Hawthorn pectin mitigates high-fat diet induced hyperlipidemia in mice through promoting Dubosiella newyorkensis.

Hawthorn fruit is rich in pectins; however, the gut microbiota-modulating effects of hawthorn pectin remain unclear. In this study, enzyme-extracted hawthorn pectin (Mw: 126.24 kDa; HG/RG-I ratio: 55.64 %/37.93 %; branching degree: 2.44) was fractionated into two distinct components: D1 (spherical, 345.76 kDa, HG/RG-I 57.48 %/37.25 %, branching degree 2.16) and D2 (flexible, 17.20 kDa, HG/RG-I 78.24 %/21.76 %, branching degree 1.33). Hawthorn pectin directly stimulated Dubosiella newyorkensis (D. newyorkensis) and Bifidobacterium bifidum (B. bifidum) growth in vitro. In hyperlipidemic mice, it alleviated dyslipidemia and enriched the abundance of Lactobacillus and Dubosiella. Parallel experiments confirmed that D. newyorkensis supplementation similarly alleviated dyslipidemia and increased Lactobacillus abundance, which was mediated by bacterial acetate production. Notably, only D1 emulated the pectin's prebiotic activity, promoting D. newyorkensis and B. bifidum growth. The high-RG-I D1, with elevated branching and larger Mw, was identified as the key driver of hawthorn pectin's prebiotic effect. These findings highlight that hawthorn pectin, particularly D1, specifically targets probiotic D. newyorkensis to synergize with Lactobacillus against hyperlipidemia.