Needle extracts of Pinus squamata X.W. Li ameliorate obesity and modulate cecal microbiota in high-fat diet-induced obese mice

Obesity is closely associated with excessive adipose accumulation, chronic low-grade inflammation, and gut microbiota dysbiosis. Although needle extracts from several Pinus species have been reported to attenuate body weight gain and modulate the gut microbiota, the pharmacological properties of Pinus squamata X.W. Li—an endangered coniferous species endemic to northeastern Yunnan, China—remain largely unexplored. This study evaluated the effects of Pinus squamata needle extract (PSNE) on high-fat diet (HFD)-induced obesity in mice. Our results demonstrated that PSNE significantly mitigated HFD-induced body weight gain, adipose accumulation, hepatic steatosis and injury, dyslipidaemia, oxidative stress, and systemic low-grade inflammation, while concomitantly improving glucose homeostasis. Furthermore, 16S rRNA amplicon sequencing of cecal contents revealed that PSNE increased amplicon sequence variant (ASV) richness and α-diversity, remodelled the cecal microbiota, and reversed HFD-associated dysbiosis. These beneficial alterations were characterised by significant enrichment of taxa with reported metabolic benefits, such as Bacteroides, Muribaculaceae and Ruminococcaceae, together with a concomitant reduction in obesity-associated lineages. Collectively, these findings establish PSNE as a promising preclinical candidate for alleviating obesity and related metabolic disorders, potentially through targeted remodelling of the cecal microbiota.