Metformin has been demonstrated to attenuate hyperglycaemia by modulating the gut microbiota. However, the mechanisms through which the microbiome mediates metformin monotherapy failure (MMF) are unclear. Herein, in a prospective clinical cohort study of newly diagnosed type 2 diabetes mellitus (T2DM) patients treated with metformin monotherapy, metagenomic sequencing of faecal samples revealed that Phocaeicola vulgatus abundance was approximately 12 times higher in nonresponders than in responders. P. vulgatus rapidly hydrolysed taurine-conjugated bile acids, leading to ceramide accumulation and reversing the improvements in glucose intolerance conferred by metformin in high-fat diet-fed mice. Interestingly, C22:0 ceramide bound to mitochondrial fission factor to induce mitochondrial fragmentation and impair hepatic oxidative phosphorylation in P. vulgatus-colonized hyperglycaemic mice, which could be exacerbated by metformin. This work suggests that metformin may be unsuitable for P. vulgatus-rich T2DM patients and that clinicians should be aware of metformin toxicity to mitochondria. Suppressing P. vulgatus growth with cefaclor or improving mitochondrial function using adenosylcobalamin may represent simple, safe, effective therapeutic strategies for addressing MMF.

Cancer is a group of various diseases, all of which involve unregulated cell growth. Many currently used chemotherapeutic drugs are derived from botanicals. Thus, searching botanical sources for novel oncology medications, including identifying the lead compounds and their derivatives for chemoprevention, is an essential step in advancing cancer therapeutics. This article mainly focuses on the data from our previous American ginseng anti-colon cancer studies. In addition to the potential role of American ginseng on cancer, the herb as an adjuvant for cancer treatment is presented, including describing the attenuation of adverse events induced by chemotherapeutic agents and increasing of quality of cancer patient life. Since heat-treated American ginseng and ginsenoside gut microbiome metabolites showed significant increases in cancer chemopreventive effects, active constituents of the steamed herb and their gut metabolites should be clearly identified, and the structure-activity relationship should be further explored. Data obtained from herbal medicine studies and clinical trials will help develop useful anticancer agents.