Abstract: Flavonoids (FLS) are important bioactive components in Citrus paradisi cv. Changshanhuyou, which have a potential anti-obesity effect. To investigate their regulatory effect on the gut microbiota of obese mice, FLS from Citrus paradisi cv. Changshanhuyou were intragastrically administered to a high fat diet-induced obese mouse model for 8 weeks. During this period, feces were collected and all animals were killed to collect serum and liver tissues at the end. High-throughput sequencing technology was used to analyze the effects of FLS on the diversity and composition of the intestinal flora in mice. The results showed that FLS could significantly suppress body mass gain in obese mice (P < 0.05), decrease the contents of serum total cholesterol, triglyceride and low-density lipoprotein cholesterol (P < 0.05), increase serum high-density lipoprotein cholesterol content (P < 0.05), and attenuate hepatic lipid deposition. Further analysis showed that FLS significantly increased the abundance and diversity of intestinal microflora (P < 0.05). Although there was an inter-individual variation, the relative abundance of Bacteroidetes and Firmicutes at the phylum level increased and decreased, respectively, thereby leading to decreased ratio of F/B. At the genus level, FLS intervention increased the relative abundance of beneficial bacteria such as Bifidobacterium, Akkermansia, and Blautia that can produce short-chain fatty acids. Therefore, flavonoids from Citrus paradisi cv. Changshanhuyou can positively regulate the gut microbiota of high fat diet-induced obese mice so that they can be used as a functional food component to prevent intestinal microecological imbalance and reduce body fat by regulating the composition of intestinal microflora.

Key words: Citrus paradisi cv. Changshanhuyou; flavonoids; gut microbiota; obesity; 16S rDNA