A mixture of blackberry leaf and fruit extracts decreases fat deposition in HepG2 cells, modifying the gut microbiome

Abstract

More effective treatments are needed for non-alcoholic fatty liver disease (NAFLD). We hypothesized that water extracts of blackberry fruits (BF) and leaves (BL) and their combinations (BFL) reduce fat deposition in HepG2 cells and modulate shortchain fatty acids (SCFA) and fecal bacteria in vitro. HepG2 cells were treated with BF, BL, BFL1:2, and BFL1:3 for 1 h, and 0.5 mM palmitate was added to the cells. Moreover, low (30 μg/mL) and high doses (90 μg/mL) of BL and BF were applied to fecal bacteria in vitro, and SCFA was measured by GC. BL, BF, BFL1:2, and BFL1:3 reduced triglyceride deposition in the cells in a dose-dependent manner, and BFL1:2 and BFL1:3 had a stronger effect than BF. The content of malondialdehyde, an index of oxidative stress, was also reduced in BL, BF, and BFL1:2 with increasing superoxide dismutase and glutathione peroxidase activities. The mRNA expression of acetyl CoA carboxylase, fatty acid synthase, and sterol regulatory element-binding protein-1c was reduced in BL, BF, BFL1:2, and BFL1:3 compared to the control, and BFL1:2 had the strongest effect. By contrast, the carnitine palmitolytransferase-1expression, a regulator of fatty acid oxidation, increased mostly in BFL1:2 and BFL1:3. Tumor necrosis factor-α and interleukin-1β expression was reduced in BL compared to that in BF and BFL1:2 in HepG2 cells. Interestingly, BL increased propionate production, and BF increased butyrate and propionate production and increased total SCFA content in fecal incubation. BF increased the contents of Bifidobacteriales and Lactobacillales and decreased those of Clostridiales, whereas BL elevated the contents of Bacteroidales and decreased those of Enterobacteriales. In conclusion, BFL1:2 and BFL1:3 may be potential therapeutic candidates for NAFLD.