AIM:This study aims to investigate the impact of nobiletin(NOB)on the gut microbiota and short-chain fatty acids(SCFAs)in high-fat diet-induced obese rats.METHODS:A total of 22 SD rats were randomly di-vided into the control(CON)group and high-fat diet(HFD)group.The HFD induced obesity,upon successful modeling,the rats were further divided into the HFD and NOB group,each group consisting of 6 rats.The NOB group received nobi-letin solution(100 mg·kg-1·d-1)via gavage for 21 consecutive days.Body weight was measured bi-daily,and hematoxylin-eosin(HE)staining was employed to observe pathological changes in adipose tissue and liver.Serum lipid levels were as-sessed using an auto-biochemical analyzer.Analysis of the gut microbiota was performed using 16S ribosomal RNA(rRNA)sequencing,while high-performance liquid chromatography mass spectrometry(LC-MS)was used to determine SCFAs levels in rat feces.RESULTS:Compared with CON group,HFD-fed demonstrated a substantial increase in body weight(P<0.01),accompanied by an augmentation in adipocyte diameter and the presence of hepatic cell vacuolization,indicative of cellular steatosis and inflammation.Moreover,there was a notable elevation in TG and TC levels(P<0.05).At the phylum level,the HFD rats exhibited an altered composition,characterized by an increase in Firmicutes and a con-current decrease in Bacteroidetes.At the genus level,Bacteroides,Lactobacillus and Blautia experienced a significant de-crease,while Colidextribacter showed an increase.Notably,there was a substantial reduction in the expression of propion-ic acid and butyric acid.In comparison to the HFD group,rats administered with NOB demonstrated a marked decrease in body weight(P<0.05),a reduction in adipocyte diameter,and an amelioration in hepatic cell vacuolization and cellular steatosis.Furthermore,TG and TC levels exhibited a significant decrease(P<0.05).At the phylum level,Firmicutes de-creased,and Bacteroidetes increased.At the genus level,Bacteroides,Lactobacillus and Blautia exhibited a significant in-crease,while Colidextribacter displayed a decrease.Additionally,there was an up-regulation of propionic acid and butyric acid levels in the NOB group.CONCLUSION:Nobiletin,through its multifaceted actions,demonstrates a potential anti-obesity effect by effectively reducing body weight in obese rats.This includes the regulation of gut microbiota structure,modulation of SCFAs content,and enhancement of lipid metabolism.