## 2 Results and Discussion
### Distribution of ARR VOCs In Vivo in Rats
#### 2.2.1 Distribution of VOCs in ARR Powder-Treated Group  
A total of 134 VOCs (98/12/24) of ARR were identified in the powder-treated group. Twenty-four original constituents can be absorbed into the blood, including M20 (_dl_-camphor), M22 (eucarvone), M37 (estragole), M44 (borneol), M60 (3,5-DMT), M64 (safrole), M79 (methyleugenol), M82 (2,3,5-TMT), M83 (3,4,5-TMT), M107 (elemicin), and M138 (kakuol). Fifteen of these 24 original constituents can be distributed to the brain: eucarvone, estragole, 3,5-DMT, safrole, methyleugenol, 2,3,5-TMT, 3,4,5-TMT, M87 (\(E\)-isocroweacin), M95 (4-methoxysafrole), M99 (\(p\)-methoxypropiophenone), elemicin, M108 (3,4,5-TMT isomer), M122 (3,4-methylenedioxypropiophenone), kakuol, and M148 (2',4'-dimethoxy-3'-methylproiophenone). Except for M99 and M108, the other 13 constituents identified in the brain were also found in the heart. Additionally, M20, identified in the heart, was not detected in the brain. Because the main pharmacological effect of ARR is analgesia and the toxicity of ARR powder is mainly respiratory paralysis, it is speculated that the constituents that can be distributed to the blood, lungs, and brain might be the main active VOCs of ARR. Similarly, 27 and 36 original constituents of ARR were found in the liver and kidney, respectively. Moreover, as the main digestive organs, 59 and 33 original constituents were identified in the stomach and small intestine, and the peak areas of the main identified constituents (3,5-DMT, 2,3,5-TMT, 3,4,5-TMT, methyleugenol, and safrole) were higher than those in the other organs. The ratio between the peak area of 3,5-DMT in the stomach and in the brain, heart, lung, spleen, liver, and kidney was 14.2, 24.2, 27.7, 18.9, 5.0, and 7.6, respectively. For the small intestine, the ratio was 5.3, 9.0, 10.3, 7.0, 1.8, and 2.8, respectively. The distribution of 2,3,5-TMT, 3,4,5-TMT, methyleugenol, and safrole in the different organs showed the same pattern. The peak areas of the main identified constituents are shown in Table 4.  
The main constituents found in the feces, 3,5-DMT, borneol, 3,4,5-TMT, 2,3,5-TMT, safrole, 4-methoxysafrole, M81 (isosafrole), methyleugenol, kakuol, and M98 (thymol), were all original constituents of ARR, and the sum of peak areas of these constituents account for more than 90% of the total peak area. Kakuol, M93 (eugenol), borneol, M88 (dihydroeugenol), M127 (kakuol isomer), M94 (1,2,4-TMT isomer), and 3,4,5-TMT were the main VOCs detected in the urine, and the sum of their peak areas accounts for more than 80% of the total peak area. Among them, M88 and M94 were not original constituents and were speculated to be metabolites of eugenol and 2,3,5-TMT. In general, the polarity of the constituents identified in the feces was lower than that detected in the urine. Monoterpens were detected in the feces rather than urine, including M1 (\(\alpha\)-pinene), M2 (camphene), M3 (\(\beta\)-pinene), M4 (sabinene), M5 (3-carene), M6 (\(\beta\)-myrcene), M8 (limonene), and M11 (terpinolene). It was assumed that these low-polarity constituents remained in the residue of the ARR powder and were excreted directly through the digestive tract. A total of nine VOCs could be detected in all samples of feces, urine, blood, and eight organs of the rats after oral administration of ARR powder: 2,3,5-TMT, 3,4,5-TMT, methyleugenol, safrole, eugenol, eucarvone, 3,5-DMT, 3,4-methylenedioxypropiophenone, and kakuol. Additionally, 12 metabolites were identified in the powder-treated group. Most of the metabolites were detected in the urine (9/12) and kidney (4/12). As a reduced metabolite of eugenol, dihydroeugenol was more widely distributed in the urine, liver, kidney, and small intestine than the other metabolites. No metabolite of ARR was found in the blood. The distribution of metabolites is shown in Table 3.