Allicin Modifies the Composition and Function of the Gut Microbiota in Alcoholic Hepatic Steatosis Mice

Abstract

The intestinal microbiome plays an important role in the pathogenesis of liver diseases. Alcohol intake induces gut microbiota dysbiosis and alters its function. This study investigated the antibiotic effect of allicin in mice with hepatic steatosis. Male C57BL/6 mice were administered an ethanol diet supplemented with allicin (5 and 20 mg/(kg bw day)) for 4 weeks. Allicin modified the gut microbiota composition. Cecal microbiota exhibited a positive correlation with alcohol and hepatic triacylglycerol, but were suppressed with allicin. Ethanol diet with 5 mg of allicin induced a lower intestinal permeability compared to the ethanol diet alone. Allicin mediated the lipopolysaccharide (LPS)–CD14–toll-like receptor 4 (TLR4)-induced hepatic inflammation pathway by reducing LPS, CD14, TLR4, and pro-inflammatory cytokinestumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6. However, hepatic inflammation primarily resulted from alcohol toxicity rather than LPS production in the gut. The prediction of functional profiles from metagenomic 16S ribosomal RNA (rRNA) data revealed different functional profiles in each group. The predicted aldehyde dehydrogenase tended to increase in alcoholic mice administered allicin. The predicted LPS-related pathway and LPS biosynthesis protein results exhibited a similar trend as plasma LPS levels. Thus, alcohol and allicin intake shapes the gut microbiota and its functional profile and improves the CD14–TLR4 pathway to alleviate inflammation in the liver.

Plant-Based Foods and Their Bioactive Compounds on Fatty Liver Disease: Effects, Mechanisms, and Clinical Application

“…Curcumin processed a variety of bioactivities such as antioxidant, anti-inflammatory, and hepatoprotective effects, and a systematic review and dose-response meta-analysis of randomized controlled trials demonstrated that curcumin could ameliorate visceral fat and abdominal obesity in NAFLD patients [60]. Allicin (diallyl thiosulfonate), a bioactive component from the aqueous extracts of garlic, could decrease the abundance of gut microbiota, like Christensenellaceae and Ruminococcaceae, in alcoholic hepatic steatosis mice, resulting in a reduction of hepatic triacylglycerol level [61,62].…”

“…Collectively, spices like onion and curcumin from turmeric could prevent NAFLD through improving lipid metabolism, oxidative stress, and inflammation (Table 1) 9 Oxidative Medicine and Cellular Longevity [107]. Also, allicin could alleviate alcohol-induced hepatic steatosis in C57BL/6 mice by modifying gut dysbiosis and then reducing the production of lipopolysaccharide (LPS) and further inhibiting TLR4-mediated inflammation [62]. Besides, the consumption of the ginger extract could significantly regulate lipid homeostasis in Wistar rats by increasing the expression of hepatocyte nuclear factor 4 α gene (HNF4A), while decreasing the expression of the protein tyrosine phosphatase 1B gene (PTP1B) [108,148].…”

Beneficial effects of Chinese herbs in the treatment of fatty liver diseases

“…Allicin, ethanol extracts of bitter gourd, and lychee exhibited anti-inflammatory effects against AFLD. In addition, allicin 72 and lychee have been shown to suppress the LPS-CD14-toll-like receptor 4 pathway, and modulate intestinal microbiota dysbiosis and intestinal barrier dysfunction. 73 …”

Effect of nicotinamide riboside on lipid metabolism and gut microflora‐bile acid axis in alcohol‐exposed mice

“…Alcohol consumption could cause the imbalance of gut microflora and destroy the homeostasis of bile acid metabolism. Recently, the critical role of gut microflora and bile acids in ALD has been demonstrated (Hartmann et al., 2018; Panyod et al., 2020). Moreover, Wahlstrom et al (Wahlström et al., 2017) have confirmed the concept of gut microflora‐bile acid axis.…”