Gokulan Kuppan, Kolluru Pranav, Cerniglia Carl E, Khare Sangeeta
Division of Microbiology, National Center for Toxicological Research, United States Food and Drug Administration, Jefferson, AR, United States.
Front Microbiol. 2019 Mar 26;10:474. doi: 10.3389/fmicb.2019.00474. eCollection 2019.
Aloe leaf or purified aloin products possess numerous therapeutic and pharmaceutical properties. It is widely used as ingredients in a variety of food, cosmetic and pharmaceutical products. Animal studies have shown that consumption of aloe or purified aloin cause intestinal goblet cell hyperplasia, and malignancy. Here, we tested antibacterial effects of aloin, against intestinal commensal microbiota. Minimum inhibitory concentration of aloin for several human commensal bacterial species (Gram-positive and Gram-negative) ranged from 1 to 4 mg/ml. Metabolism studies indicated that was capable of degrading aloin into aloe-emodin at a slower-rate compared to spp. As a proof of concept, we incubated 3% rat fecal-slurry (an model to simulate human colon content) with 0.5, 1, and 2 mg/ml of aloin to test antimicrobial properties. Low aloin concentrations showed minor perturbations to intestinal bacteria, whereas high concentration increased sp. counts. Aloin also decreased butyrate-production in fecal microbiota in a dose-dependent manner after 24 h exposure. The 16S rRNA sequence-data revealed that aloin decreases the abundance of butyrate-producing bacterial species. Transepithelial resistant result revealed that aloin alters the intestinal barrier-function at higher concentrations (500 μM). In conclusion, aloin exhibits antibacterial property for certain commensal bacteria and decreases butyrate-production in a dose -dependent manner. HIGHLIGHTS -Aloin exhibits antibacterial properties for certain intestinal commensal bacteria. -In rat fecal slurry (an model to simulate human colon content), longer aloin exposure (24 h) decreases the butyrate production in dose dependent manner. -The 16s rRNA sequencing data show that aloin decreased the abundance of butyrate producing bacterial species. -Rat intestinal commensal bacteria metabolized aloin into aloe-emodin. -Aloin altered the intestinal epithelial cells barrier integrity, however, the metabolic product of aloin - Aloe-emodin did not alter epithelial cells permeability.
芦荟叶或纯化的芦荟素产品具有多种治疗和药用特性。它被广泛用作各种食品、化妆品和药品的成分。动物研究表明，食用芦荟或纯化的芦荟素会导致肠道杯状细胞增生和恶性肿瘤。在此，我们测试了芦荟素对肠道共生微生物群的抗菌作用。芦荟素对几种人类共生细菌物种（革兰氏阳性和革兰氏阴性）的最低抑菌浓度范围为1至4毫克/毫升。代谢研究表明，与[具体菌种]相比，[具体菌种]能够以较慢的速率将芦荟素降解为芦荟大黄素。作为概念验证，我们将3%的大鼠粪便悬液（一种模拟人类结肠内容物的模型）与0.5、1和2毫克/毫升的芦荟素一起孵育，以测试其抗菌特性。低浓度的芦荟素对肠道细菌的干扰较小，而高浓度则增加了[具体菌种]的数量。在暴露24小时后，芦荟素还以剂量依赖的方式降低了粪便微生物群中丁酸盐的产生。16S rRNA序列数据显示，芦荟素降低了产生丁酸盐的细菌物种的丰度。跨上皮电阻结果显示，芦荟素在较高浓度（500μM）下会改变肠道屏障功能。总之，芦荟素对某些共生细菌具有抗菌特性，并以剂量依赖的方式降低丁酸盐的产生。
亮点
芦荟素对某些肠道共生细菌具有抗菌特性。
在大鼠粪便悬液（一种模拟人类结肠内容物的模型）中，较长时间暴露于芦荟素（24小时）会以剂量依赖的方式降低丁酸盐的产生。
16s rRNA测序数据表明，芦荟素降低了产生丁酸盐的细菌物种的丰度。
大鼠肠道共生细菌将芦荟素代谢为芦荟大黄素。
芦荟素改变了肠道上皮细胞屏障的完整性，然而，芦荟素的代谢产物芦荟大黄素并未改变上皮细胞的通透性。
