNOS mRNA expression levels (b) in LPS-stimulated RAW 264.7 cells. (a) Raw 264.7 cells were pretreated with LPS for 2 h, then cells were treated with XF or SBXF water extract in the presence of LPS for another 24 h. NO production was determined by the Griess reagent. (b) Raw 264.7 cells were pretreated with LPS for 2 h, then cells were treated with XF or SBXF water extract in the presence of LPS for another 18 h. iNOS mRNA expression was assessed by real-time PCR. All data were presented as mean ± SD. **p<0.01 vs. control; &&p<0.01 vs. LPS; ^# p<0.05, ^## p<0.01 vs. XF

Fig. 3

The representative negative base peak intensity (BPI) chromatograms of XF and SBXF. (a): Chemical profile of XF detected by UPLC/Q-TOF-MS analyses. (b): Chemical profile of SBXF detected by UPLC/Q-TOF-MS analyses

Fig. 4

Quantitative analyses of CATR and ATR. (a) The typical HPLC chromatograms of ten batches of XF and corresponding SBXF; (b) The contents of CATR and ATR in ten batches of XF and corresponding SBXF. CATR: Carboxyatractyloside; ATR: Atractyloside