Human beings are superporganisms who are made of cells and gut bacteria. About 1000 species, 3.9×1013 complex and abundant microorganisms inhabited in the human gastrointestinal tract, which are equal to the human cells. These gut bacteria play important roles in the host's physiological function. They can get energy from the food, produce important metabolites, accelerate the growth and maturity of the immune system and protect the host from the infection and so on. Metabolizing enzymes produced by the gut bacteria play a key role in performing these functions. Glycosidase is the most important metabolizing enzyme produced by the gut bacteria. α- Glucosidases, β-glucosidases and β-glucuronidases play important parts in energy metabolism, drugs absorption and metabolism and drug therapy. Amoxapine is a listed antidepressant in America in 1980. Some researches reported in 2014 indicate that amoxapine is a potent inhibitor of gut bacterial β- glucuronidases after screening all the drugs approved by FDA and it can relief the side effect of irinotecan. But the therapeutic effect of amoxapine did not meet the expectation especially in the late phase. To find out the reason and to develop better β- glucuronidases inhibitors, our project firstly analyzed the distribution of the β- glucuronidases，β-glucosidase and α-glucosidases in human gut microbiota and the effects of amoxapine on their enzyme activities. Then, we isolated and identified 35 bacterial strains and analyzed the distribution of the enzymes and the effect of amxapine on the enzyme activities. Finally, we investigated the effect of amoxapine on the growth of gut bacteria. Although amoxapine showed potent inhibition on E. coil β- glucuronidase, amoxapine did not inhibit β-glucuronidases activities in human gut bacteria (10 healthy individuals, samples 1-10) significantly. Amoxapine showed no inhibition on the β-glucuronidases activities in sample No.1 and partial inhibition on samples No.7 and No.10 (IC50 525700nM and 5227nM, respectively). Among 35 bacterial strains isolated, 25 bacterial strains showed β-glucuronidases activity, while only β-glucuronidases activity from Streptococcus gallolyticus subsp. pasteurianus CIP 107122（3X12，3X13） and Staphylococcus pasteuri ATCC 51129（3I10） can be partially inhibited. Amoxapine could partly inhibit the β-glucuronidases activity of Staphylococcus pasteuri 3I10, which can help us to explain why amoxapine did not show potent inhibition on human gut bacteria β-glucuronidases in some degree. vi Interestingly, amoxapine effectively inhibited microbial β-glucosidases activity. At 100μM, amoxapine showed 50% inhibition on the β-glucosidases in pooled human gut microbiota, but has no effect on the α-glucosidases activity. Moreover, amoxapine (0~128μM) showed no inhibitory effect on the growth of the gut bacteria, while at 256μM amoxapine can affect the growth of gut bacteria from different individuals at different extents. To conclude, amoxapine is not a potent human microbiol β- glucuronidases inhibitor which may limit its application in alleviating β- glucuronidases-mediated drug toxicity.

人是由自身的細胞和腸道菌組成的超級生物體，在人的腸道中生活著大約 1000 種細菌，其數量在 3.9*1013 個左右，與人體細胞數量相當。這些腸道菌在 维持宿主生理功能上起著非常重要的作用, 比如從食物中攝取能量、產生重要的 代謝產物、促進免疫系統的發育與成熟、保護宿主免受病原的感染等。而腸道 菌產生的代謝酶在發揮這些功能的時候扮演著重要的角色，其中非常重要的一 類代謝酶就是糖苷水解酶。糖苷水解酶家族中的 β-葡萄糖醛酸苷酶，β-葡萄糖 苷酶，α-葡萄糖苷酶在能量代謝，藥物吸收和代謝以及藥物治療等過程中起著 非常重要的作用。阿莫沙平是 1980 年在美國上市的抗抑鬱藥，2014 年有研究表 明它還是腸道菌 β-葡萄糖醛酸苷酶的強效抑制劑，能夠有效抑制大腸桿菌產生 的 β-葡萄糖醛酸苷酶（IC50=388nM）。通過小鼠實驗證明，阿莫沙平可以緩解 抗癌藥伊立替康產生的腹瀉的副作用，但是在用藥後期，它的療效並不是很理 想。為了探討其療效不佳的原因，也為了更好地開發以腸道菌 β-葡萄糖醛酸苷 酶為靶點的藥物，本課題首先分析了健康人體內腸道菌中 β-葡萄糖醛酸苷酶， β-葡萄糖苷酶，α-葡萄糖苷酶的活性分佈情況以及阿莫沙平對它們活性的影響; 进一步分離鑒定了 35 株腸道菌菌株，並分析了这些菌株中 β-葡萄糖醛酸苷酶， β-葡萄糖苷酶，α-葡萄糖苷酶的活性以及阿莫沙平對它們活性的影響；最後观 察了阿莫沙平對人腸道菌生長的作用，以评估临床使用该药对菌群的影响。研 究表明，儘管阿莫沙平對大腸桿菌的 β-葡萄糖醛酸苷酶有很強的抑制作用，但 無論是肠道菌整體還是分离得到的大多数肠道菌菌株個體，阿莫沙平對人腸道 菌的 β-葡萄糖醛酸苷酶活性的抑制作用较弱；且阿莫沙平對来自不同个体的肠 道菌的β-葡萄糖醛酸苷酶表现出不同程度的抑制，沒有明顯抑制或呈部分抑制 （比如，7 號个体 IC50=525700nM，10 號个体 IC50=5227nM）。比较阿莫沙平对 筛选出的具有 β-葡萄糖醛酸苷酶活性的单一菌株的半數抑制率發現，阿莫沙平 對不同单一菌株的抑制强度不同，对 Staphylococcus pasteuri 3I10 產生的 β-葡萄 糖醛酸苷酶只有部分抑制效果，其 IC50（2950nM）遠遠高於阿莫沙平對大腸桿 菌 β-葡萄糖醛酸苷酶的半數抑制率（IC50=388nM），這在一定程度上能够解釋 阿莫沙平對混合腸道菌抑制效果不佳的原因。有趣的是，阿莫沙平對人腸道菌 的 β-葡萄糖苷酶有較強的抑制作用，在 100μM 的抑制率達到 50%，而阿莫沙平 iv 對α-葡萄糖苷酶沒有明顯的抑制作用。阿莫沙平（0~128μM）對正常腸道菌的 生長沒有明显影響，而在 256μM 阿莫沙平能抑制正常腸道菌的生長，抑制率存 在个体差异，其中對 6 號个体樣品的抑制率最大，最大抑制率約為 50%。綜上， 阿莫沙平並不是一個强效的腸道菌β-葡萄糖醛酸苷酶的有效抑制劑，應該篩選 其他來源的β-葡萄糖醛酸苷酶的有效抑制劑。