Kudzu and foxglove roots extract improves metabolic dysfunctions through microbiome composition change in Korean menopausal women: A randomized, placebo-controlled trial

Background and objectives: Kudzu (Pueraria lobata) is known as an important source of puerarin, an isoflavone compound. The dried root of foxglove (Rehmannia glutinosa) is among the most common ingredients to combine with kudzu to have complementary effects. Ovariectomized-induced rat studies reported that kudzu and foxglove roots extract (KF) supplementation could affect bone turnover rate and insulin resistance. However, its effect on humans has not been investigated. So, this study aimed to evaluate the effects of KF on menopausal metabolic changes in women associated with microbiome composition alteration. Methods: In this randomized, placebo-controlled, double-blind trial, 75 menopausal women aged 45 to 70 were enrolled and assigned to receive either a placebo or low-dose (0.63 g/day) or high-dose (0.95 g/day) for 12 weeks. Out of 61 subjects who completed the 12-week intervention, 50 (25 in the placebo group and 25 in the high-dose KF group) were analyzed for 16S rRNA gene-based metagenomics in urine. To test differences in 32 clinical features between two groups, we accurately predicted whether subjects were treated with KF using the least absolute shrinkage and selection operator (LASSO)-panelized logistic regression model. The differential genera between groups that showed significant results in at least 4 out of 7 statistical methods were determined, and the correlation with the selected clinical markers was confirmed. Different functional Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways between groups were predicted through the Tax4Fun analysis. Results: LASSO-panelized logistic regression model selected 17 clinical features, including body weight, C-terminal telopeptides of type I collagen (CTX), asymmetric dimethylarginine, and high-density lipoprotein cholesterol (HDL-cholesterol). In metagenomic analysis, the relative abundances of 16 genera were significantly different between groups. Spearman's correlation between 17 clinical features and 16 altered genera showed that CTX and HDL-cholesterol had negative correlations with Lachnospiraceae NC2004 group and Escherichia-Shigella, respectively. Moreover, functional prediction determined that three KEGG pathways in amino acid metabolism and two in xenobiotics biodegradation were different between groups. Conclusions:The KF supplementation for 12 weeks may improve bone, vascular, and lipid-related metabolism in menopausal women by altering microbiome composition.